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/*
* A demonstration of using the GLX functions. This program is in the
* public domain.
*
* Brian Paul
*/
#include <GL/gl.h>
#include <GL/glx.h>
#include <stdio.h>
#include <stdlib.h>
static void redraw( Display *dpy, Window w )
{
printf("Redraw event\n");
glClear( GL_COLOR_BUFFER_BIT );
glColor3f( 1.0, 1.0, 0.0 );
glRectf( -0.8, -0.8, 0.8, 0.8 );
glXSwapBuffers( dpy, w );
}
static void resize( unsigned int width, unsigned int height )
{
printf("Resize event\n");
glViewport( 0, 0, width, height );
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glOrtho( -1.0, 1.0, -1.0, 1.0, -1.0, 1.0 );
}
static Window make_rgb_db_window( Display *dpy,
unsigned int width, unsigned int height )
{
int attrib[] = { 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;
GLXContext ctx;
XVisualInfo *visinfo;
scrnum = DefaultScreen( dpy );
root = RootWindow( dpy, scrnum );
visinfo = glXChooseVisual( dpy, scrnum, attrib );
if (!visinfo) {
printf("Error: couldn't get an RGB, Double-buffered visual\n");
exit(1);
}
/* window attributes */
attr.background_pixel = 0;
attr.border_pixel = 0;
attr.colormap = XCreateColormap( dpy, root, visinfo->visual, AllocNone);
attr.event_mask = StructureNotifyMask | ExposureMask | ButtonPressMask;
mask = CWBackPixel | CWBorderPixel | CWColormap | CWEventMask;
win = XCreateWindow( dpy, root, 0, 0, width, height,
0, visinfo->depth, InputOutput,
visinfo->visual, mask, &attr );
XStoreName(dpy, win, "GLXDemo");
ctx = glXCreateContext( dpy, visinfo, NULL, True );
if (!ctx) {
printf("Error: glXCreateContext failed\n");
exit(1);
}
glXMakeCurrent( dpy, win, ctx );
return win;
}
static void new_colour(Display *dpy, Window win)
{
GLfloat r, g, b;
r = (GLfloat)random() / (GLfloat)RAND_MAX;
g = (GLfloat)random() / (GLfloat)RAND_MAX;
b = (GLfloat)random() / (GLfloat)RAND_MAX;
glClearColor(r, g, b, 1.0);
redraw(dpy, win);
}
static void event_loop( Display *dpy )
{
XEvent event;
while (1) {
XNextEvent( dpy, &event );
switch (event.type) {
case Expose:
redraw( dpy, event.xany.window );
break;
case ConfigureNotify:
resize( event.xconfigure.width, event.xconfigure.height );
break;
case ButtonPress:
new_colour(dpy, event.xany.window);
break;
}
}
}
int main( int argc, char *argv[] )
{
Display *dpy;
Window win;
dpy = XOpenDisplay(NULL);
win = make_rgb_db_window( dpy, 300, 300 );
glShadeModel( GL_FLAT );
glClearColor( 0.5, 0.5, 0.5, 1.0 );
XMapWindow( dpy, win );
event_loop( dpy );
return 0;
}
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