Add engine module

src/engine.rs

@@ -0,0 +1,68 @@
+extern crate piston_window;
+
+use piston_window::*;
+
+struct Position {
+    x: f64,
+    y: f64,
+}
+
+struct Player {
+   pos: Position,
+   angle: f64, // radian or degree
+}
+
+pub struct Engine {
+    w: f64,
+    h: f64,
+    horiz_fov: f64,
+    player: Player,
+}
+
+impl Engine {
+    pub fn new(size: Size) -> Engine {
+        Engine {
+            w: size.width as f64,
+            h: size.height as f64,
+            horiz_fov: 90.,
+            player: Player {
+                pos: Position { x: 2., y: 2. },
+                angle: 0.,
+            }
+        }
+    }
+
+    pub fn render(&mut self, context: Context, graphics: &mut G2d) {
+
+        clear([1.0; 4], graphics);
+
+        // Ceiling
+        let ceiling_color = [0.3, 0.3, 0.3, 1.0];
+        rectangle(ceiling_color,
+                  [0.0, 0.0, self.w, self.h / 2.0],
+                  context.transform,
+                  graphics);
+
+        // Floor
+        let floor_color = [0.5, 0.5, 0.5, 1.0];
+        rectangle(floor_color,
+                  [0.0, self.h / 2.0, self.w, self.h / 2.0],
+                  context.transform,
+                  graphics);
+
+        // Walls
+        let left = self.player.angle + (self.horiz_fov / 2.0);
+        let right = self.player.angle - (self.horiz_fov / 2.0);
+        // for every angle (range / w)
+        let step = (left - right) / self.w;
+        let mut ray_angle = left;
+        let width = self.w as i32;
+        for n in 0..width {
+            //   cast a ray
+            //   see what wall it hits
+            //   compute wall height
+            //   draw wall portion
+            ray_angle += step;
+        }
+    }
+}