do some 16-bit GLchan computations in floating point (Gerk Huisma)

diff --git a/src/mesa/swrast/s_texture.c b/src/mesa/swrast/s_texture.c
index fa450db3fdbbd16b3a324d968257a12a3dae7dc2..f5c974214d1cebf3702a2c25337df0bf4f8af22b 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 1.34 2001/07/14 17:53:04 brianp Exp $ */
+/* $Id: s_texture.c,v 1.35 2001/07/18 14:10:51 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -324,15 +324,14 @@ sample_1d_linear(GLcontext *ctx,
    {
       const GLfloat a = FRAC(u);
 
-#if CHAN_TYPE == GL_FLOAT
+#if CHAN_TYPE == GL_FLOAT || CHAN_TYPE == GL_UNSIGNED_SHORT
       const GLfloat w0 = (1.0F-a);
       const GLfloat w1 =       a ;
-#else /* CHAN_BITS == 8 || CHAN_BITS == 16 */
+#else /* CHAN_BITS == 8 */
       /* compute sample weights in fixed point in [0,WEIGHT_SCALE] */
       const GLint w0 = IROUND_POS((1.0F - a) * WEIGHT_SCALE);
       const GLint w1 = IROUND_POS(        a  * WEIGHT_SCALE);
 #endif
-
       GLchan t0[4], t1[4];  /* texels */
 
       if (useBorderColor & I0BIT) {
@@ -359,7 +358,12 @@ sample_1d_linear(GLcontext *ctx,
       rgba[1] = w0 * t0[1] + w1 * t1[1];
       rgba[2] = w0 * t0[2] + w1 * t1[2];
       rgba[3] = w0 * t0[3] + w1 * t1[3];
-#else /* CHAN_BITS == 8 || CHAN_BITS == 16 */
+#elif CHAN_TYPE == GL_UNSIGNED_SHORT
+      rgba[0] = (GLchan) (w0 * t0[0] + w1 * t1[0] + 0.5);
+      rgba[1] = (GLchan) (w0 * t0[1] + w1 * t1[1] + 0.5);
+      rgba[2] = (GLchan) (w0 * t0[2] + w1 * t1[2] + 0.5);
+      rgba[3] = (GLchan) (w0 * t0[3] + w1 * t1[3] + 0.5);
+#else /* CHAN_BITS == 8 */
       rgba[0] = (GLchan) ((w0 * t0[0] + w1 * t1[0]) >> WEIGHT_SHIFT);
       rgba[1] = (GLchan) ((w0 * t0[1] + w1 * t1[1]) >> WEIGHT_SHIFT);
       rgba[2] = (GLchan) ((w0 * t0[2] + w1 * t1[2]) >> WEIGHT_SHIFT);
@@ -647,19 +651,18 @@ sample_2d_linear(GLcontext *ctx,
       const GLfloat a = FRAC(u);
       const GLfloat b = FRAC(v);
 
-#if CHAN_TYPE == GL_FLOAT
+#if CHAN_TYPE == GL_FLOAT || CHAN_TYPE == GL_UNSIGNED_SHORT
       const GLfloat w00 = (1.0F-a) * (1.0F-b);
       const GLfloat w10 =       a  * (1.0F-b);
       const GLfloat w01 = (1.0F-a) *       b ;
       const GLfloat w11 =       a  *       b ;
-#else /* CHAN_BITS == 8 || CHAN_BITS == 16 */
+#else /* CHAN_BITS == 8 */
       /* compute sample weights in fixed point in [0,WEIGHT_SCALE] */
       const GLint w00 = IROUND_POS((1.0F-a) * (1.0F-b) * WEIGHT_SCALE);
       const GLint w10 = IROUND_POS(      a  * (1.0F-b) * WEIGHT_SCALE);
       const GLint w01 = IROUND_POS((1.0F-a) *       b  * WEIGHT_SCALE);
       const GLint w11 = IROUND_POS(      a  *       b  * WEIGHT_SCALE);
 #endif
-
       GLchan t00[4];
       GLchan t10[4];
       GLchan t01[4];
@@ -706,11 +709,24 @@ sample_2d_linear(GLcontext *ctx,
       rgba[1] = w00 * t00[1] + w10 * t10[1] + w01 * t01[1] + w11 * t11[1];
       rgba[2] = w00 * t00[2] + w10 * t10[2] + w01 * t01[2] + w11 * t11[2];
       rgba[3] = w00 * t00[3] + w10 * t10[3] + w01 * t01[3] + w11 * t11[3];
-#else /* CHAN_BITS == 8 || CHAN_BITS == 16 */
-      rgba[0] = (GLchan) ((w00 * t00[0] + w10 * t10[0] + w01 * t01[0] + w11 * t11[0]) >> WEIGHT_SHIFT);
-      rgba[1] = (GLchan) ((w00 * t00[1] + w10 * t10[1] + w01 * t01[1] + w11 * t11[1]) >> WEIGHT_SHIFT);
-      rgba[2] = (GLchan) ((w00 * t00[2] + w10 * t10[2] + w01 * t01[2] + w11 * t11[2]) >> WEIGHT_SHIFT);
-      rgba[3] = (GLchan) ((w00 * t00[3] + w10 * t10[3] + w01 * t01[3] + w11 * t11[3]) >> WEIGHT_SHIFT);
+#elif CHAN_TYPE == GL_UNSIGNED_SHORT
+      rgba[0] = (GLchan) (w00 * t00[0] + w10 * t10[0] +
+                          w01 * t01[0] + w11 * t11[0] + 0.5);
+      rgba[1] = (GLchan) (w00 * t00[1] + w10 * t10[1] +
+                          w01 * t01[1] + w11 * t11[1] + 0.5);
+      rgba[2] = (GLchan) (w00 * t00[2] + w10 * t10[2] +
+                          w01 * t01[2] + w11 * t11[2] + 0.5);
+      rgba[3] = (GLchan) (w00 * t00[3] + w10 * t10[3] +
+                          w01 * t01[3] + w11 * t11[3] + 0.5);
+#else /* CHAN_BITS == 8 */
+      rgba[0] = (GLchan) ((w00 * t00[0] + w10 * t10[0] +
+                           w01 * t01[0] + w11 * t11[0]) >> WEIGHT_SHIFT);
+      rgba[1] = (GLchan) ((w00 * t00[1] + w10 * t10[1] +
+                           w01 * t01[1] + w11 * t11[1]) >> WEIGHT_SHIFT);
+      rgba[2] = (GLchan) ((w00 * t00[2] + w10 * t10[2] +
+                           w01 * t01[2] + w11 * t11[2]) >> WEIGHT_SHIFT);
+      rgba[3] = (GLchan) ((w00 * t00[3] + w10 * t10[3] +
+                           w01 * t01[3] + w11 * t11[3]) >> WEIGHT_SHIFT);
 #endif
 
    }
@@ -1092,7 +1108,7 @@ sample_3d_linear(GLcontext *ctx,
       const GLfloat b = FRAC(v);
       const GLfloat c = FRAC(w);
 
-#if CHAN_TYPE == GL_FLOAT
+#if CHAN_TYPE == GL_FLOAT || CHAN_TYPE == GL_UNSIGNED_SHORT
       /* compute sample weights in fixed point in [0,WEIGHT_SCALE] */
       GLfloat w000 = (1.0F-a) * (1.0F-b) * (1.0F-c);
       GLfloat w100 =       a  * (1.0F-b) * (1.0F-c);
@@ -1102,7 +1118,7 @@ sample_3d_linear(GLcontext *ctx,
       GLfloat w101 =       a  * (1.0F-b) *       c ;
       GLfloat w011 = (1.0F-a) *       b  *       c ;
       GLfloat w111 =       a  *       b  *       c ;
-#else /* CHAN_BITS == 8 || CHAN_BITS == 16 */
+#else /* CHAN_BITS == 8 */
       /* compute sample weights in fixed point in [0,WEIGHT_SCALE] */
       GLint w000 = IROUND_POS((1.0F-a) * (1.0F-b) * (1.0F-c) * WEIGHT_SCALE);
       GLint w100 = IROUND_POS(      a  * (1.0F-b) * (1.0F-c) * WEIGHT_SCALE);
@@ -1200,7 +1216,24 @@ sample_3d_linear(GLcontext *ctx,
                 w100*t100[2] + w110*t110[2] + w101*t101[2] + w111*t111[2];
       rgba[3] = w000*t000[3] + w010*t010[3] + w001*t001[3] + w011*t011[3] +
                 w100*t100[3] + w110*t110[3] + w101*t101[3] + w111*t111[3];
-#else /* CHAN_BITS == 8 || CHAN_BITS == 16 */
+#elif CHAN_TYPE == GL_UNSIGNED_SHORT
+      rgba[0] = (GLchan) (w000*t000[0] + w010*t010[0] +
+                          w001*t001[0] + w011*t011[0] +
+                          w100*t100[0] + w110*t110[0] +
+                          w101*t101[0] + w111*t111[0] + 0.5);
+      rgba[1] = (GLchan) (w000*t000[1] + w010*t010[1] +
+                          w001*t001[1] + w011*t011[1] +
+                          w100*t100[1] + w110*t110[1] +
+                          w101*t101[1] + w111*t111[1] + 0.5);
+      rgba[2] = (GLchan) (w000*t000[2] + w010*t010[2] +
+                          w001*t001[2] + w011*t011[2] +
+                          w100*t100[2] + w110*t110[2] +
+                          w101*t101[2] + w111*t111[2] + 0.5);
+      rgba[3] = (GLchan) (w000*t000[3] + w010*t010[3] +
+                          w001*t001[3] + w011*t011[3] +
+                          w100*t100[3] + w110*t110[3] +
+                          w101*t101[3] + w111*t111[3] + 0.5);
+#else /* CHAN_BITS == 8 */
       rgba[0] = (GLchan) (
                  (w000*t000[0] + w010*t010[0] + w001*t001[0] + w011*t011[0] +
                   w100*t100[0] + w110*t110[0] + w101*t101[0] + w111*t111[0] )