The Pixel Shader unit expects a Sampler configured for default filtering to be set at Slot 0 [...]

Question

I don't understand this error. The full output being :

The Pixel Shader unit expects a Sampler configured for default filtering to be set at Slot 0, but the sampler bound at this slot is configured for comparison filtering.

Here is how I create the sampler state.

// Skybox sampler description
D3D11_SAMPLER_DESC skyboxSamplerDesc;
ZeroMemory(&skyboxSamplerDesc, sizeof(D3D11_SAMPLER_DESC));
skyboxSamplerDesc.Filter = D3D11_FILTER_COMPARISON_MIN_MAG_LINEAR_MIP_POINT;
skyboxSamplerDesc.AddressU = D3D11_TEXTURE_ADDRESS_CLAMP;
skyboxSamplerDesc.AddressV = D3D11_TEXTURE_ADDRESS_CLAMP;
skyboxSamplerDesc.AddressW = D3D11_TEXTURE_ADDRESS_CLAMP;
skyboxSamplerDesc.MipLODBias = 0.0f;
skyboxSamplerDesc.MaxAnisotropy = 16;
skyboxSamplerDesc.ComparisonFunc = D3D11_COMPARISON_EQUAL;
skyboxSamplerDesc.MinLOD = 0;
skyboxSamplerDesc.MaxLOD = D3D11_FLOAT32_MAX;

// Create the skybox texture sampler state
hr = g_d3dDevice->CreateSamplerState(&skyboxSamplerDesc, &g_SkyboxSamplerState);
if (FAILED(hr)) return false;

The bindings.

ID3D11SamplerState* samplerStates[2];
samplerStates[0] = g_SkyboxSamplerState;
samplerStates[1] = g_PixelDepthSamplerState;
g_d3dDeviceContext->PSSetSamplers(0, 2, samplerStates);

HLSL side.

SamplerState sbSamplerState : register (s0) {
    Filter = MIN_MAG_LINEAR_MIP_POINT;
    AddressU = CLAMP;
    AddressV = CLAMP;
    AddressW = CLAMP;
    ComparisonFunc = EQUAL;
};

Answer 1

If your C++ code should specify the actual filtering state, your HLSL shader should not specify it, since everything written there will overwrite it (which is a feature of the effect-framework, not HLSL itself). This might be a bit weird, but works normally just fine. However, you are using a comparison filter on the C++ side (in your case D3D11_FILTER_COMPARISON_MIN_MAG_LINEAR_MIP_POINT) and not on the HLSL side. Since everything should work without the effect-framework (the part that specifies the state within the shader), you are not allowed to set the comparision filter in the C++ code, since the HLSL code expects a default (non-comparision) sampler state type. So you need SamplerComparisonState instead:

SamplerComparisonState sbSamplerState : register (s0);

If you want, you can still keep the filtering state in the shader, but in any case the sampler state type (comparison or not) needs to be the same, both in the HLSL code and in the C++ code.