From 980384e00a7649b9fbc18f9b6af21e423b9b1bcd Mon Sep 17 00:00:00 2001
From: Brian Paul <brianp@vmware.com>
Date: Wed, 10 Dec 2014 09:45:00 -0700
Subject: [PATCH] swrast: fix a few attribute loop issues in clip_span()

The loop over the sw_span::interpMask attributes was incorrect.  We only
need to process the attributes which correspond to the SPAN_x flags.

Also, a bit test for span->arrayAttribs was using a 32-bit mask instead
of a 64-bit mask.

Bugzilla: http://bugs.freedesktop.org/show_bug.cgi?id=87136
---
 src/mesa/swrast/s_span.c | 13 ++++++++-----
 src/mesa/swrast/s_span.h |  1 +
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/mesa/swrast/s_span.c b/src/mesa/swrast/s_span.c
index 10aa33c..b946838 100644
--- a/src/mesa/swrast/s_span.c
+++ b/src/mesa/swrast/s_span.c
@@ -760,11 +760,12 @@ clip_span( struct gl_context *ctx, SWspan *span )
          ASSERT(x + n > xmin);
 
          /* Clip 'leftClip' pixels from the left side.
-          * The span->leftClip field will be applied when we interpolate
-          * fragment attributes.
-          * For arrays of values, shift them left.
+          * Loop over the fixed-function, SPAN_x attributes and adjust
+          * the attrStart values.  Note that we don't need to do this
+          * for the generic attributes since the leftClip factor is
+          * applied in interpolate_active_attribs().
           */
-         for (i = 0; i < VARYING_SLOT_MAX; i++) {
+         for (i = 0; i < SPAN_NUM_ATTRIBS; i++) {
             if (span->interpMask & (1 << i)) {
                GLuint j;
                for (j = 0; j < 4; j++) {
@@ -773,6 +774,7 @@ clip_span( struct gl_context *ctx, SWspan *span )
             }
          }
 
+         /* adjust the fixed-point attributes */
          span->red += leftClip * span->redStep;
          span->green += leftClip * span->greenStep;
          span->blue += leftClip * span->blueStep;
@@ -782,11 +784,12 @@ clip_span( struct gl_context *ctx, SWspan *span )
          span->intTex[0] += leftClip * span->intTexStep[0];
          span->intTex[1] += leftClip * span->intTexStep[1];
 
+         /* left-shift values in attribute arrays */
 #define SHIFT_ARRAY(ARRAY, SHIFT, LEN) \
          memmove(ARRAY, ARRAY + (SHIFT), (LEN) * sizeof(ARRAY[0]))
 
          for (i = 0; i < VARYING_SLOT_MAX; i++) {
-            if (span->arrayAttribs & (1 << i)) {
+            if (span->arrayAttribs & BITFIELD64_BIT(i)) {
                /* shift array elements left by 'leftClip' */
                SHIFT_ARRAY(span->array->attribs[i], leftClip, n - leftClip);
             }
diff --git a/src/mesa/swrast/s_span.h b/src/mesa/swrast/s_span.h
index 794f671..6d96684 100644
--- a/src/mesa/swrast/s_span.h
+++ b/src/mesa/swrast/s_span.h
@@ -55,6 +55,7 @@ struct gl_renderbuffer;
 #define SPAN_MASK       0x10  /**< was array.mask[] filled in by caller? */
 #define SPAN_LAMBDA     0x20  /**< array.lambda[] valid? */
 #define SPAN_COVERAGE   0x40  /**< array.coverage[] valid? */
+#define SPAN_NUM_ATTRIBS 7
 /*@}*/
 
 
-- 
1.9.1