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>
(cherry picked from commit d7bf7969b90f66ee614f2d2225f3a821d5396a89)

diff --git a/src/mesa/drivers/dri/i915/intel_render.c b/src/mesa/drivers/dri/i915/intel_render.c
index 5962dad..df21c66 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 2fbd353..7938c53 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 7be3954..443ada4 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] );