feat (examples): Added isometric 2D example

examples/isometric2d.rs

@@ -0,0 +1,89 @@
+// Example: Isometric 2D
+// Shows basic specialized usage of the Camera2D API.
+
+use macroquad::prelude::*;
+
+const TILE_SIZE: IVec2 = ivec2(64, 64);
+const MAP_SIZE: IVec2 = ivec2(10, 10);
+
+#[macroquad::main("Isometric 2D")]
+async fn main() {
+    set_pc_assets_folder("examples");
+
+    let texture = load_texture("grass_v1.png").await.unwrap();
+    // Set camera area to some multiple of tile size (in this case 64x64).
+    let cam_area = vec2(768., 576.);
+    // Assumption here is the world origin is 0, 0.
+    let cam_pos = vec2(-cam_area.x / 2., -cam_area.y / 4.);
+    let mut camera =
+        Camera2D::from_display_rect(Rect::new(cam_pos.x, cam_pos.y, cam_area.x, cam_area.y));
+
+    loop {
+        clear_background(BLUE);
+
+        // Exit when `ESC` is pressed.
+        if is_key_pressed(KeyCode::Escape) {
+            break;
+        }
+
+        // Control the camera.
+        // W, A, S, D for moving the camera and scroll to zoom.
+        let cam_speed = 10.;
+        if is_key_down(KeyCode::W) || is_key_down(KeyCode::Up) {
+            camera.target.y -= cam_speed
+        }
+        if is_key_down(KeyCode::A) || is_key_down(KeyCode::Left) {
+            camera.target.x -= cam_speed;
+        }
+        if is_key_down(KeyCode::S) || is_key_down(KeyCode::Down) {
+            camera.target.y += cam_speed;
+        }
+        if is_key_down(KeyCode::D) || is_key_down(KeyCode::Right) {
+            camera.target.x += cam_speed;
+        }
+        let (_, scroll_y) = mouse_wheel();
+        camera.zoom *= 1.1_f32.powf(scroll_y);
+
+        // Draw tiles in camera perspective.
+        set_camera(&camera);
+        for y in 0..MAP_SIZE.y {
+            for x in 0..MAP_SIZE.x {
+                let world_pos = map_to_world(ivec2(x, y));
+                draw_texture(texture, world_pos.x, world_pos.y, WHITE);
+            }
+        }
+        set_default_camera();
+
+        let mouse_in_world = camera.screen_to_world(mouse_position().into());
+        draw_text(
+            &format!("Pointing at: {}", world_to_map(mouse_in_world)),
+            0.,
+            20.,
+            20.,
+            BLACK,
+        );
+
+        next_frame().await;
+    }
+}
+
+// Transform world position to map position.
+// Reference: https://youtu.be/04oQ2jOUjkU
+fn world_to_map(world_pos: Vec2) -> IVec2 {
+    let ihat = vec2(0.5, 0.25) * TILE_SIZE.as_vec2();
+    let jhat = vec2(-0.5, 0.25) * TILE_SIZE.as_vec2();
+    let inverse = mat2(ihat, jhat).inverse();
+
+    inverse.mul_vec2(world_pos).as_ivec2()
+}
+
+// Transform map position to world position.
+// Reference: https://youtu.be/04oQ2jOUjkU
+fn map_to_world(map_pos: IVec2) -> Vec2 {
+    let ihat = vec2(0.5, 0.25) * TILE_SIZE.as_vec2();
+    let jhat = vec2(-0.5, 0.25) * TILE_SIZE.as_vec2();
+    let transform = mat2(ihat, jhat);
+    let offset = ivec2(-TILE_SIZE.x / 2, 0);
+
+    transform.mul_vec2(map_pos.as_vec2()) + offset.as_vec2()
+}