[Mesa-dev] [PATCH 1/5] i965/fs: Fix the FS inputs setup when some SF outputs aren't used in the FS.

[Eric Anholt]

From: Olivier Galibert <galibert at pobox.com>

If there was an edge flag or a two-side-color pair present, we'd end up
mismatched and read values from earlier in the VUE for later FS inputs.

v2: Fix regression in gles2conform shaders generating point size. (change by
    anholt)

Signed-off-by: Olivier Galibert <galibert at pobox.com>
Reviewed-by: Eric Anholt <eric at anholt.net>
NOTE: This is a candidate for the 8.0 branch.
---
 src/mesa/drivers/dri/i965/brw_fs.cpp     |   13 ++++++++++++-
 src/mesa/drivers/dri/i965/brw_wm_pass2.c |   14 +++++++++++++-
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index d06858e..0fd5799 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -954,11 +954,22 @@ fs_visitor::calculate_urb_setup()
    } else {
       /* FINISHME: The sf doesn't map VS->FS inputs for us very well. */
       for (unsigned int i = 0; i < VERT_RESULT_MAX; i++) {
+         /* Point size is packed into the header, not as a general attribute */
+         if (i == VERT_RESULT_PSIZ)
+            continue;
+
 	 if (c->key.vp_outputs_written & BITFIELD64_BIT(i)) {
 	    int fp_index = _mesa_vert_result_to_frag_attrib((gl_vert_result) i);
 
+	    /* The back color slot is skipped when the front color is
+	     * also written to.  In addition, some slots can be
+	     * written in the vertex shader and not read in the
+	     * fragment shader.  So the register number must always be
+	     * incremented, mapped or not.
+	     */
 	    if (fp_index >= 0)
-	       urb_setup[fp_index] = urb_next++;
+	       urb_setup[fp_index] = urb_next;
+            urb_next++;
 	 }
       }
 
diff --git a/src/mesa/drivers/dri/i965/brw_wm_pass2.c b/src/mesa/drivers/dri/i965/brw_wm_pass2.c
index 27c0a94..562a189 100644
--- a/src/mesa/drivers/dri/i965/brw_wm_pass2.c
+++ b/src/mesa/drivers/dri/i965/brw_wm_pass2.c
@@ -93,12 +93,24 @@ static void init_registers( struct brw_wm_compile *c )
       }
    } else {
       for (j = 0; j < VERT_RESULT_MAX; j++) {
+         /* Point size is packed into the header, not as a general attribute */
+         if (j == VERT_RESULT_PSIZ)
+            continue;
+
 	 if (c->key.vp_outputs_written & BITFIELD64_BIT(j)) {
 	    int fp_index = _mesa_vert_result_to_frag_attrib(j);
 
 	    nr_interp_regs++;
+
+	    /* The back color slot is skipped when the front color is
+	     * also written to.  In addition, some slots can be
+	     * written in the vertex shader and not read in the
+	     * fragment shader.  So the register number must always be
+	     * incremented, mapped or not.
+	     */
 	    if (fp_index >= 0)
-	       prealloc_reg(c, &c->payload.input_interp[fp_index], i++);
+	       prealloc_reg(c, &c->payload.input_interp[fp_index], i);
+            i++;
 	 }
       }
       assert(nr_interp_regs >= 1);
-- 
1.7.10.4