Merge branch 'Koura-fix/input-bound-checking'

book/src/chapter_2.md

@@ -57,6 +57,7 @@ At the top of `main.rs` we add a few lines of code:
 ```rust
 use rltk::{Console, GameState, Rltk, RGB, VirtualKeyCode};
 use specs::prelude::*;
+use std::cmp::{max, min};
 #[macro_use]
 extern crate specs_derive;
 ```
@@ -237,6 +238,7 @@ If you've typed all of that in correctly, your `main.rs` now looks like this:
 ```rust
 use rltk::{Console, GameState, Rltk, RGB};
 use specs::prelude::*;
+use std::cmp::{max, min};
 #[macro_use]
 extern crate specs_derive;
 
@@ -402,6 +404,7 @@ So your code now looks like this:
 ```rust
 use rltk::{Console, GameState, Rltk, RGB};
 use specs::prelude::*;
+use std::cmp::{max, min};
 #[macro_use]
 extern crate specs_derive;
 
@@ -540,13 +543,8 @@ fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
     let mut players = ecs.write_storage::<Player>();
 
     for (_player, pos) in (&mut players, &mut positions).join() {
-        pos.x += delta_x;
-        pos.y += delta_y;
-
-        if pos.x < 0 { pos.x = 0; }
-        if pos.x > 79 { pos.y = 79; }
-        if pos.y < 0 { pos.y = 0; }
-        if pos.y > 49 { pos.y = 49; }
+        pos.x = min(79 , max(0, pos.x + delta_x));
+        pos.y = min(49, max(0, pos.y + delta_y));
     }
 }
 ```
@@ -598,6 +596,7 @@ The source code for this completed example may be found ready-to-run in `chapter
 ```rust
 use rltk::{Console, GameState, Rltk, RGB, VirtualKeyCode};
 use specs::prelude::*;
+use std::cmp::{max, min};
 #[macro_use]
 extern crate specs_derive;
 
@@ -631,13 +630,8 @@ fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
     let mut players = ecs.write_storage::<Player>();
 
     for (_player, pos) in (&mut players, &mut positions).join() {
-        pos.x += delta_x;
-        pos.y += delta_y;
-
-        if pos.x < 0 { pos.x = 0; }
-        if pos.x > 79 { pos.y = 79; }
-        if pos.y < 0 { pos.y = 0; }
-        if pos.y > 49 { pos.y = 49; }
+        pos.x = min(79 , max(0, pos.x + delta_x));
+        pos.y = min(49, max(0, pos.y + delta_y));
     }
 }
 

book/src/chapter_3.md

@@ -161,13 +161,8 @@ fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
     for (_player, pos) in (&mut players, &mut positions).join() {
         let destination_idx = xy_idx(pos.x + delta_x, pos.y + delta_y);
         if map[destination_idx] != TileType::Wall {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
         }
     }
 }
@@ -184,6 +179,7 @@ The full program now looks like this:
 ```rust
 use rltk::{Console, GameState, Rltk, RGB, VirtualKeyCode};
 use specs::prelude::*;
+use std::cmp::{max, min};
 #[macro_use]
 extern crate specs_derive;
 
@@ -255,13 +251,8 @@ fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
     for (_player, pos) in (&mut players, &mut positions).join() {
         let destination_idx = xy_idx(pos.x + delta_x, pos.y + delta_y);
         if map[destination_idx] != TileType::Wall {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
         }
     }
 }

book/src/chapter_5.md

@@ -449,13 +449,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
     for (_player, pos, viewshed) in (&mut players, &mut positions, &mut viewsheds).join() {
         let destination_idx = map.xy_idx(pos.x + delta_x, pos.y + delta_y);
         if map.tiles[destination_idx] != TileType::Wall {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
         }

book/src/chapter_7.md

@@ -267,33 +267,33 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::Paused } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::Y => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::U => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             _ => { return RunState::Paused }

book/src/contributors.md

@@ -15,7 +15,7 @@ The following people have contributed to this project:
 * Herbert Wolverson, the primary author.
 * [Marius Gedminas](https://github.com/mgedmin) provided some fixes to the visibility system, and chapter 5. Corrected a typo in chapter 7, fixed a Markdown error in chapter 7, fixed indentation in chapter 13, and a typo in chapter 18. He also fixed some code in my hunger clock to let monsters get hungry too, if we so desire.
 * [Ben Morrison](https://github.com/gbmor) fixed an issue in chapter 4, correctly matching room passing-by-reference with the accompanying source code.
-* [Tommi Jalkanen](https://github.com/Koura) helped me remove some Dispatcher code that I'd accidentally left in place.
+* [Tommi Jalkanen](https://github.com/Koura) helped me remove some Dispatcher code that I'd accidentally left in place. He also found an issue with bounds checking on movement, for which I am eternally grateful!
 * [Gabriel Martinez](https://github.com/mystal) helped me fix the Vi keys.
 
 ---

chapter-02-helloecs/src/main.rs

@@ -1,5 +1,6 @@
 use rltk::{Console, GameState, Rltk, RGB, VirtualKeyCode};
 use specs::prelude::*;
+use std::cmp::{max, min};
 #[macro_use]
 extern crate specs_derive;
 
@@ -33,13 +34,8 @@ fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
     let mut players = ecs.write_storage::<Player>();
 
     for (_player, pos) in (&mut players, &mut positions).join() {
-        pos.x += delta_x;
-        pos.y += delta_y;
-
-        if pos.x < 0 { pos.x = 0; }
-        if pos.x > 79 { pos.y = 79; }
-        if pos.y < 0 { pos.y = 0; }
-        if pos.y > 49 { pos.y = 49; }
+        pos.x = min(79 , max(0, pos.x + delta_x));
+        pos.y = min(49, max(0, pos.y + delta_y));
     }
 }
 

chapter-03-walkmap/src/main.rs

@@ -71,13 +71,8 @@ fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
     for (_player, pos) in (&mut players, &mut positions).join() {
         let destination_idx = xy_idx(pos.x + delta_x, pos.y + delta_y);
         if map[destination_idx] != TileType::Wall {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
         }
     }
 }

chapter-04-newmap/src/player.rs

@@ -10,13 +10,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
     for (_player, pos) in (&mut players, &mut positions).join() {
         let destination_idx = xy_idx(pos.x + delta_x, pos.y + delta_y);
         if map[destination_idx] != TileType::Wall {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
         }
     }
 }

chapter-05-fov/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, TileType, State, Map};
 
 pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
@@ -13,13 +14,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
     for (_player, pos, viewshed) in (&mut players, &mut positions, &mut viewsheds).join() {
         let destination_idx = map.xy_idx(pos.x + delta_x, pos.y + delta_y);
         if map.tiles[destination_idx] != TileType::Wall {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
         }

chapter-06-monsters/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, TileType, State, Map, RunState};
 
 pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
@@ -13,13 +14,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
     for (_player, pos, viewshed) in (&mut players, &mut positions, &mut viewsheds).join() {
         let destination_idx = map.xy_idx(pos.x + delta_x, pos.y + delta_y);
         if map.tiles[destination_idx] != TileType::Wall {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();

chapter-07-damage/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee};
 
 pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
@@ -25,13 +26,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
@@ -46,33 +42,33 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             _ => { return RunState::AwaitingInput }

chapter-08-ui/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee};
 
 pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
@@ -25,13 +26,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
@@ -46,33 +42,33 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             _ => { return RunState::AwaitingInput }

chapter-09-items/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem};
 
@@ -26,13 +27,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
@@ -71,33 +67,33 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Picking up items

chapter-10-ranged/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem};
 
@@ -26,13 +27,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
@@ -71,33 +67,33 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Picking up items

chapter-11-loadsave/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem};
 
@@ -26,13 +27,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
@@ -71,33 +67,33 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Picking up items

chapter-12-delvingdeeper/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem, TileType};
 
@@ -26,13 +27,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
@@ -84,33 +80,33 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Level changes

chapter-13-difficulty/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem, TileType, Monster};
 
@@ -26,13 +27,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
@@ -113,33 +109,33 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Skip Turn

chapter-14-gear/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem, TileType, Monster};
 
@@ -26,13 +27,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
@@ -113,37 +109,37 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Skip Turn
-            VirtualKeyCode::Numpad5 => return skip_turn(&mut gs.ecs),
+            VirtualKeyCode::Numpad5 |
             VirtualKeyCode::Space => return skip_turn(&mut gs.ecs),
 
             // Level changes

chapter-16-nicewalls/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem, TileType, Monster};
 
@@ -26,13 +27,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
@@ -113,37 +109,37 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Skip Turn
-            VirtualKeyCode::Numpad5 => return skip_turn(&mut gs.ecs),
+            VirtualKeyCode::Numpad5 |
             VirtualKeyCode::Space => return skip_turn(&mut gs.ecs),
 
             // Level changes

chapter-17-blood/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem, TileType, Monster};
 
@@ -26,13 +27,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
@@ -113,37 +109,37 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Skip Turn
-            VirtualKeyCode::Numpad5 => return skip_turn(&mut gs.ecs),
+            VirtualKeyCode::Numpad5 |
             VirtualKeyCode::Space => return skip_turn(&mut gs.ecs),
 
             // Level changes

chapter-18-particles/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem, TileType, Monster};
 
@@ -26,13 +27,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
@@ -113,37 +109,37 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Skip Turn
-            VirtualKeyCode::Numpad5 => return skip_turn(&mut gs.ecs),
+            VirtualKeyCode::Numpad5 |
             VirtualKeyCode::Space => return skip_turn(&mut gs.ecs),
 
             // Level changes

chapter-19-food/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem, TileType, Monster, HungerClock, HungerState};
 
@@ -26,13 +27,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
@@ -123,37 +119,37 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Skip Turn
-            VirtualKeyCode::Numpad5 => return skip_turn(&mut gs.ecs),
+            VirtualKeyCode::Numpad5 |
             VirtualKeyCode::Space => return skip_turn(&mut gs.ecs),
 
             // Level changes

chapter-20-magicmapping/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem, TileType, Monster, HungerClock, HungerState};
 
@@ -26,13 +27,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
@@ -123,37 +119,37 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Skip Turn
-            VirtualKeyCode::Numpad5 => return skip_turn(&mut gs.ecs),
+            VirtualKeyCode::Numpad5 |
             VirtualKeyCode::Space => return skip_turn(&mut gs.ecs),
 
             // Level changes

chapter-21-rexmenu/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem, TileType, Monster, HungerClock, HungerState};
 
@@ -26,13 +27,8 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
-
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
@@ -123,33 +119,33 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Skip Turn

chapter-22-simpletraps/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem, TileType, Monster, HungerClock, HungerState, EntityMoved};
 
@@ -27,15 +28,10 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
             entity_moved.insert(entity, EntityMoved{}).expect("Unable to insert marker");
 
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
-
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
             ppos.x = pos.x;
@@ -125,37 +121,37 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Skip Turn
-            VirtualKeyCode::Numpad5 => return skip_turn(&mut gs.ecs),
+            VirtualKeyCode::Numpad5 |
             VirtualKeyCode::Space => return skip_turn(&mut gs.ecs),
 
             // Level changes

chapter-23-generic-map/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem, TileType, Monster, HungerClock, HungerState, EntityMoved};
 
@@ -27,15 +28,10 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
             entity_moved.insert(entity, EntityMoved{}).expect("Unable to insert marker");
 
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
-
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
             ppos.x = pos.x;
@@ -125,37 +121,37 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Skip Turn
-            VirtualKeyCode::Numpad5 => return skip_turn(&mut gs.ecs),
+            VirtualKeyCode::Numpad5 |
             VirtualKeyCode::Space => return skip_turn(&mut gs.ecs),
 
             // Level changes

chapter-24-map-testing/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem, TileType, Monster, HungerClock, HungerState, EntityMoved};
 
@@ -27,15 +28,10 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
             entity_moved.insert(entity, EntityMoved{}).expect("Unable to insert marker");
 
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
-
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
             ppos.x = pos.x;
@@ -125,37 +121,37 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Skip Turn
-            VirtualKeyCode::Numpad5 => return skip_turn(&mut gs.ecs),
+            VirtualKeyCode::Numpad5 |
             VirtualKeyCode::Space => return skip_turn(&mut gs.ecs),
 
             // Level changes

chapter-25-bsproom-dungeons/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem, TileType, Monster, HungerClock, HungerState, EntityMoved};
 
@@ -27,15 +28,10 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
             entity_moved.insert(entity, EntityMoved{}).expect("Unable to insert marker");
 
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
-
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
             ppos.x = pos.x;
@@ -125,37 +121,37 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Skip Turn
-            VirtualKeyCode::Numpad5 => return skip_turn(&mut gs.ecs),
+            VirtualKeyCode::Numpad5 |
             VirtualKeyCode::Space => return skip_turn(&mut gs.ecs),
 
             // Level changes

chapter-26-bsp-interiors/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem, TileType, Monster, HungerClock, HungerState, EntityMoved};
 
@@ -27,15 +28,10 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
             entity_moved.insert(entity, EntityMoved{}).expect("Unable to insert marker");
 
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
-
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
             ppos.x = pos.x;
@@ -125,37 +121,37 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Skip Turn
-            VirtualKeyCode::Numpad5 => return skip_turn(&mut gs.ecs),
+            VirtualKeyCode::Numpad5 |
             VirtualKeyCode::Space => return skip_turn(&mut gs.ecs),
 
             // Level changes

chapter-27-cellular-automota/src/player.rs

@@ -2,6 +2,7 @@ extern crate rltk;
 use rltk::{VirtualKeyCode, Rltk, Point};
 extern crate specs;
 use specs::prelude::*;
+use std::cmp::{max, min};
 use super::{Position, Player, Viewshed, State, Map, RunState, CombatStats, WantsToMelee, Item,
     gamelog::GameLog, WantsToPickupItem, TileType, Monster, HungerClock, HungerState, EntityMoved};
 
@@ -27,15 +28,10 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         }
 
         if !map.blocked[destination_idx] {
-            pos.x += delta_x;
-            pos.y += delta_y;
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
             entity_moved.insert(entity, EntityMoved{}).expect("Unable to insert marker");
 
-            if pos.x < 0 { pos.x = 0; }
-            if pos.x > 79 { pos.y = 79; }
-            if pos.y < 0 { pos.y = 0; }
-            if pos.y > 49 { pos.y = 49; }
-
             viewshed.dirty = true;
             let mut ppos = ecs.write_resource::<Point>();
             ppos.x = pos.x;
@@ -125,37 +121,37 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
         None => { return RunState::AwaitingInput } // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad4 => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left |
+            VirtualKeyCode::Numpad4 |
             VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            VirtualKeyCode::Numpad6 => try_move_player(1, 0, &mut gs.ecs),            
+            VirtualKeyCode::Right |
+            VirtualKeyCode::Numpad6 |
             VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
 
-            VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            VirtualKeyCode::Numpad8 => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up |
+            VirtualKeyCode::Numpad8 |
             VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            VirtualKeyCode::Numpad2 => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down |
+            VirtualKeyCode::Numpad2 |
             VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
 
             // Diagonals
-            VirtualKeyCode::Numpad9 => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad9 |
             VirtualKeyCode::U => try_move_player(1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad7 => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::Numpad7 |
             VirtualKeyCode::Y => try_move_player(-1, -1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad3 => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad3 |
             VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
 
-            VirtualKeyCode::Numpad1 => try_move_player(-1, 1, &mut gs.ecs),
+            VirtualKeyCode::Numpad1 |
             VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
 
             // Skip Turn
-            VirtualKeyCode::Numpad5 => return skip_turn(&mut gs.ecs),
+            VirtualKeyCode::Numpad5 |
             VirtualKeyCode::Space => return skip_turn(&mut gs.ecs),
 
             // Level changes