More color macro clean-ups.

FLOAT_TO_CHAN() macro removed.

diff --git a/src/mesa/drivers/glide/fxdrv.h b/src/mesa/drivers/glide/fxdrv.h
index 3e3147e..38ce0ce 100644 (file)
--- a/src/mesa/drivers/glide/fxdrv.h
+++ b/src/mesa/drivers/glide/fxdrv.h
@@ -93,8 +93,6 @@ extern float gl_ubyte_to_float_255_color_tab[256];
     (*(int *)&(f)) = ((int *)gl_ubyte_to_float_255_color_tab)[c]
 
 
-#define LINTERP(T, A, B)       ((A) + (T) * ((B) - (A)))
-
 
 
 /* Should have size == 16 * sizeof(float).

diff --git a/src/mesa/main/colormac.h b/src/mesa/main/colormac.h
index 6101ab0..94e4af5 100644 (file)
--- a/src/mesa/main/colormac.h
+++ b/src/mesa/main/colormac.h
@@ -1,4 +1,4 @@
-/* $Id: colormac.h,v 1.5 2001/01/02 22:02:51 brianp Exp $ */
+/* $Id: colormac.h,v 1.6 2001/01/03 15:59:30 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -52,7 +52,6 @@
 #define UINT_TO_CHAN(i)   ((GLchan) ((i) >> 24))
 
 #define CHAN_TO_FLOAT(c)  UBYTE_TO_FLOAT(c)
-#define FLOAT_TO_CHAN(f)  ( (GLchan) IROUND((f) * CHAN_MAXF) )
 
 #define CLAMPED_FLOAT_TO_CHAN(c, f)    CLAMPED_FLOAT_TO_UBYTE(c, f)
 #define UNCLAMPED_FLOAT_TO_CHAN(c, f)  UNCLAMPED_FLOAT_TO_UBYTE(c, f)
@@ -72,7 +71,6 @@
 #define UINT_TO_CHAN(i)   ((GLchan) ((i) >> 16))
 
 #define CHAN_TO_FLOAT(c)  ((GLfloat) ((c) * (1.0 / CHAN_MAXF) + 0.5F))
-#define FLOAT_TO_CHAN(f)  ((GLchan) IROUND((f) * CHAN_MAXF))
 
 #define CLAMPED_FLOAT_TO_CHAN(c, f) \
    c = ((GLchan) IROUND((f) * CHAN_MAXF))
@@ -95,9 +93,8 @@
 #define UINT_TO_CHAN(i)   ((GLfloat) ((i) * (1.0F / 4294967295.0F)))
 
 #define CHAN_TO_FLOAT(c)  (c)
-#define FLOAT_TO_CHAN(f)  (f)
 
-#define CLAMPED_FLOAT_COLOR_TO_CHAN(c, f)  c = (f)
+#define CLAMPED_FLOAT_TO_CHAN(c, f)  c = (f)
 #define UNCLAMPED_FLOAT_TO_CHAN(c, f)      c = (f)
 
 #define COPY_CHAN4(DST, SRC)  COPY_4V(DST, SRC)
@@ -115,12 +112,24 @@
 /*
  * Convert 3 channels at once.
  */
-#define FLOAT_RGB_TO_CHAN_RGB(dst, f)          \
+#define UNCLAMPED_FLOAT_TO_RGB_CHAN(dst, f)    \
 do {                                           \
    UNCLAMPED_FLOAT_TO_CHAN(dst[0], f[0]);      \
    UNCLAMPED_FLOAT_TO_CHAN(dst[1], f[1]);      \
    UNCLAMPED_FLOAT_TO_CHAN(dst[2], f[2]);      \
-} while(0)
+} while (0)
+
+
+/*
+ * Convert 4 channels at once.
+ */
+#define UNCLAMPED_FLOAT_TO_RGBA_CHAN(dst, f)   \
+do {                                           \
+   UNCLAMPED_FLOAT_TO_CHAN(dst[0], f[0]);      \
+   UNCLAMPED_FLOAT_TO_CHAN(dst[1], f[1]);      \
+   UNCLAMPED_FLOAT_TO_CHAN(dst[2], f[2]);      \
+   UNCLAMPED_FLOAT_TO_CHAN(dst[3], f[3]);      \
+} while (0)
 
 
 #endif /* COLORMAC_H */

diff --git a/src/mesa/main/image.c b/src/mesa/main/image.c
index 6c50fed..de56f0b 100644 (file)
--- a/src/mesa/main/image.c
+++ b/src/mesa/main/image.c
@@ -1,4 +1,4 @@
-/* $Id: image.c,v 1.51 2001/01/02 22:02:51 brianp Exp $ */
+/* $Id: image.c,v 1.52 2001/01/03 15:59:30 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -2721,7 +2721,7 @@ _mesa_unpack_chan_color_span( GLcontext *ctx,
          GLchan *dst = dest;
          GLuint i;
          for (i = 0; i < n; i++) {
-            dst[dstRedIndex] = FLOAT_TO_CHAN(rgba[i][RCOMP]);
+            CLAMPED_FLOAT_TO_CHAN(dst[dstRedIndex], rgba[i][RCOMP]);
             dst += dstComponents;
          }
       }
@@ -2730,7 +2730,7 @@ _mesa_unpack_chan_color_span( GLcontext *ctx,
          GLchan *dst = dest;
          GLuint i;
          for (i = 0; i < n; i++) {
-            dst[dstGreenIndex] = FLOAT_TO_CHAN(rgba[i][GCOMP]);
+            CLAMPED_FLOAT_TO_CHAN(dst[dstGreenIndex], rgba[i][GCOMP]);
             dst += dstComponents;
          }
       }
@@ -2739,7 +2739,7 @@ _mesa_unpack_chan_color_span( GLcontext *ctx,
          GLchan *dst = dest;
          GLuint i;
          for (i = 0; i < n; i++) {
-            dst[dstBlueIndex] = FLOAT_TO_CHAN(rgba[i][BCOMP]);
+            CLAMPED_FLOAT_TO_CHAN(dst[dstBlueIndex], rgba[i][BCOMP]);
             dst += dstComponents;
          }
       }
@@ -2748,7 +2748,7 @@ _mesa_unpack_chan_color_span( GLcontext *ctx,
          GLchan *dst = dest;
          GLuint i;
          for (i = 0; i < n; i++) {
-            dst[dstAlphaIndex] = FLOAT_TO_CHAN(rgba[i][ACOMP]);
+            CLAMPED_FLOAT_TO_CHAN(dst[dstAlphaIndex], rgba[i][ACOMP]);
             dst += dstComponents;
          }
       }
@@ -2760,7 +2760,7 @@ _mesa_unpack_chan_color_span( GLcontext *ctx,
          assert(dstComponents == 1);
          for (i = 0; i < n; i++) {
             /* Intensity comes from red channel */
-            dst[i] = FLOAT_TO_CHAN(rgba[i][RCOMP]);
+            CLAMPED_FLOAT_TO_CHAN(dst[i], rgba[i][RCOMP]);
          }
       }
 
@@ -2770,7 +2770,7 @@ _mesa_unpack_chan_color_span( GLcontext *ctx,
          assert(dstLuminanceIndex == 0);
          for (i = 0; i < n; i++) {
             /* Luminance comes from red channel */
-            dst[0] = FLOAT_TO_CHAN(rgba[i][RCOMP]);
+            CLAMPED_FLOAT_TO_CHAN(dst[0], rgba[i][RCOMP]);
             dst += dstComponents;
          }
       }

diff --git a/src/mesa/main/pixel.c b/src/mesa/main/pixel.c
index 6bbbbdf..270cbc7 100644 (file)
--- a/src/mesa/main/pixel.c
+++ b/src/mesa/main/pixel.c
@@ -1,4 +1,4 @@
-/* $Id: pixel.c,v 1.22 2000/12/26 05:09:29 keithw Exp $ */
+/* $Id: pixel.c,v 1.23 2001/01/03 15:59:30 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -1126,10 +1126,10 @@ _mesa_map_ci_to_rgba_chan( const GLcontext *ctx, GLuint n,
    const GLfloat *aMap = ctx->Pixel.MapItoA;
    GLuint i;
    for (i=0;i<n;i++) {
-      rgba[i][RCOMP] = FLOAT_TO_CHAN(rMap[index[i] & rmask]);
-      rgba[i][GCOMP] = FLOAT_TO_CHAN(gMap[index[i] & gmask]);
-      rgba[i][BCOMP] = FLOAT_TO_CHAN(bMap[index[i] & bmask]);
-      rgba[i][ACOMP] = FLOAT_TO_CHAN(aMap[index[i] & amask]);
+      CLAMPED_FLOAT_TO_CHAN(rgba[i][RCOMP], rMap[index[i] & rmask]);
+      CLAMPED_FLOAT_TO_CHAN(rgba[i][GCOMP], gMap[index[i] & gmask]);
+      CLAMPED_FLOAT_TO_CHAN(rgba[i][BCOMP], bMap[index[i] & bmask]);
+      CLAMPED_FLOAT_TO_CHAN(rgba[i][ACOMP], aMap[index[i] & amask]);
    }
 #endif
 }
@@ -1194,10 +1194,10 @@ _mesa_map_ci8_to_rgba( const GLcontext *ctx, GLuint n, const GLubyte index[],
    const GLfloat *aMap = ctx->Pixel.MapItoA;
    GLuint i;
    for (i=0;i<n;i++) {
-      rgba[i][RCOMP] = FLOAT_TO_CHAN(rMap[index[i] & rmask]);
-      rgba[i][GCOMP] = FLOAT_TO_CHAN(gMap[index[i] & gmask]);
-      rgba[i][BCOMP] = FLOAT_TO_CHAN(bMap[index[i] & bmask]);
-      rgba[i][ACOMP] = FLOAT_TO_CHAN(aMap[index[i] & amask]);
+      CLAMPED_FLOAT_TO_CHAN(rgba[i][RCOMP], rMap[index[i] & rmask]);
+      CLAMPED_FLOAT_TO_CHAN(rgba[i][GCOMP], gMap[index[i] & gmask]);
+      CLAMPED_FLOAT_TO_CHAN(rgba[i][BCOMP], bMap[index[i] & bmask]);
+      CLAMPED_FLOAT_TO_CHAN(rgba[i][ACOMP], aMap[index[i] & amask]);
    }
 #endif
 }

diff --git a/src/mesa/swrast/s_drawpix.c b/src/mesa/swrast/s_drawpix.c
index ccb48a7..63281b2 100644 (file)
--- a/src/mesa/swrast/s_drawpix.c
+++ b/src/mesa/swrast/s_drawpix.c
@@ -1,4 +1,4 @@
-/* $Id: s_drawpix.c,v 1.5 2000/12/26 05:09:32 keithw Exp $ */
+/* $Id: s_drawpix.c,v 1.6 2001/01/03 15:59:30 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -605,11 +605,12 @@ draw_depth_pixels( GLcontext *ctx, GLint x, GLint y,
 
    /* Colors or indexes */
    if (ctx->Visual.RGBAflag) {
-      GLint r = FLOAT_TO_CHAN(ctx->Current.RasterColor[0]);
-      GLint g = FLOAT_TO_CHAN(ctx->Current.RasterColor[1]);
-      GLint b = FLOAT_TO_CHAN(ctx->Current.RasterColor[2]);
-      GLint a = FLOAT_TO_CHAN(ctx->Current.RasterColor[3]);
       GLint i;
+      GLint r, g, b, a;
+      UNCLAMPED_FLOAT_TO_CHAN(r, ctx->Current.RasterColor[0]);
+      UNCLAMPED_FLOAT_TO_CHAN(g, ctx->Current.RasterColor[1]);
+      UNCLAMPED_FLOAT_TO_CHAN(b, ctx->Current.RasterColor[2]);
+      UNCLAMPED_FLOAT_TO_CHAN(a, ctx->Current.RasterColor[3]);
       for (i = 0; i < drawWidth; i++) {
          rgba[i][RCOMP] = r;
          rgba[i][GCOMP] = g;

diff --git a/src/mesa/swrast/s_fog.c b/src/mesa/swrast/s_fog.c
index 0e65f78..6e6c207 100644 (file)
--- a/src/mesa/swrast/s_fog.c
+++ b/src/mesa/swrast/s_fog.c
@@ -1,4 +1,4 @@
-/* $Id: s_fog.c,v 1.6 2001/01/02 21:09:50 brianp Exp $ */
+/* $Id: s_fog.c,v 1.7 2001/01/03 15:59:30 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -49,10 +49,12 @@ _mesa_fog_rgba_pixels( const GLcontext *ctx,
                       const GLfixed fog[], 
                       GLchan rgba[][4] )
 {
-   const GLchan rFog = FLOAT_TO_CHAN(ctx->Fog.Color[RCOMP]);
-   const GLchan gFog = FLOAT_TO_CHAN(ctx->Fog.Color[GCOMP]);
-   const GLchan bFog = FLOAT_TO_CHAN(ctx->Fog.Color[BCOMP]);
    GLuint i;
+   GLchan rFog, gFog, bFog;
+
+   UNCLAMPED_FLOAT_TO_CHAN(rFog, ctx->Fog.Color[RCOMP]);
+   UNCLAMPED_FLOAT_TO_CHAN(gFog, ctx->Fog.Color[GCOMP]);
+   UNCLAMPED_FLOAT_TO_CHAN(bFog, ctx->Fog.Color[BCOMP]);
 
 #if CHAN_TYPE == GL_FLOAT
    for (i = 0; i < n; i++) {

diff --git a/src/mesa/swrast/s_texture.c b/src/mesa/swrast/s_texture.c
index bcc5f26..29d6b46 100644 (file)
--- a/src/mesa/swrast/s_texture.c
+++ b/src/mesa/swrast/s_texture.c
@@ -1,4 +1,4 @@
-/* $Id: s_texture.c,v 1.5 2001/01/02 22:02:52 brianp Exp $ */
+/* $Id: s_texture.c,v 1.6 2001/01/03 15:59:30 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -1841,8 +1841,8 @@ _mesa_texture_combine(const GLcontext *ctx,
             break;
          case GL_CONSTANT_EXT:
             {
-               GLchan (*c)[4] = ccolor[j];
-               GLchan alpha = FLOAT_TO_CHAN(textureUnit->EnvColor[3]);
+               GLchan alpha, (*c)[4] = ccolor[j];
+               UNCLAMPED_FLOAT_TO_CHAN(alpha, textureUnit->EnvColor[3]);
                for (i = 0; i < n; i++)
                   c[i][ACOMP] = alpha;
                argA[j] = ccolor[j];
@@ -1865,9 +1865,10 @@ _mesa_texture_combine(const GLcontext *ctx,
          case GL_CONSTANT_EXT:
             {
                GLchan (*c)[4] = ccolor[j];
-               const GLchan red   = FLOAT_TO_CHAN(textureUnit->EnvColor[0]);
-               const GLchan green = FLOAT_TO_CHAN(textureUnit->EnvColor[1]);
-               const GLchan blue  = FLOAT_TO_CHAN(textureUnit->EnvColor[2]);
+               GLchan red, green, blue;
+               UNCLAMPED_FLOAT_TO_CHAN(red,   textureUnit->EnvColor[0]);
+               UNCLAMPED_FLOAT_TO_CHAN(green, textureUnit->EnvColor[1]);
+               UNCLAMPED_FLOAT_TO_CHAN(blue,  textureUnit->EnvColor[2]);
                for (i = 0; i < n; i++) {
                   c[i][RCOMP] = red;
                   c[i][GCOMP] = green;

diff --git a/src/mesa/tnl/t_imm_eval.c b/src/mesa/tnl/t_imm_eval.c
index 419f449..235baa3 100644 (file)
--- a/src/mesa/tnl/t_imm_eval.c
+++ b/src/mesa/tnl/t_imm_eval.c
@@ -1,4 +1,4 @@
-/* $Id: t_imm_eval.c,v 1.2 2000/12/27 22:30:29 keithw Exp $ */
+/* $Id: t_imm_eval.c,v 1.3 2001/01/03 15:59:30 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -154,13 +154,14 @@ static void eval1_color( GLvector4ub *dest,
    GLubyte (*to)[4] = dest->data;
    GLuint i;
 
-   for (i = 0 ; !(flags[i] & VERT_END_VB) ; i++)
+   for (i = 0 ; !(flags[i] & VERT_END_VB) ; i++) {
       if (flags[i] & (VERT_EVAL_C1|VERT_EVAL_P1)) {
         GLfloat u = (coord[i][0] - u1) * du;
         GLfloat fcolor[4];
         _math_horner_bezier_curve(map->Points, fcolor, u, 4, map->Order);
-        FLOAT_RGBA_TO_CHAN_RGBA(to[i], fcolor);
+         UNCLAMPED_FLOAT_TO_RGBA_CHAN(to[i], fcolor);
       }
+   }
 }
 
 
@@ -287,16 +288,16 @@ static void eval2_color( GLvector4ub *dest,
    GLubyte (*to)[4] = dest->data;
    GLuint i;
 
-   for (i = 0 ; !(flags[i] & VERT_END_VB) ; i++)
+   for (i = 0 ; !(flags[i] & VERT_END_VB) ; i++) {
       if (flags[i] & (VERT_EVAL_C2|VERT_EVAL_P2)) {
         GLfloat u = (coord[i][0] - u1) * du;
         GLfloat v = (coord[i][1] - v1) * dv;
         GLfloat fcolor[4];
         _math_horner_bezier_surf(map->Points, fcolor, u, v, 4,
                                  map->Uorder, map->Vorder);
-        FLOAT_RGBA_TO_CHAN_RGBA(to[i], fcolor);
+         UNCLAMPED_FLOAT_TO_RGBA_CHAN(to[i], fcolor);
       }
-
+   }
 }
 
 

diff --git a/src/mesa/tnl/t_vb_lighttmp.h b/src/mesa/tnl/t_vb_lighttmp.h
index f2bcde6..656ffff 100644 (file)
--- a/src/mesa/tnl/t_vb_lighttmp.h
+++ b/src/mesa/tnl/t_vb_lighttmp.h
@@ -1,4 +1,4 @@
-/* $Id: t_vb_lighttmp.h,v 1.1 2000/12/26 05:09:33 keithw Exp $ */
+/* $Id: t_vb_lighttmp.h,v 1.2 2001/01/03 15:59:30 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -269,13 +269,13 @@ static void TAG(light_rgba_spec)( GLcontext *ctx,
         }
       } /*loop over lights*/
 
-      FLOAT_RGB_TO_CHAN_RGB( Fcolor[j], sum[0] );
-      FLOAT_RGB_TO_CHAN_RGB( Fspec[j], spec[0] );
+      UNCLAMPED_FLOAT_TO_RGB_CHAN( Fcolor[j], sum[0] );
+      UNCLAMPED_FLOAT_TO_RGB_CHAN( Fspec[j], spec[0] );
       Fcolor[j][3] = sumA[0];
       
       if (IDX & LIGHT_TWOSIDE) {
-        FLOAT_RGB_TO_CHAN_RGB( Bcolor[j], sum[1] );
-        FLOAT_RGB_TO_CHAN_RGB( Bspec[j], spec[1] );
+        UNCLAMPED_FLOAT_TO_RGB_CHAN( Bcolor[j], sum[1] );
+        UNCLAMPED_FLOAT_TO_RGB_CHAN( Bspec[j], spec[1] );
         Bcolor[j][3] = sumA[1];
       }
    } 
@@ -475,11 +475,11 @@ static void TAG(light_rgba)( GLcontext *ctx,
         ACC_SCALE_SCALAR_3V( sum[side], attenuation, contrib );
       } 
 
-      FLOAT_RGB_TO_CHAN_RGB( Fcolor[j], sum[0] );
+      UNCLAMPED_FLOAT_TO_RGB_CHAN( Fcolor[j], sum[0] );
       Fcolor[j][3] = sumA[0];
 
       if (IDX & LIGHT_TWOSIDE) {
-        FLOAT_RGB_TO_CHAN_RGB( Bcolor[j], sum[1] );
+        UNCLAMPED_FLOAT_TO_RGB_CHAN( Bcolor[j], sum[1] );
         Bcolor[j][3] = sumA[1];
       }
    } 
@@ -556,12 +556,12 @@ static void TAG(light_fast_rgba_single)( GLcontext *ctx,
       {
         COPY_3V(base[0], light->_MatAmbient[0]);
         ACC_3V(base[0], ctx->Light._BaseColor[0] );
-        FLOAT_RGB_TO_CHAN_RGB( baseubyte[0], base[0] );
+        UNCLAMPED_FLOAT_TO_RGB_CHAN( baseubyte[0], base[0] );
         
         if (IDX & LIGHT_TWOSIDE) {
            COPY_3V(base[1], light->_MatAmbient[1]);
            ACC_3V(base[1], ctx->Light._BaseColor[1]);
-           FLOAT_RGB_TO_CHAN_RGB( baseubyte[1], base[1]);
+           UNCLAMPED_FLOAT_TO_RGB_CHAN( baseubyte[1], base[1]);
         }
       }
 
@@ -582,7 +582,7 @@ static void TAG(light_fast_rgba_single)( GLcontext *ctx,
                  GET_SHINE_TAB_ENTRY( ctx->_ShineTable[1], n_dot_h, spec );
                  ACC_SCALE_SCALAR_3V(sum, spec, light->_MatSpecular[1]);
               } 
-              FLOAT_RGB_TO_CHAN_RGB(Bcolor[j], sum );
+              UNCLAMPED_FLOAT_TO_RGB_CHAN(Bcolor[j], sum );
            }
         } else {
            GLfloat n_dot_h = DOT3(normal, light->_h_inf_norm);
@@ -595,7 +595,7 @@ static void TAG(light_fast_rgba_single)( GLcontext *ctx,
               ACC_SCALE_SCALAR_3V(sum, spec, light->_MatSpecular[0]);
 
            }
-           FLOAT_RGB_TO_CHAN_RGB(Fcolor[j], sum );
+           UNCLAMPED_FLOAT_TO_RGB_CHAN(Fcolor[j], sum );
         }
 
         j++;
@@ -709,11 +709,11 @@ static void TAG(light_fast_rgba)( GLcontext *ctx,
            }
         }
 
-        FLOAT_RGB_TO_CHAN_RGB( Fcolor[j], sum[0] );
+        UNCLAMPED_FLOAT_TO_RGB_CHAN( Fcolor[j], sum[0] );
         Fcolor[j][3] = sumA[0];
         
         if (IDX & LIGHT_TWOSIDE) {
-           FLOAT_RGB_TO_CHAN_RGB( Bcolor[j], sum[1] );
+           UNCLAMPED_FLOAT_TO_RGB_CHAN( Bcolor[j], sum[1] );
            Bcolor[j][3] = sumA[1];
         }
 

diff --git a/src/mesa/tnl/t_vb_render.c b/src/mesa/tnl/t_vb_render.c
index 1d0a1aa..b3fef23 100644 (file)
--- a/src/mesa/tnl/t_vb_render.c
+++ b/src/mesa/tnl/t_vb_render.c
@@ -1,4 +1,4 @@
-/* $Id: t_vb_render.c,v 1.4 2000/12/28 22:11:06 keithw Exp $ */
+/* $Id: t_vb_render.c,v 1.5 2001/01/03 15:59:31 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -119,19 +119,19 @@ do {                                                              \
 
 #if 1
 
-#define LINTERP_RGBA(nr, t, out, a, b) {               \
+#define LINTERP_RGBA(nr, t, out, a, b) {       \
    int i;                                      \
    for (i = 0; i < nr; i++) {                  \
       GLfloat fa = CHAN_TO_FLOAT(a[i]);                \
       GLfloat fb = CHAN_TO_FLOAT(b[i]);                \
       GLfloat fo = LINTERP(t, fa, fb);         \
-      FLOAT_COLOR_TO_CHAN(out[i], fo);         \
+      CLAMPED_FLOAT_TO_CHAN(out[i], fo);       \
    }                                           \
 }
 
 #else
 
-#define LINTERP_RGBA(nr, t, out, a, b) {                               \
+#define LINTERP_RGBA(nr, t, out, a, b) {                       \
    int n;                                                      \
    const GLuint ti = FloatToInt(t*256.0F);                     \
    const GLubyte *Ib = (const GLubyte *)&a[0];                 \