/*
 * camcube: static cube with moving camera
 *
 * P Flynn 021703: based on Angel's cube.c
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <glut.h>
#include <math.h>


	GLfloat vertices[][3] = {{-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[][3] = {{0.3,0.6,0.7},{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}};

void polygon(int a, int b, int c , int d) {
 /* draw a polygon via list of vertices */
 glBegin(GL_POLYGON);
 //glBegin(GL_LINE_LOOP);
 glColor3fv(colors[a]);
 glVertex3fv(vertices[a]);
 glColor3fv(colors[b]);
 glVertex3fv(vertices[b]);
 glColor3fv(colors[c]);
 glVertex3fv(vertices[c]);
 glColor3fv(colors[d]);
 glVertex3fv(vertices[d]);
 glEnd();
 }

void colorcube(void) {
 /* map vertices to faces */
 polygon(0,3,2,1);
 polygon(2,3,7,6);
 polygon(0,4,7,3);
 polygon(1,2,6,5);
 polygon(4,5,6,7);
 polygon(0,1,5,4);
 }

/*
 * The camera:
 *  - looks at the origin always
 *  - is located on a sphere of radius r 
 *  - thea and phi control eye point and view-up vector
 */

static GLfloat theta = 0.0, phi=0.0;
static r = 2;

void display(void) {
 float xeye, yeye, zeye;
/* display callback, clear frame buffer and z buffer,
   rotate cube and draw, swap buffers */
 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 glMatrixMode(GL_MODELVIEW);
 glLoadIdentity();
 xeye = r * cos(phi*M_PI/180.0) * cos(theta*M_PI/180.0);
 yeye = r * cos(phi*M_PI/180.0) * sin(theta*M_PI/180.0);
 zeye = r * sin(phi*M_PI/180.0);
 gluLookAt(xeye,yeye,zeye,    // eye
           0.0,0.0,0.0,    // at
           0.0,0.0,1.0);   // vup
 // draw coordinate axes
 glLineWidth(3.0);
 glBegin(GL_LINES);
  glColor3f(1.0,0.0,0.0);
  glVertex3f(0.0,0.0,0.0);
  glVertex3f(1.5,0.0,0.0);
  glColor3f(0.0,1.0,0.0);
  glVertex3f(0.0,0.0,0.0);
  glVertex3f(0.0,1.5,0.0);
  glColor3f(0.0,0.0,1.0);
  glVertex3f(0.0,0.0,0.0);
  glVertex3f(0.0,0.0,1.5);
 glEnd();
 colorcube();
 glFlush();
 glutSwapBuffers();
}

void spinCube()
{
}

void mouse(int btn, int state, int x, int y) {
 if(btn==GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
  theta += 2;
  if (theta >= 360.0) theta -= 360.0;
  };
 if(btn==GLUT_MIDDLE_BUTTON && state == GLUT_DOWN) {
  phi += 2;
  if (phi >= 360.0) phi -= 360.0;
  };
 glutPostRedisplay();
}


 /* pjf note: this function is called prior to first display, so can be
    used as an init function as well... I think that's what Angel did here */
void myReshape(int w, int h)
{
    glViewport(0, 0, w,h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    if (w <= h)
        glOrtho(-2.0, 2.0, -2.0 * (GLfloat) h / (GLfloat) w,
            2.0 * (GLfloat) h / (GLfloat) w, -10.0, 10.0);
    else
        glOrtho(-2.0 * (GLfloat) w / (GLfloat) h,
            2.0 * (GLfloat) w / (GLfloat) h, -2.0, 2.0, -10.0, 10.0);
    glMatrixMode(GL_MODELVIEW);
}

void
main(int argc, char **argv)
{
    glutInit(&argc, argv);

/* need both double buffering and z buffer */

    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 */
   /* pjf this should be in a separate init function! */
   //glShadeModel(GL_FLAT);
    glutMainLoop();
}