I am trying to implement alpha blending in Direct3D (7.0). What I ideally want is to give an alpha value that would correspond to the level of translucency. Say 0.0 would be totally clear and 1.0 would be totally visable, 0.5 partially visible with whatever lies behind the object partially visable (like say a stained glass window or something). To make a long story short, I can''t figure out how to do this. I''ve been messing around with the renderstate and texturestate options for hours. I suppose I could set the individual alpha values in the texture, but I want to be able to change them on the fly, so wouldn''t changing all the alpha values for a texture be very slow? Also, then I couldn''t use the same texture with different levels of translucency on different objects. It almost seems like 3ddevice->SetRenderState(D3DRENDERSTATE_TEXTUREFACTOR, color); is what I want, but this didn''t seem to work. So basically, is there even a way to do this? Thanks in advance!!!!!!

Thanks for the response!

So I tried doing that. This is the code I''m using:

if(SUCCEEDED(d3d_device->BeginScene()))
{
d3d_device->SetRenderState(D3DRENDERSTATE_ALPHABLENDENABLE, TRUE);

d3d_device->SetRenderState(D3DRENDERSTATE_TEXTUREFACTOR, D3DRGB(0.5f, 0.5f, 0.5f));

d3d_device->SetTextureStageState(0, D3DTSS_COLORARG1, D3DTA_TEXTURE);
d3d_device->SetTextureStageState(0, D3DTSS_COLOROP, D3DTOP_SELECTARG1);

d3d_device->SetTextureStageState(0, D3DTSS_ALPHAARG1, D3DTA_TFACTOR);
d3d_device->SetTextureStageState(0, D3DTSS_ALPHAOP, D3DTOP_SELECTARG1);

d3d_device->SetTexture(0, lpTexture);
d3d_device->DrawPrimitive(D3DPT_TRIANGLESTRIP, D3DFVF_LVERTEX, &vertices, 4, 0);

d3d_device->SetRenderState(D3DRENDERSTATE_ALPHABLENDENABLE, FALSE);
}

But this isn''t working. It just draws the textures regularly. (I am just drawing three textured squares) Would this have something to do with how I created the textures or how lighting is set up? Or the types of vertices (LVERTEX) I''m using?

Any help would be most appreciated!

i think your looking for D3DTOP_BLENDFACTORALPHA (see sdk)