Cannot draw primitives with SharpDX on Windows 10 Universal App (but still able to clear the background)

Question

Sorry because of my bad English. I am trying to write a very simple DirectX 11 on Windows 10 app with SharpDX, which draws a triangle at the middle of the windows. The problem is the triangle is not displayed while I can still change the background color (using ClearRenderTargetView). I verified that the render function is called periodically and my triangle is front-face (clockwise). What I have tried:

Disable back-face culling
Set static width and height
Try other primitives (line, triangle strip)
Change vertex shader input from float3 to float4 and vice-versa

I found that this post has very similar symptoms but still not work!

I have posted my code on GitHub at: https://github.com/minhcly/UWP3DTest

Here is my initialization code (where I think the problem resides):

    D3D11.Device2 device;
    D3D11.DeviceContext deviceContext;
    DXGI.SwapChain2 swapChain;
    D3D11.Texture2D backBufferTexture;
    D3D11.RenderTargetView backBufferView;

    private void InitializeD3D()
    {
        using (D3D11.Device defaultDevice = new D3D11.Device(D3D.DriverType.Hardware, D3D11.DeviceCreationFlags.Debug))
            this.device = defaultDevice.QueryInterface<D3D11.Device2>();
        this.deviceContext = this.device.ImmediateContext2;

        DXGI.SwapChainDescription1 swapChainDescription = new DXGI.SwapChainDescription1()
        {
            AlphaMode = DXGI.AlphaMode.Ignore,
            BufferCount = 2,
            Format = DXGI.Format.R8G8B8A8_UNorm,
            Height = (int)(this.swapChainPanel.RenderSize.Height),
            Width = (int)(this.swapChainPanel.RenderSize.Width),
            SampleDescription = new DXGI.SampleDescription(1, 0),
            Scaling = SharpDX.DXGI.Scaling.Stretch,
            Stereo = false,
            SwapEffect = DXGI.SwapEffect.FlipSequential,
            Usage = DXGI.Usage.RenderTargetOutput
        };

        using (DXGI.Device3 dxgiDevice3 = this.device.QueryInterface<DXGI.Device3>())
        using (DXGI.Factory3 dxgiFactory3 = dxgiDevice3.Adapter.GetParent<DXGI.Factory3>())
        {
            DXGI.SwapChain1 swapChain1 = new DXGI.SwapChain1(dxgiFactory3, this.device, ref swapChainDescription);
            this.swapChain = swapChain1.QueryInterface<DXGI.SwapChain2>();
        }

        using (DXGI.ISwapChainPanelNative nativeObject = ComObject.As<DXGI.ISwapChainPanelNative>(this.swapChainPanel))
            nativeObject.SwapChain = this.swapChain;

        this.backBufferTexture = this.swapChain.GetBackBuffer<D3D11.Texture2D>(0);
        this.backBufferView = new D3D11.RenderTargetView(this.device, this.backBufferTexture);
        this.deviceContext.OutputMerger.SetRenderTargets(this.backBufferView);

        deviceContext.Rasterizer.State = new D3D11.RasterizerState(device, new D3D11.RasterizerStateDescription()
        {
            CullMode = D3D11.CullMode.None,
            FillMode = D3D11.FillMode.Solid,
            IsMultisampleEnabled = true
        });
        deviceContext.Rasterizer.SetViewport(0, 0, (int)swapChainPanel.Width, (int)swapChainPanel.Height);

        CompositionTarget.Rendering += CompositionTarget_Rendering;
        Application.Current.Suspending += Current_Suspending;

        isDXInitialized = true;
    }

InitScene() function:

    D3D11.Buffer triangleVertBuffer;
    D3D11.VertexShader vs;
    D3D11.PixelShader ps;
    D3D11.InputLayout vertLayout;
    RawVector3[] verts;

    private void InitScene()
    {
        D3D11.InputElement[] inputElements = new D3D11.InputElement[]
        {
            new D3D11.InputElement("POSITION", 0, DXGI.Format.R32G32B32_Float, 0)
        };

        using (CompilationResult vsResult = ShaderBytecode.CompileFromFile("vs.hlsl", "main", "vs_4_0"))
        {
            vs = new D3D11.VertexShader(device, vsResult.Bytecode.Data);
            vertLayout = new D3D11.InputLayout(device, vsResult.Bytecode, inputElements);
        }

        using (CompilationResult psResult = ShaderBytecode.CompileFromFile("ps.hlsl", "main", "ps_4_0"))
            ps = new D3D11.PixelShader(device, psResult.Bytecode.Data);

        deviceContext.VertexShader.Set(vs);
        deviceContext.PixelShader.Set(ps);

        verts = new RawVector3[] {
            new RawVector3( 0.0f, 0.5f, 0.5f ),
            new RawVector3( 0.5f, -0.5f, 0.5f ),
            new RawVector3( -0.5f, -0.5f, 0.5f )
        };
        triangleVertBuffer = D3D11.Buffer.Create(device, D3D11.BindFlags.VertexBuffer, verts);

        deviceContext.InputAssembler.InputLayout = vertLayout;
        deviceContext.InputAssembler.PrimitiveTopology = D3D.PrimitiveTopology.TriangleList;
    }

Render function:

    private void RenderScene()
    {
        this.deviceContext.ClearRenderTargetView(this.backBufferView, new RawColor4(red, green, blue, 0));

        deviceContext.InputAssembler.SetVertexBuffers(0,
            new D3D11.VertexBufferBinding(triangleVertBuffer, Utilities.SizeOf<RawVector3>(), 0));
        deviceContext.Draw(verts.Length, 0);

        this.swapChain.Present(0, DXGI.PresentFlags.None);
    }

Thank you for your help.

minhcly minhcly · Accepted Answer · 2016-07-30T04:18:20

I have solved the problem. I have used the Graphics Debugger in Visual Studio and detect that the OutputMerger has no RenderTarget. So I move the line

this.deviceContext.OutputMerger.SetRenderTargets(this.backBufferView);

to the RenderScene() function and it works. However, I can't understand why I must reset this every frame. I'm new in Direct3D so if any one has an anwswer, please comment. Thank you.

P/s: I have committed the working project on the GitHub for anyone who encounters the same problem with me.

Cannot draw primitives with SharpDX on Windows 10 Universal App (but still able to clear the background)

1 Answers