test the standard stencil op modes too (Philipp Klaus Krause)

progs/tests/stencilwrap.c

@@ -10,73 +10,117 @@
 #include <math.h>
 #include <GL/glut.h>
 
+GLboolean wrapping;
 
 static void RunTest(void)
 {
    const GLenum prim = GL_QUAD_STRIP;
    GLubyte val;
    int bits, max, i;
+   int expected;
    GLboolean failed;
 
    glGetIntegerv(GL_STENCIL_BITS, &bits);
    max = (1 << bits) - 1;
 
-   glClearStencil(0);
+   
    glEnable(GL_STENCIL_TEST);
    glStencilFunc(GL_ALWAYS, 0, ~0);
 
-   /* test GL_INCR (saturation) */
+   /* test GL_KEEP */
+   glClearStencil(max);
    glClear(GL_STENCIL_BUFFER_BIT);
-   glStencilOp(GL_KEEP, GL_KEEP, GL_INCR);
+   glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
    failed = GL_FALSE;
-   printf("Testing GL_INCR...\n");
-   for (i = 1; i < max+10; i++) {
-      int expected = (i > max) ? max : i;
-      glBegin(prim);
-      glVertex2f(0, 0);      glVertex2f(10, 0);
-      glVertex2f(0, 10);      glVertex2f(10, 10);
-      glEnd();
-
-      glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
-      if (val != expected) {
-	 printf( "Failed GL_INCR test on iteration #%u "
-		 "(got %u, expected %u)\n", i, val, expected );
-	 failed = GL_TRUE;
-      }	   
+   printf("Testing GL_KEEP...\n");
+   expected = max;
+   glBegin(prim);
+   glVertex2f(0, 0);
+   glVertex2f(10, 0);
+   glVertex2f(0, 10);
+   glVertex2f(10, 10);
+   glEnd();
+   glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
+   if (val != expected) {
+      printf("Failed GL_KEEP test(got %u, expected %u)\n", val, expected);
+      failed = GL_TRUE;
    }
+   else
+      printf("OK!\n");
 
-   if ( !failed ) printf("OK!\n");
+   /* test GL_ZERO */
+   glClearStencil(max);
+   glClear(GL_STENCIL_BUFFER_BIT);
+   glStencilOp(GL_KEEP, GL_KEEP, GL_ZERO);
+   failed = GL_FALSE;
+   printf("Testing GL_ZERO...\n");
+   expected = 0;
+   glBegin(prim);
+   glVertex2f(0, 0);
+   glVertex2f(10, 0);
+   glVertex2f(0, 10);
+   glVertex2f(10, 10);
+   glEnd();
+   glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
+   if (val != expected) {
+      printf("Failed GL_ZERO test(got %u, expected %u)\n", val, expected);
+      failed = GL_TRUE;
+   }
+   else
+      printf("OK!\n");
 
+   /* test GL_REPLACE */
+   glClearStencil(max);
+   glClear(GL_STENCIL_BUFFER_BIT);
+   glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
+   failed = GL_FALSE;
+   printf("Testing GL_REPLACE...\n");
+   expected = 0;
+   glBegin(prim);
+   glVertex2f(0, 0);
+   glVertex2f(10, 0);
+   glVertex2f(0, 10);
+   glVertex2f(10, 10);
+   glEnd();
+   glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
+   if (val != expected) {
+      printf("Failed GL_REPLACE test(got %u, expected %u)\n", val, expected);
+      failed = GL_TRUE;
+   }
+   else
+      printf("OK!\n");
 
-   /* test GL_INCR_WRAP_EXT (wrap around) */
+   /* test GL_INCR (saturation) */
+   glClearStencil(0);
    glClear(GL_STENCIL_BUFFER_BIT);
-   glStencilOp(GL_KEEP, GL_KEEP, GL_INCR_WRAP_EXT);
+   glStencilOp(GL_KEEP, GL_KEEP, GL_INCR);
    failed = GL_FALSE;
-   printf("Testing GL_INCR_WRAP_EXT...\n");
+   printf("Testing GL_INCR...\n");
    for (i = 1; i < max+10; i++) {
-      int expected = i % (max + 1);
+      expected = (i > max) ? max : i;
       glBegin(prim);
       glVertex2f(0, 0);      glVertex2f(10, 0);
       glVertex2f(0, 10);      glVertex2f(10, 10);
       glEnd();
+
       glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
       if (val != expected) {
-	 printf( "Failed GL_INCR_WRAP test on iteration #%u "
+	 printf( "Failed GL_INCR test on iteration #%u "
 		 "(got %u, expected %u)\n", i, val, expected );
 	 failed = GL_TRUE;
       }	   
    }
-   if ( !failed ) printf("OK!\n");
+   if ( !failed )
+      printf("OK!\n");
 
+   /* test GL_DECR (saturation) */
    glClearStencil(max);
-
-   /* test GL_INCR (saturation) */
    glClear(GL_STENCIL_BUFFER_BIT);
    glStencilOp(GL_KEEP, GL_KEEP, GL_DECR);
    failed = GL_FALSE;
    printf("Testing GL_DECR...\n");
    for (i = max-1; i > -10; i--) {
-      int expected = (i < 0) ? 0 : i;
+      expected = (i < 0) ? 0 : i;
       glBegin(prim);
       glVertex2f(0, 0);      glVertex2f(10, 0);
       glVertex2f(0, 10);      glVertex2f(10, 10);
@@ -88,27 +132,76 @@ static void RunTest(void)
 	 failed = GL_TRUE;
       }	   
    }
-   if ( !failed ) printf("OK!\n");
+   if ( !failed )
+      printf("OK!\n");
 
-   /* test GL_INCR_WRAP_EXT (wrap-around) */
+   /* test GL_INVERT */
+   glClearStencil(0);
    glClear(GL_STENCIL_BUFFER_BIT);
-   glStencilOp(GL_KEEP, GL_KEEP, GL_DECR_WRAP_EXT);
+   glStencilOp(GL_KEEP, GL_KEEP, GL_INVERT);
    failed = GL_FALSE;
-   printf("Testing GL_DECR_WRAP_EXT...\n");
-   for (i = max-1; i > -10; i--) {
-      int expected = (i < 0) ? max + i + 1: i;
-      glBegin(prim);
-      glVertex2f(0, 0);      glVertex2f(10, 0);
-      glVertex2f(0, 10);      glVertex2f(10, 10);
-      glEnd();
-      glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
-      if (val != expected) {
-	 printf( "Failed GL_DECR_WRAP test on iteration #%u "
-		 "(got %u, expected %u)\n", max - i, val, expected );
-	 failed = GL_TRUE;
-      }	   
+   printf("Testing GL_INVERT...\n");
+   expected = max;
+   glBegin(prim);
+   glVertex2f(0, 0);
+   glVertex2f(10, 0);
+   glVertex2f(0, 10);
+   glVertex2f(10, 10);
+   glEnd();
+   glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
+   if (val != expected) {
+      printf("Failed GL_INVERT test(got %u, expected %u)\n", val, expected);
+      failed = GL_TRUE;
+   }
+   else
+      printf("OK!\n");
+
+   if(wrapping)
+   {
+      /* test GL_INCR_WRAP_EXT (wrap around) */
+      glClearStencil(0);
+      glClear(GL_STENCIL_BUFFER_BIT);
+      glStencilOp(GL_KEEP, GL_KEEP, GL_INCR_WRAP_EXT);
+      failed = GL_FALSE;
+      printf("Testing GL_INCR_WRAP_EXT...\n");
+      for (i = 1; i < max+10; i++) {
+         expected = i % (max + 1);
+         glBegin(prim);
+         glVertex2f(0, 0);      glVertex2f(10, 0);
+         glVertex2f(0, 10);      glVertex2f(10, 10);
+         glEnd();
+         glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
+         if (val != expected) {
+	    printf( "Failed GL_INCR_WRAP test on iteration #%u "
+		 "(got %u, expected %u)\n", i, val, expected );
+	    failed = GL_TRUE;
+         }	   
+      }
+      if ( !failed )
+         printf("OK!\n");
+
+      /* test GL_DECR_WRAP_EXT (wrap-around) */
+      glClearStencil(max);
+      glClear(GL_STENCIL_BUFFER_BIT);
+      glStencilOp(GL_KEEP, GL_KEEP, GL_DECR_WRAP_EXT);
+      failed = GL_FALSE;
+      printf("Testing GL_DECR_WRAP_EXT...\n");
+      for (i = max-1; i > -10; i--) {
+         expected = (i < 0) ? max + i + 1: i;
+         glBegin(prim);
+         glVertex2f(0, 0);      glVertex2f(10, 0);
+         glVertex2f(0, 10);      glVertex2f(10, 10);
+         glEnd();
+         glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
+         if (val != expected) {
+            printf( "Failed GL_DECR_WRAP test on iteration #%u "
+               "(got %u, expected %u)\n", max - i, val, expected );
+            failed = GL_TRUE;
+         }	   
+      }
+      if ( !failed )
+         printf("OK!\n");
    }
-   if ( !failed ) printf("OK!\n");
 
    glDisable(GL_STENCIL_TEST);
 }
@@ -158,7 +251,7 @@ static void Init( void )
 
 
    /* Check for both the extension string and GL version 1.4 on the
-    * outside chance that some silly vendor exports version 1.4 but doesn't
+    * outside chance that some vendor exports version 1.4 but doesn't
     * export the extension string.  The stencil-wrap modes are a required
     * part of GL 1.4.
     */
@@ -166,11 +259,9 @@ static void Init( void )
    ver_str = glGetString( GL_VERSION );
    version = (ver_str == NULL) ? 1.0 : atof( ver_str );
 
-   if ( !glutExtensionSupported("GL_EXT_stencil_wrap")
-	&& (version < 1.4) ) {
-      printf("Sorry, GL_EXT_stencil_wrap not supported.\n");
-      exit(1);
-   }
+   wrapping = (glutExtensionSupported("GL_EXT_stencil_wrap") || (version >= 1.4));
+   if (!wrapping)
+      printf("GL_EXT_stencil_wrap not supported. Only testing the rest.\n");
 }