Test implementation of proposed GL_EXT_shadow_funcs extension. This just

generalizes the R/texture comparision operators to include all eight of
the depth test comparisons.

4 files changed, 119 insertions, 58 deletions

diff --git a/src/mesa/main/extensions.c b/src/mesa/main/extensions.c
index 9f0542395c..f9cdf07168 100644
--- a/src/mesa/main/extensions.c
+++ b/src/mesa/main/extensions.c
@@ -1,4 +1,4 @@
-/* $Id: extensions.c,v 1.70 2002/03/13 04:33:16 brianp Exp $ */
+/* $Id: extensions.c,v 1.71 2002/03/23 16:33:53 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -90,6 +90,7 @@ static struct {
    { ON,  "GL_EXT_polygon_offset",             F(EXT_polygon_offset) },
    { ON,  "GL_EXT_rescale_normal",             F(EXT_rescale_normal) },
    { OFF, "GL_EXT_secondary_color",            F(EXT_secondary_color) },
+   { OFF, "GL_EXT_shadow_funcs",               F(EXT_shadow_funcs) },
    { OFF, "GL_EXT_shared_texture_palette",     F(EXT_shared_texture_palette) },
    { OFF, "GL_EXT_stencil_wrap",               F(EXT_stencil_wrap) },
    { ON,  "GL_EXT_texture3D",                  F(EXT_texture3D) },
@@ -159,6 +160,7 @@ _mesa_enable_sw_extensions(GLcontext *ctx)
       "GL_EXT_histogram",
       "GL_EXT_paletted_texture",
       "GL_EXT_point_parameters",
+      "GL_EXT_shadow_funcs",
       "GL_EXT_secondary_color",
       "GL_EXT_shared_texture_palette",
       "GL_EXT_stencil_wrap",
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 807a7b24cc..a47b472c28 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -1,4 +1,4 @@
-/* $Id: mtypes.h,v 1.67 2002/03/16 00:53:15 brianp Exp $ */
+/* $Id: mtypes.h,v 1.68 2002/03/23 16:33:53 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -1408,6 +1408,7 @@ struct gl_extensions {
    GLboolean EXT_point_parameters;
    GLboolean EXT_polygon_offset;
    GLboolean EXT_rescale_normal;
+   GLboolean EXT_shadow_funcs;
    GLboolean EXT_secondary_color;
    GLboolean EXT_shared_texture_palette;
    GLboolean EXT_stencil_wrap;
diff --git a/src/mesa/main/texstate.c b/src/mesa/main/texstate.c
index 373cfdcce2..3eadc53e73 100644
--- a/src/mesa/main/texstate.c
+++ b/src/mesa/main/texstate.c
@@ -1,4 +1,4 @@
-/* $Id: texstate.c,v 1.65 2002/03/23 01:48:18 brianp Exp $ */
+/* $Id: texstate.c,v 1.66 2002/03/23 16:33:53 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -1125,6 +1125,16 @@ _mesa_TexParameterfv( GLenum target, GLenum pname, const GLfloat *params )
                FLUSH_VERTICES(ctx, _NEW_TEXTURE);
                texObj->CompareFunc = params[0];
             }
+            else if (ctx->Extensions.EXT_shadow_funcs &&
+                     (func == GL_EQUAL ||
+                      func == GL_NOTEQUAL ||
+                      func == GL_LESS ||
+                      func == GL_GREATER ||
+                      func == GL_ALWAYS ||
+                      func == GL_NEVER)) {
+               FLUSH_VERTICES(ctx, _NEW_TEXTURE);
+               texObj->CompareFunc = params[0];
+            }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM,
                            "glTexParameter(bad GL_TEXTURE_COMPARE_FUNC_ARB)");
diff --git a/src/mesa/swrast/s_texture.c b/src/mesa/swrast/s_texture.c
index a487bd8970..e1ba958417 100644
--- a/src/mesa/swrast/s_texture.c
+++ b/src/mesa/swrast/s_texture.c
@@ -1,4 +1,4 @@
-/* $Id: s_texture.c,v 1.56 2002/03/16 18:02:08 brianp Exp $ */
+/* $Id: s_texture.c,v 1.57 2002/03/23 16:33:53 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -2030,7 +2030,7 @@ sample_depth_texture( GLcontext *ctx, GLuint unit,
    const GLuint width = texImage->Width;
    const GLuint height = texImage->Height;
    const GLchan ambient = tObj->ShadowAmbient;
-   GLboolean lequal, gequal;
+   GLenum function;
    GLchan result;
 
    (void) unit;
@@ -2044,29 +2044,19 @@ sample_depth_texture( GLcontext *ctx, GLuint unit,
    if (tObj->CompareFlag) {
       /* GL_SGIX_shadow */
       if (tObj->CompareOperator == GL_TEXTURE_LEQUAL_R_SGIX) {
-         lequal = GL_TRUE;
-         gequal = GL_FALSE;
+         function = GL_LEQUAL;
       }
       else {
          ASSERT(tObj->CompareOperator == GL_TEXTURE_GEQUAL_R_SGIX);
-         lequal = GL_FALSE;
-         gequal = GL_TRUE;
+         function = GL_GEQUAL;
       }
    }
    else if (tObj->CompareMode == GL_COMPARE_R_TO_TEXTURE_ARB) {
       /* GL_ARB_shadow */
-      if (tObj->CompareFunc == GL_LEQUAL) {
-         lequal = GL_TRUE;
-         gequal = GL_FALSE;
-      }
-      else {
-         ASSERT(tObj->CompareFunc == GL_GEQUAL);
-         lequal = GL_FALSE;
-         gequal = GL_TRUE;
-      }
+      function = tObj->CompareFunc;
    }
    else {
-      lequal = gequal = GL_FALSE;
+      function = GL_NONE;  /* pass depth through as grayscale */
    }
 
    if (tObj->MagFilter == GL_NEAREST) {
@@ -2078,21 +2068,37 @@ sample_depth_texture( GLcontext *ctx, GLuint unit,
          COMPUTE_NEAREST_TEXEL_LOCATION(tObj->WrapT, texcoords[i][1], height, row);
          depthSample = *((const GLfloat *) texImage->Data + row * width + col);
 
-         if (lequal) {
-            if (texcoords[i][2] <= depthSample)
-               result = CHAN_MAX;
-            else
-               result = ambient;
-         }
-         else if (gequal) {
-            if (texcoords[i][2] >= depthSample)
-               result = CHAN_MAX;
-            else
-               result = ambient;
-         }
-         else {
-            /* no comparison */
+         switch (function) {
+         case GL_LEQUAL:
+            result = (texcoords[i][2] <= depthSample) ? CHAN_MAX : ambient;
+            break;
+         case GL_GEQUAL:
+            result = (texcoords[i][2] >= depthSample) ? CHAN_MAX : ambient;
+            break;
+         case GL_LESS:
+            result = (texcoords[i][2] < depthSample) ? CHAN_MAX : ambient;
+            break;
+         case GL_GREATER:
+            result = (texcoords[i][2] > depthSample) ? CHAN_MAX : ambient;
+            break;
+         case GL_EQUAL:
+            result = (texcoords[i][2] == depthSample) ? CHAN_MAX : ambient;
+            break;
+         case GL_NOTEQUAL:
+            result = (texcoords[i][2] != depthSample) ? CHAN_MAX : ambient;
+            break;
+         case GL_ALWAYS:
+            result = CHAN_MAX;
+            break;
+         case GL_NEVER:
+            result = ambient;
+            break;
+         case GL_NONE:
             CLAMPED_FLOAT_TO_CHAN(result, depthSample);
+            break;
+         default:
+            _mesa_problem(ctx, "Bad compare func in sample_depth_texture");
+            return;
          }
 
          switch (tObj->DepthMode) {
@@ -2181,8 +2187,8 @@ sample_depth_texture( GLcontext *ctx, GLuint unit,
             const GLfloat w11 = (       a) * (       b);
             const GLfloat depthSample = w00 * depth00 + w10 * depth10
                                       + w01 * depth01 + w11 * depth11;
-            if ((depthSample <= texcoords[i][2] && lequal) ||
-                (depthSample >= texcoords[i][2] && gequal)) {
+            if ((depthSample <= texcoords[i][2] && function == GL_LEQUAL) ||
+                (depthSample >= texcoords[i][2] && function == GL_GEQUAL)) {
                result  = ambient;
             }
             else {
@@ -2196,31 +2202,73 @@ sample_depth_texture( GLcontext *ctx, GLuint unit,
              */
             const GLfloat d = (CHAN_MAXF - (GLfloat) ambient) * 0.25F;
             GLfloat luminance = CHAN_MAXF;
-            if (lequal) {
-               if (depth00 <= texcoords[i][2])   luminance -= d;
-               if (depth01 <= texcoords[i][2])   luminance -= d;
-               if (depth10 <= texcoords[i][2])   luminance -= d;
-               if (depth11 <= texcoords[i][2])   luminance -= d;
+
+            switch (function) {
+            case GL_LEQUAL:
+               if (depth00 <= texcoords[i][2])  luminance -= d;
+               if (depth01 <= texcoords[i][2])  luminance -= d;
+               if (depth10 <= texcoords[i][2])  luminance -= d;
+               if (depth11 <= texcoords[i][2])  luminance -= d;
                result = (GLchan) luminance;
-            }
-            else if (gequal) {
-               if (depth00 >= texcoords[i][2])   luminance -= d;
-               if (depth01 >= texcoords[i][2])   luminance -= d;
-               if (depth10 >= texcoords[i][2])   luminance -= d;
-               if (depth11 >= texcoords[i][2])   luminance -= d;
+               break;
+            case GL_GEQUAL:
+               if (depth00 >= texcoords[i][2])  luminance -= d;
+               if (depth01 >= texcoords[i][2])  luminance -= d;
+               if (depth10 >= texcoords[i][2])  luminance -= d;
+               if (depth11 >= texcoords[i][2])  luminance -= d;
                result = (GLchan) luminance;
-            }
-            else {
-               /* no comparison, just bilinear sampling */
-               const GLfloat a = FRAC(u + 1.0F);
-               const GLfloat b = FRAC(v + 1.0F);
-               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);
-               const GLfloat depthSample = w00 * depth00 + w10 * depth10
-                                         + w01 * depth01 + w11 * depth11;
-               CLAMPED_FLOAT_TO_CHAN(result, depthSample);
+               break;
+            case GL_LESS:
+               if (depth00 < texcoords[i][2])  luminance -= d;
+               if (depth01 < texcoords[i][2])  luminance -= d;
+               if (depth10 < texcoords[i][2])  luminance -= d;
+               if (depth11 < texcoords[i][2])  luminance -= d;
+               result = (GLchan) luminance;
+               break;
+            case GL_GREATER:
+               if (depth00 > texcoords[i][2])  luminance -= d;
+               if (depth01 > texcoords[i][2])  luminance -= d;
+               if (depth10 > texcoords[i][2])  luminance -= d;
+               if (depth11 > texcoords[i][2])  luminance -= d;
+               result = (GLchan) luminance;
+               break;
+            case GL_EQUAL:
+               if (depth00 == texcoords[i][2])  luminance -= d;
+               if (depth01 == texcoords[i][2])  luminance -= d;
+               if (depth10 == texcoords[i][2])  luminance -= d;
+               if (depth11 == texcoords[i][2])  luminance -= d;
+               result = (GLchan) luminance;
+               break;
+            case GL_NOTEQUAL:
+               if (depth00 != texcoords[i][2])  luminance -= d;
+               if (depth01 != texcoords[i][2])  luminance -= d;
+               if (depth10 != texcoords[i][2])  luminance -= d;
+               if (depth11 != texcoords[i][2])  luminance -= d;
+               result = (GLchan) luminance;
+               break;
+            case GL_ALWAYS:
+               result = 0;
+               break;
+            case GL_NEVER:
+               result = CHAN_MAXF;
+               break;
+            case GL_NONE:
+               /* ordinary bilinear filtering */
+               {
+                  const GLfloat a = FRAC(u + 1.0F);
+                  const GLfloat b = FRAC(v + 1.0F);
+                  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);
+                  const GLfloat depthSample = w00 * depth00 + w10 * depth10
+                                            + w01 * depth01 + w11 * depth11;
+                  CLAMPED_FLOAT_TO_CHAN(result, depthSample);
+               }
+               break;
+            default:
+               _mesa_problem(ctx, "Bad compare func in sample_depth_texture");
+               return;
             }
          }