fixed glXChooseVisual to return NULL if using Glide and user requests too deep of visual parameters

src/mesa/drivers/x11/fakeglx.c

@@ -1,4 +1,4 @@
-/* $Id: fakeglx.c,v 1.34.4.3 2000/10/05 17:38:03 brianp Exp $ */
+/* $Id: fakeglx.c,v 1.34.4.4 2000/11/03 02:35:54 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -858,7 +858,7 @@ Fake_glXChooseVisual( Display *dpy, int screen, int *list )
    int *parselist;
    XVisualInfo *vis;
    int min_ci = 0;
-   int min_red=0, min_green=0, min_blue=0;
+   int min_red=0, min_green=0, min_blue=0, min_alpha=0;
    GLboolean rgb_flag = GL_FALSE;
    GLboolean alpha_flag = GL_FALSE;
    GLboolean double_flag = GL_FALSE;
@@ -922,10 +922,8 @@ Fake_glXChooseVisual( Display *dpy, int screen, int *list )
 	    break;
 	 case GLX_ALPHA_SIZE:
 	    parselist++;
-            {
-               GLint size = *parselist++;
-               alpha_flag = size>0 ? 1 : 0;
-            }
+            min_alpha = *parselist++;
+            alpha_flag = (min_alpha > 0);
 	    break;
 	 case GLX_DEPTH_SIZE:
 	    parselist++;
@@ -1004,6 +1002,16 @@ Fake_glXChooseVisual( Display *dpy, int screen, int *list )
       }
    }
 
+   /* DEBUG
+   printf("glXChooseVisual:\n");
+   printf("  GLX_RED_SIZE = %d\n", min_red);
+   printf("  GLX_GREEN_SIZE = %d\n", min_green);
+   printf("  GLX_BLUE_SIZE = %d\n", min_blue);
+   printf("  GLX_ALPHA_SIZE = %d\n", min_alpha);
+   printf("  GLX_DEPTH_SIZE = %d\n", depth_size);
+   printf("  GLX_STENCIL_SIZE = %d\n", stencil_size);
+   */
+
    /*
     * Since we're only simulating the GLX extension this function will never
     * find any real GL visuals.  Instead, all we can do is try to find an RGB
@@ -1060,6 +1068,22 @@ Fake_glXChooseVisual( Display *dpy, int screen, int *list )
       else if (depth_size > 0)
          depth_size = DEFAULT_SOFTWARE_DEPTH_BITS; /*16*/
 
+      /* If using Glide, make sure we don't try to setup an impossible
+       * visual.  This fixes the Q3 bug in which 24-bit Z was being reported.
+       */
+      {
+         const char *fx = getenv("MESA_GLX_FX");
+         if (fx && fx[0] != 'd')
+            if (depth_size > 16 ||
+                stencil_size > 0 ||
+                (min_red > 1 && min_red > 5) ||
+                (min_green > 1 && min_green > 6) ||
+                (min_blue > 1 && min_blue > 5) ||
+                alpha_flag)
+               return NULL;
+      }
+
+
       /* we only support one size of stencil and accum buffers. */
       if (stencil_size > 0)
          stencil_size = STENCIL_BITS;