/*************************************************************************
  FILE:   interface.cc
          Interface callback functions, window manipulation, display.

  Author: Dana Vrajitoru, IUSB
  Class:  C481 B581 Computer Graphics
**************************************************************************/

#include "glheader.h"
#include <cmath>
#include <fstream>
#include <iostream>
using namespace std;
#include "geometry.h"

static GLfloat theta[] = {0.0,0.0,0.0};
static GLint axis = 2;
static GLfloat trans[] = {0.0,0.0,1};

// display function, calls the display list
void display(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glEnable(GL_DEPTH_TEST);
    glLoadIdentity();
    gluLookAt(0, 0, 3.5, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
    
    glTranslatef(trans[0], trans[1], 0);
    glScalef(trans[2], trans[2], trans[2]);
    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);
    draw1();
    glFlush();
    glutSwapBuffers();
}

// Idle callback, spin cube 2 degrees about selected axis
void spinObject()
{
    theta[axis] += 1.0;
    if( theta[axis] > 360.0 ) 
        theta[axis] -= 360.0;
    glutPostRedisplay();
}

// callback for a mouse event, selects an axis about which to rotate
void mouse(int btn, int state, int x, int y)
{
    if (state == GLUT_DOWN)
        glutIdleFunc(spinObject);
    else
        glutIdleFunc(NULL);
    
    switch (btn) {
    case GLUT_LEFT_BUTTON:
        axis = 0;
        break;
    case GLUT_MIDDLE_BUTTON:
        axis = 1;
        break;
    case GLUT_RIGHT_BUTTON:
        axis = 2;
    }
}

// callback for the window size changing
void myReshape(int w, int h)
{
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(90.0, w/h, 1.0, 40.0); 
    /*  if (w<=h) 
        glFrustum(-10.0, 10.0, -10.0 * (GLfloat) h/ (GLfloat) w, 
        10.0* (GLfloat) h / (GLfloat) w, -10.0, 20.0);
        else 
        glFrustum(-10.0, 10.0, -10.0 * (GLfloat) w/ (GLfloat) h, 
        10.0* (GLfloat) w / (GLfloat) h, -10.0, 20.0);
    */
    glMatrixMode(GL_MODELVIEW);
}

// callback for key action
void key(int key, int x, int y)
{
    switch (key) {
    case GLUT_KEY_LEFT:
        trans[0] -= 0.1;
        break;
    case GLUT_KEY_RIGHT:
        trans[0] += 0.1;
        break;
    case GLUT_KEY_UP:
        trans[1] += 0.1;
        break;
    case GLUT_KEY_DOWN:
        trans[1] -= 0.1;
        break;
    case GLUT_KEY_PAGE_UP:
        trans[2] += 0.1;
        break;
    case GLUT_KEY_PAGE_DOWN:
        trans[2] -= 0.1;
    }
    display();
}

// various application parameters
void myinit()
{
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(-1.25, 1.25, -1.25, 1.25);
    glMatrixMode(GL_MODELVIEW);
    glClearColor (1.0, 0.95, 0.9, 1.0);
    glColor3f(1.0,0.0,0.0);
    glutDisplayFunc(display);
    glutIdleFunc(NULL);
    glutMouseFunc(mouse);
    //  glutKeyboardFunc(key);
    glutReshapeFunc(myReshape);
    glutSpecialFunc(key);
    glClearColor(1.0, 1.0, 1.0, 1.0);
    glColor3f(1.0, 0.0, 0.0);
}