Mesa (master): softpipe: use shadow_compare4() to compare texcoord to four texture samples

[Brian Paul]

Module: Mesa
Branch: master
Commit: efe9faf0612778db2423a4f8835b318b95d9efd7
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=efe9faf0612778db2423a4f8835b318b95d9efd7

Author: Brian Paul <brianp at vmware.com>
Date:   Mon Jun 29 16:45:02 2009 -0600

softpipe: use shadow_compare4() to compare texcoord to four texture samples

---

 src/gallium/drivers/softpipe/sp_tex_sample.c |   90 ++++++++++++++++++++++----
 1 files changed, 78 insertions(+), 12 deletions(-)

diff --git a/src/gallium/drivers/softpipe/sp_tex_sample.c b/src/gallium/drivers/softpipe/sp_tex_sample.c
index 6af0fcb..a1d3bad 100644
--- a/src/gallium/drivers/softpipe/sp_tex_sample.c
+++ b/src/gallium/drivers/softpipe/sp_tex_sample.c
@@ -705,6 +705,9 @@ get_texel(const struct tgsi_sampler *tgsi_sampler,
  * Compare texcoord 'p' (aka R) against texture value 'rgba[0]'
  * When we sampled the depth texture, the depth value was put into all
  * RGBA channels.  We look at the red channel here.
+ * \param rgba  quad of (depth) texel values
+ * \param p  texture 'P' components for four pixels in quad
+ * \param j  which pixel in the quad to test [0..3]
  */
 static INLINE void
 shadow_compare(const struct pipe_sampler_state *sampler,
@@ -751,6 +754,78 @@ shadow_compare(const struct pipe_sampler_state *sampler,
 
 
 /**
+ * As above, but do four z/texture comparisons.
+ */
+static INLINE void
+shadow_compare4(const struct pipe_sampler_state *sampler,
+                float rgba[NUM_CHANNELS][QUAD_SIZE],
+                const float p[QUAD_SIZE])
+{
+   int j, k0, k1, k2, k3;
+   float val;
+
+   /* compare four texcoords vs. four texture samples */
+   switch (sampler->compare_func) {
+   case PIPE_FUNC_LESS:
+      k0 = p[0] < rgba[0][0];
+      k1 = p[1] < rgba[0][1];
+      k2 = p[2] < rgba[0][2];
+      k3 = p[3] < rgba[0][3];
+      break;
+   case PIPE_FUNC_LEQUAL:
+      k0 = p[0] <= rgba[0][0];
+      k1 = p[1] <= rgba[0][1];
+      k2 = p[2] <= rgba[0][2];
+      k3 = p[3] <= rgba[0][3];
+      break;
+   case PIPE_FUNC_GREATER:
+      k0 = p[0] > rgba[0][0];
+      k1 = p[1] > rgba[0][1];
+      k2 = p[2] > rgba[0][2];
+      k3 = p[3] > rgba[0][3];
+      break;
+   case PIPE_FUNC_GEQUAL:
+      k0 = p[0] >= rgba[0][0];
+      k1 = p[1] >= rgba[0][1];
+      k2 = p[2] >= rgba[0][2];
+      k3 = p[3] >= rgba[0][3];
+      break;
+   case PIPE_FUNC_EQUAL:
+      k0 = p[0] == rgba[0][0];
+      k1 = p[1] == rgba[0][1];
+      k2 = p[2] == rgba[0][2];
+      k3 = p[3] == rgba[0][3];
+      break;
+   case PIPE_FUNC_NOTEQUAL:
+      k0 = p[0] != rgba[0][0];
+      k1 = p[1] != rgba[0][1];
+      k2 = p[2] != rgba[0][2];
+      k3 = p[3] != rgba[0][3];
+      break;
+   case PIPE_FUNC_ALWAYS:
+      k0 = k1 = k2 = k3 = 1;
+      break;
+   case PIPE_FUNC_NEVER:
+      k0 = k1 = k2 = k3 = 0;
+      break;
+   default:
+      k0 = k1 = k2 = k3 = 0;
+      assert(0);
+      break;
+   }
+
+   /* convert four pass/fail values to an intensity in [0,1] */
+   val = 0.25F * (k0 + k1 + k2 + k3);
+
+   /* XXX returning result for default GL_DEPTH_TEXTURE_MODE = GL_LUMINANCE */
+   for (j = 0; j < 4; j++) {
+      rgba[0][j] = rgba[1][j] = rgba[2][j] = val;
+      rgba[3][j] = 1.0F;
+   }
+}
+
+
+/**
  * Common code for sampling 1D/2D/cube textures.
  * Could probably extend for 3D...
  */
@@ -832,10 +907,7 @@ sp_get_samples_2d_common(const struct tgsi_sampler *tgsi_sampler,
             get_texel(tgsi_sampler, faces[j], level0, x0[j], y1[j], 0, tx, 2);
             get_texel(tgsi_sampler, faces[j], level0, x1[j], y1[j], 0, tx, 3);
             if (sampler->compare_mode == PIPE_TEX_COMPARE_R_TO_TEXTURE) {
-               shadow_compare(sampler, tx, p, 0);
-               shadow_compare(sampler, tx, p, 1);
-               shadow_compare(sampler, tx, p, 2);
-               shadow_compare(sampler, tx, p, 3);
+               shadow_compare4(sampler, tx, p);
             }
 
             /* interpolate R, G, B, A */
@@ -857,10 +929,7 @@ sp_get_samples_2d_common(const struct tgsi_sampler *tgsi_sampler,
                get_texel(tgsi_sampler, faces[j], level1, x0[j], y1[j], 0, tx, 2);
                get_texel(tgsi_sampler, faces[j], level1, x1[j], y1[j], 0, tx, 3);
                if (sampler->compare_mode == PIPE_TEX_COMPARE_R_TO_TEXTURE){
-                  shadow_compare(sampler, tx, p, 0);
-                  shadow_compare(sampler, tx, p, 1);
-                  shadow_compare(sampler, tx, p, 2);
-                  shadow_compare(sampler, tx, p, 3);
+                  shadow_compare4(sampler, tx, p);
                }
 
                /* interpolate R, G, B, A */
@@ -1119,10 +1188,7 @@ sp_get_samples_rect(const struct tgsi_sampler *tgsi_sampler,
             get_texel(tgsi_sampler, face, level0, x0[j], y1[j], 0, tx, 2);
             get_texel(tgsi_sampler, face, level0, x1[j], y1[j], 0, tx, 3);
             if (sampler->compare_mode == PIPE_TEX_COMPARE_R_TO_TEXTURE) {
-               shadow_compare(sampler, tx, p, 0);
-               shadow_compare(sampler, tx, p, 1);
-               shadow_compare(sampler, tx, p, 2);
-               shadow_compare(sampler, tx, p, 3);
+               shadow_compare4(sampler, tx, p);
             }
             for (c = 0; c < 4; c++) {
                rgba[c][j] = lerp_2d(xw[j], yw[j],