X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=hacks%2Fglx%2Fxlock-gl.c;h=0f313e52946f94f4b2229c0061741723133293c3;hb=ccb7f4903325f92555a9722bba74b58346654ba0;hp=828128617a052a824b97ee15bc34cb05373b359b;hpb=ce3185de9d9705e259f2b60dd4b5509007fa17d4;p=xscreensaver

diff --git a/hacks/glx/xlock-gl.c b/hacks/glx/xlock-gl.c
index 82812861..0f313e52 100644
--- a/hacks/glx/xlock-gl.c
+++ b/hacks/glx/xlock-gl.c
@@ -1,5 +1,5 @@
-/* xlock-gc.c --- xscreensaver compatibility layer for xlockmore GL modules.
- * xscreensaver, Copyright (c) 1997, 1998 Jamie Zawinski <jwz@jwz.org>
+/* xlock-gl.c --- xscreensaver compatibility layer for xlockmore GL modules.
+ * xscreensaver, Copyright (c) 1997-2002 Jamie Zawinski <jwz@jwz.org>
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that
@@ -19,6 +19,7 @@
 #include "xlockmoreI.h"
 
 #include <GL/gl.h>
+#include <GL/glu.h>
 #include <GL/glx.h>
 
 /* Gag -- we use this to turn X errors from glXCreateContext() into
@@ -88,6 +89,28 @@ init_GL(ModeInfo * mi)
       }
   }
 
+
+  /* jwz: the doc for glDrawBuffer says "The initial value is GL_FRONT
+     for single-buffered contexts, and GL_BACK for double-buffered
+     contexts."  However, I find that this is not always the case,
+     at least with Mesa 3.4.2 -- sometimes the default seems to be
+     GL_FRONT even when glGet(GL_DOUBLEBUFFER) is true.  So, let's
+     make sure.
+
+     Oh, hmm -- maybe this only happens when we are re-using the
+     xscreensaver window, and the previous GL hack happened to die with
+     the other buffer selected?  I'm not sure.  Anyway, this fixes it.
+   */
+  {
+    GLboolean d = False;
+    glGetBooleanv (GL_DOUBLEBUFFER, &d);
+    if (d)
+      glDrawBuffer (GL_BACK);
+    else
+      glDrawBuffer (GL_FRONT);
+  }
+
+
   /* GLXContext is already a pointer type.
      Why this function returns a pointer to a pointer, I have no idea...
    */
@@ -99,82 +122,40 @@ init_GL(ModeInfo * mi)
 }
 
 
-Visual *
-get_gl_visual (Screen *screen, char *name, char *class)
-{
-  char *string = get_string_resource (name, class);
-  XVisualInfo *vi = 0;
-  Bool done_once = False;
-
- AGAIN:
-  if (!string || !*string ||
-      !strcmp (string, "best") ||
-      !strcmp (string, "color") ||
-      !strcmp (string, "default"))
-    {
-      Display *dpy = DisplayOfScreen (screen);
-      int screen_num = screen_number (screen);
-      int attrs[20];
-      int i = 0;
-      Bool dbuf_p = !get_boolean_resource ("noBuffer", "NoBuffer");
-
-      done_once = True;
-
-      attrs[i++] = GLX_RGBA;
-      attrs[i++] = GLX_RED_SIZE;   attrs[i++] = 1;
-      attrs[i++] = GLX_GREEN_SIZE; attrs[i++] = 1;
-      attrs[i++] = GLX_BLUE_SIZE;  attrs[i++] = 1;
-      attrs[i++] = GLX_DEPTH_SIZE; attrs[i++] = 1;
-      if (dbuf_p)
-	attrs[i++] = GLX_DOUBLEBUFFER;
-      attrs[i++] = 0;
-
-      vi = glXChooseVisual (dpy, screen_num, attrs);
-      if (vi) goto DONE;
-
-      /* Try without double-buffering. */
-      attrs[i - 1] = 0;
-      vi = glXChooseVisual (dpy, screen_num, attrs);
-      if (vi) goto DONE;
-
-      /* Try mono. */
-      i = 0;
-      if (dbuf_p)
-	attrs[i++] = GLX_DOUBLEBUFFER;
-      attrs[i++] = 0;
-      vi = glXChooseVisual (dpy, screen_num, attrs);
-      if (vi) goto DONE;
-
-      /* Try mono without double-buffering. */
-      attrs[0] = 0;
-      vi = glXChooseVisual (dpy, screen_num, attrs);
-    }
+
 
- DONE:
-  {
-    Visual *v;
-    if (vi)
-      {
-	v = vi->visual;
-	XFree (vi);
-      }
-    else
-      {
-	v = get_visual (screen, string, False, True);
-	if (!v)
-	  {
-	    if (done_once)
-	      v = DefaultVisualOfScreen (screen);
-	    else
-	      {
-		free (string);
-		string = 0;
-		goto AGAIN;
-	      }
-	  }
-      }
+/* clear away any lingering error codes */
+void
+clear_gl_error (void)
+{
+  while (glGetError() != GL_NO_ERROR)
+    ;
+}
 
-    free (string);
-    return v;
+/* report a GL error. */
+void
+check_gl_error (const char *type)
+{
+  char buf[100];
+  GLenum i;
+  const char *e;
+  switch ((i = glGetError())) {
+  case GL_NO_ERROR: return;
+  case GL_INVALID_ENUM:          e = "invalid enum";      break;
+  case GL_INVALID_VALUE:         e = "invalid value";     break;
+  case GL_INVALID_OPERATION:     e = "invalid operation"; break;
+  case GL_STACK_OVERFLOW:        e = "stack overflow";    break;
+  case GL_STACK_UNDERFLOW:       e = "stack underflow";   break;
+  case GL_OUT_OF_MEMORY:         e = "out of memory";     break;
+#ifdef GL_TABLE_TOO_LARGE_EXT
+  case GL_TABLE_TOO_LARGE_EXT:   e = "table too large";   break;
+#endif
+#ifdef GL_TEXTURE_TOO_LARGE_EXT
+  case GL_TEXTURE_TOO_LARGE_EXT: e = "texture too large"; break;
+#endif
+  default:
+    e = buf; sprintf (buf, "unknown error %d", (int) i); break;
   }
+  fprintf (stderr, "%s: %s error: %s\n", progname, type, e);
+  exit (1);
 }