/* cubev.c           */

/* E. Angel, Interactive Computer Graphics */
/* A Top-Down Approach with OpenGL, Third Edition */
/* Addison-Wesley Longman, 2003 */

/* rotating cube using vertex arrays */
#include <stdlib.h>#include <GL/glut.h>	GLfloat vertices[] = {-1.0,-1.0,-1.0,1.0,-1.0,-1.0,	1.0,1.0,-1.0, -1.0,1.0,-1.0, -1.0,-1.0,1.0, 	1.0,-1.0,1.0, 1.0,1.0,1.0, -1.0,1.0,1.0};	GLfloat colors[] = {0.0,0.0,0.0,1.0,0.0,0.0,	1.0,1.0,0.0, 0.0,1.0,0.0, 0.0,0.0,1.0, 	1.0,0.0,1.0, 1.0,1.0,1.0, 0.0,1.0,1.0};    GLubyte cubeIndices[]={0,3,2,1,2,3,7,6,0,4,7,3,1,2,6,5,4,5,6,7,0,1,5,4};static GLfloat theta[] = {0.0,0.0,0.0};static GLint axis = 2;void display(void){/* display callback, clear frame buffer and z buffer,   rotate cube and draw, swap buffers */    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);	glLoadIdentity();	gluLookAt(1.0,1.0,1.0,0.0,0.0,0.0,0.0,1.0,0.0);	glTranslatef(0.0, 3.0, 0.0);	glRotatef(theta[0], 1.0, 0.0, 0.0);	glRotatef(theta[1], 0.0, 1.0, 0.0);	glRotatef(theta[2], 0.0, 0.0, 1.0);    glColorPointer(3,GL_FLOAT, 0, colors);     glDrawElements(GL_QUADS, 24, GL_UNSIGNED_BYTE, cubeIndices);	glutSwapBuffers(); }void spinCube(){/* Idle callback, spin cube 2 degrees about selected axis */	theta[axis] += 2.0;	if( theta[axis] > 360.0 ) theta[axis] -= 360.0;	glutPostRedisplay();}void mouse(int btn, int state, int x, int y){/* mouse callback, selects an axis about which to rotate */	if(btn==GLUT_LEFT_BUTTON && state == GLUT_DOWN) axis = 0;	if(btn==GLUT_MIDDLE_BUTTON && state == GLUT_DOWN) axis = 1;	if(btn==GLUT_RIGHT_BUTTON && state == GLUT_DOWN) axis = 2;}void myReshape(int w, int h){    glViewport(0, 0, w, h);    glMatrixMode(GL_PROJECTION);    glLoadIdentity();    if (w <= h)        glOrtho(-4.0, 4.0, -3.0 * (GLfloat) h / (GLfloat) w,            5.0 * (GLfloat) h / (GLfloat) w, -10.0, 10.0);    else        glOrtho(-4.0 * (GLfloat) w / (GLfloat) h,            4.0 * (GLfloat) w / (GLfloat) h, -3.0, 5.0, -10.0, 10.0);    glMatrixMode(GL_MODELVIEW);}voidmain(int argc, char **argv){/* need both double buffering and z buffer */    glutInit(&argc, argv);    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);    glutInitWindowSize(500, 500);    glutCreateWindow("colorcube");    glutReshapeFunc(myReshape);    glutDisplayFunc(display);    glutIdleFunc(spinCube);    glutMouseFunc(mouse);    glEnable(GL_DEPTH_TEST); /* Enable hidden--surface--removal */ 	glEnableClientState(GL_COLOR_ARRAY); 	glEnableClientState(GL_VERTEX_ARRAY);	glVertexPointer(3, GL_FLOAT, 0, vertices);    glColorPointer(3,GL_FLOAT, 0, colors); 	glClearColor(1.0,1.0,1.0,1.0);	glColor3f(1.0,1.0,1.0);    glutMainLoop();}