A code template for OpenGL / GLUT

Submitted by:Tim Kelly

Date added:29 May, 2016

Category:C++

A Template for building OpenGL applications using GLUT.

Tags: template building , glut

Code Snippet:

<pre> /***********************************************************
* A Template for building OpenGL applications using GLUT
*
* Author: Perspective @ cprogramming.com
* Date : Jan, 2005
*
* Description:
* This code initializes an OpenGL ready window
* using GLUT. Some of the most common callbacks
* are registered to empty or minimal functions.
*
* This code is intended to be a quick starting point
* when building GLUT applications.
*
***********************************************************/

//#include <windows.h>
#include <iostream>
#include <GL/glut.h>


/* process menu option 'op' */
void menu(int op) {

switch(op) {
case 'Q':
case 'q':
exit(0);
}
}

/* executed when a regular key is pressed */
void keyboardDown(unsigned char key, int x, int y) {

switch(key) {
case 'Q':
case 'q':
case 27: // ESC
exit(0);
}
}

/* executed when a regular key is released */
void keyboardUp(unsigned char key, int x, int y) {

}

/* executed when a special key is pressed */
void keyboardSpecialDown(int k, int x, int y) {

}

/* executed when a special key is released */
void keyboardSpecialUp(int k, int x, int y) {

}

/* reshaped window */
void reshape(int width, int height) {

GLfloat fieldOfView = 90.0f;
glViewport (0, 0, (GLsizei) width, (GLsizei) height);

glMatrixMode (GL_PROJECTION);
glLoadIdentity();
gluPerspective(fieldOfView, (GLfloat) width/(GLfloat) height, 0.1, 500.0);

glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}

/* executed when button 'button' is put into state 'state' at screen position ('x', 'y') */
void mouseClick(int button, int state, int x, int y) {

}

/* executed when the mouse moves to position ('x', 'y') */
void mouseMotion(int x, int y) {

}

/* render the scene */
void draw() {

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();

/* render the scene here */

glFlush();
glutSwapBuffers();
}

/* executed when program is idle */
void idle() {

}

/* initialize OpenGL settings */
void initGL(int width, int height) {

reshape(width, height);

glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glClearDepth(1.0f);

glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
}

/* initialize GLUT settings, register callbacks, enter main loop */
int main(int argc, char** argv) {

glutInit(&argc, argv);

glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(800, 600);
glutInitWindowPosition(100, 100);
glutCreateWindow("Perspective's GLUT Template");

// register glut call backs
glutKeyboardFunc(keyboardDown);
glutKeyboardUpFunc(keyboardUp);
glutSpecialFunc(keyboardSpecialDown);
glutSpecialUpFunc(keyboardSpecialUp);
glutMouseFunc(mouseClick);
glutMotionFunc(mouseMotion);
glutReshapeFunc(reshape);
glutDisplayFunc(draw);
glutIdleFunc(idle);
glutIgnoreKeyRepeat(true); // ignore keys held down

// create a sub menu
int subMenu = glutCreateMenu(menu);
glutAddMenuEntry("Do nothing", 0);
glutAddMenuEntry("Really Quit", 'q');

// create main "right click" menu
glutCreateMenu(menu);
glutAddSubMenu("Sub Menu", subMenu);
glutAddMenuEntry("Quit", 'q');
glutAttachMenu(GLUT_RIGHT_BUTTON);

initGL(800, 600);

glutMainLoop();
return 0;
}
</pre>
 
 

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