HLSL: struct member initialization?

[chaoticbob]

Seems like this has been asked before, but I wasn't able to find an issue with it - and also couldn't find an item that matched it on #362. Was wondering if a shader like this could be supported via SPIR-V:

cbuffer ubo {
  float x = 0.0;
};

float4 main(float4 pos : POSITION) : SV_POSITION {
  return pos + float4(x, 0, 0, 0);
}

[johnkslang]

I believe this is because it is a Vulkan, or meta, issue. See related issue #701.

This "initialization" does not actually mean the shader initializes the struct member. Rather, it is a request that the driver pre-initialize the memory for the shader. If you look at fxc output, the initializer is actually in a comment, not the code.

If we do something to support this in glslang, something else will have to consume it to finish the job. So, we need a complete proposal of what to do:

• does it come with new Vulkan functionality?
• new driver support?
• some boiler plate application code the app can call to initialize buffers with?
• etc.

[chaoticbob]

Thanks for clearing this up. Will keep tracking it on #701.