I originally posted this question on stack overflow, but realised it might be better here. The original question can be found here

I'm using SlimDX, targeting DirectX 11 with shader model 4. I have a pixel shader "preProc" which processes my vertices and saves three textures of data. One for per-pixel normals, one for per-pixel position data and one for color (which I'm currently setting as black).

I then later use these textures in a postprocessing shader in order to implement Screen Space Ambient Occlusion, however it seems none of the data is getting saved in the first shader.

Here's my pixel shader:

PS_OUT PS( PS_IN input )
    PS_OUT output;
    output.col = float4(0,0,0,0);
    output.norm = float4(input.norm,1);
    output.pos = input.pos;
    return output;

which outputs the following struct:

struct PS_OUT
    float4 col : SV_TARGET0;
    float4 norm : SV_TARGET1;
    float4 pos : SV_TARGET2;

and takes the following struct for input:

struct PS_IN
    float4 pos : SV_POSITION;
    float2 tex : TEXCOORD0;
    float3 norm : TEXCOORD1;

My post processing shader simply outputs the colour I set in my preShader, which should be black. However when I run the code I get a light blue, which is the colour I reset my render targets to when I clear them. If I change the pixelshader to instead sample the randomTex texture (which my code previously loaded from a file and is not from a render target) everything is rendered fine, so I am confident it is not my post processing shader.

In case it's my slimDX code that's failing here's what I do:

Creating my textures, shaderresourvecviews and rendertargetviews:

Texture2DDescription textureDescription = new Texture2DDescription()
                    SampleDescription = new SlimDX.DXGI.SampleDescription(1,0),
                    BindFlags = BindFlags.RenderTarget | BindFlags.ShaderResource,
                    CpuAccessFlags= CpuAccessFlags.None,
                    OptionFlags = ResourceOptionFlags.None,
                    Usage= ResourceUsage.Default,
            texture = new Texture2D(device, textureDescription);

            renderTargetView = new RenderTargetView[3];
            shaderResourceView = new ShaderResourceView[3];

            for (int i = 0; i < 3; i++)
                RenderTargetViewDescription renderTargetViewDescription = new RenderTargetViewDescription()
                        Format = textureDescription.Format,
                        Dimension = RenderTargetViewDimension.Texture2D,
                        MipSlice = 0,

                renderTargetView[i] = new RenderTargetView(device, texture, renderTargetViewDescription);

                ShaderResourceViewDescription shaderResourceViewDescription = new ShaderResourceViewDescription()
                        Format = textureDescription.Format,
                        Dimension = ShaderResourceViewDimension.Texture2D,
                        MostDetailedMip = 0,
                        MipLevels = 1

                shaderResourceView[i] = new ShaderResourceView(device, texture, shaderResourceViewDescription);

Rendering to my multiple render targets:

private void renderToTexture(Shader shader)
        //set the vertex and pixel shaders

        //send texture data and a linear sampler to the shader
        context.PixelShader.SetShaderResource(texture, 0);
        context.PixelShader.SetSampler(samplerState, 0);

        //set the input assembler

        //reset the camera's constant buffer

        //set the render targets to the textures we will render to
        context.OutputMerger.SetTargets(depthStencilView, renderTargetViews);
        //clear the render targets and depth stencil
        foreach (RenderTargetView view in renderTargetViews)
             context.ClearRenderTargetView(view, color);
        context.ClearDepthStencilView(depthStencilView, DepthStencilClearFlags.Depth, 1.0f, 0);
            //draw the scene


and then the function when I render my postProcessing shader to the screen:

private void renderTexture(Shader shader)
            //get a single quad to be the screen we render
            Mesh mesh = CreateScreenFace();
            //set vertex and pixel shaders
            //set the input assembler
            //point the render target to the screen
            context.OutputMerger.SetTargets(depthStencil, renderTarget);
            //send the rendered textures and a linear sampler to the shader
                context.PixelShader.SetShaderResource(renderTargetViews[0], 1);
            context.PixelShader.SetShaderResource(renderTargetViews[1], 2);
            context.PixelShader.SetShaderResource(renderTargetViews[2], 3);
            context.PixelShader.SetShaderResource(random, 4);
            context.PixelShader.SetSampler(samplerState, 0);
            //clear the render targets and depth stencils
            context.ClearRenderTargetView(renderTarget, new Color4(0.52734375f, 0.8046875f, 0.9765625f));
            context.ClearDepthStencilView(depthStencil, DepthStencilClearFlags.Depth, 1, 0);
            //set the vertex and index buffers from the quad
            context.InputAssembler.SetVertexBuffers(0, new VertexBufferBinding(mesh.VertexBuffer, Marshal.SizeOf(typeof(Vertex)), 0));
            context.InputAssembler.SetIndexBuffer(mesh.IndexBuffer, Format.R16_UInt, 0);
            //draw the quad
            context.DrawIndexed(mesh.indices, 0, 0);
            //dispose of the buffers

This is the PIX function call output for a single frame of the current run:

Frame 40
<0x06BDA1D8> ID3D11DeviceContext::ClearRenderTargetView(0x06B66190, 0x0028F068)
<0x06BDA1D8> ID3D11DeviceContext::ClearDepthStencilView(0x06B66138, 1, 1.000f, 0)
<0x0059FF78> ID3D11Device::CreateBuffer(0x0028F010, 0x0028EFF8, 0x0028F00C --> 0x06BF8EE0)
CreateObject(D3D11 Buffer, 0x06BF8EE0)
<0x06BDA1D8> ID3D11DeviceContext::PSSetConstantBuffers(0, 1, 0x0028F084 --> { 0x06BF8EE0 })
<0x0059FF78> ID3D11Device::CreateBuffer(0x0F8DEB58, 0x0F8DEB40, 0x0F8DEB54 --> 0x06BF8F68)
CreateObject(D3D11 Buffer, 0x06BF8F68)
<0x0059FF78> ID3D11Device::CreateBuffer(0x0F70EAD8, 0x0F70EAC0, 0x0F70EAD4 --> 0x06BF8FF0)
CreateObject(D3D11 Buffer, 0x06BF8FF0)
<0x0059FF78> ID3D11Device::CreateBuffer(0x0FAAE9A8, 0x0FAAE990, 0x0FAAE9A4 --> 0x06BF9078)
CreateObject(D3D11 Buffer, 0x06BF9078)
<0x0059FF78> ID3D11Device::GetImmediateContext(0x06BDA1D8 --> 0x5BA8A8D8)
<0x0059FF78> ID3D11Device::CreateBuffer(0x0F8DEB58, 0x0F8DEB40, 0x0F8DEB54 --> 0x06BF9100)
CreateObject(D3D11 Buffer, 0x06BF9100)
<0x0059FF78> ID3D11Device::CreateBuffer(0x0F70EAD8, 0x0F70EAC0, 0x0F70EAD4 --> 0x06BF9188)
CreateObject(D3D11 Buffer, 0x06BF9188)
<0x06BDA1D8> ID3D11DeviceContext::Release()
<0x06BDA1D8> ID3D11DeviceContext::UpdateSubresource(0x06B59270, 0, NULL, 0x06287FA0, 0, 0)
<0x0059FF78> ID3D11Device::CreateBuffer(0x0FAAE9A8, 0x0FAAE990, 0x0FAAE9A4 --> 0x06BF9210)
CreateObject(D3D11 Buffer, 0x06BF9210)
<0x06BDA1D8> ID3D11DeviceContext::VSSetShader(0x06B66298, NULL, 0)
<0x0059FF78> ID3D11Device::CreateBuffer(0x0FC0E978, 0x0FC0E960, 0x0FC0E974 --> 0x06BF9298)
CreateObject(D3D11 Buffer, 0x06BF9298)
<0x0059FF78> ID3D11Device::CreateBuffer(0x0FE8EDE8, 0x0FE8EDD0, 0x0FE8EDE4 --> 0x06BF9320)
CreateObject(D3D11 Buffer, 0x06BF9320)
<0x06BDA1D8> ID3D11DeviceContext::PSSetShader(0x06B666F8, NULL, 0)
<0x0059FF78> ID3D11Device::CreateBuffer(0x0FC0E978, 0x0FC0E960, 0x0FC0E974 --> 0x06BF93A8)
CreateObject(D3D11 Buffer, 0x06BF93A8)
<0x0059FF78> ID3D11Device::CreateBuffer(0x0FE8EDE8, 0x0FE8EDD0, 0x0FE8EDE4 --> 0x06BF9430)
CreateObject(D3D11 Buffer, 0x06BF9430)
<0x0059FF78> ID3D11Device::CreateInputLayout(0x0028EBE0, 3, 0x06286CB8, 152, 0x0028EBD8 --> 0x06BF9D68)
CreateObject(D3D11 Input Layout, 0x06BF9D68)
<0x06BDA1D8> ID3D11DeviceContext::IASetInputLayout(0x06BF9D68)
<0x06BDA1D8> ID3D11DeviceContext::IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST)
<0x0059FF78> ID3D11Device::GetImmediateContext(0x06BDA1D8 --> 0x5BA8A8D8)
<0x06BDA1D8> ID3D11DeviceContext::Release()
<0x06BDA1D8> ID3D11DeviceContext::VSSetConstantBuffers(0, 1, 0x0028F024 --> { 0x06B59270 })
<0x06BDA1D8> ID3D11DeviceContext::OMSetRenderTargets(3, 0x0028F004 --> { 0x06B65708, 0x06B657B8, 0x06B582E0 }, 0x06B66138)
<0x06BDA1D8> ID3D11DeviceContext::ClearRenderTargetView(0x06B65708, 0x0028EFEC)
<0x06BDA1D8> ID3D11DeviceContext::ClearRenderTargetView(0x06B657B8, 0x0028EFEC)
<0x06BDA1D8> ID3D11DeviceContext::ClearRenderTargetView(0x06B582E0, 0x0028EFEC)
<0x06BDA1D8> ID3D11DeviceContext::ClearDepthStencilView(0x06B66138, 1, 1.000f, 0)
//draw scene for preproc shader (this should output the three render targets)
<0x0059FF78> ID3D11Device::CreateBuffer(0x0028EE04, 0x0028EDEC, 0x0028EE00 --> 0x06BF94B8)
CreateObject(D3D11 Buffer, 0x06BF94B8)
<0x0059FF78> ID3D11Device::CreateBuffer(0x0028EE04, 0x0028EDEC, 0x0028EE00 --> 0x06BF9540)
CreateObject(D3D11 Buffer, 0x06BF9540)
<0x06BDA1D8> ID3D11DeviceContext::VSSetShader(0x06B66BB8, NULL, 0)
<0x06BDA1D8> ID3D11DeviceContext::PSSetShader(0x06B66E50, NULL, 0)
<0x0059FF78> ID3D11Device::CreateInputLayout(0x0028EB64, 3, 0x05E988E0, 120, 0x0028EB5C --> 0x06BF9E28)
CreateObject(D3D11 Input Layout, 0x06BF9E28)
<0x06BDA1D8> ID3D11DeviceContext::IASetInputLayout(0x06BF9E28)
<0x06BDA1D8> ID3D11DeviceContext::IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST)
<0x06BDA1D8> ID3D11DeviceContext::OMSetRenderTargets(1, 0x0028EFC0 --> { 0x06B66190 }, 0x06B66138)
<0x06BDA1D8> ID3D11DeviceContext::PSSetShaderResources(1, 3, 0x0028EF3C --> { 0x06B65760, 0x06B58288, 0x06B58338 })
<0x06BDA1D8> ID3D11DeviceContext::PSSetShaderResources(4, 1, 0x0028EFC0 --> { 0x06B66FA0 })
<0x06BDA1D8> ID3D11DeviceContext::ClearRenderTargetView(0x06B66190, 0x0028EFA4)
<0x06BDA1D8> ID3D11DeviceContext::ClearDepthStencilView(0x06B66138, 1, 1.000f, 0)
<0x06BDA1D8> ID3D11DeviceContext::IASetVertexBuffers(0, 1, 0x0028EFAC --> { 0x06BF94B8 }, 0x0028EFB0, 0x0028EFB4)
<0x06BDA1D8> ID3D11DeviceContext::IASetIndexBuffer(0x06BF9540, DXGI_FORMAT_R16_UINT, 0)
//draw quad for post proc shader. This shader takes the three textures in, as well as a random texture, which is added in the second PSSetShaderResources call. The random texture outputs fine.
<0x06BDA1D8> ID3D11DeviceContext::DrawIndexed(6, 0, 0)
<0x06BF94B8> ID3D11Buffer::Release()
<0x06BF9540> ID3D11Buffer::Release()
<0x06B65B00> IDXGISwapChain::Present(0, 0)

EDIT: I've been doing some reading and perhaps I need to deallocate the textures as render targets after the preProc pass before I pass them in as ShaderResourceViews to my postProcess shader. I assumed calling context.OutputMerger.SetTargets() would deallocate all of the currently assigned render targets and then assign only the render targets specified in the function's parameters. If this isn't the case (I can't yet be sure if it is or isn't), then how would I go about unassigning the render targets in SlimDX?

EDIT2: Ah, according to this MSDN page, calling OutputMerger.SetRenderTargets() "overrides all bounded render targets and the depth stencil target regardless of the number of render targets in ppRenderTargetViews." so all of my render targets are getting deallocated automatically when I tell the OutputMerger to render to the screen. This leaves me back to square one.


1 Answer 1


Fixed it by discovering just how silly I am.

When I create my rendertarget I create a Texture2DArray but I'm treating it like an array of Texture2D objects, instead of one object. I have since altered my code to use an array of Texture2D objects and it works very well.

  • \$\begingroup\$ Would love to, but StackExchange mandates a 24 hour waiting period. \$\endgroup\$
    – Nick Udell
    Aug 2, 2011 at 13:16
  • \$\begingroup\$ Oki doke! Good find anyway, weird you weren't getting any other errors or warnings. \$\endgroup\$ Aug 2, 2011 at 13:22
  • \$\begingroup\$ Yes, I'm concerned I've accidentally turned off all debugging as I'm getting some weird results now \$\endgroup\$
    – Nick Udell
    Aug 2, 2011 at 13:28

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