New IMAGE_RED_TO_LUMINANCE flag passed to _mesa_pack_rgba_span_float() to fix glGetTexImage(GL_LUMINANCE) bug #10232.

1 files changed, 14 insertions, 5 deletions

diff --git a/src/mesa/main/image.c b/src/mesa/main/image.c
index fc8e1f0f57..eb91ebb611 100644
--- a/src/mesa/main/image.c
+++ b/src/mesa/main/image.c
@@ -1182,15 +1182,24 @@ _mesa_pack_rgba_span_float(GLcontext *ctx, GLuint n, GLfloat rgba[][4],
 
    if (dstFormat == GL_LUMINANCE || dstFormat == GL_LUMINANCE_ALPHA) {
       /* compute luminance values */
-      if (dstType != GL_FLOAT || ctx->Color.ClampReadColor == GL_TRUE) {
+      if (transferOps & IMAGE_RED_TO_LUMINANCE) {
+         /* Luminance = Red (glGetTexImage) */
          for (i = 0; i < n; i++) {
-            GLfloat sum = rgba[i][RCOMP] + rgba[i][GCOMP] + rgba[i][BCOMP];
-            luminance[i] = CLAMP(sum, 0.0F, 1.0F);
+            luminance[i] = rgba[i][RCOMP];
          }
       }
       else {
-         for (i = 0; i < n; i++) {
-            luminance[i] = rgba[i][RCOMP] + rgba[i][GCOMP] + rgba[i][BCOMP];
+         /* Luminance = Red + Green + Blue (glReadPixels) */
+         if (dstType != GL_FLOAT || ctx->Color.ClampReadColor == GL_TRUE) {
+            for (i = 0; i < n; i++) {
+               GLfloat sum = rgba[i][RCOMP] + rgba[i][GCOMP] + rgba[i][BCOMP];
+               luminance[i] = CLAMP(sum, 0.0F, 1.0F);
+            }
+         }
+         else {
+            for (i = 0; i < n; i++) {
+               luminance[i] = rgba[i][RCOMP] + rgba[i][GCOMP] + rgba[i][BCOMP];
+            }
          }
       }
    }