Introduction to GL Geb Thomas

Example Code int main(int argc, char **argv) { glutInit(&argc, argv); glutInitDisplayMode ( GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH); glutInitWindowPosition(100,100); glutInitWindowSize(300,300); glutCreateWindow ("square"); glClearColor(0.0, 0.0, 0.0, 0.0); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(0.0, 10.0, 0.0, 10.0, -1.0, 1.0); glutDisplayFunc(display); glutMainLoop(); return 0; void display(void) { glClear( GL_COLOR_BUFFER_BIT); glColor3f(0.0, 1.0, 0.0); glBegin(GL_POLYGON); glVertex3f(2.0, 4.0, 0.0); glVertex3f(8.0, 4.0, 0.0); glVertex3f(8.0, 6.0, 0.0); glVertex3f(2.0, 6.0, 0.0); glEnd(); glFlush(); }

What’s Going On? OpenGL – The graphics calls GLUT – Utility for opening windows Both have header files and libraries Opengl32.dll, glut32.dll opengl.h, glut32.h

Using GLUT To Initialize the Display glutInit(&argc, argv); glutInitDisplayMode ( GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);

Setting Up and Opening the Window glutInitWindowPosition(100,100); glutInitWindowSize(300,300); glutCreateWindow ("square");

Setting Up the Matrices glClearColor(0.0, 0.0, 0.0, 0.0); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(0.0, 10.0, 0.0, 10.0, -1.0, 1.0);

Defining the Drawing Routine glutDisplayFunc(display);

Drawing Some Stuff void display(void) { glClear( GL_COLOR_BUFFER_BIT); glColor3f(0.0, 1.0, 0.0); glBegin(GL_POLYGON); glVertex3f(2.0, 4.0, 0.0); glVertex3f(8.0, 4.0, 0.0); glVertex3f(8.0, 6.0, 0.0); glVertex3f(2.0, 6.0, 0.0); glEnd(); glFlush(); }

Repeating the Loop glutMainLoop();

Details are Here Good book: Open GL Programmer’s Guide