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/* xlock-gl.c --- xscreensaver compatibility layer for xlockmore GL modules.
* xscreensaver, Copyright (c) 1997-2015 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 "xlockmoreI.h"
#include "texfont.h"
#ifndef isupper
# define isupper(c) ((c) >= 'A' && (c) <= 'Z')
#endif
#ifndef _tolower
# define _tolower(c) ((c) - 'A' + 'a')
#endif
/* 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;
XVisualInfo vi_in, *vi_out;
int out_count;
if (mi->glx_context) {
glXMakeCurrent (dpy, window, mi->glx_context);
return &mi->glx_context;
}
# ifdef HAVE_JWZGLES
jwzgles_make_current(jwzgles_make_state(state));
# endif
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);
mi->glx_context = glXCreateContext (dpy, vi_out, 0, GL_TRUE);
XSync (dpy, False);
XSetErrorHandler (orig_ehandler);
if (got_error)
mi->glx_context = 0;
}
XFree((char *) vi_out);
if (!mi->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, mi->glx_context);
{
GLboolean rgba_mode = 0;
glGetBooleanv(GL_RGBA_MODE, &rgba_mode);
if (!rgba_mode)
{
glIndexi (WhitePixelOfScreen (screen));
glClearIndex (BlackPixelOfScreen (screen));
}
}
/* 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);
}
/* Sometimes glDrawBuffer() throws "invalid op". Dunno why. Ignore. */
clear_gl_error ();
/* Process the -background argument. */
{
char *s = get_string_resource(mi->dpy, "background", "Background");
XColor c = { 0, };
if (! XParseColor (dpy, mi->xgwa.colormap, s, &c))
fprintf (stderr, "%s: can't parse color %s; using black.\n",
progname, s);
if (s) free (s);
glClearColor (c.red / 65535.0,
c.green / 65535.0,
c.blue / 65535.0,
1.0);
}
glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
/* GLXContext is already a pointer type.
Why this function returns a pointer to a pointer, I have no idea...
*/
return &mi->glx_context;
}
/* clear away any lingering error codes */
void
clear_gl_error (void)
{
while (glGetError() != GL_NO_ERROR)
;
}
/* 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_INVALID_FRAMEBUFFER_OPERATION
case GL_INVALID_FRAMEBUFFER_OPERATION:
e = "invalid framebuffer operation";
break;
#endif
#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);
}
/* Callback in xscreensaver_function_table, via xlockmore.c.
*/
Visual *
xlockmore_pick_gl_visual (Screen *screen)
{
/* pick the "best" visual by interrogating the GL library instead of
by asking Xlib. GL knows better.
*/
Visual *v = 0;
Display *dpy = DisplayOfScreen (screen);
char *string = get_string_resource (dpy, "visualID", "VisualID");
char *s;
if (string)
for (s = string; *s; s++)
if (isupper (*s)) *s = _tolower (*s);
if (!string || !*string ||
!strcmp (string, "gl") ||
!strcmp (string, "best") ||
!strcmp (string, "color") ||
!strcmp (string, "default"))
v = get_gl_visual (screen); /* from ../utils/visual-gl.c */
if (string)
free (string);
return v;
}
/* Callback in xscreensaver_function_table, via xlockmore.c.
*/
Bool
xlockmore_validate_gl_visual (Screen *screen, const char *name, Visual *visual)
{
return validate_gl_visual (stderr, screen, name, visual);
}
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