Fix blood canvas blitting

CHANGELOG.md

@@ -20,7 +20,11 @@
   with `get_sprite_culling`, e.g. if you wish to build an inspector window to control this.
 - Added `enable_child_transforms` on `GameConfig` allowing the user to disable child/parent
   transform update. If you have a lot of entities (10k+) but aren't using child transforms,
-  setting this to false may give you extra few percent of free performance. This is enabled by default.
+  setting this to false may give you extra few percent of free performance. This is enabled
+  by default.
+- Added `flip_x/y` and `blood_canvas_blit_at_pro` which allows blitting sprites with arbitrary
+  flipping. Note that this also fixes a long standing bug when in some cases sprites would be
+  blitted flipped upside down.
 
 # v0.3.0
 

comfy-core/src/blood_canvas.rs

@@ -189,10 +189,18 @@ impl BloodCanvas {
 
             for x in 0..rect.size.x {
                 for y in 0..rect.size.y {
-                    let px = image.get_pixel(
-                        (x + rect.offset.x) as u32,
-                        (y + rect.offset.y) as u32,
-                    );
+                    let mut read_x = x + rect.offset.x;
+                    let mut read_y = y + rect.offset.y;
+
+                    if flip_x {
+                        read_x = rect.offset.x + rect.size.x - x - 1;
+                    }
+
+                    if !flip_y {
+                        read_y = rect.offset.y + rect.size.y - y - 1;
+                    }
+
+                    let px = image.get_pixel(read_x as u32, read_y as u32);
 
                     if px.0[3] > 0 {
                         let px_pos = position + vec2(x as f32, y as f32) / 16.0 -
@@ -214,8 +222,6 @@ impl BloodCanvas {
                                 Into::<Color>::into(*px) * tint,
                             );
                         }
-
-                        // self.set_pixel(px_pos, Into::<Color>::into(*px) * tint);
                     }
                 }
             }

comfy-wgpu/src/blood_canvas.rs

@@ -58,6 +58,24 @@ pub fn blood_canvas_blit_at(
     );
 }
 
+pub fn blood_canvas_blit_at_pro(
+    texture: TextureHandle,
+    position: Vec2,
+    source_rect: Option<IRect>,
+    tint: Color,
+    flip_x: bool,
+    flip_y: bool,
+) {
+    BLOOD_CANVAS.get().unwrap().borrow_mut().blit_at(
+        texture,
+        position,
+        source_rect,
+        tint,
+        flip_x,
+        flip_y,
+    );
+}
+
 pub fn blood_canvas_blit_at_sized(
     texture: TextureHandle,
     position: Vec2,

comfy/examples/blood_canvas.rs

@@ -81,11 +81,13 @@ fn update(_c: &mut EngineContext) {
     }
 
     if is_mouse_button_pressed(MouseButton::Right) {
-        blood_canvas_blit_at(
+        blood_canvas_blit_at_pro(
             texture_id("error"),
             mouse_world(),
             None,
-            RED.alpha(0.5),
+            RED.alpha(0.7),
+            flip_coin(0.5),
+            flip_coin(0.5),
         );
     }
 
@@ -126,7 +128,11 @@ fn update(_c: &mut EngineContext) {
             animated_sprite.play("idle");
         }
 
-        if is_key_pressed(KeyCode::Space) {}
+        if is_key_pressed(KeyCode::Space) {
+            blood_canvas_blit_quad_draw(
+                animated_sprite.to_quad_draw(transform),
+            );
+        }
 
         main_camera_mut().center = transform.position;
     }