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/*
* A demonstration of using the GLXPixmap functions. This program is in
* the public domain.
*
* Brian Paul
*/
#include <GL/gl.h>
#define GLX_GLXEXT_PROTOTYPES
#include <GL/glx.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
static GLXContext ctx;
static XVisualInfo *visinfo;
static GC gc;
static Window make_rgb_window( Display *dpy,
unsigned int width, unsigned int height )
{
const int sbAttrib[] = { GLX_RGBA,
GLX_RED_SIZE, 1,
GLX_GREEN_SIZE, 1,
GLX_BLUE_SIZE, 1,
None };
const int dbAttrib[] = { GLX_RGBA,
GLX_RED_SIZE, 1,
GLX_GREEN_SIZE, 1,
GLX_BLUE_SIZE, 1,
GLX_DOUBLEBUFFER,
None };
int scrnum;
XSetWindowAttributes attr;
unsigned long mask;
Window root;
Window win;
scrnum = DefaultScreen( dpy );
root = RootWindow( dpy, scrnum );
visinfo = glXChooseVisual( dpy, scrnum, (int *) sbAttrib );
if (!visinfo) {
visinfo = glXChooseVisual( dpy, scrnum, (int *) dbAttrib );
if (!visinfo) {
printf("Error: couldn't get an RGB visual\n");
exit(1);
}
}
/* window attributes */
attr.background_pixel = 0;
attr.border_pixel = 0;
/* TODO: share root colormap if possible */
attr.colormap = XCreateColormap( dpy, root, visinfo->visual, AllocNone);
attr.event_mask = StructureNotifyMask | ExposureMask;
mask = CWBackPixel | CWBorderPixel | CWColormap | CWEventMask;
win = XCreateWindow( dpy, root, 0, 0, width, height,
0, visinfo->depth, InputOutput,
visinfo->visual, mask, &attr );
/* make an X GC so we can do XCopyArea later */
gc = XCreateGC( dpy, win, 0, NULL );
/* need indirect context */
ctx = glXCreateContext( dpy, visinfo, NULL, False );
if (!ctx) {
printf("Error: glXCreateContext failed\n");
exit(-1);
}
printf("Direct rendering: %s\n", glXIsDirect(dpy, ctx) ? "Yes" : "No");
return win;
}
static GLXPixmap make_pixmap( Display *dpy, Window win,
unsigned int width, unsigned int height,
Pixmap *pixmap)
{
Pixmap pm;
GLXPixmap glxpm;
XWindowAttributes attr;
pm = XCreatePixmap( dpy, win, width, height, visinfo->depth );
if (!pm) {
printf("Error: XCreatePixmap failed\n");
exit(-1);
}
XGetWindowAttributes( dpy, win, &attr );
/*
* IMPORTANT:
* Use the glXCreateGLXPixmapMESA funtion when using Mesa because
* Mesa needs to know the colormap associated with a pixmap in order
* to render correctly. This is because Mesa allows RGB rendering
* into any kind of visual, not just TrueColor or DirectColor.
*/
#ifdef GLX_MESA_pixmap_colormap
if (strstr(glXQueryExtensionsString(dpy, 0), "GLX_MESA_pixmap_colormap")) {
/* stand-alone Mesa, specify the colormap */
glxpm = glXCreateGLXPixmapMESA( dpy, visinfo, pm, attr.colormap );
}
else {
glxpm = glXCreateGLXPixmap( dpy, visinfo, pm );
}
#else
/* This will work with Mesa too if the visual is TrueColor or DirectColor */
glxpm = glXCreateGLXPixmap( dpy, visinfo, pm );
#endif
if (!glxpm) {
printf("Error: GLXCreateGLXPixmap failed\n");
exit(-1);
}
*pixmap = pm;
return glxpm;
}
static void event_loop( Display *dpy, GLXPixmap pm )
{
XEvent event;
while (1) {
XNextEvent( dpy, &event );
switch (event.type) {
case Expose:
printf("Redraw\n");
/* copy the image from GLXPixmap to window */
XCopyArea( dpy, pm, event.xany.window, /* src, dest */
gc, 0, 0, 300, 300, /* gc, src pos, size */
0, 0 ); /* dest pos */
break;
case ConfigureNotify:
/* nothing */
break;
}
}
}
int main( int argc, char *argv[] )
{
Display *dpy;
Window win;
Pixmap pm;
GLXPixmap glxpm;
dpy = XOpenDisplay(NULL);
win = make_rgb_window( dpy, 300, 300 );
glxpm = make_pixmap( dpy, win, 300, 300, &pm );
glXMakeCurrent( dpy, glxpm, ctx );
printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
/* Render an image into the pixmap */
glShadeModel( GL_FLAT );
glClearColor( 0.5, 0.5, 0.5, 1.0 );
glClear( GL_COLOR_BUFFER_BIT );
glViewport( 0, 0, 300, 300 );
glOrtho( -1.0, 1.0, -1.0, 1.0, -1.0, 1.0 );
glColor3f( 0.0, 1.0, 1.0 );
glRectf( -0.75, -0.75, 0.75, 0.75 );
glFlush();
glXWaitGL();
XMapWindow( dpy, win );
event_loop( dpy, pm );
return 0;
}
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