Using the Fixed Function rendering pipeline in DirectX 9, it's quite easy to set a texture and render vertices by doing the following:

```
struct vert { float x, y, z, u, v; };

device->SetFVF(D3DFVF_XYZ | D3DFVF_TEX1);
device->SetTexture(0, MyTexture);

//Draw vertices here

```

However, I'd like to add an additional float value to each vertex, which is then multiplied by the resulting colour output from the texture. (So the value would be between 0 and 1)

EG (psuedocode) `Colour = TextureColour(u, v) * CustomFloat`

I think there is a way using `device->SetTextureStageState`, but I am unsure of how to do it... Can anyone help me?