fix: Use composition to fix window transparency when using D3D

Cargo.toml

@@ -25,6 +25,7 @@ tracy-context-switch-tracing = ["tracy-client-sys?/context-switch-tracing"]
 tracy-sampling = ["tracy-client-sys?/sampling"]
 tracy-code-transfer = ["tracy-client-sys?/code-transfer"]
 tracy-callstack-inlines = ["tracy-client-sys?/callstack-inlines"]
+d3d_debug = [] # Enable the D3D debug layer
 
 [dependencies]
 anyhow = { version = "1.0.75", features = ["backtrace"] }
@@ -89,6 +90,7 @@ skia-safe = { version = "0.73.0", features = ["gl", "d3d", "textlayout"] }
 windows = { version = "0.56.0", features = [
     "Win32_Graphics_Direct3D",
     "Win32_Graphics_Direct3D12",
+    "Win32_Graphics_DirectComposition",
     "Win32_Graphics_Dwm",
     "Win32_Graphics_Dxgi",
     "Win32_Graphics_Dxgi_Common",

src/renderer/d3d.rs

@@ -11,18 +11,24 @@ use windows::core::{Interface, Result, PCWSTR};
 use windows::Win32::Foundation::{CloseHandle, HANDLE, HWND};
 use windows::Win32::Graphics::Direct3D::D3D_FEATURE_LEVEL_11_0;
 use windows::Win32::Graphics::Direct3D12::{
-    D3D12CreateDevice, D3D12GetDebugInterface, ID3D12CommandQueue, ID3D12Debug, ID3D12Device,
-    ID3D12Fence, ID3D12Resource, D3D12_COMMAND_LIST_TYPE_DIRECT, D3D12_COMMAND_QUEUE_DESC,
-    D3D12_COMMAND_QUEUE_FLAG_NONE, D3D12_FENCE_FLAG_NONE, D3D12_RESOURCE_STATE_PRESENT,
+    D3D12CreateDevice, ID3D12CommandQueue, ID3D12Device, ID3D12Fence, ID3D12Resource,
+    D3D12_COMMAND_LIST_TYPE_DIRECT, D3D12_COMMAND_QUEUE_DESC, D3D12_COMMAND_QUEUE_FLAG_NONE,
+    D3D12_FENCE_FLAG_NONE, D3D12_RESOURCE_STATE_PRESENT,
+};
+#[cfg(feature = "d3d_debug")]
+use windows::Win32::Graphics::Direct3D12::{D3D12GetDebugInterface, ID3D12Debug};
+use windows::Win32::Graphics::DirectComposition::{
+    DCompositionCreateDevice2, IDCompositionDevice, IDCompositionTarget, IDCompositionVisual,
 };
 use windows::Win32::Graphics::Dxgi::Common::{
-    DXGI_ALPHA_MODE_UNSPECIFIED, DXGI_FORMAT_R8G8B8A8_UNORM, DXGI_SAMPLE_DESC,
+    DXGI_ALPHA_MODE_PREMULTIPLIED, DXGI_FORMAT_R8G8B8A8_UNORM, DXGI_FORMAT_UNKNOWN,
+    DXGI_SAMPLE_DESC,
 };
 use windows::Win32::Graphics::Dxgi::{
     CreateDXGIFactory2, IDXGIAdapter1, IDXGIFactory4, IDXGISwapChain1, IDXGISwapChain3,
-    DXGI_ADAPTER_FLAG, DXGI_ADAPTER_FLAG_SOFTWARE, DXGI_CREATE_FACTORY_DEBUG, DXGI_SCALING_NONE,
+    DXGI_ADAPTER_FLAG, DXGI_ADAPTER_FLAG_SOFTWARE, DXGI_CREATE_FACTORY_DEBUG, DXGI_SCALING_STRETCH,
     DXGI_SWAP_CHAIN_DESC1, DXGI_SWAP_CHAIN_FLAG_FRAME_LATENCY_WAITABLE_OBJECT,
-    DXGI_SWAP_EFFECT_FLIP_DISCARD, DXGI_USAGE_RENDER_TARGET_OUTPUT,
+    DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL, DXGI_USAGE_RENDER_TARGET_OUTPUT,
 };
 use windows::Win32::System::Threading::{CreateEventW, WaitForSingleObjectEx, INFINITE};
 use winit::{
@@ -83,17 +89,20 @@ pub struct D3DSkiaRenderer {
     #[cfg(feature = "gpu_profiling")]
     pub device: ID3D12Device,
     _adapter: IDXGIAdapter1,
+    _composition_device: IDCompositionDevice,
+    _target: IDCompositionTarget,
+    _visual: IDCompositionVisual,
     window: Window,
 }
 
 impl D3DSkiaRenderer {
     pub fn new(window: Window) -> Self {
-        let mut debug_controller: Option<ID3D12Debug> = None;
+        #[cfg(feature = "d3d_debug")]
         unsafe {
+            let mut debug_controller: Option<ID3D12Debug> = None;
             D3D12GetDebugInterface(&mut debug_controller)
                 .expect("Failed to create Direct3D debug controller");
-        }
-        unsafe {
+
             debug_controller
                 .expect("Failed to enable debug layer")
                 .EnableDebugLayer();
@@ -102,6 +111,7 @@ impl D3DSkiaRenderer {
         let dxgi_factory: IDXGIFactory4 = unsafe {
             CreateDXGIFactory2(DXGI_CREATE_FACTORY_DEBUG).expect("Failed to create DXGI factory")
         };
+
         let adapter = get_hardware_adapter(&dxgi_factory)
             .expect("Failed to find any suitable Direct3D 12 adapters");
 
@@ -124,10 +134,12 @@ impl D3DSkiaRenderer {
                 .expect("Failed to create the Direct3D command queue")
         };
 
+        let size = window.inner_size();
+
         // Describe and create the swap chain.
         let swap_chain_desc = DXGI_SWAP_CHAIN_DESC1 {
-            Width: 0,
-            Height: 0,
+            Width: size.width,
+            Height: size.height,
             Format: DXGI_FORMAT_R8G8B8A8_UNORM,
             Stereo: false.into(),
             SampleDesc: DXGI_SAMPLE_DESC {
@@ -136,9 +148,9 @@ impl D3DSkiaRenderer {
             },
             BufferUsage: DXGI_USAGE_RENDER_TARGET_OUTPUT,
             BufferCount: 2,
-            Scaling: DXGI_SCALING_NONE,
-            SwapEffect: DXGI_SWAP_EFFECT_FLIP_DISCARD,
-            AlphaMode: DXGI_ALPHA_MODE_UNSPECIFIED,
+            Scaling: DXGI_SCALING_STRETCH,
+            SwapEffect: DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL,
+            AlphaMode: DXGI_ALPHA_MODE_PREMULTIPLIED,
             Flags: DXGI_SWAP_CHAIN_FLAG_FRAME_LATENCY_WAITABLE_OBJECT.0 as u32,
         };
 
@@ -147,20 +159,14 @@ impl D3DSkiaRenderer {
             .expect("Failed to fetch window handle")
             .as_raw()
         {
-            handle.hwnd
+            HWND(handle.hwnd.get())
         } else {
             panic!("Not a Win32 window");
         };
 
         let swap_chain = unsafe {
             dxgi_factory
-                .CreateSwapChainForHwnd(
-                    &command_queue,
-                    HWND(hwnd.get()),
-                    &swap_chain_desc,
-                    None,
-                    None,
-                )
+                .CreateSwapChainForComposition(&command_queue, &swap_chain_desc, None)
                 .expect("Failed to create the Direct3D swap chain")
         };
 
@@ -172,6 +178,31 @@ impl D3DSkiaRenderer {
                 .SetMaximumFrameLatency(1)
                 .expect("Failed to set maximum frame latency");
         }
+        let composition_device: IDCompositionDevice = unsafe {
+            DCompositionCreateDevice2(None).expect("Could not create composition device")
+        };
+        let target = unsafe {
+            composition_device
+                .CreateTargetForHwnd(hwnd, true)
+                .expect("Could not create composition target")
+        };
+        let visual = unsafe {
+            composition_device
+                .CreateVisual()
+                .expect("Could not create composition visual")
+        };
+
+        unsafe {
+            visual
+                .SetContent(&swap_chain)
+                .expect("Failed to set composition content");
+            target
+                .SetRoot(&visual)
+                .expect("Failed to set composition root");
+            composition_device
+                .Commit()
+                .expect("Failed to commit composition");
+        }
 
         let swap_chain_waitable = unsafe { swap_chain.GetFrameLatencyWaitableObject() };
         if swap_chain_waitable.is_invalid() {
@@ -219,6 +250,9 @@ impl D3DSkiaRenderer {
             fence_event,
             frame_swapped: true,
             frame_index,
+            _composition_device: composition_device,
+            _target: target,
+            _visual: visual,
             window,
         };
         ret.setup_surfaces();
@@ -372,7 +406,7 @@ impl SkiaRenderer for D3DSkiaRenderer {
                     0,
                     size.width,
                     size.height,
-                    self.swap_chain_desc.Format,
+                    DXGI_FORMAT_UNKNOWN,
                     self.swap_chain_desc.Flags,
                 )
                 .expect("Failed to resize buffers");

src/window/mod.rs

@@ -28,6 +28,9 @@ use winit::platform::macos::WindowBuilderExtMacOS;
 #[cfg(target_os = "linux")]
 use winit::platform::{wayland::WindowBuilderExtWayland, x11::WindowBuilderExtX11};
 
+#[cfg(target_os = "windows")]
+use winit::platform::windows::WindowBuilderExtWindows;
+
 #[cfg(target_os = "macos")]
 use winit::platform::macos::EventLoopBuilderExtMacOS;
 
@@ -161,6 +164,13 @@ pub fn create_window(
         .with_transparent(true)
         .with_visible(false);
 
+    #[cfg(target_os = "windows")]
+    let winit_window_builder = if !cmd_line_settings.opengl {
+        WindowBuilderExtWindows::with_no_redirection_bitmap(winit_window_builder, true)
+    } else {
+        winit_window_builder
+    };
+
     let frame_decoration = cmd_line_settings.frame;
 
     #[cfg(target_os = "macos")]