I'm trying to implement dynamic shader linkage, but the compiler just doesn't recognize the interface.


[bquote]D3D11: ERROR: ID3D11DeviceContext::PSSetShader: NumClassInstances should be zero for shaders that don't have interfaces. [ STATE_SETTING ERROR #2097306: DEVICE_SETSHADER_INTERFACE_COUNT_MISMATCH ] [/bquote]


The Shader:

struct PSIn
{
float4 Position : SV_POSITION;
float4 Normal : NORMAL0;
float2 Texcoord : TEXCOORD0;

noperspective float4 Dist : Dist;
};


interface IAlbedoProvider
{
float3 ProvideAlbedo(PSIn input);
};

class ConstantAlbedoProvider : IAlbedoProvider
{
float3 ProvideAlbedo(PSIn input)
{
return float3(0.5f, 0.3f, 0.7f);
}
};

cbuffer Interfaces : register(b0)
{
ConstantAlbedoProvider constantAlbedo;
}

IAlbedoProvider albedoProvider;


PSOut PSMain(PSIn Input)
{
PSOut Output;

Output.Albedo = float4(albedoProvider.ProvideAlbedo(Input), 1.f);

...

return Output;
}


On the cpu-side I'm basically creating a class linkage per effect, creating the pixel shader object referring to the class linkage object, retrieving the class instance from the class linkage ("constantAlbedo", 0), and finally while setting the pixel shader, I'm passing over the class instance. Debugging with PIX revealed that everything went perfectly well on the cpu-side. But it just doesn't recognize the interface in the shader...

One might guess that the cbuffer is getting optimized away at compile time, since the shader itself is not explicitly using it. But the variable inside the cbuffer is only used as a specific class instance. But I could as well be creating the class instance outside the shader with the D3D11-API (ID3D11ClassLinkage::CreateClassInstance). Since the error implies that the shader doesn't have any interfaces that the class instance could be assigned to, the class instance "constantAlbedo" can't really be the problem. For some reason it just doesn't recognize the interface variable "albedoProvider", and I just can't figure out why.

What am I doing wrong?


Update: I can't work on it currently, but I figured out, that the class instance could indeed be the problem. The compiler throws away all zero-sized objects, so the class instance must have at least one data member. I guess, that it might even throw out the interface since the classes are already thrown out because they don't have any data members. I'm going to try it out later today, but maybe there's still another bug in there.

Update 2: Ok, that actually was the mistake...