Figured out how texture stages work, thanks to this:
http://www.toymaker.info/Games/html/texture_states.html
Both color and alpha source modulation work now! :)
--- a/src/video/win32/SDL_d3drender.c Mon Aug 28 04:03:32 2006 +0000
+++ b/src/video/win32/SDL_d3drender.c Mon Aug 28 04:39:37 2006 +0000
@@ -382,9 +382,24 @@
IDirect3DDevice9_SetVertexShader(data->device, NULL);
IDirect3DDevice9_SetFVF(data->device,
D3DFVF_XYZRHW | D3DFVF_DIFFUSE | D3DFVF_TEX1);
+ IDirect3DDevice9_SetRenderState(data->device, D3DRS_ZENABLE, D3DZB_FALSE);
IDirect3DDevice9_SetRenderState(data->device, D3DRS_CULLMODE,
D3DCULL_NONE);
IDirect3DDevice9_SetRenderState(data->device, D3DRS_LIGHTING, FALSE);
+ /* Enable color modulation by diffuse color */
+ IDirect3DDevice9_SetTextureStageState(data->device, 0, D3DTSS_COLOROP,
+ D3DTOP_MODULATE);
+ IDirect3DDevice9_SetTextureStageState(data->device, 0, D3DTSS_COLORARG1,
+ D3DTA_TEXTURE);
+ IDirect3DDevice9_SetTextureStageState(data->device, 0, D3DTSS_COLORARG2,
+ D3DTA_DIFFUSE);
+ /* Enable alpha modulation by diffuse alpha */
+ IDirect3DDevice9_SetTextureStageState(data->device, 0, D3DTSS_ALPHAOP,
+ D3DTOP_MODULATE);
+ IDirect3DDevice9_SetTextureStageState(data->device, 0, D3DTSS_ALPHAARG1,
+ D3DTA_TEXTURE);
+ IDirect3DDevice9_SetTextureStageState(data->device, 0, D3DTSS_ALPHAARG2,
+ D3DTA_DIFFUSE);
return renderer;
}