device->SetRenderState(D3DRS_ALPHABLENDENABLE, TRUE);
device->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_ONE);
device->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);

device->SetRenderState(D3DRS_TEXTUREFACTOR, color);

device->SetTextureStageState(0, D3DTSS_COLORARG1, D3DTA_DIFFUSE);
device->SetTextureStageState(0, D3DTSS_COLOROP, D3DTOP_MODULATE);
device->SetTextureStageState(0, D3DTSS_COLORARG2, D3DTA_TFACTOR);

device->SetTextureStageState(0, D3DTSS_ALPHAARG1, D3DTA_DIFFUSE);
device->SetTextureStageState(0, D3DTSS_ALPHAOP, D3DTOP_MODULATE);
device->SetTextureStageState(0, D3DTSS_ALPHAARG2, D3DTA_TFACTOR);

こんな設定です。