Directx 12 mrt working - 1st iteration

examples/mrt/main.go

@@ -127,7 +127,7 @@ func main() {
 	ebiten.SetVsyncEnabled(false)
 	ebiten.SetWindowTitle("MRT (Ebitengine Demo)")
 	if err := ebiten.RunGameWithOptions(&Game{}, &ebiten.RunGameOptions{
-		GraphicsLibrary: ebiten.GraphicsLibraryOpenGL,
+		GraphicsLibrary: ebiten.GraphicsLibraryDirectX,
 	}); err != nil {
 		log.Fatal(err)
 	}

internal/graphicsdriver/directx/graphics11_windows.go

@@ -625,6 +625,7 @@ func (g *graphics11) DrawTriangles(dstIDs [graphics.ShaderDstImageCount]graphics
 	if targetCount > 1 || firstTarget > 0 {
 		targetCount = graphics.ShaderDstImageCount
 	}
+	
 	g.deviceContext.RSSetViewports(viewports[:targetCount])
 
 	if err := g.setAsRenderTargets(dsts[:targetCount], fillRule != graphicsdriver.FillAll); err != nil {

internal/graphicsdriver/directx/graphics12_windows.go

@@ -1082,7 +1082,78 @@ func (g *graphics12) NewShader(program *shaderir.Program) (graphicsdriver.Shader
 	return s, nil
 }
 
-func (g *graphics12) DrawTriangles(dstIDs [graphics.ShaderDstImageCount]graphicsdriver.ImageID, srcs [graphics.ShaderSrcImageCount]graphicsdriver.ImageID, shaderID graphicsdriver.ShaderID, dstRegions []graphicsdriver.DstRegion, indexOffset int, blend graphicsdriver.Blend, uniforms []uint32, fillRule graphicsdriver.FillRule) error {
+func (g *graphics12) setAsRenderTargets(dsts []*image12, useStencil bool) error {
+	var rtvs []_D3D12_CPU_DESCRIPTOR_HANDLE
+	var dsvPtr *_D3D12_CPU_DESCRIPTOR_HANDLE
+
+	for i, img := range dsts {
+		// Ignore a nil image in case of MRT
+		if img == nil {
+			_ = i
+			rtvBase, err := g.rtvDescriptorHeap.GetCPUDescriptorHandleForHeapStart()
+			if err != nil {
+				return err
+			}
+			rtv := rtvBase
+			rtv.Offset(int32(g.frameIndex), g.rtvDescriptorSize)
+			rtvs = append(rtvs, rtv)
+			continue
+		}
+
+		if err := img.ensureRenderTargetView(g.device); err != nil {
+			return err
+		}
+
+		if img.screen {
+			if useStencil {
+				return fmt.Errorf("directx: stencils are not available on the screen framebuffer")
+			}
+
+			rtvBase, err := g.rtvDescriptorHeap.GetCPUDescriptorHandleForHeapStart()
+			if err != nil {
+				return err
+			}
+			rtv := rtvBase
+			rtv.Offset(int32(g.frameIndex), g.rtvDescriptorSize)
+			rtvs = append(rtvs, rtv)
+			continue
+		}
+
+		rtvBase, err := img.rtvDescriptorHeap.GetCPUDescriptorHandleForHeapStart()
+		if err != nil {
+			return err
+		}
+
+		rtv := rtvBase
+		rtvs = append(rtvs, rtv)
+
+		if !useStencil || dsvPtr != nil {
+			continue
+		}
+
+		if err := img.ensureDepthStencilView(g.device); err != nil {
+			return err
+		}
+		dsv, err := img.dsvDescriptorHeap.GetCPUDescriptorHandleForHeapStart()
+		if err != nil {
+			return err
+		}
+		dsvPtr = &dsv
+	}
+
+	if !useStencil {
+		g.drawCommandList.OMSetRenderTargets(rtvs, false, nil)
+		return nil
+	}
+
+	g.drawCommandList.OMSetStencilRef(0)
+	g.drawCommandList.OMSetRenderTargets(rtvs, false, dsvPtr)
+	g.drawCommandList.ClearDepthStencilView(*dsvPtr, _D3D12_CLEAR_FLAG_STENCIL, 0, 0, nil)
+
+	return nil
+}
+
+func (g *graphics12) DrawTriangles(dstIDs [graphics.ShaderDstImageCount]graphicsdriver.ImageID, srcIDs [graphics.ShaderSrcImageCount]graphicsdriver.ImageID, shaderID graphicsdriver.ShaderID, dstRegions []graphicsdriver.DstRegion, indexOffset int, blend graphicsdriver.Blend, uniforms []uint32, fillRule graphicsdriver.FillRule) error {
 	if shaderID == graphicsdriver.InvalidShaderID {
 		return fmt.Errorf("directx: shader ID is invalid")
 	}
@@ -1103,20 +1174,46 @@ func (g *graphics12) DrawTriangles(dstIDs [graphics.ShaderDstImageCount]graphics
 		g.pipelineStates.releaseConstantBuffers(g.frameIndex)
 	}
 
-	dst := g.images[dstIDs[0]] // TODO: handle array
 	var resourceBarriers []_D3D12_RESOURCE_BARRIER_Transition
-	if rb, ok := dst.transiteState(_D3D12_RESOURCE_STATE_RENDER_TARGET); ok {
-		resourceBarriers = append(resourceBarriers, rb)
-	}
 
-	var srcImages [graphics.ShaderSrcImageCount]*image12
+	var dsts [graphics.ShaderDstImageCount]*image12
-	for i, srcID := range srcs {
+	var viewports [graphics.ShaderDstImageCount]_D3D12_VIEWPORT
-		src := g.images[srcID]
+	var targetCount int
-		if src == nil {
+	firstTarget := -1
+	for i, id := range dstIDs {
+		img := g.images[id]
+		if img == nil {
 			continue
 		}
-		srcImages[i] = src
+		if firstTarget == -1 {
-		if rb, ok := src.transiteState(_D3D12_RESOURCE_STATE_PIXEL_SHADER_RESOURCE); ok {
+			firstTarget = i
+		}
+		dsts[i] = img
+		w, h := img.internalSize()
+		viewports[i] = _D3D12_VIEWPORT{
+			TopLeftX: 0,
+			TopLeftY: 0,
+			Width:    float32(w),
+			Height:   float32(h),
+			MinDepth: _D3D12_MIN_DEPTH,
+			MaxDepth: _D3D12_MAX_DEPTH,
+		}
+
+		if rb, ok := img.transiteState(_D3D12_RESOURCE_STATE_RENDER_TARGET); ok {
+			resourceBarriers = append(resourceBarriers, rb)
+		}
+
+		targetCount++
+	}
+
+	var srcs [graphics.ShaderSrcImageCount]*image12
+	for i, srcID := range srcIDs {
+		img := g.images[srcID]
+		if img == nil {
+			continue
+		}
+		srcs[i] = img
+		if rb, ok := img.transiteState(_D3D12_RESOURCE_STATE_PIXEL_SHADER_RESOURCE); ok {
 			resourceBarriers = append(resourceBarriers, rb)
 		}
 	}
@@ -1125,25 +1222,26 @@ func (g *graphics12) DrawTriangles(dstIDs [graphics.ShaderDstImageCount]graphics
 		g.drawCommandList.ResourceBarrier(resourceBarriers)
 	}
 
-	if err := dst.setAsRenderTarget(g.drawCommandList, g.device, fillRule != graphicsdriver.FillAll); err != nil {
+	// If the number of targets is more than one, or if the only target is the first one, then
+	// it is safe to assume that MRT is used.
+	// Also, it only matters in order to specify empty targets/viewports when not all slots are
+	// being filled.
+	usesMRT := targetCount > 1 || firstTarget > 0
+	if usesMRT {
+		targetCount = graphics.ShaderDstImageCount
+	}
+
+	g.drawCommandList.RSSetViewports(viewports[:targetCount])
+
+	if err := g.setAsRenderTargets(dsts[:targetCount], fillRule != graphicsdriver.FillAll); err != nil {
 		return err
 	}
 
 	shader := g.shaders[shaderID]
 	adjustedUniforms := adjustUniforms(shader.uniformTypes, shader.uniformOffsets, uniforms)
 
-	w, h := dst.internalSize()
 	g.needFlushDrawCommandList = true
-	g.drawCommandList.RSSetViewports([]_D3D12_VIEWPORT{
+
-		{
-			TopLeftX: 0,
-			TopLeftY: 0,
-			Width:    float32(w),
-			Height:   float32(h),
-			MinDepth: _D3D12_MIN_DEPTH,
-			MaxDepth: _D3D12_MAX_DEPTH,
-		},
-	})
 	g.drawCommandList.IASetPrimitiveTopology(_D3D_PRIMITIVE_TOPOLOGY_TRIANGLELIST)
 	g.drawCommandList.IASetVertexBuffers(0, []_D3D12_VERTEX_BUFFER_VIEW{
 		{
@@ -1158,7 +1256,7 @@ func (g *graphics12) DrawTriangles(dstIDs [graphics.ShaderDstImageCount]graphics
 		Format:         _DXGI_FORMAT_R32_UINT,
 	})
 
-	if err := g.pipelineStates.drawTriangles(g.device, g.drawCommandList, g.frameIndex, dst.screen, srcImages, shader, dstRegions, adjustedUniforms, blend, indexOffset, fillRule); err != nil {
+	if err := g.pipelineStates.drawTriangles(g.device, g.drawCommandList, g.frameIndex, !usesMRT && dsts[firstTarget].screen, srcs, shader, dstRegions, adjustedUniforms, blend, indexOffset, fillRule); err != nil {
 		return err
 	}
 

internal/graphicsdriver/directx/pipeline12_windows.go

@@ -510,6 +510,90 @@ func (p *pipelineStates) newPipelineState(device *_ID3D12Device, vsh, psh *_ID3D
 					LogicOp:               _D3D12_LOGIC_OP_NOOP,
 					RenderTargetWriteMask: writeMask,
 				},
+				{
+					BlendEnable:           1,
+					LogicOpEnable:         0,
+					SrcBlend:              blendFactorToBlend12(blend.BlendFactorSourceRGB, false),
+					DestBlend:             blendFactorToBlend12(blend.BlendFactorDestinationRGB, false),
+					BlendOp:               blendOperationToBlendOp12(blend.BlendOperationRGB),
+					SrcBlendAlpha:         blendFactorToBlend12(blend.BlendFactorSourceAlpha, true),
+					DestBlendAlpha:        blendFactorToBlend12(blend.BlendFactorDestinationAlpha, true),
+					BlendOpAlpha:          blendOperationToBlendOp12(blend.BlendOperationAlpha),
+					LogicOp:               _D3D12_LOGIC_OP_NOOP,
+					RenderTargetWriteMask: writeMask,
+				},
+				{
+					BlendEnable:           1,
+					LogicOpEnable:         0,
+					SrcBlend:              blendFactorToBlend12(blend.BlendFactorSourceRGB, false),
+					DestBlend:             blendFactorToBlend12(blend.BlendFactorDestinationRGB, false),
+					BlendOp:               blendOperationToBlendOp12(blend.BlendOperationRGB),
+					SrcBlendAlpha:         blendFactorToBlend12(blend.BlendFactorSourceAlpha, true),
+					DestBlendAlpha:        blendFactorToBlend12(blend.BlendFactorDestinationAlpha, true),
+					BlendOpAlpha:          blendOperationToBlendOp12(blend.BlendOperationAlpha),
+					LogicOp:               _D3D12_LOGIC_OP_NOOP,
+					RenderTargetWriteMask: writeMask,
+				},
+				{
+					BlendEnable:           1,
+					LogicOpEnable:         0,
+					SrcBlend:              blendFactorToBlend12(blend.BlendFactorSourceRGB, false),
+					DestBlend:             blendFactorToBlend12(blend.BlendFactorDestinationRGB, false),
+					BlendOp:               blendOperationToBlendOp12(blend.BlendOperationRGB),
+					SrcBlendAlpha:         blendFactorToBlend12(blend.BlendFactorSourceAlpha, true),
+					DestBlendAlpha:        blendFactorToBlend12(blend.BlendFactorDestinationAlpha, true),
+					BlendOpAlpha:          blendOperationToBlendOp12(blend.BlendOperationAlpha),
+					LogicOp:               _D3D12_LOGIC_OP_NOOP,
+					RenderTargetWriteMask: writeMask,
+				},
+				{
+					BlendEnable:           1,
+					LogicOpEnable:         0,
+					SrcBlend:              blendFactorToBlend12(blend.BlendFactorSourceRGB, false),
+					DestBlend:             blendFactorToBlend12(blend.BlendFactorDestinationRGB, false),
+					BlendOp:               blendOperationToBlendOp12(blend.BlendOperationRGB),
+					SrcBlendAlpha:         blendFactorToBlend12(blend.BlendFactorSourceAlpha, true),
+					DestBlendAlpha:        blendFactorToBlend12(blend.BlendFactorDestinationAlpha, true),
+					BlendOpAlpha:          blendOperationToBlendOp12(blend.BlendOperationAlpha),
+					LogicOp:               _D3D12_LOGIC_OP_NOOP,
+					RenderTargetWriteMask: writeMask,
+				},
+				{
+					BlendEnable:           1,
+					LogicOpEnable:         0,
+					SrcBlend:              blendFactorToBlend12(blend.BlendFactorSourceRGB, false),
+					DestBlend:             blendFactorToBlend12(blend.BlendFactorDestinationRGB, false),
+					BlendOp:               blendOperationToBlendOp12(blend.BlendOperationRGB),
+					SrcBlendAlpha:         blendFactorToBlend12(blend.BlendFactorSourceAlpha, true),
+					DestBlendAlpha:        blendFactorToBlend12(blend.BlendFactorDestinationAlpha, true),
+					BlendOpAlpha:          blendOperationToBlendOp12(blend.BlendOperationAlpha),
+					LogicOp:               _D3D12_LOGIC_OP_NOOP,
+					RenderTargetWriteMask: writeMask,
+				},
+				{
+					BlendEnable:           1,
+					LogicOpEnable:         0,
+					SrcBlend:              blendFactorToBlend12(blend.BlendFactorSourceRGB, false),
+					DestBlend:             blendFactorToBlend12(blend.BlendFactorDestinationRGB, false),
+					BlendOp:               blendOperationToBlendOp12(blend.BlendOperationRGB),
+					SrcBlendAlpha:         blendFactorToBlend12(blend.BlendFactorSourceAlpha, true),
+					DestBlendAlpha:        blendFactorToBlend12(blend.BlendFactorDestinationAlpha, true),
+					BlendOpAlpha:          blendOperationToBlendOp12(blend.BlendOperationAlpha),
+					LogicOp:               _D3D12_LOGIC_OP_NOOP,
+					RenderTargetWriteMask: writeMask,
+				},
+				{
+					BlendEnable:           1,
+					LogicOpEnable:         0,
+					SrcBlend:              blendFactorToBlend12(blend.BlendFactorSourceRGB, false),
+					DestBlend:             blendFactorToBlend12(blend.BlendFactorDestinationRGB, false),
+					BlendOp:               blendOperationToBlendOp12(blend.BlendOperationRGB),
+					SrcBlendAlpha:         blendFactorToBlend12(blend.BlendFactorSourceAlpha, true),
+					DestBlendAlpha:        blendFactorToBlend12(blend.BlendFactorDestinationAlpha, true),
+					BlendOpAlpha:          blendOperationToBlendOp12(blend.BlendOperationAlpha),
+					LogicOp:               _D3D12_LOGIC_OP_NOOP,
+					RenderTargetWriteMask: writeMask,
+				},
 			},
 		},
 		SampleMask: math.MaxUint32,
@@ -532,9 +616,10 @@ func (p *pipelineStates) newPipelineState(device *_ID3D12Device, vsh, psh *_ID3D
 			NumElements:        uint32(len(inputElementDescsForDX12)),
 		},
 		PrimitiveTopologyType: _D3D12_PRIMITIVE_TOPOLOGY_TYPE_TRIANGLE,
-		NumRenderTargets:      1,
+		NumRenderTargets:      graphics.ShaderDstImageCount,
 		RTVFormats: [8]_DXGI_FORMAT{
-			rtvFormat,
+			rtvFormat, rtvFormat, rtvFormat, rtvFormat,
+			rtvFormat, rtvFormat, rtvFormat, rtvFormat,
 		},
 		DSVFormat: dsvFormat,
 		SampleDesc: _DXGI_SAMPLE_DESC{