implement bounce.rs

Makefile

@@ -1,2 +1,10 @@
+.PHONY: all
+
+all: rect bounce
+
 rect: rect.rs
 	rustc -L./raylib/ -lraylib $< -o bin/$@
+
+bounce: bounce.rs
+	rustc -L./raylib/ -lraylib $< -o bin/$@
+

bounce.rs

@@ -0,0 +1,42 @@
+mod raylib;
+
+use raylib::*;
+
+fn main() {
+    let screen: Vector2<u32> = Vector2 { x: 800, y: 600 };
+    let ball_radius: f32 = 100.0;
+    let mut pos: Vector2<f32> = Vector2 {
+        x: screen.x as f32 / 2.0,
+        y: screen.y as f32 / 2.0,
+    };
+    let mut velocity: Vector2<f32> = Vector2 { x: 200.0, y: 200.0 };
+
+    init_window(screen.x, screen.y, "Bouncing ball");
+    set_target_fps(60);
+
+    while !window_should_close() {
+        begin_drawing();
+        clear_background(colors::BLACK);
+        
+        let dt: f32 = get_frame_time();
+        velocity.y += dt * 1000.0;
+
+        let x: f32 = pos.x + velocity.x * dt;
+        if x - ball_radius < 0.0 || x + ball_radius >= screen.x as f32{
+            velocity.x *= -1.0;
+        } else {
+            pos.x = x;
+        }
+
+        let y: f32 = pos.y + velocity.y * dt;
+        if y - ball_radius < 0.0 || y + ball_radius >= screen.y as f32 {
+            velocity.y *= -1.0;
+        } else {
+            pos.y = y;
+        }
+
+        draw_circle_v(pos, ball_radius, colors::RED);
+        end_drawing();
+    }
+}
+

raylib.rs

@@ -11,8 +11,12 @@ extern {
     fn SetTargetFPS(fps: u32);
     fn BeginDrawing();
     fn EndDrawing();
+
     fn DrawRectangle(pos_x: u32, pos_y: u32, width: u32, height: u32, color: Color);
+    fn DrawCircleV(center: Vector2<f32>, radius: f32, color: Color);
+
     fn IsKeyDown(key: u32) -> bool;
+    fn GetFrameTime() -> f32;
 }
 
 #[derive(Copy, Clone)]
@@ -29,6 +33,13 @@ pub mod colors {
     pub const BLACK: Color = Color(0, 0, 0, 0);
 }
 
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct Vector2<S> {
+    pub x: S,
+    pub y: S,
+}
+
 pub fn init_window(width: u32, height: u32, title: &str) {
     unsafe { 
         let title = CString::new(title).unwrap();
@@ -60,7 +71,15 @@ pub fn draw_rect(pos_x: u32, pos_y: u32, width:u32, height: u32, color: Color) {
     unsafe { DrawRectangle(pos_x, pos_y, width, height, color); }
 }
 
+pub fn draw_circle_v(center: Vector2<f32>, radius: f32, color: Color) {
+    unsafe { DrawCircleV(center, radius, color) }
+}
+
 pub fn is_key_down(key: Key) -> bool {
     unsafe { IsKeyDown(key as u32) }
 }
 
+pub fn get_frame_time() -> f32 {
+    unsafe { GetFrameTime() }
+}
+

rect.rs

@@ -1,13 +1,8 @@
 mod raylib;
 
-pub struct Vector2<S> {
-    pub x: S,
-    pub y: S,
-}
-
 fn main() {
-    let screen = Vector2::<u32> { x: 800, y: 600 };
+    let screen = raylib::Vector2::<u32> { x: 800, y: 600 };
-    let mut pos = Vector2::<u32> {
+    let mut pos = raylib::Vector2::<u32> {
         x: screen.x / 2,
         y: screen.y / 2
     };