load level in engine

src/engine.rs

@@ -1,6 +1,7 @@
 extern crate piston_window;
 use piston_window::*;
-use std::f64::consts;
+
+use std::f64::consts::*;
 
 #[derive(PartialEq, Debug)]
 struct Position {
@@ -13,11 +14,23 @@ struct Player {
    angle: f64, // radian or degree
 }
 
+pub enum Tile {
+    Empty,
+    Wall,
+}
+
+pub struct Level {
+    pub width: u16,
+    pub height: u16,
+    pub tiles: Vec<Tile>,
+}
+
 pub struct Engine {
     w: f64,
     h: f64,
     horiz_fov: f64,
     player: Player,
+    level: Level,
 }
 
 impl Engine {
@@ -29,12 +42,34 @@ impl Engine {
             player: Player {
                 pos: Position { x: 2., y: 2. },
                 angle: 0.,
-            }
+            },
+            level: Level {
+                width: 0,
+                height: 0,
+                tiles: vec![],
+            },
         }
     }
 
-    fn closest_point(pos: Position, angle: f64) -> Position {
-        return Position {x: 2., y: 2.}
+    fn closest_point(pos: &Position, angle: f64) -> (Tile, Position) {
+        // First let's find the closest intersections with the grid
+        let dx = angle.cos();
+        let x_dist = if dx > 0.0 { 1.0 - pos.x.fract() } else { pos.x.fract() };
+        let x_relative_dist = x_dist / dx.abs();
+        let dy = angle.sin();
+        let y_dist = if dy > 0.0 { 1.0 - pos.y.fract() } else { pos.y.fract() };
+        let y_relative_dist = y_dist / dy.abs();
+        if x_relative_dist > y_relative_dist {
+            // first grid hit is horizontal line
+        } else {
+            // first grid hit is vertical line
+        }
+
+        // see Game Engine Black Book
+        let xstep = angle.tan();
+        let ystep = ((PI / 2.0) - angle).tan();
+
+        (Tile::Empty, Position {x: 2., y: 2.})
     }
 
     pub fn render(&mut self, context: Context, graphics: &mut G2d) {
@@ -64,12 +99,17 @@ impl Engine {
         let width = self.w as i32;
         for n in 0..width {
             //   cast a ray
+            let (tile, pos) = Engine::closest_point(&self.player.pos, ray_angle);
             //   see what wall it hits
             //   compute wall height
             //   draw wall portion
             ray_angle += step;
         }
     }
+
+    pub fn load_level(&mut self, level: Level) {
+        self.level = level;
+    }
 }
 
 #[cfg(test)]

src/main.rs

@@ -1,11 +1,8 @@
 extern crate piston_window;
 use piston_window::*;
-mod engine;
 
-enum Tile {
-    Empty,
-    Wall,
-}
+mod engine;
+use engine::Tile;
 
 fn main() {
     let mut window: PistonWindow =
@@ -15,18 +12,24 @@ fn main() {
         .build()
         .unwrap_or_else(|e| { panic!("Failed to build PistonWindow: {}", e) });
 
-    let level: [Tile; 5 * 5] = [
+    let mut engine = engine::Engine::new(window.size());
+
+    let tiles = vec![
         Tile::Wall, Tile::Wall, Tile::Wall, Tile::Wall, Tile::Wall,
         Tile::Wall, Tile::Empty, Tile::Empty, Tile::Empty, Tile::Wall,
         Tile::Wall, Tile::Empty, Tile::Empty, Tile::Empty, Tile::Wall,
         Tile::Wall, Tile::Empty, Tile::Empty, Tile::Empty, Tile::Wall,
         Tile::Wall, Tile::Wall, Tile::Wall, Tile::Wall, Tile::Wall,
     ];
-
-    let mut engine = engine::Engine::new(window.size());
+    let level = engine::Level {
+        width:5,
+        height: 5,
+        tiles
+    };
+    engine.load_level(level);
 
     while let Some(event) = window.next() {
-        window.draw_2d(&event, |context, graphics, device| {
+        window.draw_2d(&event, |context, graphics, _device| {
             engine.render(context, graphics);
         });
     }