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/* $Id: winpos.c,v 1.6 2002/12/03 03:13:17 brianp Exp $ */
/*
* Example of how to use the GL_MESA_window_pos extension.
* Brian Paul This file is in the public domain.
*/
#include <math.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#ifdef _WIN32
#include <windows.h>
#endif
#define GL_GLEXT_PROTOTYPES
#include "GL/glut.h"
#include "readtex.c" /* a hack, I know */
#define IMAGE_FILE "../images/girl.rgb"
#ifndef M_PI
# define M_PI 3.14159265
#endif
static GLubyte *Image;
static int ImgWidth, ImgHeight;
static GLenum ImgFormat;
static void (*WindowPosFunc)(GLfloat x, GLfloat y);
static void draw( void )
{
GLfloat angle;
glClear( GL_COLOR_BUFFER_BIT );
for (angle = -45.0; angle <= 135.0; angle += 10.0) {
GLfloat x = 50.0 + 200.0 * cos( angle * M_PI / 180.0 );
GLfloat y = 50.0 + 200.0 * sin( angle * M_PI / 180.0 );
/* Don't need to worry about the modelview or projection matrices!!! */
(*WindowPosFunc)( x, y );
glDrawPixels( ImgWidth, ImgHeight, ImgFormat, GL_UNSIGNED_BYTE, Image );
}
glFinish();
}
static void key( unsigned char key, int x, int y )
{
(void) x;
(void) y;
switch (key) {
case 27:
exit(0);
}
}
/* new window size or exposure */
static void reshape( int width, int height )
{
glViewport(0, 0, (GLint)width, (GLint)height);
}
static void init( void )
{
#ifdef GL_ARB_window_pos
if (glutExtensionSupported("GL_ARB_window_pos")) {
printf("Using GL_ARB_window_pos\n");
WindowPosFunc = &glWindowPos2fARB;
}
else
#elif defined(GL_ARB_window_pos)
if (glutExtensionSupported("GL_MESA_window_pos")) {
printf("Using GL_MESA_window_pos\n");
WindowPosFunc = &glWindowPos2fMESA;
}
else
#endif
{
printf("Sorry, GL_ARB/MESA_window_pos extension not available.\n");
exit(1);
}
Image = LoadRGBImage( IMAGE_FILE, &ImgWidth, &ImgHeight, &ImgFormat );
if (!Image) {
printf("Couldn't read %s\n", IMAGE_FILE);
exit(0);
}
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
}
int main( int argc, char *argv[] )
{
glutInitWindowPosition(0, 0);
glutInitWindowSize(500, 500);
glutInitDisplayMode( GLUT_RGB );
if (glutCreateWindow("winpos") <= 0) {
exit(0);
}
init();
glutReshapeFunc( reshape );
glutKeyboardFunc( key );
glutDisplayFunc( draw );
glutMainLoop();
return 0;
}
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