ComputeBuffers in OpenGLES3.1 Shader

echofourpapa · Sep 2015

Hi everyone,

I'm curious about something. I'm using structured buffers to send data in a vert/frag shader wrapped in a DX11 api check.

With the new experimental OpenGL stuff I was hoping that those might "just work" like compute shaders. This is sadly not the case.

Has anyone else tried this? From what I understand about OpenGL(which isn't a lot), there isn't an exact cross over for DX StructuredBuffers, but is there something else that Unity's compute buffers will work with?

echofourpapa · Sep 2015

Update!

It turns out using surface shaders are what's failing, not the structured buffer conversion:

This works just fine:

            CGPROGRAM
            #include "UnityCG.cginc"
            #pragma vertex vert
            #pragma fragment frag
            #pragma target 5.0
 
            StructuredBuffer<float4> Buffer_A;

This does not:

        CGPROGRAM
 
       
        #include "UnityCG.cginc"
       
        #pragma surface surf StandardSpecular vertex:vert
        #pragma target 5.0
 
        StructuredBuffer<float4> Buffer_A;

it fails at the line StructuredBuffer with "Syntax Error"

RyanB · Sep 2015

Maybe what you want.
http://forum.unity3d.com/threads/structuredbuffer-with-surface-shader.173000/

I think it should work. Here's a snipped that will be in the documentation really soon:

"DirectX 11 HLSL syntax and Surface Shaders

Currently some parts of surface shader compilation pipeline do not understand DX11-specific HLSL syntax. If you're HLSL features like StructuredBuffers, RWTextures and other non-DX9 syntax, you have to wrap it into a DX11-only preprocessor macro:

#ifdef SHADER_API_D3D11
// DX11-specific code, e.g.
StructuredBuffer<float4> myColors;
RWTexture2D<float4> myRandomWriteTexture;
#endif
"

echofourpapa · Sep 2015

Right, this is with the new/experimental OpenGL backend to bring these features to OpenGL.

I normally have it wrapped in the API checks, but I can't do that if compiling to OpenGL or OpenGLES.

cupsster · Feb 2016

You need to add RW to be able to write to them. I did not tested this only from my own experience with compute shaders. RW prepend works.

ComputeBuffers in OpenGLES3.1 Shader

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