(fix) Smooth resizing for macOS (#7)

Author: LukasBombach

src/graphics.rs

@@ -65,6 +65,22 @@ impl<'window> Gpu<'window> {
         let surface = instance.create_surface(Arc::clone(&window)).unwrap();
         let push_const_size = std::mem::size_of::<[f32; 2]>() as u32;
 
+        // Jitter when resizing windows on macOS
+        // https://github.com/gfx-rs/wgpu/issues/3756
+        // https://github.com/gfx-rs/wgpu/pull/6107
+        // https://thume.ca/2019/06/19/glitchless-metal-window-resizing/
+        // https://raphlinus.github.io/rust/gui/2019/06/21/smooth-resize-test.html
+        #[allow(invalid_reference_casting)]
+        unsafe {
+            surface.as_hal::<wgpu::hal::metal::Api, _, ()>(|surface| {
+                if let Some(surface_ref) = surface {
+                    let surface_mut = &mut *(surface_ref as *const wgpu::hal::metal::Surface
+                        as *mut wgpu::hal::metal::Surface);
+                    surface_mut.present_with_transaction = true;
+                }
+            });
+        }
+
         let adapter = instance
             .request_adapter(&wgpu::RequestAdapterOptions {
                 power_preference: wgpu::PowerPreference::default(),