How can I compile a Direct3D 9 effect from a file?

Question

I started working with shaders recently in DirectX9. I noticed that there is a D3DXCompileShaderFromFile function for IDirect3DVertexShader9 and pixel shader. Which compiles the shader and gives you the compiled code so you can put that into a file and then read it.

But is there a way to do it with the ID3DXEffect or is IDirect3DVertexShader9 the only way?

Answer 1

Use the D3DXCreateEffectFromFile function.

The parameter list is a bit daunting, but most of the parameters are optional and can support null values. Do note, however, the comment for the flags parameter:

If pSrcFile contains a text effect, flags can be a combination of D3DXSHADER Flags and D3DXFX flags; otherwise, pSrcFile contains a binary effect and the only flags honored are D3DXFX flags. The Direct3D 10 HLSL compiler is now the default. See Effect-Compiler Tool for details.

Typical usage would be:

LPD3DXEFFECT effect = nullptr;
LPD3DXBUFFER errors = nullptr;
HRESULT result = D3DXCreateEffectFromFile(
  direct3DDevice,
  "Path/To/Your/Effect.fx",
  nullptr,
  nullptr,
  0,
  nullptr,
  &effect,
  &errors
)

If the HRESULT isn't successful, compilation errors can be recovered from the errors buffer (it's just a string; you can case the void * returned from GetBufferPointer).