diff --git a/src/mesa/drivers/dri/tdfx/tdfx_texstate.c b/src/mesa/drivers/dri/tdfx/tdfx_texstate.c
index bbd2c8cfee9..3f737878ed9 100644
--- a/src/mesa/drivers/dri/tdfx/tdfx_texstate.c
+++ b/src/mesa/drivers/dri/tdfx/tdfx_texstate.c
@@ -1314,7 +1314,7 @@ SetupDoubleTexEnvVoodoo3(GLcontext *ctx, int tmu0,
       fxMesa->TexCombine[0].InvertRGB = FXFALSE;
       fxMesa->TexCombine[0].InvertAlpha = FXFALSE;
 
-      if ((baseFormat0 == GL_RGB) && (baseFormat0 == GL_LUMINANCE)) {
+      if ((baseFormat0 == GL_RGB) || (baseFormat0 == GL_LUMINANCE)) {
          fxMesa->AlphaCombine.Function = GR_COMBINE_FUNCTION_LOCAL;
          fxMesa->AlphaCombine.Factor = GR_COMBINE_FACTOR_NONE;
          fxMesa->AlphaCombine.Local = locala;