D3D10 Constant buffer not working

Question

I am using a constant buffer to transfer data to my pixel shader

The problem is that the buffer contains 0s in the shader during runtime for x, y, z, and w of the float4 member, regardless of what data is updated to the buffer

Structure definitions are as follows:

// (C++)
struct Buffer
{
    XMMATRIX mvp_;
    XMFLOAT4 rgba_;
    int usemvp_;
};


// HLSL
cbuffer Buffer : register( b0 )
{
    matrix mvp_;
    float4 rgba_;
    int usemvp_;
};

Any help is much appreciated

Answer 1

You need to pad your struct to make it 16 byte aligned.

// (C++)
struct Buffer
{
    XMMATRIX mvp_;
    XMFLOAT4 rgba_;
    int usemvp_;
    float padding[3];
};

Also you have to make sure that you are setting the constant buffer into the correct shader stage, ie VSSetConstantBuffers vs PSSetConstantBuffers.