mesa: Reject glDrawPixels(integer format).

When folding GL_EXT_texture_integer into the core, a new (and very
sensible) restriction was added.

Reviewed-by: Brian Paul <brianp@vmware.com>

src/mesa/main/drawpix.c

@@ -30,6 +30,7 @@
 #include "enums.h"
 #include "feedback.h"
 #include "framebuffer.h"
+#include "image.h"
 #include "mfeatures.h"
 #include "pbo.h"
 #include "readpix.h"
@@ -76,6 +77,23 @@ _mesa_DrawPixels( GLsizei width, GLsizei height,
       goto end;      /* the error code was recorded */
    }
 
+   /* GL 3.0 introduced a new restriction on glDrawPixels() over what was in
+    * GL_EXT_texture_integer.  From section 3.7.4 ("Rasterization of Pixel
+    * Rectangles) on page 151 of the GL 3.0 specification:
+    *
+    *     "If format contains integer components, as shown in table 3.6, an
+    *      INVALID OPERATION error is generated."
+    *
+    * Since DrawPixels rendering would be merely undefined if not an error (due
+    * to a lack of defined mapping from integer data to gl_Color fragment shader
+    * input), NVIDIA's implementation also just returns this error despite
+    * exposing GL_EXT_texture_integer, just return an error regardless.
+    */
+   if (_mesa_is_integer_format(format)) {
+      _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawPixels(integer format)");
+      goto end;
+   }
+
    if (_mesa_error_check_format_type(ctx, format, type, GL_TRUE)) {
       goto end;      /* the error code was recorded */
    }