/*
 * Reshape.cpp
 * Demonstrates reshape of window
 *
 *  Created on: Mar 1, 2013
 *      Author: debure
 */

#include <GL/glut.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <iostream>
using namespace std;

GLint winHeight = 500, winWidth = 500;  // initial window size for gluInitWindowSize
GLint view_xmin, view_xmax, view_ymin, view_ymax;   // extents of viewing volume
GLdouble aspectX = 1, aspectY = 1;   // winWidth/winHeight

GLfloat theta;
bool sqStart = false;

GLfloat rsFactor = 50;        // scale factor for rotating square
GLint rsX = 250, rsY = 325;   // center of rotating square

void myinit(void) {

	glClearColor(0.0, 0.0, 0.0, 1.0);
	glColor3f(0.0, 0.0, 0.0);

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(0, 500, 500, 0);
	glMatrixMode(GL_MODELVIEW);
	glEnableClientState(GL_VERTEX_ARRAY);
}

void display(void) {

	// square is created at the origin
	GLfloat sq_vertices[4][2] = { { -1.0, -1.0 }, { 1.0, -1.0 }, { 1.0, 1.0 }, {
			-1.0, 1.0 } };
	GLubyte sqIndices[4] = { 0, 3, 2, 1 };

	glClear(GL_COLOR_BUFFER_BIT);

	// code for rotating square
	glVertexPointer(2, GL_FLOAT, 0, sq_vertices);
	glColor3ub(75, 75, 255);           // assign color using unsigned byte 0-255
	glPushMatrix();
	glLoadIdentity();
	glTranslatef(rsX, rsY, 0.0);           // center of rotating square
	glScalef(rsFactor, rsFactor, 0.0);
	glRotatef(theta, 0.0, 0.0, 1.0);
	glDrawElements(GL_QUADS, 4, GL_UNSIGNED_BYTE, sqIndices);
	glPopMatrix();

	glutSwapBuffers();
	glFlush();
}

void idle(void) {

	if (sqStart) {
		theta += 1;            // modify rotation angle that is used in display
	}

	glutPostRedisplay();
}

void mouse(int button, int state, int x, int y) {

	if (button == GLUT_RIGHT_BUTTON && state == GLUT_DOWN)
		exit(0);
}


void reshape(int w, int h) {
	// Set viewport & save window dimensions in globals
	glViewport(0, 0, w, h);
	winWidth = w;
	winHeight = h;

	// Set up projection
	// Save max/min x/y coords in globals
	// Projection is orthographic. Aspect ratio is correct,

	if (w > h) {
		aspectX = (GLdouble) w / h;
		aspectY = 1;
		rsFactor = winWidth / 10.0;
	} else {
		aspectY = (GLdouble) h / w;
		aspectX = 1;
		rsFactor = winHeight / 10.0;
	}
	rsX = winWidth / 2.0;
	rsY = winHeight / 2.0;

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(0, winWidth, winHeight, 0);

	glMatrixMode(GL_MODELVIEW);  // Next transforms affect objects
}

int main(int argc, char** argv) {

	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
	glutInitWindowSize(winHeight, winWidth);
	glutInitWindowPosition(0, 0);
	glutCreateWindow("Reshape");
	glutDisplayFunc(display);
	glutReshapeFunc(reshape);
	glutMouseFunc(mouse);
	glutIdleFunc(idle);

	myinit();
	glutMainLoop();
	return 0;
}