commit b1b0f221e712f6ac35a12f425e172b063153fd01
Author: Olivier Galibert <galibert@pobox.com>
Date:   Sun Jun 24 11:08:05 2012 +0200

    st_program.c: gl_ClipDistance must be interpolated in 3d space.
    
    That old bug was hidden but the clipper always interpolating in 3d
    space no matter what it should have been doing.  Now that the
    interpolation has been fixed, the bug shows up.
    
    Fixes bugzilla 51364.
    
    Signed-off-by: Olivier Galibert <galibert@pobox.com>

diff --git a/src/mesa/state_tracker/st_program.c b/src/mesa/state_tracker/st_program.c
index e6664fb..9f98298 100644
--- a/src/mesa/state_tracker/st_program.c
+++ b/src/mesa/state_tracker/st_program.c
@@ -569,12 +569,12 @@ st_translate_fragment_program(struct st_context *st,
          case FRAG_ATTRIB_CLIP_DIST0:
             input_semantic_name[slot] = TGSI_SEMANTIC_CLIPDIST;
             input_semantic_index[slot] = 0;
-            interpMode[slot] = TGSI_INTERPOLATE_LINEAR;
+            interpMode[slot] = TGSI_INTERPOLATE_PERSPECTIVE;
             break;
          case FRAG_ATTRIB_CLIP_DIST1:
             input_semantic_name[slot] = TGSI_SEMANTIC_CLIPDIST;
             input_semantic_index[slot] = 1;
-            interpMode[slot] = TGSI_INTERPOLATE_LINEAR;
+            interpMode[slot] = TGSI_INTERPOLATE_PERSPECTIVE;
             break;
             /* In most cases, there is nothing special about these
              * inputs, so adopt a convention to use the generic