• Advertisement
Sign in to follow this  

DX11 [SharpDX] Understanding DX11 blend states

This topic is 1748 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

In dx9, the blend state was fairly simple. In dx11, it's a lot more complicated and I'm having trouble understanding how I need to have it set. I have a small app that is supposed to draw several instances of tessellated bezier triangles, and even though I have the pixel shader set to just paint one color, I'm not seeing that color on my screen at all. I've looked at my app with PIX (I use VS 2012 Express so it's my only debugging option for now.) and my vertex buffers seem to be doing what they are supposed to.

 

Right now I'm wondering about the blend state because I don't fully understand it. Here is how I have it set in my render method:

 

            RenderTargetBlendDescription rendBlendDesc = new RenderTargetBlendDescription();
            rendBlendDesc.SourceAlphaBlend = BlendOption.One;
            rendBlendDesc.DestinationAlphaBlend = BlendOption.Zero;
            rendBlendDesc.BlendOperation = BlendOperation.Add;
            rendBlendDesc.SourceBlend = BlendOption.One;
            rendBlendDesc.DestinationBlend = BlendOption.Zero;

            BlendStateDescription blendDesc = new BlendStateDescription();
            blendDesc.AlphaToCoverageEnable = false;
            blendDesc.IndependentBlendEnable = false;
            blendDesc.RenderTarget[0] = rendBlendDesc;

            BlendState blendState = new BlendState(Game.GraphicsDevice, blendDesc);
            Game.GraphicsDevice.ImmediateContext.OutputMerger.SetBlendState(blendState);

 

Do you see anything here that would prevent drawing from being visible?

Share this post


Link to post
Share on other sites
Advertisement

Your blend state will result in the pixel shader value being written to the render target(s), and completely overwriting any existing contents of the render target. This is pretty standard for rendering without any blending. If you're not seeing your primitives, then the problem is probably somewhere else.

I would recommend enabling device debug messages if you haven't already, and checking for any warning or messages. Pass the "Debug" flag when creating your device to specify that you want messages, and then enable native debugging for your project. You should then get messages in your debugger output window. If you're using an express version of VS or you don't want to turn on native debugging, you can use a program like DebugView to view the native debugger output stream.

Share this post


Link to post
Share on other sites

I used to use DebugView for my dx9 stuff and it was very useful. This time though I'm not seeing any warnings in the DebugView window even though I have created my device with the debug option. Does dx11 have a messaging level like dx9 had? I haven't used DebugView for a couple of years, and I can't remember all the steps necessary to capture messages from my app.

Share this post


Link to post
Share on other sites

Do you see the triangles without this blending turned on?
If not, then 2 quick tips: forgot to transpose the viewprojection matrix, or forgot to set some constant buffer to the proper shaders. At least those are my main 2 sources of pain nowadays. rolleyes.gif

You can turn on dx debug in sdk->utilities->Directx control panel, if you haven't already. I got some usefull info about not setting the proper patch type for my hull shader, which made the driver reset, so it can be usefull,but not a magic bullet.

Share this post


Link to post
Share on other sites

I used to use DebugView for my dx9 stuff and it was very useful. This time though I'm not seeing any warnings in the DebugView window even though I have created my device with the debug option. Does dx11 have a messaging level like dx9 had? I haven't used DebugView for a couple of years, and I can't remember all the steps necessary to capture messages from my app.


There's not really a "message level" anymore. There's functionality to filter out certain warnings/errors using the ID3D11InfoQueue interface, but by default you get all possible warnings and errors.

If you're not getting any messages, then it's possible you're not causing any errors or warnings. To find out for sure, you could try to deliberately cause an error by passing an incorrect parameter to a function, or something like that.

Share this post


Link to post
Share on other sites

You will be able to see D3D11 messages directly from the output window if you check "Enable native code debugging" in the Project Properties/Debug tab (you need to use the debugger to see the messages) otherwise DebugView is still an option.

Share this post


Link to post
Share on other sites

Thanks everyone, of course things are made worse by the fact that I have to stick with express version of VS for now. Very hard to learn dx11 with express.

Share this post


Link to post
Share on other sites

You will be able to see D3D11 messages directly from the output window if you check "Enable native code debugging" in the Project Properties/Debug tab (you need to use the debugger to see the messages) otherwise DebugView is still an option.

 Oh my gosh! This is working with express! Somebody told me it wouldn't. Now I have about 100 pages of warnings to examine. Thanks!

Share this post


Link to post
Share on other sites

I'm not sure how easy it would be to interface with that API from C# though, as the SharpDX implementation looks incomplete.

It is not incomplete, the class is marked as "partial" so the other part of the code is generated at built time by the DirectX C++ to C# code generator used in SharpDX.

 

Edit: Though there are here some NotImplementedException for GetStorageFilter/GetRetrievalFilter, will have to double check :D

Edited by xoofx

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
  • Advertisement
  • Popular Now

  • Advertisement
  • Similar Content

    • By AxeGuywithanAxe
      I wanted to see how others are currently handling descriptor heap updates and management.
      I've read a few articles and there tends to be three major strategies :
      1 ) You split up descriptor heaps per shader stage ( i.e one for vertex shader , pixel , hull, etc)
      2) You have one descriptor heap for an entire pipeline
      3) You split up descriptor heaps for update each update frequency (i.e EResourceSet_PerInstance , EResourceSet_PerPass , EResourceSet_PerMaterial, etc)
      The benefits of the first two approaches is that it makes it easier to port current code, and descriptor / resource descriptor management and updating tends to be easier to manage, but it seems to be not as efficient.
      The benefits of the third approach seems to be that it's the most efficient because you only manage and update objects when they change.
    • By evelyn4you
      hi,
      until now i use typical vertexshader approach for skinning with a Constantbuffer containing the transform matrix for the bones and an the vertexbuffer containing bone index and bone weight.
      Now i have implemented realtime environment  probe cubemaping so i have to render my scene from many point of views and the time for skinning takes too long because it is recalculated for every side of the cubemap.
      For Info i am working on Win7 an therefore use one Shadermodel 5.0 not 5.x that have more options, or is there a way to use 5.x in Win 7
      My Graphic Card is Directx 12 compatible NVidia GTX 960
      the member turanszkij has posted a good for me understandable compute shader. ( for Info: in his engine he uses an optimized version of it )
      https://turanszkij.wordpress.com/2017/09/09/skinning-in-compute-shader/
      Now my questions
       is it possible to feed the compute shader with my orignial vertexbuffer or do i have to copy it in several ByteAdressBuffers as implemented in the following code ?
        the same question is about the constant buffer of the matrixes
       my more urgent question is how do i feed my normal pipeline with the result of the compute Shader which are 2 RWByteAddressBuffers that contain position an normal
      for example i could use 2 vertexbuffer bindings
      1 containing only the uv coordinates
      2.containing position and normal
      How do i copy from the RWByteAddressBuffers to the vertexbuffer ?
       
      (Code from turanszkij )
      Here is my shader implementation for skinning a mesh in a compute shader:
      1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 struct Bone { float4x4 pose; }; StructuredBuffer<Bone> boneBuffer;   ByteAddressBuffer vertexBuffer_POS; // T-Pose pos ByteAddressBuffer vertexBuffer_NOR; // T-Pose normal ByteAddressBuffer vertexBuffer_WEI; // bone weights ByteAddressBuffer vertexBuffer_BON; // bone indices   RWByteAddressBuffer streamoutBuffer_POS; // skinned pos RWByteAddressBuffer streamoutBuffer_NOR; // skinned normal RWByteAddressBuffer streamoutBuffer_PRE; // previous frame skinned pos   inline void Skinning(inout float4 pos, inout float4 nor, in float4 inBon, in float4 inWei) {  float4 p = 0, pp = 0;  float3 n = 0;  float4x4 m;  float3x3 m3;  float weisum = 0;   // force loop to reduce register pressure  // though this way we can not interleave TEX - ALU operations  [loop]  for (uint i = 0; ((i &lt; 4) &amp;&amp; (weisum&lt;1.0f)); ++i)  {  m = boneBuffer[(uint)inBon].pose;  m3 = (float3x3)m;   p += mul(float4(pos.xyz, 1), m)*inWei;  n += mul(nor.xyz, m3)*inWei;   weisum += inWei;  }   bool w = any(inWei);  pos.xyz = w ? p.xyz : pos.xyz;  nor.xyz = w ? n : nor.xyz; }   [numthreads(1024, 1, 1)] void main( uint3 DTid : SV_DispatchThreadID ) {  const uint fetchAddress = DTid.x * 16; // stride is 16 bytes for each vertex buffer now...   uint4 pos_u = vertexBuffer_POS.Load4(fetchAddress);  uint4 nor_u = vertexBuffer_NOR.Load4(fetchAddress);  uint4 wei_u = vertexBuffer_WEI.Load4(fetchAddress);  uint4 bon_u = vertexBuffer_BON.Load4(fetchAddress);   float4 pos = asfloat(pos_u);  float4 nor = asfloat(nor_u);  float4 wei = asfloat(wei_u);  float4 bon = asfloat(bon_u);   Skinning(pos, nor, bon, wei);   pos_u = asuint(pos);  nor_u = asuint(nor);   // copy prev frame current pos to current frame prev pos streamoutBuffer_PRE.Store4(fetchAddress, streamoutBuffer_POS.Load4(fetchAddress)); // write out skinned props:  streamoutBuffer_POS.Store4(fetchAddress, pos_u);  streamoutBuffer_NOR.Store4(fetchAddress, nor_u); }  
    • By mister345
      Hi, can someone please explain why this is giving an assertion EyePosition!=0 exception?
       
      _lightBufferVS->viewMatrix = DirectX::XMMatrixLookAtLH(XMLoadFloat3(&_lightBufferVS->position), XMLoadFloat3(&_lookAt), XMLoadFloat3(&up));
      It looks like DirectX doesnt want the 2nd parameter to be a zero vector in the assertion, but I passed in a zero vector with this exact same code in another program and it ran just fine. (Here is the version of the code that worked - note XMLoadFloat3(&m_lookAt) parameter value is (0,0,0) at runtime - I debugged it - but it throws no exceptions.
          m_viewMatrix = DirectX::XMMatrixLookAtLH(XMLoadFloat3(&m_position), XMLoadFloat3(&m_lookAt), XMLoadFloat3(&up)); Here is the repo for the broken code (See LightClass) https://github.com/mister51213/DirectX11Engine/blob/master/DirectX11Engine/LightClass.cpp
      and here is the repo with the alternative version of the code that is working with a value of (0,0,0) for the second parameter.
      https://github.com/mister51213/DX11Port_SoftShadows/blob/master/Engine/lightclass.cpp
    • By mister345
      Hi, can somebody please tell me in clear simple steps how to debug and step through an hlsl shader file?
      I already did Debug > Start Graphics Debugging > then captured some frames from Visual Studio and
      double clicked on the frame to open it, but no idea where to go from there.
       
      I've been searching for hours and there's no information on this, not even on the Microsoft Website!
      They say "open the  Graphics Pixel History window" but there is no such window!
      Then they say, in the "Pipeline Stages choose Start Debugging"  but the Start Debugging option is nowhere to be found in the whole interface.
      Also, how do I even open the hlsl file that I want to set a break point in from inside the Graphics Debugger?
       
      All I want to do is set a break point in a specific hlsl file, step thru it, and see the data, but this is so unbelievably complicated
      and Microsoft's instructions are horrible! Somebody please, please help.
       
       
       

    • By mister345
      I finally ported Rastertek's tutorial # 42 on soft shadows and blur shading. This tutorial has a ton of really useful effects and there's no working version anywhere online.
      Unfortunately it just draws a black screen. Not sure what's causing it. I'm guessing the camera or ortho matrix transforms are wrong, light directions, or maybe texture resources not being properly initialized.  I didnt change any of the variables though, only upgraded all types and functions DirectX3DVector3 to XMFLOAT3, and used DirectXTK for texture loading. If anyone is willing to take a look at what might be causing the black screen, maybe something pops out to you, let me know, thanks.
      https://github.com/mister51213/DX11Port_SoftShadows
       
      Also, for reference, here's tutorial #40 which has normal shadows but no blur, which I also ported, and it works perfectly.
      https://github.com/mister51213/DX11Port_ShadowMapping
       
  • Advertisement