#include <GL/glut.h> void display(void) { /* clear all pixels */ glClear (GL_COLOR_BUFFER_BIT). /* draw white polygon (rectangle) with corners at * (0.25, 0.25, 0.0) and (0.75, 0.75, 0.0) */ glColor3f (1.0, 1.0, 1.0). glBegin(GL_POLYGON). glVertex3f (0.25, 0.25, 0.0). glVertex3f (0.75, 0.25, 0.0). glVertex3f (0.75, 0.75, 0.0). glVertex3f (0.25, 0.75, 0.0). glEnd(). /* don t wait! * start processing buffered OpenGL routines */ glFlush (). } void init (void) { /* 0select clearing color */ glClearColor (0.0, 0.0, 0.0, 0.0). /* initialize viewing values */ glMatrixMode(GL_PROJECTION). glLoadIdentity(). glOrtho(0.0, 1.0, 0.0, 1.0, -1.0, 1.0). } /* * Declare initial window size, position, and display mode * (single buffer and RGBA). Open window with "hello" * in its title bar. Call initialization routines. * Register callback function to display graphics. * Enter main loop and process events. */ int main(int argc, char** argv) { glutInit(&.argc, argv). glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB). glutInitWindowSize (250, 250). glutInitWindowPosition (100, 100). glutCreateWindow ("hello"). init (). glutDisplayFunc(display). glutMainLoop(). return 0. /* ANSI C requires main to return int. */ }
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