/*  

In this lab, we will consider interpolation, and how we can do an affine mapping
between two different 2-D shapes.

NOTE:  you won't attempt to compile until step 7 below...

  1.  Scroll through the source code below.  Take particular note of the 
	- Point2 and Color 3 vectors
	- delta and deltaT variables
	- TWEEN vector
	- note how the IDLE function, CalcTween, calculates the new vertices and then posts a redisplay
	- note how the display function simply renders the 6 vertices of the TWEEN vector
	- note that the clipping volume is (-100,-100) to (100,100)

  2.  Fill in the x-y values for 6 vertices of some 2-D shape, in the shape1 vector

  3.  Fill in the x-y values for 6 vertices of some 2-D shape, in the shape2 vector

  4.  Define your two colors in color1 and color2 vectors

  5.  fill in the code to calculate the interpolated colors

  6.  fill-in the code to calculate the interpolated vertices

  7.  compile your code, fixing any errors, and then run it

  8.  demo the code for your instructor

*/
#include <GL/glut.h>
#include <cstdlib>
#include <iostream>
using namespace std;

#define WINDOWSIZE 400

//  defining a type "point," of size 2
typedef GLfloat Point2[2];

//  defining a type "color," of size 3
typedef GLfloat Color3[3];


#define NUMPOINTS 12

// define a 2-d shape, using 6 vertices
//Point2 shape1[NUMPOINTS]={ {-25, 25},{-50,  0},{-25,-25},{ 25,-25},{ 50,  0},{ 25, 25} };
// define a 2-d shape, using 12 vertices
Point2 shape1[NUMPOINTS]={ {-25,-25},{25,-25},{25,50},{50,50},{50,25},{50,-25},
{50,-50}, {-50,-50},{-50,-25},{-50,25},{-50,50},{-25,50} };

// define another 2-d shape, using 6 vertices
//Point2 shape2[NUMPOINTS]={ {-50, 50},{-25,  0},{-50,-50},{ 50,-50},{ 25,  0},{ 50, 50} };
// define another 2-d shape, using 12 vertices
Point2 shape2[NUMPOINTS]={ {-25,50},{25,50},{25,25},{13,25},{13,-25},{25,-25},
{25,-50},{-25,-50},{-25,-25},{-13,-25},{-13,25},{-25,25}};

// array used for the points beTWEEN shapes
Point2 tween[NUMPOINTS];

// define your first color
//orange
Color3 color1={ 1 , 0.5  , 0 };

// define your second color
//blue
Color3 color2={ 0 , 0  , 1 };

// define the parameters
GLfloat t=0.0;
GLfloat deltaT=0.005;


void myInit()
{
	// initialize the beTWEEN array
	GLint i,j;
	for (i=0;i<NUMPOINTS;i++) {
		for (j=0;j<2;j++) {
		  tween[i][j]=shape1[i][j];
		}
	}

	glClearColor(1.0,1.0,1.0,0.0);

	// initialize the color
	glColor3f( color1[0] , color1[1] , color1[2] );


	glLineWidth(4.0);


	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(-100,100,-100,100);
	glMatrixMode(GL_MODELVIEW);
}


void display() {
	GLint i;

	glClear(GL_COLOR_BUFFER_BIT);

	// render the morphed shape
	glBegin(GL_LINE_LOOP);
		for (i=0;i<NUMPOINTS;i++) {
			glVertex2fv(tween[i]);
		}
	glEnd();

	glutSwapBuffers();
}


void CalcTween()
{
	GLint i,j;

	t+=deltaT;

	// calculate the morphed color
	glColor3f( color1[0] + t*(color2[0]-color1[0])
			,  color1[1] + t*(color2[1]-color1[1])
			,  color1[2] + t*(color2[2]-color1[2])  );
	
	// calculate the morphed shape
	for (i=0;i<NUMPOINTS;i++) {
		for (j=0;j<2;j++) {
		  tween[i][j]=   shape1[i][j] + t*(shape2[i][j] - shape1[i][j]) ;                    ;
		}
	}

	if (t>=1.0 || t<= 0.0) deltaT = -deltaT;

	glutPostRedisplay();
}


void mouse (GLint btn, GLint state, GLint x, GLint y)
{
	if (btn==GLUT_LEFT_BUTTON && state==GLUT_DOWN) {
		glutIdleFunc(CalcTween);
	}

	if (btn==GLUT_RIGHT_BUTTON && state==GLUT_DOWN) {
		glutIdleFunc(NULL);
	}
}


int main( int argc , char **argv )
{
	glutInit(&argc,argv);
	glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB);
	glutInitWindowSize(WINDOWSIZE,WINDOWSIZE);
	glutInitWindowPosition(0,0);
	glutCreateWindow("Interpolation");
    
	myInit();
	
	glutDisplayFunc(display); 
	glutMouseFunc(mouse);
	glutMainLoop();
	
	return 0;
}