/* * 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 #include "GL/glew.h" #include "GL/glut.h" #include "readtex.h" #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 PFNGLWINDOWPOS2FPROC WindowPosFunc; 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 ) { if (GLEW_ARB_window_pos) { printf("Using GL_ARB_window_pos\n"); WindowPosFunc = glWindowPos2fARB; } else if (GLEW_MESA_window_pos) { printf("Using GL_MESA_window_pos\n"); WindowPosFunc = glWindowPos2fMESA; } else { 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[] ) { glutInitWindowSize(500, 500); glutInit(&argc, argv); glutInitDisplayMode( GLUT_RGB ); if (glutCreateWindow("winpos") <= 0) { exit(0); } glewInit(); init(); glutReshapeFunc( reshape ); glutKeyboardFunc( key ); glutDisplayFunc( draw ); glutMainLoop(); return 0; }