app,internal/d3d11: [Windows] present with the flip model

app/d3d11_windows.go

@@ -18,6 +18,8 @@ type d3d11Context struct {
 	swchain       *d3d11.IDXGISwapChain
 	renderTarget  *d3d11.RenderTargetView
 	width, height int
+	// resized is set until the first Present of a new size.
+	resized bool
 }
 
 const debugDirectX = false
@@ -60,7 +62,14 @@ func (c *d3d11Context) RenderTarget() (gpu.RenderTarget, error) {
 }
 
 func (c *d3d11Context) Present() error {
-	return wrapErr(c.swchain.Present(1, 0))
+	syncInterval := 1
+	if c.resized {
+		// Interval 0 replaces any frame still queued, so the new size shows
+		// at the next composition instead of the old frame stretched to it.
+		syncInterval = 0
+		c.resized = false
+	}
+	return wrapErr(c.swchain.Present(syncInterval, 0))
 }
 
 func wrapErr(err error) error {
@@ -82,19 +91,29 @@ func (c *d3d11Context) Refresh() error {
 	if c.renderTarget != nil && width == c.width && height == c.height {
 		return nil
 	}
+	// ResizeBuffers fails while the context binds a view of the back buffer
+	// or the destruction of a released view is still deferred.
+	c.ctx.OMSetRenderTargets(nil, nil)
 	c.releaseFBO()
+	c.ctx.Flush()
 	if err := c.swchain.ResizeBuffers(0, 0, 0, d3d11.DXGI_FORMAT_UNKNOWN, 0); err != nil {
 		return wrapErr(err)
 	}
 	c.width = width
 	c.height = height
+	c.resized = true
 
 	backBuffer, err := c.swchain.GetBuffer(0, &d3d11.IID_Texture2D)
 	if err != nil {
 		return err
 	}
 	texture := (*d3d11.Resource)(unsafe.Pointer(backBuffer))
-	renderTarget, err := c.dev.CreateRenderTargetView(texture)
+	// The view, not the buffer, is sRGB: flip-model buffers cannot have an
+	// _SRGB format.
+	renderTarget, err := c.dev.CreateRenderTargetViewTEX2D(texture, &d3d11.RENDER_TARGET_VIEW_DESC_TEX2D{
+		Format:        d3d11.DXGI_FORMAT_R8G8B8A8_UNORM_SRGB,
+		ViewDimension: d3d11.RTV_DIMENSION_TEXTURE2D,
+	})
 	d3d11.IUnknownRelease(unsafe.Pointer(backBuffer), backBuffer.Vtbl.Release)
 	if err != nil {
 		return err
@@ -116,6 +135,11 @@ func (c *d3d11Context) Release() {
 		d3d11.IUnknownRelease(unsafe.Pointer(c.swchain), c.swchain.Vtbl.Release)
 	}
 	if c.ctx != nil {
+		// A window can have one flip-model swap chain, and the destruction of
+		// the old one is deferred: a new context after a lost device would
+		// fail to create its own without this.
+		c.ctx.ClearState()
+		c.ctx.Flush()
 		d3d11.IUnknownRelease(unsafe.Pointer(c.ctx), c.ctx.Vtbl.Release)
 	}
 	if c.dev != nil {

internal/d3d11/d3d11_windows.go

@@ -451,6 +451,16 @@ type TEX2D_DSV struct {
 	MipSlice uint32
 }
 
+type RENDER_TARGET_VIEW_DESC_TEX2D struct {
+	Format        uint32
+	ViewDimension uint32
+	Texture2D     TEX2D_RTV
+}
+
+type TEX2D_RTV struct {
+	MipSlice uint32
+}
+
 type BLEND_DESC struct {
 	AlphaToCoverageEnable  uint32
 	IndependentBlendEnable uint32
@@ -529,6 +539,23 @@ type IDXGIDevice struct {
 	}
 }
 
+type IDXGIDevice1 struct {
+	Vtbl *struct {
+		_IUnknownVTbl
+		SetPrivateData          uintptr
+		SetPrivateDataInterface uintptr
+		GetPrivateData          uintptr
+		GetParent               uintptr
+		GetAdapter              uintptr
+		CreateSurface           uintptr
+		QueryResourceResidency  uintptr
+		SetGPUThreadPriority    uintptr
+		GetGPUThreadPriority    uintptr
+		SetMaximumFrameLatency  uintptr
+		GetMaximumFrameLatency  uintptr
+	}
+}
+
 type IUnknown struct {
 	Vtbl *struct {
 		_IUnknownVTbl
@@ -614,6 +641,7 @@ var (
 	IID_Texture2D    = GUID{0x6f15aaf2, 0xd208, 0x4e89, 0x9a, 0xb4, 0x48, 0x95, 0x35, 0xd3, 0x4f, 0x9c}
 	IID_IDXGIDebug   = GUID{0x119E7452, 0xDE9E, 0x40fe, 0x88, 0x06, 0x88, 0xF9, 0x0C, 0x12, 0xB4, 0x41}
 	IID_IDXGIDevice  = GUID{0x54ec77fa, 0x1377, 0x44e6, 0x8c, 0x32, 0x88, 0xfd, 0x5f, 0x44, 0xc8, 0x4c}
+	IID_IDXGIDevice1 = GUID{0x77db970f, 0x6276, 0x48ba, 0xba, 0x28, 0x07, 0x01, 0x43, 0xb4, 0x39, 0x2c}
 	IID_IDXGIFactory = GUID{0x7b7166ec, 0x21c7, 0x44ae, 0xb2, 0x1a, 0xc9, 0xae, 0x32, 0x1a, 0xe3, 0x69}
 	IID_ID3D11Debug  = GUID{0x79cf2233, 0x7536, 0x4948, 0x9d, 0x36, 0x1e, 0x46, 0x92, 0xdc, 0x57, 0x60}
 
@@ -635,21 +663,19 @@ const (
 	SDK_VERSION          = 7
 	DRIVER_TYPE_HARDWARE = 1
 
-	DXGI_FORMAT_UNKNOWN             = 0
-	DXGI_FORMAT_R16_FLOAT           = 54
-	DXGI_FORMAT_R32_FLOAT           = 41
-	DXGI_FORMAT_R32_TYPELESS        = 39
-	DXGI_FORMAT_R32G32_FLOAT        = 16
-	DXGI_FORMAT_R32G32B32_FLOAT     = 6
-	DXGI_FORMAT_R32G32B32A32_FLOAT  = 2
-	DXGI_FORMAT_R8G8B8A8_UNORM      = 28
-	DXGI_FORMAT_R8G8B8A8_UNORM_SRGB = 29
-	DXGI_FORMAT_R16_SINT            = 59
-	DXGI_FORMAT_R16G16_SINT         = 38
-	DXGI_FORMAT_R16_UINT            = 57
-	DXGI_FORMAT_D24_UNORM_S8_UINT   = 45
-	DXGI_FORMAT_R16G16_FLOAT        = 34
-	DXGI_FORMAT_R16G16B16A16_FLOAT  = 10
+	DXGI_FORMAT_UNKNOWN            = 0
+	DXGI_FORMAT_R16_FLOAT          = 54
+	DXGI_FORMAT_R32_FLOAT          = 41
+	DXGI_FORMAT_R32_TYPELESS       = 39
+	DXGI_FORMAT_R32G32_FLOAT       = 16
+	DXGI_FORMAT_R32G32B32_FLOAT    = 6
+	DXGI_FORMAT_R32G32B32A32_FLOAT = 2
+	DXGI_FORMAT_R16_SINT           = 59
+	DXGI_FORMAT_R16G16_SINT        = 38
+	DXGI_FORMAT_R16_UINT           = 57
+	DXGI_FORMAT_D24_UNORM_S8_UINT  = 45
+	DXGI_FORMAT_R16G16_FLOAT       = 34
+	DXGI_FORMAT_R16G16B16A16_FLOAT = 10
 
 	DXGI_DEBUG_RLO_SUMMARY         = 0x1
 	DXGI_DEBUG_RLO_DETAIL          = 0x2
@@ -664,8 +690,6 @@ const (
 
 	MAP_READ = 1
 
-	DXGI_SWAP_EFFECT_DISCARD = 0
-
 	FEATURE_LEVEL_9_1  = 0x9100
 	FEATURE_LEVEL_9_3  = 0x9300
 	FEATURE_LEVEL_11_0 = 0xb000
@@ -714,6 +738,7 @@ const (
 	CLEAR_STENCIL = 0x2
 
 	DSV_DIMENSION_TEXTURE2D = 3
+	RTV_DIMENSION_TEXTURE2D = 4
 
 	DEPTH_WRITE_MASK_ALL = 1
 
@@ -1055,6 +1080,23 @@ func (d *Device) CreateRenderTargetView(res *Resource) (*RenderTargetView, error
 	return target, nil
 }
 
+func (d *Device) CreateRenderTargetViewTEX2D(res *Resource, desc *RENDER_TARGET_VIEW_DESC_TEX2D) (*RenderTargetView, error) {
+	var target *RenderTargetView
+	r, _, _ := syscall.Syscall6(
+		d.Vtbl.CreateRenderTargetView,
+		4,
+		uintptr(unsafe.Pointer(d)),
+		uintptr(unsafe.Pointer(res)),
+		uintptr(unsafe.Pointer(desc)),
+		uintptr(unsafe.Pointer(&target)),
+		0, 0,
+	)
+	if r != 0 {
+		return nil, ErrorCode{Name: "DeviceCreateRenderTargetView", Code: uint32(r)}
+	}
+	return target, nil
+}
+
 func (d *Device) CreateBlendState(desc *BLEND_DESC) (*BlendState, error) {
 	var state *BlendState
 	r, _, _ := syscall.Syscall(
@@ -1486,6 +1528,24 @@ func (c *DeviceContext) OMSetRenderTargets(target *RenderTargetView, depthStenci
 	)
 }
 
+func (c *DeviceContext) ClearState() {
+	syscall.Syscall(
+		c.Vtbl.ClearState,
+		1,
+		uintptr(unsafe.Pointer(c)),
+		0, 0,
+	)
+}
+
+func (c *DeviceContext) Flush() {
+	syscall.Syscall(
+		c.Vtbl.Flush,
+		1,
+		uintptr(unsafe.Pointer(c)),
+		0, 0,
+	)
+}
+
 func (c *DeviceContext) Draw(count, start uint32) {
 	syscall.Syscall(
 		c.Vtbl.Draw,
@@ -1574,6 +1634,20 @@ func (d *IDXGIFactory) CreateSwapChain(device *IUnknown, desc *DXGI_SWAP_CHAIN_D
 	return swchain, nil
 }
 
+func (d *IDXGIDevice1) SetMaximumFrameLatency(frames uint32) error {
+	r, _, _ := syscall.Syscall(
+		d.Vtbl.SetMaximumFrameLatency,
+		2,
+		uintptr(unsafe.Pointer(d)),
+		uintptr(frames),
+		0,
+	)
+	if r != 0 {
+		return ErrorCode{Name: "IDXGIDevice1SetMaximumFrameLatency", Code: uint32(r)}
+	}
+	return nil
+}
+
 func (d *IDXGIDevice) GetAdapter() (*IDXGIAdapter, error) {
 	var adapter *IDXGIAdapter
 	r, _, _ := syscall.Syscall(
@@ -1643,29 +1717,46 @@ func CreateSwapChain(dev *Device, hwnd windows.Handle) (*IDXGISwapChain, error)
 	if err != nil {
 		return nil, fmt.Errorf("NewContext: %v", err)
 	}
-	swchain, err := (*IDXGIFactory)(unsafe.Pointer(dxgiFactory)).CreateSwapChain(
-		(*IUnknown)(unsafe.Pointer(dev)),
-		&DXGI_SWAP_CHAIN_DESC{
-			BufferDesc: DXGI_MODE_DESC{
-				Format: DXGI_FORMAT_R8G8B8A8_UNORM_SRGB,
-			},
-			SampleDesc: DXGI_SAMPLE_DESC{
-				Count: 1,
+	// Best effort: the default latency of 3 frames only costs input lag.
+	_ = setMaximumFrameLatency(dev, maxFrameLatency)
+	factory := (*IDXGIFactory)(unsafe.Pointer(dxgiFactory))
+	var swchain *IDXGISwapChain
+	err = firstSwapChain(func(cfg swapChainConfig) error {
+		var err error
+		swchain, err = factory.CreateSwapChain(
+			(*IUnknown)(unsafe.Pointer(dev)),
+			&DXGI_SWAP_CHAIN_DESC{
+				BufferDesc: DXGI_MODE_DESC{
+					Format: cfg.format,
+				},
+				SampleDesc: DXGI_SAMPLE_DESC{
+					Count: 1,
+				},
+				BufferUsage:  DXGI_USAGE_RENDER_TARGET_OUTPUT,
+				BufferCount:  cfg.bufferCount,
+				OutputWindow: hwnd,
+				Windowed:     1,
+				SwapEffect:   cfg.effect,
 			},
-			BufferUsage:  DXGI_USAGE_RENDER_TARGET_OUTPUT,
-			BufferCount:  1,
-			OutputWindow: hwnd,
-			Windowed:     1,
-			SwapEffect:   DXGI_SWAP_EFFECT_DISCARD,
-		},
-	)
+		)
+		return err
+	})
 	IUnknownRelease(unsafe.Pointer(dxgiFactory), dxgiFactory.Vtbl.Release)
 	if err != nil {
 		return nil, fmt.Errorf("NewContext: %v", err)
 	}
 	return swchain, nil
 }
 
+func setMaximumFrameLatency(dev *Device, frames uint32) error {
+	dxgiDev, err := IUnknownQueryInterface(unsafe.Pointer(dev), dev.Vtbl.QueryInterface, &IID_IDXGIDevice1)
+	if err != nil {
+		return err
+	}
+	defer IUnknownRelease(unsafe.Pointer(dxgiDev), dxgiDev.Vtbl.Release)
+	return (*IDXGIDevice1)(unsafe.Pointer(dxgiDev)).SetMaximumFrameLatency(frames)
+}
+
 func CreateDepthView(d *Device, width, height, depthBits int) (*DepthStencilView, error) {
 	depthTex, err := d.CreateTexture2D(&TEXTURE2D_DESC{
 		Width:     uint32(width),

internal/d3d11/swapchain.go

@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package d3d11
+
+const (
+	DXGI_FORMAT_R8G8B8A8_UNORM      = 28
+	DXGI_FORMAT_R8G8B8A8_UNORM_SRGB = 29
+
+	DXGI_SWAP_EFFECT_DISCARD      = 0
+	DXGI_SWAP_EFFECT_FLIP_DISCARD = 4
+
+	maxFrameLatency = 1
+)
+
+type swapChainConfig struct {
+	effect, format, bufferCount uint32
+}
+
+// swapChainConfigs are tried in order. Windows before 10, and some VMs and
+// drivers, cannot create a flip-model swap chain.
+var swapChainConfigs = [...]swapChainConfig{
+	{DXGI_SWAP_EFFECT_FLIP_DISCARD, DXGI_FORMAT_R8G8B8A8_UNORM, 2},
+	{DXGI_SWAP_EFFECT_DISCARD, DXGI_FORMAT_R8G8B8A8_UNORM_SRGB, 1},
+}
+
+func firstSwapChain(create func(swapChainConfig) error) error {
+	var err error
+	for _, cfg := range swapChainConfigs {
+		if err = create(cfg); err == nil {
+			return nil
+		}
+	}
+	return err
+}