1 files changed, 49 insertions, 13 deletions

diff --git a/progs/demos/shadowtex.c b/progs/demos/shadowtex.c
index 59253e8c1e..c2d40bda74 100644
--- a/progs/demos/shadowtex.c
+++ b/progs/demos/shadowtex.c
@@ -84,6 +84,7 @@ static const char *FragProgNames[] = {
    "program with \"OPTION ARB_fragment_program_shadow\"",
 };
 
+static GLboolean HaveShadow = GL_FALSE;
 static GLboolean HaveFBO = GL_FALSE;
 static GLboolean UseFBO = GL_FALSE;
 static GLboolean HaveVP = GL_FALSE;
@@ -529,7 +530,10 @@ ShowShadowMap(void)
    DisableTexgen();
 
    /* interpret texture's depth values as luminance values */
-   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB, GL_NONE);
+   if (HaveShadow) {
+      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB, GL_NONE);
+   }
+
    glTexParameteri(GL_TEXTURE_2D, GL_DEPTH_TEXTURE_MODE_ARB, GL_LUMINANCE);
    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
 
@@ -596,7 +600,9 @@ Display(void)
       }
 
       if (DisplayMode == SHOW_DEPTH_MAPPING) {
-         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB, GL_NONE);
+         if (HaveShadow) {
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB, GL_NONE);
+         }
          glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
          glEnable(GL_TEXTURE_2D);
 
@@ -614,8 +620,10 @@ Display(void)
       }
       else {
          assert(DisplayMode == SHOW_SHADOWS);
-         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB,
-                         GL_COMPARE_R_TO_TEXTURE_ARB);
+         if (HaveShadow) {
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB,
+                            GL_COMPARE_R_TO_TEXTURE_ARB);
+         }
 
          if (curr_frag > 0) {
             glEnable(GL_FRAGMENT_PROGRAM_ARB);
@@ -723,6 +731,10 @@ Key(unsigned char key, int x, int y)
          break;
       case 'M':
          curr_frag = (1 + curr_frag) % max_frag;
+         if (!HaveShadow && (curr_frag == 0)) {
+            curr_frag = 1;
+         }
+
          printf("Using fragment %s\n", FragProgNames[curr_frag]);
 
          if (HaveFP) {
@@ -740,8 +752,10 @@ Key(unsigned char key, int x, int y)
             if (Operator >= 8)
                Operator = 0;
             printf("Operator: %s\n", OperatorName[Operator]);
-            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC_ARB,
-                            OperatorFunc[Operator]);
+            if (HaveShadow) {
+               glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC_ARB,
+                               OperatorFunc[Operator]);
+            }
          }
          break;
       case 'p':
@@ -858,17 +872,31 @@ Init(void)
 {
    static const GLfloat borderColor[4] = {1.0, 0.0, 0.0, 0.0};
 
-   if (!glutExtensionSupported("GL_ARB_depth_texture") ||
-       !glutExtensionSupported("GL_ARB_shadow")) {
-      printf("Sorry, this demo requires the GL_ARB_depth_texture and GL_ARB_shadow extensions\n");
+   if (!glutExtensionSupported("GL_ARB_depth_texture")) {
+      printf("Sorry, this demo requires the GL_ARB_depth_texture extension\n");
       exit(1);
    }
-   printf("Using GL_ARB_depth_texture and GL_ARB_shadow\n");
 
+   HaveShadow = glutExtensionSupported("GL_ARB_shadow");
    HaveVP = glutExtensionSupported("GL_ARB_vertex_program");
    HaveFP = glutExtensionSupported("GL_ARB_fragment_program");
    HaveFP_Shadow = glutExtensionSupported("GL_ARB_fragment_program_shadow");
 
+   if (!HaveShadow && !HaveFP) {
+      printf("Sorry, this demo requires either the GL_ARB_shadow extension "
+	     "or the GL_ARB_fragment_program extension\n");
+      exit(1);
+   }
+
+   printf("Using GL_ARB_depth_texture\n");
+   if (HaveShadow) {
+      printf("and GL_ARB_shadow\n");
+   }
+
+   if (HaveFP) {
+      printf("and GL_ARB_fragment_program\n");
+   }
+
    HaveShadowAmbient = glutExtensionSupported("GL_ARB_shadow_ambient");
    if (HaveShadowAmbient) {
       printf("and GL_ARB_shadow_ambient\n");
@@ -895,9 +923,12 @@ Init(void)
    glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_BORDER_COLOR, borderColor);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
-   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB,
-                   GL_COMPARE_R_TO_TEXTURE_ARB);
-   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC_ARB, GL_LEQUAL);
+
+   if (HaveShadow) {
+      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB,
+                      GL_COMPARE_R_TO_TEXTURE_ARB);
+      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC_ARB, GL_LEQUAL);
+   }
 
    if (HaveShadowAmbient) {
       glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FAIL_VALUE_ARB, 0.3);
@@ -954,6 +985,11 @@ Init(void)
       max_frag = 3;
    }
 
+   if (!HaveShadow) {
+      curr_frag = 1;
+      glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, frag_progs[curr_frag]);
+   }
+
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);