/*
 * ThreePicks.cpp
 * Picks and animates objects - this program illustrates how to pick objects on the screen and
 * animate them in response.
 *   Three different methods of picking are illustrated:
 *   Bounding box, distance to center, frame buffer contents
 *
 *   Also illustrates/compares two methods of animating a wheel
 *
 *  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;

GLfloat theta;
bool sqStart = false,         // booleans for state of each object:
		whStart = false,         // square rotating, wheel rolling,
		sqGrowShrink = false;    // square changing size
bool grow = true;             // true if growing, false if shrinking

GLfloat grFactor = 50;        // scale factor for growing circle
GLint gsX = 100, gsY = 100;   // center of growing circle

GLfloat transClock = 0;       // factor ranging 0 to 1
GLfloat scalefac = 50;        // radius of rolling wheel
GLint goX = 30, goY = 375;   // center of "go" button

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

// Color from framebuffer for third pick method
GLubyte theColor[3] = { 0, 0, 0 }; // Pixel color read from framebuffer

void myinit(void) {

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

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(0.0, 500.0, 500.0, 0.0);
	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 };
	GLfloat ci_vertices[38][2] = { { 0, 0 }, { 1, 0 }, { 0.984808, 0.173648 }, {
			0.939693, 0.34202 }, { 0.866025, 0.5 }, { 0.766044, 0.642788 }, {
			0.642788, 0.766044 }, { 0.5, 0.866025 }, { 0.34202, 0.939693 }, {
			0.173648, 0.984808 }, { 0, 1 }, { -0.173648, 0.984808 }, { -0.34202,
			0.939693 }, { -0.5, 0.866025 }, { -0.642788, 0.766044 }, {
			-0.766044, 0.642788 }, { -0.866025, 0.5 }, { -0.939693, 0.34202 }, {
			-0.984808, 0.173648 }, { -1, 1.22461e-016 },
			{ -0.984808, -0.173648 }, { -0.939693, -0.34202 },
			{ -0.866025, -0.5 }, { -0.766044, -0.642788 }, { -0.642788,
					-0.766044 }, { -0.5, -0.866025 }, { -0.34202, -0.939693 }, {
					-0.173648, -0.984808 }, { 0, -1 }, { 0.173648, -0.984808 },
			{ 0.34202, -0.939693 }, { 0.5, -0.866025 }, { 0.642788, -0.766044 },
			{ 0.766044, -0.642788 }, { 0.866025, -0.5 }, { 0.939693, -0.34202 },
			{ 0.984808, -0.173648 }, { 1, 0 } };

	GLubyte ciIndices[38] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
			15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
			32, 33, 34, 35, 36, 37 };
	GLubyte whIndices[38] = { 0, 1, 0, 3, 0, 5, 0, 7, 0, 9, 0, 11, 0, 13, 0,
			15, 0, 17, 0, 19, 0, 21, 0, 23, 0, 25, 0, 27, 0, 29, 0, 31,
			0, 33, 0, 35, 0, 37 };

	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();

	// code for growing circle
	glColor3f(0.0, 1.0, 1.0);
	glVertexPointer(2, GL_FLOAT, 0, ci_vertices);
	glPushMatrix();
	glLoadIdentity();
	glTranslatef(gsX, gsY, 0.0);         // center of grow/shrink circle
	glScalef(grFactor, grFactor, 0.0);
	glDrawElements(GL_TRIANGLE_FAN, 38, GL_UNSIGNED_BYTE, ciIndices);
	glPopMatrix();

	// code for rolling wheel
	glColor3f(1.0, 0.3, 1.0);
	glVertexPointer(2, GL_FLOAT, 0, ci_vertices);
	glPushMatrix();
	glLoadIdentity();
	//glTranslatef(gsX/2 + 2 * 3.14159 * scalefac*transClock, gsY+350, 0.0);  // correct translation for roll
	glTranslatef(gsX/2 + 25 * scalefac * transClock, gsY + 350, 0.0); // irrelevant translation
	glScalef(scalefac, scalefac, 0.0);
	glRotatef(transClock * 360, 0, 0, 1);
	glDrawElements(GL_TRIANGLE_FAN, 38, GL_UNSIGNED_BYTE, ciIndices);
	glColor3f(0.0, 0.0, 0.0);
	glDrawElements(GL_LINES, 38, GL_UNSIGNED_BYTE, whIndices);
	glPopMatrix();

	// code for square button to rotate wheel
	glVertexPointer(2, GL_FLOAT, 0, sq_vertices);
	glColor3f(1.0, 0.3, 1.0);
	glPushMatrix();
	glLoadIdentity();
	glTranslatef(goX, goY, 0.0);           // center of square "go" button
	glScalef(5, 5, 0.0);
	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
	}
	if (whStart) {
		transClock += 0.0001;   // modify how far wheel has moved/rotated
	}
	if (sqGrowShrink) {
		if (grFactor > 100)
			grow = false;
		else if (grFactor < -100)
			grow = true;
		if (grow)
			grFactor = grFactor + 0.05;
		else
			grFactor = grFactor - 0.05;

	}
	glutPostRedisplay();
}

// readPixel - Adapted from: G. Chappell
// Reads pixel at mouse position (given, GLUT format)
// Puts color in theColor (global GLfloat [3]).
void readPixel(int x, int y) {
	glReadPixels(x, 500 - y,   // Read pixel at mouse position
			                   // not fb position is not affected by viewport
	        1, 1,              // 1 x 1 block (single pixel)
			GL_RGB,            // Get R, G, B
			GL_UNSIGNED_BYTE,  // Return GLubyte, value 0..255
			theColor);         // Place to put the result
}

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

	double dist = sqrt((gsX - x) * (gsX - x) + (gsY - y) * (gsX - y)); // compute distance from cyan circle center to mouse

	if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN && dist < grFactor) { // check if inside growing circle
		sqGrowShrink = !sqGrowShrink;                  // using dist from center
	}

	if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN && x >= goX - 5
			&& x <= goX + 5 && y >= goY - 5 && y <= goY + 5) { // check if inside button using bounding box
		whStart = !whStart;                         // already rotating: stop it
	}

	readPixel(x, y);
	if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN && theColor[0] == 75
			&& theColor[1] == 75 && theColor[2] == 255) { // check if inside rotating square using fb read
		                                            // checks if pixel is color of rotating square - blue
		sqStart = !sqStart;                         // already rotating: stop it
	}

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

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

	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
	glutInitWindowSize(500, 500);
	glutInitWindowPosition(0, 0);
	glutCreateWindow("Pick to Go");
	glutDisplayFunc(display);
	glutMouseFunc(mouse);
	glutIdleFunc(idle);

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