t_dd_dmatmp: Make "count" actually be the count

The value passed in count previously was "vertex after the last vertex
to be processed."  Calling that "count" was misleading and kind of mean.
Looking at the code, many functions immediately do "count-start" to get
back the true count.  That's just silly.

If it is better for the loops to be 'for (j = start; j < (start +
count); j++)', GCC will do that transformation.

NOTE: There is some strange formatting left by this patch.  That was
done to make it more obvious that the before and after code is
equivalent.  These will be fixed in the next patch.

No piglit regressions on i915 (G33) or radeon (Radeon 7500).

v2: Fix a remaining (count-start) in render_quad_strip_verts.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Brian Paul <brianp@vmware.com> [v1]
Cc: "10.6 11.0" <mesa-stable@lists.freedesktop.org>

diff --git a/src/mesa/drivers/dri/i915/intel_render.c b/src/mesa/drivers/dri/i915/intel_render.c
index 5962dad7d11e0d6e3e3c1489c7462f3529ace6a7..df21c6651dfe6efec93eeac15c825497830316bc 100644 (file)
--- a/src/mesa/drivers/dri/i915/intel_render.c
+++ b/src/mesa/drivers/dri/i915/intel_render.c
@@ -251,7 +251,7 @@ intel_run_render(struct gl_context * ctx, struct tnl_pipeline_stage *stage)
          continue;
 
       intel_render_tab_verts[prim & PRIM_MODE_MASK] (ctx, start,
-                                                     start + length, prim);
+                                                     length, prim);
    }
 
    tnl->Driver.Render.Finish(ctx);

diff --git a/src/mesa/drivers/dri/radeon/radeon_swtcl.c b/src/mesa/drivers/dri/radeon/radeon_swtcl.c
index 2fbd353297b1323c480e2b0400dc955a91671600..7938c5301dac5d96a3d89d01281649e1dd02c39e 100644 (file)
--- a/src/mesa/drivers/dri/radeon/radeon_swtcl.c
+++ b/src/mesa/drivers/dri/radeon/radeon_swtcl.c
@@ -446,7 +446,7 @@ static GLboolean radeon_run_render( struct gl_context *ctx,
                 start, start+length);
 
       if (length)
-        tab[prim & PRIM_MODE_MASK]( ctx, start, start + length, prim );
+         tab[prim & PRIM_MODE_MASK](ctx, start, length, prim);
    }
 
    tnl->Driver.Render.Finish( ctx );

diff --git a/src/mesa/tnl_dd/t_dd_dmatmp.h b/src/mesa/tnl_dd/t_dd_dmatmp.h
index 7be39541e43821c3746b592e8db9f1d689d21187..443ada413a988a01c3a676865221ccd4c6847909 100644 (file)
--- a/src/mesa/tnl_dd/t_dd_dmatmp.h
+++ b/src/mesa/tnl_dd/t_dd_dmatmp.h
@@ -121,9 +121,9 @@ static void TAG(render_points_verts)( struct gl_context *ctx,
       if (currentsz < 8)
         currentsz = dmasz;
 
-      for (j = start; j < count; j += nr ) {
+      for (j = 0; j < count; j += nr) {
         nr = MIN2( currentsz, count - j );
-        TAG(emit_verts)( ctx, j, nr, ALLOC_VERTS(nr) );
+         TAG(emit_verts)(ctx, start + j, nr, ALLOC_VERTS(nr));
         currentsz = dmasz;
       }
 
@@ -148,7 +148,7 @@ static void TAG(render_lines_verts)( struct gl_context *ctx,
 
       /* Emit whole number of lines in total and in each buffer:
        */
-      count -= (count-start) & 1;
+      count -= count & 1;
       currentsz = GET_CURRENT_VB_MAX_VERTS();
       currentsz -= currentsz & 1;
       dmasz -= dmasz & 1;
@@ -156,9 +156,9 @@ static void TAG(render_lines_verts)( struct gl_context *ctx,
       if (currentsz < 8)
         currentsz = dmasz;
 
-      for (j = start; j < count; j += nr ) {
+      for (j = 0; j < count; j += nr) {
         nr = MIN2( currentsz, count - j );
-        TAG(emit_verts)( ctx, j, nr, ALLOC_VERTS(nr) );
+         TAG(emit_verts)(ctx, start + j, nr, ALLOC_VERTS(nr));
         currentsz = dmasz;
       }
 
@@ -186,9 +186,9 @@ static void TAG(render_line_strip_verts)( struct gl_context *ctx,
       if (currentsz < 8)
         currentsz = dmasz;
 
-      for (j = start; j + 1 < count; j += nr - 1 ) {
+      for (j = 0; j + 1 < count; j += nr - 1 ) {
         nr = MIN2( currentsz, count - j );
-        TAG(emit_verts)( ctx, j, nr, ALLOC_VERTS(nr) );
+         TAG(emit_verts)(ctx, start + j, nr, ALLOC_VERTS(nr));
         currentsz = dmasz;
       }
  
@@ -215,9 +215,9 @@ static void TAG(render_line_loop_verts)( struct gl_context *ctx,
       INIT( GL_LINE_STRIP );
 
       if (flags & PRIM_BEGIN)
-        j = start;
+        j = 0;
       else
-        j = start + 1;
+        j = 1;
 
       /* Ensure last vertex won't wrap buffers:
        */
@@ -234,23 +234,23 @@ static void TAG(render_line_loop_verts)( struct gl_context *ctx,
            nr = MIN2( currentsz, count - j );
 
            if (j + nr >= count &&
-               start < count - 1 && 
+               0 < count - 1 &&
                (flags & PRIM_END)) 
            {
               void *tmp;
               tmp = ALLOC_VERTS(nr+1);
-              tmp = TAG(emit_verts)( ctx, j, nr, tmp );
+               tmp = TAG(emit_verts)(ctx, start + j, nr, tmp);
               tmp = TAG(emit_verts)( ctx, start, 1, tmp );
               (void) tmp;
            }
            else {
-              TAG(emit_verts)( ctx, j, nr, ALLOC_VERTS(nr) );
+               TAG(emit_verts)(ctx, start + j, nr, ALLOC_VERTS(nr));
               currentsz = dmasz;
            }
         }
 
       }
-      else if (start + 1 < count && (flags & PRIM_END)) {
+      else if (1 < count && (flags & PRIM_END)) {
         void *tmp;
         tmp = ALLOC_VERTS(2);
         tmp = TAG(emit_verts)( ctx, start+1, 1, tmp );
@@ -284,14 +284,14 @@ static void TAG(render_triangles_verts)( struct gl_context *ctx,
    /* Emit whole number of tris in total.  dmasz is already a multiple
     * of 3.
     */
-   count -= (count-start)%3;
+   count -= count % 3;
 
    if (currentsz < 8)
       currentsz = dmasz;
 
-   for (j = start; j < count; j += nr) {
+   for (j = 0; j < count; j += nr) {
       nr = MIN2( currentsz, count - j );
-      TAG(emit_verts)( ctx, j, nr, ALLOC_VERTS(nr) );
+      TAG(emit_verts)(ctx, start + j, nr, ALLOC_VERTS(nr));
       currentsz = dmasz;
    }
 }
@@ -322,9 +322,9 @@ static void TAG(render_tri_strip_verts)( struct gl_context *ctx,
       dmasz -= (dmasz & 1);
       currentsz -= (currentsz & 1);
 
-      for (j = start ; j + 2 < count; j += nr - 2 ) {
+      for (j = 0; j + 2 < count; j += nr - 2) {
         nr = MIN2( currentsz, count - j );
-        TAG(emit_verts)( ctx, j, nr, ALLOC_VERTS(nr) );
+         TAG(emit_verts)(ctx, start + j, nr, ALLOC_VERTS(nr));
         currentsz = dmasz;
       }
 
@@ -354,12 +354,12 @@ static void TAG(render_tri_fan_verts)( struct gl_context *ctx,
         currentsz = dmasz;
       }
 
-      for (j = start + 1 ; j + 1 < count; j += nr - 2 ) {
+      for (j = 1; j + 1 < count; j += nr - 2) {
         void *tmp;
         nr = MIN2( currentsz, count - j + 1 );
         tmp = ALLOC_VERTS( nr );
         tmp = TAG(emit_verts)( ctx, start, 1, tmp );
-        tmp = TAG(emit_verts)( ctx, j, nr - 1, tmp );
+         tmp = TAG(emit_verts)( ctx, start + j, nr - 1, tmp );
         (void) tmp;
         currentsz = dmasz;
       }
@@ -394,12 +394,12 @@ static void TAG(render_poly_verts)( struct gl_context *ctx,
         currentsz = dmasz;
       }
 
-      for (j = start + 1 ; j + 1 < count ; j += nr - 2 ) {
+      for (j = 1 ; j + 1 < count ; j += nr - 2 ) {
         void *tmp;
         nr = MIN2( currentsz, count - j + 1 );
         tmp = ALLOC_VERTS( nr );
         tmp = TAG(emit_verts)( ctx, start, 1, tmp );
-        tmp = TAG(emit_verts)( ctx, j, nr - 1, tmp );
+         tmp = TAG(emit_verts)(ctx, start + j, nr - 1, tmp);
         (void) tmp;
         currentsz = dmasz;
       }
@@ -437,9 +437,9 @@ static void TAG(render_quad_strip_verts)( struct gl_context *ctx,
       dmasz -= (dmasz & 2);
       currentsz -= (currentsz & 2);
 
-      for (j = start ; j + 3 < count; j += nr - 2 ) {
+      for (j = 0; j + 3 < count; j += nr - 2 ) {
         nr = MIN2( currentsz, count - j );
-        TAG(emit_verts)( ctx, j, nr, ALLOC_VERTS(nr) );
+         TAG(emit_verts)(ctx, start + j, nr, ALLOC_VERTS(nr));
         currentsz = dmasz;
       }
 
@@ -465,7 +465,7 @@ static void TAG(render_quad_strip_verts)( struct gl_context *ctx,
         /* Emit whole number of quads in total, and in each buffer.
          */
         dmasz -= dmasz & 1;
-        count -= (count-start) & 1;
+        count -= count & 1;
         currentsz -= currentsz & 1;
 
         if (currentsz < 12)
@@ -474,14 +474,14 @@ static void TAG(render_quad_strip_verts)( struct gl_context *ctx,
         currentsz = currentsz/6*2;
         dmasz = dmasz/6*2;
 
-        for (j = start; j + 3 < count; j += nr - 2 ) {
+        for (j = 0; j + 3 < count; j += nr - 2) {
            nr = MIN2( currentsz, count - j );
            if (nr >= 4) {
               GLint quads = (nr/2)-1;
               GLint i;
               ELTS_VARS( ALLOC_ELTS( quads*6 ) );
 
-              for ( i = j-start ; i < j-start+quads*2 ; i+=2 ) {
+               for (i = j; i < j + quads * 2; i += 2) {
                  EMIT_TWO_ELTS( 0, (i+0), (i+1) );
                  EMIT_TWO_ELTS( 2, (i+2), (i+1) );
                  EMIT_TWO_ELTS( 4, (i+3), (i+2) );
@@ -519,15 +519,15 @@ static void TAG(render_quad_strip_verts)( struct gl_context *ctx,
       dmasz -= dmasz & 1;
       currentsz = GET_CURRENT_VB_MAX_VERTS();
       currentsz -= currentsz & 1;
-      count -= (count-start) & 1;
+      count -= count & 1;
 
       if (currentsz < 8) {
         currentsz = dmasz;
       }
 
-      for (j = start; j + 3 < count; j += nr - 2 ) {
+      for (j = 0; j + 3 < count; j += nr - 2) {
         nr = MIN2( currentsz, count - j );
-        TAG(emit_verts)( ctx, j, nr, ALLOC_VERTS(nr) );
+         TAG(emit_verts)(ctx, start + j, nr, ALLOC_VERTS(nr));
         currentsz = dmasz;
       }
 
@@ -556,15 +556,15 @@ static void TAG(render_quads_verts)( struct gl_context *ctx,
       /* Emit whole number of quads in total.  dmasz is already a multiple
        * of 4.
        */
-      count -= (count-start)%4;
+      count -= count % 4;
 
       currentsz = (GET_CURRENT_VB_MAX_VERTS()/4) * 4;
       if (currentsz < 8)
          currentsz = dmasz;
 
-      for (j = start; j < count; j += nr) {
+      for (j = 0; j < count; j += nr) {
          nr = MIN2( currentsz, count - j );
-         TAG(emit_verts)( ctx, j, nr, ALLOC_VERTS(nr) );
+         TAG(emit_verts)(ctx, start + j, nr, ALLOC_VERTS(nr));
          currentsz = dmasz;
       }
    }
@@ -587,7 +587,7 @@ static void TAG(render_quads_verts)( struct gl_context *ctx,
       /* Emit whole number of quads in total, and in each buffer.
        */
       dmasz -= dmasz & 3;
-      count -= (count-start) & 3;
+      count -= count & 3;
       currentsz -= currentsz & 3;
 
       /* Adjust for rendering as triangles:
@@ -598,14 +598,14 @@ static void TAG(render_quads_verts)( struct gl_context *ctx,
       if (currentsz < 8)
         currentsz = dmasz;
 
-      for (j = start; j < count; j += nr ) {
+      for (j = 0; j < count; j += nr ) {
         nr = MIN2( currentsz, count - j );
         if (nr >= 4) {
            GLint quads = nr/4;
            GLint i;
            ELTS_VARS( ALLOC_ELTS( quads*6 ) );
 
-           for ( i = j-start ; i < j-start+quads*4 ; i+=4 ) {
+            for (i = j; i < j + quads * 4; i += 4) {
               EMIT_TWO_ELTS( 0, (i+0), (i+1) );
               EMIT_TWO_ELTS( 2, (i+3), (i+1) );
               EMIT_TWO_ELTS( 4, (i+2), (i+3) );
@@ -629,15 +629,15 @@ static void TAG(render_quads_verts)( struct gl_context *ctx,
 
       INIT(GL_TRIANGLES);
 
-      for (j = start; j < count-3; j += 4) {
+      for (j = 0; j < count-3; j += 4) {
         void *tmp = ALLOC_VERTS( 6 );
         /* Send v0, v1, v3
          */
-        tmp = EMIT_VERTS(ctx, j,     2, tmp);
-        tmp = EMIT_VERTS(ctx, j + 3, 1, tmp);
+        tmp = EMIT_VERTS(ctx, start + j,     2, tmp);
+        tmp = EMIT_VERTS(ctx, start + j + 3, 1, tmp);
         /* Send v1, v2, v3
          */
-        tmp = EMIT_VERTS(ctx, j + 1, 3, tmp);
+        tmp = EMIT_VERTS(ctx, start + j + 1, 3, tmp);
         (void) tmp;
       }
    }
@@ -698,9 +698,9 @@ static void TAG(render_points_elts)( struct gl_context *ctx,
       if (currentsz < 8)
         currentsz = dmasz;
 
-      for (j = start; j < count; j += nr ) {
+      for (j = 0; j < count; j += nr ) {
         nr = MIN2( currentsz, count - j );
-        TAG(emit_elts)( ctx, elts+j, nr, ALLOC_ELTS(nr) );
+         TAG(emit_elts)(ctx, elts + start + j, nr, ALLOC_ELTS(nr));
         FLUSH();
         currentsz = dmasz;
       }
@@ -728,7 +728,7 @@ static void TAG(render_lines_elts)( struct gl_context *ctx,
 
       /* Emit whole number of lines in total and in each buffer:
        */
-      count -= (count-start) & 1;
+      count -= count & 1;
       currentsz -= currentsz & 1;
       dmasz -= dmasz & 1;
 
@@ -736,9 +736,9 @@ static void TAG(render_lines_elts)( struct gl_context *ctx,
       if (currentsz < 8)
         currentsz = dmasz;
 
-      for (j = start; j < count; j += nr ) {
+      for (j = 0; j < count; j += nr ) {
         nr = MIN2( currentsz, count - j );
-        TAG(emit_elts)( ctx, elts+j, nr, ALLOC_ELTS(nr) );
+         TAG(emit_elts)(ctx, elts + start + j, nr, ALLOC_ELTS(nr));
         FLUSH();
         currentsz = dmasz;
       }
@@ -768,9 +768,9 @@ static void TAG(render_line_strip_elts)( struct gl_context *ctx,
       if (currentsz < 8)
         currentsz = dmasz;
 
-      for (j = start; j + 1 < count; j += nr - 1 ) {
+      for (j = 0; j + 1 < count; j += nr - 1) {
         nr = MIN2( currentsz, count - j );
-        TAG(emit_elts)( ctx, elts+j, nr, ALLOC_ELTS(nr) );
+         TAG(emit_elts)( ctx, elts + start + j, nr, ALLOC_ELTS(nr));
         FLUSH();
         currentsz = dmasz;
       }
@@ -799,9 +799,9 @@ static void TAG(render_line_loop_elts)( struct gl_context *ctx,
       ELT_INIT( GL_LINE_STRIP );
 
       if (flags & PRIM_BEGIN)
-        j = start;
+        j = 0;
       else
-        j = start + 1;
+        j = 1;
 
       currentsz = GET_CURRENT_VB_MAX_ELTS();
       if (currentsz < 8) {
@@ -818,23 +818,23 @@ static void TAG(render_line_loop_elts)( struct gl_context *ctx,
            nr = MIN2( currentsz, count - j );
 
            if (j + nr >= count &&
-               start < count - 1 && 
+               0 < count - 1 &&
                (flags & PRIM_END)) 
            {
               void *tmp;
               tmp = ALLOC_ELTS(nr+1);
-              tmp = TAG(emit_elts)( ctx, elts+j, nr, tmp );
+               tmp = TAG(emit_elts)(ctx, elts + start + j, nr, tmp);
               tmp = TAG(emit_elts)( ctx, elts+start, 1, tmp );
               (void) tmp;
            }
            else {
-              TAG(emit_elts)( ctx, elts+j, nr, ALLOC_ELTS(nr) );
+               TAG(emit_elts)(ctx, elts + start + j, nr, ALLOC_ELTS(nr));
               currentsz = dmasz;
            }
         }
 
       }
-      else if (start + 1 < count && (flags & PRIM_END)) {
+      else if (1 < count && (flags & PRIM_END)) {
         void *tmp;
         tmp = ALLOC_ELTS(2);
         tmp = TAG(emit_elts)( ctx, elts+start+1, 1, tmp );
@@ -874,14 +874,14 @@ static void TAG(render_triangles_elts)( struct gl_context *ctx,
    /* Emit whole number of tris in total.  dmasz is already a multiple
     * of 3.
     */
-   count -= (count-start)%3;
+   count -= count % 3;
    currentsz -= currentsz%3;
    if (currentsz < 8)
       currentsz = dmasz;
 
-   for (j = start; j < count; j += nr) {
+   for (j = 0; j < count; j += nr) {
       nr = MIN2( currentsz, count - j );
-      TAG(emit_elts)( ctx, elts+j, nr, ALLOC_ELTS(nr) );
+      TAG(emit_elts)(ctx, elts + start + j, nr, ALLOC_ELTS(nr));
       FLUSH();
       currentsz = dmasz;
    }
@@ -914,9 +914,9 @@ static void TAG(render_tri_strip_elts)( struct gl_context *ctx,
       dmasz -= (dmasz & 1);
       currentsz -= (currentsz & 1);
 
-      for (j = start ; j + 2 < count; j += nr - 2 ) {
+      for (j = 0; j + 2 < count; j += nr - 2) {
         nr = MIN2( currentsz, count - j );
-        TAG(emit_elts)( ctx, elts+j, nr, ALLOC_ELTS(nr) );
+        TAG(emit_elts)( ctx, elts + start + j, nr, ALLOC_ELTS(nr) );
         FLUSH();
         currentsz = dmasz;
       }
@@ -947,12 +947,12 @@ static void TAG(render_tri_fan_elts)( struct gl_context *ctx,
         currentsz = dmasz;
       }
 
-      for (j = start + 1 ; j + 1 < count; j += nr - 2 ) {
+      for (j = 1; j + 1 < count; j += nr - 2) {
         void *tmp;
         nr = MIN2( currentsz, count - j + 1 );
         tmp = ALLOC_ELTS( nr );
         tmp = TAG(emit_elts)( ctx, elts+start, 1, tmp );
-        tmp = TAG(emit_elts)( ctx, elts+j, nr - 1, tmp );
+         tmp = TAG(emit_elts)(ctx, elts + start + j, nr - 1, tmp);
         (void) tmp;
         FLUSH();
         currentsz = dmasz;
@@ -985,12 +985,12 @@ static void TAG(render_poly_elts)( struct gl_context *ctx,
         currentsz = dmasz;
       }
 
-      for (j = start + 1 ; j + 1 < count; j += nr - 2 ) {
+      for (j = 1 ; j + 1 < count; j += nr - 2) {
         void *tmp;
         nr = MIN2( currentsz, count - j + 1 );
         tmp = ALLOC_ELTS( nr );
         tmp = TAG(emit_elts)( ctx, elts+start, 1, tmp );
-        tmp = TAG(emit_elts)( ctx, elts+j, nr - 1, tmp );
+         tmp = TAG(emit_elts)(ctx, elts + start + j, nr - 1, tmp);
         (void) tmp;
         FLUSH();
         currentsz = dmasz;
@@ -1023,7 +1023,7 @@ static void TAG(render_quad_strip_elts)( struct gl_context *ctx,
       /* Emit whole number of quads in total, and in each buffer.
        */
       dmasz -= dmasz & 1;
-      count -= (count-start) & 1;
+      count -= count & 1;
       currentsz -= currentsz & 1;
 
       if (currentsz < 12)
@@ -1035,7 +1035,7 @@ static void TAG(render_quad_strip_elts)( struct gl_context *ctx,
         currentsz = currentsz/6*2;
         dmasz = dmasz/6*2;
 
-        for (j = start; j + 3 < count; j += nr - 2 ) {
+         for (j = 0; j + 3 < count; j += nr - 2) {
            nr = MIN2( currentsz, count - j );
 
            if (nr >= 4)
@@ -1044,7 +1044,7 @@ static void TAG(render_quad_strip_elts)( struct gl_context *ctx,
               GLint quads = (nr/2)-1;
               ELTS_VARS( ALLOC_ELTS( quads*6 ) );
 
-              for ( i = j-start ; i < j-start+quads ; i++, elts += 2 ) {
+               for (i = j; i < j + quads; i++, elts += 2) {
                  EMIT_TWO_ELTS( 0, elts[0], elts[1] );
                  EMIT_TWO_ELTS( 2, elts[2], elts[1] );
                  EMIT_TWO_ELTS( 4, elts[3], elts[2] );
@@ -1060,9 +1060,9 @@ static void TAG(render_quad_strip_elts)( struct gl_context *ctx,
       else {
         ELT_INIT( GL_TRIANGLE_STRIP );
 
-        for (j = start; j + 3 < count; j += nr - 2 ) {
+         for (j = 0; j + 3 < count; j += nr - 2) {
            nr = MIN2( currentsz, count - j );
-           TAG(emit_elts)( ctx, elts+j, nr, ALLOC_ELTS(nr) );
+            TAG(emit_elts)(ctx, elts + start + j, nr, ALLOC_ELTS(nr));
            FLUSH();
            currentsz = dmasz;
         }
@@ -1088,14 +1088,14 @@ static void TAG(render_quads_elts)( struct gl_context *ctx,
 
       currentsz = GET_CURRENT_VB_MAX_ELTS()/4*4;
 
-      count -= (count-start)%4;
+      count -= count % 4;
 
       if (currentsz < 8)
         currentsz = dmasz;
 
-      for (j = start; j < count; j += nr) {
+      for (j = 0; j < count; j += nr) {
         nr = MIN2( currentsz, count - j );
-        TAG(emit_elts)( ctx, elts+j, nr, ALLOC_ELTS(nr) );
+         TAG(emit_elts)(ctx, elts + start + j, nr, ALLOC_ELTS(nr));
         FLUSH();
         currentsz = dmasz;
       }
@@ -1112,7 +1112,7 @@ static void TAG(render_quads_elts)( struct gl_context *ctx,
       /* Emit whole number of quads in total, and in each buffer.
        */
       dmasz -= dmasz & 3;
-      count -= (count-start) & 3;
+      count -= count & 3;
       currentsz -= currentsz & 3;
 
       /* Adjust for rendering as triangles:
@@ -1123,7 +1123,7 @@ static void TAG(render_quads_elts)( struct gl_context *ctx,
       if (currentsz < 8)
         currentsz = dmasz;
 
-      for (j = start; j + 3 < count; j += nr - 2 ) {
+      for (j = 0; j + 3 < count; j += nr - 2) {
         nr = MIN2( currentsz, count - j );
 
         if (nr >= 4)
@@ -1132,7 +1132,7 @@ static void TAG(render_quads_elts)( struct gl_context *ctx,
            GLint i;
            ELTS_VARS( ALLOC_ELTS( quads * 6 ) );
 
-           for ( i = j-start ; i < j-start+quads ; i++, elts += 4 ) {
+           for (i = j; i < j + quads; i++, elts += 4) {
               EMIT_TWO_ELTS( 0, elts[0], elts[1] );
               EMIT_TWO_ELTS( 2, elts[3], elts[1] );
               EMIT_TWO_ELTS( 4, elts[2], elts[3] );