/* simple open gl 3D window-based program */
// =================================================================================
// 3D TEST
// simplified from glut example in OpenGL SDK 

// =================================================================================
// INCLUDES
#include "glut.h"
#include <stdlib.h>
#include <stdio.h>
#include <math.h>

#include "materials.h"
#include "geometry.h"
#include "matrix.h"


// =================================================================================
// DEFINES
#define PI 3.14159265

// =================================================================================
// PROTOTYPE FUNCTIONS
void display(void);
void initRenderingEnvironment (void); 
void display_list_1 (void);
void parse_key(unsigned char key, int x, int y);
void parse_special_key(int key, int x, int y);
void SetCamera(void);
void Animate(void);
void myReshape(int w, int h);
void setupLights();


// =================================================================================
// GLOBALS
int frame = 0;
int angle = 0;
float eyeDistance=30.0;
float eyeAround=0.0,eyeTilt=0.0;
float eyex=1.0,eyey=3.0,eyez=4.0,coix=0.0,coiy=5.0,coiz=0.0;
float goalx=-5,goaly=5,goalz=0;
float	initAngle0=-40.0,initAngle1=20.0,initAngle2=10.0;

// =================================================================================
// MAIN
// =================================================================================
int main(int argc, char *argv[])
{
	int sz;
	
	if (argc > 1)
		sz = atoi(argv[1]);
	else
		sz = 400;
		
	// instructions
	printf("\n");
	printf(" key assignment\ns");
	printf(" arrow keys rotate the eye around the origin\n");
	printf(" 'i' zooms in; 'o' zooms out\n");
	printf(" a adds one, z subtracts one, to goal x-coordinate\n");
	printf(" s adds one, x subtracts one, to goal x-coordinate\n");
	printf(" d adds one, c subtracts one, to goal x-coordinate\n");
	printf("\n");

	// set up display window
	// glutInitDisplayMode(GLUT_DEPTH | GLUT_RGBA | GLUT_DOUBLE | GLUT_MULTISAMPLE);
	glutInitDisplayMode(GLUT_DEPTH | GLUT_RGBA | GLUT_DOUBLE);
	glutInitWindowPosition(40, 40);
	glutInitWindowSize(sz, sz);
	glutCreateWindow("Numeric Inverse Kinematics");

	// setup callbacks 
	glutDisplayFunc(display);
	glutKeyboardFunc(parse_key);
	glutSpecialFunc(parse_special_key);
	glutReshapeFunc(myReshape);
	glutIdleFunc(Animate);
	
	initRenderingEnvironment();
	initialize_numericinvkin(goalx,goaly,goalz,initAngle0,initAngle1,initAngle2);

	glutMainLoop();
	return 0;             
}

// =================================================================================
// DISPLAY
// =================================================================================
void display(void)
{
	// clear buffer
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	// display particles
	glPushMatrix();
	display_numericinvkin();
	glPopMatrix();
		
	// force out and swap buffers
	glFlush();
	glutSwapBuffers();
}

// =================================================================================
// INIT RENDERING ENVIRONMENT
// =================================================================================
void initRenderingEnvironment (void) 
{
    glShadeModel (GL_SMOOTH);
    glFrontFace(GL_CCW);
    glEnable(GL_DEPTH_TEST);
    
    setupLights();
    glClearColor(0.8,0.8,0.8,1.0);
    glColor3f(1.0, 1.0, 1.0);
    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);

    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
}

// =================================================================================
// PARSE KEY
// =================================================================================
void parse_key(unsigned char key, int x, int y)
{
	
    switch (key)
    {
		case 27: exit(0);
		case 13: angle = 0; break;
		case 105: eyeDistance /= 2.0; break;  // i: zoom In
		case 111: eyeDistance *= 2.0; break;  // o: zoom Out
		case 97: goalx++; set_goal(goalx,goaly,goalz);break;  // a: move right
		case 122: goalx--; set_goal(goalx,goaly,goalz);break; // z: move left
		case 115: goaly++; set_goal(goalx,goaly,goalz);break; // s: move up
		case 120: goaly--; set_goal(goalx,goaly,goalz);break; // x: move down
		case 100: goalz++; set_goal(goalx,goaly,goalz);break; // d: move in
		case 99: goalz--; set_goal(goalx,goaly,goalz);break;  // c: move out
		case 32: set_goal(goalx,goaly,goalz);break;  // sp: don't move, just iterate
		default: printf("%d",key);
    }
}

// =================================================================================
// PARSE SPECIAL KEY
// =================================================================================
void parse_special_key(int key, int x, int y)
{
    switch (key)
    {
	case GLUT_KEY_UP:	eyeTilt += 0.25; break;
	case GLUT_KEY_DOWN:	eyeTilt -= 0.25; break;
	case GLUT_KEY_RIGHT:	eyeAround += 0.25; break;
	case GLUT_KEY_LEFT:	eyeAround -= 0.25; break;
    }
}

// =================================================================================
// SET CAMERA
// =================================================================================
void SetCamera(void)
{

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glFrustum (-0.1, 0.1, -0.1, 0.1, 0.2, 550.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    
    eyez = eyeDistance*cos(eyeAround)*cos(eyeTilt);
    eyey = eyeDistance*sin(eyeTilt);
    eyex = eyeDistance*sin(eyeAround)*cos(eyeTilt);
	
	gluLookAt(eyex,eyey,eyez,coix,coiy,coiz,0.0,1.0,0.0);
}

// =================================================================================
// ANIMATE
// =================================================================================
void Animate(void)
{
	SetCamera();
	glutPostRedisplay();
	frame++;
}

// =================================================================================
// MY RESHAPE
// =================================================================================
void myReshape(int w, int h)
{
    SetCamera();
    glViewport (0, 0, w, h);
}

/* --------------------------------------------------------------------------- */
/* SETUP LIGHTS */
/* --------------------------------------------------------------------------- */
void setupLights()
{
  GLfloat light0_ambient[]  = { 0.1,0.1,0.1,1.0 };
  GLfloat light0_diffuse[]  = { 0.3,0.3,0.3,1.0 };
  GLfloat light0_specular[] = { 0.1,0.1,0.1,1.0 };
  GLfloat light0_position[] = { 0.0, 1.0, 3.0, 1.0 };
  
  GLfloat light1_ambient[]  = { 0.1,0.1,0.1,1.0 };
  GLfloat light1_diffuse[]  = { 0.3,0.3,0.3,1.0 };
  GLfloat light1_specular[] = { 0.3,0.3,0.3,1.0 };
  GLfloat light1_position[] = { -1.0,3.0,2.0,1.0 };
  

  glEnable(GL_LIGHTING);

  glEnable(GL_LIGHT0);
  glLightfv(GL_LIGHT0, GL_AMBIENT, light0_ambient);
  glLightfv(GL_LIGHT0, GL_DIFFUSE, light0_diffuse);
  glLightfv(GL_LIGHT0, GL_SPECULAR,light0_specular); 
  glLightfv(GL_LIGHT0, GL_POSITION,light0_position);

  glEnable(GL_LIGHT1);
  glLightfv(GL_LIGHT1, GL_AMBIENT, light1_ambient);
  glLightfv(GL_LIGHT1, GL_DIFFUSE, light1_diffuse);
  glLightfv(GL_LIGHT1, GL_SPECULAR,light1_specular); 
  glLightfv(GL_LIGHT1, GL_POSITION,light1_position);
 
}