ftp://ftp.smr.ru/pub/0/FreeBSD/releases/distfiles/xscreensaver-3.16.tar.gz

[xscreensaver] / hacks / glx / xlock-gl.c

diff --git a/hacks/glx/xlock-gl.c b/hacks/glx/xlock-gl.c
new file mode 100644 (file)
index 0000000..0256cf0
--- /dev/null
+++ b/hacks/glx/xlock-gl.c
@@ -0,0 +1,99 @@
+/* xlock-gl.c --- xscreensaver compatibility layer for xlockmore GL modules.
+ * xscreensaver, Copyright (c) 1997, 1998, 1999 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
+ * the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation.  No representations are made about the suitability of this
+ * software for any purpose.  It is provided "as is" without express or 
+ * implied warranty.
+ *
+ * This file, along with xlockmore.h, make it possible to compile an xlockmore
+ * GL module into a standalone program, and thus use it with xscreensaver.
+ * By Jamie Zawinski <jwz@jwz.org> on 31-May-97.
+ */
+
+#include <stdio.h>
+#include "screenhack.h"
+#include "xlockmoreI.h"
+
+#include <GL/gl.h>
+#include <GL/glx.h>
+
+/* Gag -- we use this to turn X errors from glXCreateContext() into
+   something that will actually make sense to the user.
+ */
+static XErrorHandler orig_ehandler = 0;
+static Bool got_error = 0;
+
+static int
+BadValue_ehandler (Display *dpy, XErrorEvent *error)
+{
+  if (error->error_code == BadValue)
+    {
+      got_error = True;
+      return 0;
+    }
+  else
+    return orig_ehandler (dpy, error);
+}
+
+
+GLXContext *
+init_GL(ModeInfo * mi)
+{
+  Display *dpy = mi->dpy;
+  Window window = mi->window;
+  Screen *screen = mi->xgwa.screen;
+  Visual *visual = mi->xgwa.visual;
+  GLXContext glx_context = 0;
+  XVisualInfo vi_in, *vi_out;
+  int out_count;
+
+  vi_in.screen = screen_number (screen);
+  vi_in.visualid = XVisualIDFromVisual (visual);
+  vi_out = XGetVisualInfo (dpy, VisualScreenMask|VisualIDMask,
+                          &vi_in, &out_count);
+  if (! vi_out) abort ();
+
+  {
+    XSync (dpy, False);
+    orig_ehandler = XSetErrorHandler (BadValue_ehandler);
+    glx_context = glXCreateContext (dpy, vi_out, 0, GL_TRUE);
+    XSync (dpy, False);
+    XSetErrorHandler (orig_ehandler);
+    if (got_error)
+      glx_context = 0;
+  }
+
+  XFree((char *) vi_out);
+
+  if (!glx_context)
+    {
+      fprintf(stderr, "%s: couldn't create GL context for visual 0x%x.\n",
+             progname, (unsigned int) XVisualIDFromVisual (visual));
+      exit(1);
+    }
+
+  glXMakeCurrent (dpy, window, glx_context);
+
+  {
+    GLboolean rgba_mode = 0;
+    glGetBooleanv(GL_RGBA_MODE, &rgba_mode);
+    if (!rgba_mode)
+      {
+       glIndexi (WhitePixelOfScreen (screen));
+       glClearIndex (BlackPixelOfScreen (screen));
+      }
+  }
+
+  /* GLXContext is already a pointer type.
+     Why this function returns a pointer to a pointer, I have no idea...
+   */
+  {
+    GLXContext *ptr = (GLXContext *) malloc(sizeof(GLXContext));
+    *ptr = glx_context;
+    return ptr;
+  }
+}