internal/graphicsdriver/directx: use QueryInterface to cast IDXGISwapChain to IDXGISwapChain4

QueryInterface is better in terms of error messages than a dumb
pointer casting.

internal/graphicsdriver/directx/dxgi_windows.go

@@ -96,11 +96,12 @@ const (
 )
 
 var (
-	_IID_IDXGIAdapter1 = windows.GUID{Data1: 0x29038f61, Data2: 0x3839, Data3: 0x4626, Data4: [...]byte{0x91, 0xfd, 0x08, 0x68, 0x79, 0x01, 0x1a, 0x05}}
+	_IID_IDXGIAdapter1   = windows.GUID{Data1: 0x29038f61, Data2: 0x3839, Data3: 0x4626, Data4: [...]byte{0x91, 0xfd, 0x08, 0x68, 0x79, 0x01, 0x1a, 0x05}}
-	_IID_IDXGIDevice   = windows.GUID{Data1: 0x54ec77fa, Data2: 0x1377, Data3: 0x44e6, Data4: [...]byte{0x8c, 0x32, 0x88, 0xfd, 0x5f, 0x44, 0xc8, 0x4c}}
+	_IID_IDXGIDevice     = windows.GUID{Data1: 0x54ec77fa, Data2: 0x1377, Data3: 0x44e6, Data4: [...]byte{0x8c, 0x32, 0x88, 0xfd, 0x5f, 0x44, 0xc8, 0x4c}}
-	_IID_IDXGIFactory  = windows.GUID{Data1: 0x7b7166ec, Data2: 0x21c7, Data3: 0x44ae, Data4: [...]byte{0xb2, 0x1a, 0xc9, 0xae, 0x32, 0x1a, 0xe3, 0x69}}
+	_IID_IDXGIFactory    = windows.GUID{Data1: 0x7b7166ec, Data2: 0x21c7, Data3: 0x44ae, Data4: [...]byte{0xb2, 0x1a, 0xc9, 0xae, 0x32, 0x1a, 0xe3, 0x69}}
-	_IID_IDXGIFactory4 = windows.GUID{Data1: 0x1bc6ea02, Data2: 0xef36, Data3: 0x464f, Data4: [...]byte{0xbf, 0x0c, 0x21, 0xca, 0x39, 0xe5, 0x16, 0x8a}}
+	_IID_IDXGIFactory4   = windows.GUID{Data1: 0x1bc6ea02, Data2: 0xef36, Data3: 0x464f, Data4: [...]byte{0xbf, 0x0c, 0x21, 0xca, 0x39, 0xe5, 0x16, 0x8a}}
-	_IID_IDXGIFactory5 = windows.GUID{Data1: 0x7632e1f5, Data2: 0xee65, Data3: 0x4dca, Data4: [...]byte{0x87, 0xfd, 0x84, 0xcd, 0x75, 0xf8, 0x83, 0x8d}}
+	_IID_IDXGIFactory5   = windows.GUID{Data1: 0x7632e1f5, Data2: 0xee65, Data3: 0x4dca, Data4: [...]byte{0x87, 0xfd, 0x84, 0xcd, 0x75, 0xf8, 0x83, 0x8d}}
+	_IID_IDXGISwapChain4 = windows.GUID{Data1: 0x3d585d5a, Data2: 0xbd4a, Data3: 0x489e, Data4: [...]byte{0xb1, 0xf4, 0x3d, 0xbc, 0xb6, 0x45, 0x2f, 0xfb}}
 )
 
 var (
@@ -498,10 +499,6 @@ type _IDXGISwapChain_Vtbl struct {
 	GetLastPresentCount     uintptr
 }
 
-func (i *_IDXGISwapChain) As(swapChain **_IDXGISwapChain4) {
-	*swapChain = (*_IDXGISwapChain4)(unsafe.Pointer(i))
-}
-
 func (i *_IDXGISwapChain) GetBuffer(buffer uint32, riid *windows.GUID) (unsafe.Pointer, error) {
 	var resource unsafe.Pointer
 	r, _, _ := syscall.Syscall6(i.vtbl.GetBuffer, 4, uintptr(unsafe.Pointer(i)),
@@ -536,6 +533,16 @@ func (i *_IDXGISwapChain) Present(syncInterval uint32, flags uint32) (occluded b
 	return false, nil
 }
 
+func (i *_IDXGISwapChain) QueryInterface(riid *windows.GUID) (unsafe.Pointer, error) {
+	var v unsafe.Pointer
+	r, _, _ := syscall.Syscall(i.vtbl.QueryInterface, 3, uintptr(unsafe.Pointer(i)), uintptr(unsafe.Pointer(riid)), uintptr(unsafe.Pointer(&v)))
+	runtime.KeepAlive(riid)
+	if uint32(r) != uint32(windows.S_OK) {
+		return nil, fmt.Errorf("directx: IDXGISwapChain::QueryInterface failed: %w", handleError(windows.Handle(uint32(r))))
+	}
+	return v, nil
+}
+
 func (i *_IDXGISwapChain) Release() uint32 {
 	r, _, _ := syscall.Syscall(i.vtbl.Release, 1, uintptr(unsafe.Pointer(i)), 0, 0)
 	return uint32(r)

internal/graphicsdriver/directx/graphics12_windows.go

@@ -497,7 +497,11 @@ func (g *graphics12) initSwapChainDesktop(width, height int) error {
 		return err
 	}
 
-	g.frameIndex = g.graphicsInfra.currentBackBufferIndex()
+	idx, err := g.graphicsInfra.currentBackBufferIndex()
+	if err != nil {
+		return err
+	}
+	g.frameIndex = idx
 
 	return nil
 }
@@ -745,7 +749,11 @@ func (g *graphics12) moveToNextFrame() error {
 	if microsoftgdk.IsXbox() {
 		g.frameIndex = (g.frameIndex + 1) % frameCount
 	} else {
-		g.frameIndex = g.graphicsInfra.currentBackBufferIndex()
+		idx, err := g.graphicsInfra.currentBackBufferIndex()
+		if err != nil {
+			return err
+		}
+		g.frameIndex = idx
 	}
 
 	if g.fence.GetCompletedValue() < g.fenceValues[g.frameIndex] {

internal/graphicsdriver/directx/graphics_windows.go

@@ -141,8 +141,9 @@ func NewGraphics() (graphicsdriver.Graphics, error) {
 }
 
 type graphicsInfra struct {
-	factory   *_IDXGIFactory
+	factory    *_IDXGIFactory
-	swapChain *_IDXGISwapChain
+	swapChain  *_IDXGISwapChain
+	swapChain4 *_IDXGISwapChain4
 
 	allowTearing bool
 
@@ -186,6 +187,10 @@ func (g *graphicsInfra) release() {
 		g.swapChain.Release()
 		g.swapChain = nil
 	}
+	if g.swapChain4 != nil {
+		g.swapChain4.Release()
+		g.swapChain4 = nil
+	}
 }
 
 // appendAdapters appends found adapters to the given adapters.
@@ -272,6 +277,10 @@ func (g *graphicsInfra) initSwapChain(width, height int, device unsafe.Pointer,
 		}
 	}()
 
+	if s4, err := g.swapChain.QueryInterface(&_IID_IDXGISwapChain4); err == nil && s4 != nil {
+		g.swapChain4 = (*_IDXGISwapChain4)(s4)
+	}
+
 	// MakeWindowAssociation should be called after swap chain creation.
 	// https://docs.microsoft.com/en-us/windows/win32/api/dxgi/nf-dxgi-idxgifactory-makewindowassociation
 	if err := g.factory.MakeWindowAssociation(window, _DXGI_MWA_NO_WINDOW_CHANGES|_DXGI_MWA_NO_ALT_ENTER); err != nil {
@@ -296,10 +305,11 @@ func (g *graphicsInfra) resizeSwapChain(width, height int) error {
 	return nil
 }
 
-func (g *graphicsInfra) currentBackBufferIndex() int {
+func (g *graphicsInfra) currentBackBufferIndex() (int, error) {
-	var swapChain4 *_IDXGISwapChain4
+	if g.swapChain4 == nil {
-	g.swapChain.As(&swapChain4)
+		return 0, fmt.Errorf("directx: IDXGISwapChain4 is not available")
-	return int(swapChain4.GetCurrentBackBufferIndex())
+	}
+	return int(g.swapChain4.GetCurrentBackBufferIndex()), nil
 }
 
 func (g *graphicsInfra) present(vsyncEnabled bool) error {