/* rotate3d.cpp written by detour@metalshell.com
 *
 * Shows how to draw and rotate a 3d object.
 *
 *
 * In order to get this to compile you must have the opengl
 * libraries, and header files.  Be sure to include opengl32.lib
 * glut32.lib and glu32.lib when compiling. 
 *
 * http://www.metalshell.com/
 *
 */
 
#include <windows.h>
#include <gl/Gl.h>
#include <gl/Glu.h>
#include <gl/glut.h>
 
void doInit() {
    /* Background and foreground color */
    glClearColor(0.0,0.0,0.0,0.0);
    glColor3f(1.0,1.0,1.0);
    glViewport(0,0,640,480);
 
    /* Select the projection matrix and reset it then
       setup our view perspective */
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(20.0f,(GLfloat)640/(GLfloat)480,0.1f,100.0f);    
    /* Select the modelview matrix, which we alter with rotatef() */
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
 
    glClearDepth(2.0f);
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LEQUAL);
}
 
void drawTriangle(double rang) {
 
    /* Clear the screen with the clearcolor */
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    /* Reset the modelview matrix */
    glLoadIdentity();
    /* Move it back 13 to bring into view */
    glTranslatef(0.0f,0.0f,-13.0f);
    /* Rotate around the y-axis with the angle rang */
    glRotatef(rang,0.0f,1.0f,0.0f);
 
    /* Draw the bottom box */
    glBegin(GL_QUADS);
        /* Top */
        glColor3f(1.0f,0.0f,1.0f);
        glVertex3f(-2.0f,-1.0f,2.0f);
        glColor3f(0.0f,0.0f,1.0f);
        glVertex3f(2.0f,-1.0f,2.0f);
        glColor3f(0.0f,0.0f,1.0f);
        glVertex3f(2.0f,-1.0f,-2.0f);
        glColor3f(1.0f,0.0f,1.0f);
        glVertex3f(-2.0f,-1.0f,-2.0f);
        
        /* Front */
        glVertex3f(-2.0f,-1.0f,2.0f);
        glVertex3f(-2.0f,-1.2f,2.0f);
        glColor3f(0.0f,0.0f,1.0f);
        glVertex3f(2.0f,-1.2f,2.0f);
        glVertex3f(2.0f,-1.0f,2.0f);
 
        /* Left */
        glColor3f(1.0f,0.0f,1.0f);
        glVertex3f(-2.0f,-1.0f,2.0f);
        glVertex3f(-2.0f,-1.2f,2.0f);
        glVertex3f(-2.0f,-1.2f,-2.0f);
        glVertex3f(-2.0f,-1.0f,-2.0f);
 
        /* Back */
        glColor3f(1.0f,0.0f,1.0f);
        glVertex3f(-2.0f,-1.0f,-2.0f);
        glVertex3f(-2.0f,-1.2f,-2.0f);
        glColor3f(0.0f,0.0f,1.0f);
        glVertex3f(2.0f,-1.2f,-2.0f);
        glVertex3f(2.0f,-1.0f,-2.0f);
 
        /* Right */
        glColor3f(0.0f,0.0f,1.0f);
        glVertex3f(2.0f,-1.0f,2.0f);
        glVertex3f(2.0f,-1.2f,2.0f);
        glVertex3f(2.0f,-1.2f,-2.0f);
        glVertex3f(2.0f,-1.0f,-2.0f);
    glEnd();
 
    /* Draw the 3d triangle */
    glBegin(GL_TRIANGLES);
        /* Front */
        glColor3f(1.0f,0.0f,1.0f);
        glVertex3f( 0.0f, 1.0f, 0.0f);
        glColor3f(0.1f,0.5f,0.5f);
        glVertex3f(-1.0f,-1.0f, 1.0f);
        glColor3f(0.5f,0.5f,1.0f);
        glVertex3f( 1.0f,-1.0f, 1.0f);
 
        /* Left */
        glColor3f(1.0f,0.0f,1.0f);
        glVertex3f(0.0f,1.0f,0.0f);
        glColor3f(0.1f,0.5f,0.5f);
        glVertex3f(-1.0f,-1.0f,1.0f);
        glColor3f(0.5f,0.5f,1.0f);
        glVertex3f(-1.0f,-1.0,-1.0f);
        
        /* Right */
        glColor3f(1.0f,0.0f,1.0f);
        glVertex3f(0.0f,1.0f,0.0f);
        glColor3f(0.5f,0.5f,1.0f);
        glVertex3f(1.0f,-1.0f,1.0f);
        glColor3f(0.1f,0.5f,0.5f);
        glVertex3f(1.0f,-1.0,-1.0f);
                
        /* Back */
        glColor3f(1.0f,0.0f,1.0f);
        glVertex3f( 0.0f, 1.0f, 0.0f);
        glColor3f(0.5f,0.5f,1.0f);
        glVertex3f(-1.0f,-1.0f, -1.0f);
        glColor3f(0.1f,0.5f,0.5f);
        glVertex3f( 1.0f,-1.0f, -1.0f);
    
    glEnd();
 
    
    /* Dump the output to the screen */
    glFlush();
    /* Use double buffering when you are doing animation */
    glutSwapBuffers();
}
 
void doDisplay() {
    static double x = 0.0;
    x += .30;
 
    drawTriangle(x);
}
 
int main(int argc, char *argv[]) {
    glutInit(&argc, argv);
    /* Double Buffer */
    glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB);
    glutInitWindowSize(640,480);
    glutInitWindowPosition(0,0);
    glutCreateWindow("Rotate 3D");
 
    glutDisplayFunc(doDisplay);
    glutIdleFunc(doDisplay);
    
    doInit();
    glutMainLoop();
 
    return 0;
}