/*
 * GLUT Shapes Demo
 *
 * Written by Nigel Stewart November 2003
 *
 * This program is test harness for the sphere, cone
 * and torus shapes in GLUT.
 *
 * Spinning wireframe and smooth shaded shapes are
 * displayed until the ESC or q key is pressed.  The
 * number of geometry stacks and slices can be adjusted
 * using the + and - keys.
 */

#ifdef __APPLE__
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif

#include <stdlib.h>
#include <stdio.h>

static int slices = 16;
static int stacks = 16;

/* GLUT callback Handlers */

static void resize(int width, int height)
{
    const float ar = (float) width / (float) height;
    glViewport(0, 0, width, height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(-320, 319, -240, 239, -1, 1);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity() ;
}

void draw8waySyemmtry(int x,int y,int zone)
{

    if(zone==0)
        glVertex2i(x,y);
    else if(zone==1)
        glVertex2i(y,x);
    else if(zone==2)
        glVertex2i(-y,x);
    else if(zone==3)
        glVertex2i(-x,y);
    else if(zone==4)
        glVertex2i(-x,-y);
    else if(zone==5)
        glVertex2i(-y,-x);
    else if(zone==6)
        glVertex2i(y,-x);
    else if(zone==7)
        glVertex2i(x,-y);

}

int cx0,cx1,cy0,cy1,cnt=0;



void mouse(int button,int state,int x,int y)
{
    if(button==GLUT_LEFT_BUTTON && state==GLUT_DOWN)
    {
        printf("%d %d\n",x,y);
        if(cnt==0)
        {
            cx0=x-320;
            cy0=-y+240;

            cx1 = cx0;
            cy1 = cy0;

            cnt=1;
        }
        else if(cnt==1)
        {
            cx1=x-320;
            cy1=-y+240;
            cnt=2;
            printf("%d %d %d %d\n",cx0,cy0,cx1,cy1);
            int dx=cx1-cx0,dy=cy1-cy0;
            if(dx>=0 && dy>=0)
            {
                if(abs(dx)>abs(dy))
                {
                    printf("Zone 0, ");
                    printf("COLOR = Blue\n");
                }
                else
                {
                    printf("Zone 1, ");
                    printf("COLOR = Green\n");
                }
            }
            else if(dx<=0 && dy>=0)
            {
                if(abs(dx)>abs(dy))
                {
                    printf("Zone 3, ");
                    printf("COLOR = Red\n");
                }
                else
                {
                    printf("Zone 2, ");
                    printf("COLOR = Yellow\n");
                }
            }
            else if(dx<=0 && dy<=0)
            {
                if(abs(dx)>abs(dy))
                {
                    printf("Zone 4, ");
                    printf("COLOR = White\n");
                }
                else
                {
                    printf("Zone 5, ");
                    printf("COLOR = Orange\n");
                }
            }
            else if(dx>=0 && dy<=0)
            {
                if(abs(dx)>abs(dy))
                {
                    printf("Zone 7, ");
                    printf("Color = Thin Green\n");
                }
                else
                {
                    printf("Zone 6, ");
                    printf("Color = Sky Blue\n");
                }
            }
            //lineDraw(cx0,cy0,cx1,cy1);

        }

    }
}

void drawLine_0(int x0,int y0,int x1,int y1,int zone)
{
    int dx=x1-x0,dy=y1-y0;
    int x,y,d=2*dy-dx;
    int dE=2*dy,dNE=2*(dy-dx);
    x=x0,y=y0;
    draw8waySyemmtry(x,y,zone);
    while(!(x==x1 && y==y1))
    {
        if(d<0)
        {
            x++;
            d+=dE;
        }
        else
        {
            x++,y++;
            d+=dNE;
        }
        draw8waySyemmtry(x,y,zone);
    }
}



void lineDraw(int x0,int y0,int x1,int y1)
{
    int dx=x1-x0,dy=y1-y0;
    if(dx>=0 && dy>=0)
    {
        if(abs(dx)>abs(dy))
        {
            glColor3d(0,0,1);
            drawLine_0(x0,y0,x1,y1,0);

        }
        else
        {
            glColor3d(0,1,0);
            drawLine_0(y0,x0,y1,x1,1);
        }
    }
    else if(dx<=0 && dy>=0)
    {
        if(abs(dx)>abs(dy))
        {
            glColor3d(1,0,0);
            drawLine_0(-x0,y0,-x1,y1,3);
        }
        else
        {
            glColor3d(1,1,0);
            drawLine_0(y0,-x0,y1,-x1,2);
        }
    }
    else if(dx<=0 && dy<=0)
    {
        if(abs(dx)>abs(dy))
        {
            glColor3d(1,1,1);
            drawLine_0(-x0,-y0,-x1,-y1,4);
        }
        else
        {
            glColor3d(1,.5,0);
            drawLine_0(-y0,-x0,-y1,-x1,5);
        }
    }
    else if(dx>=0 && dy<=0)
    {
        if(abs(dx)>abs(dy))
        {
            glColor3d(0,.5,0);
            drawLine_0(x0,-y0,x1,-y1,7);
        }
        else
        {
            glColor3d(0,.5,.5);
            drawLine_0(-y0,x0,-y1,x1,6);
        }
    }
}

static void display(void)
{
    int x = 10, y = 20;
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glColor3d(1,1,1);
    glBegin(GL_LINES);
    glVertex2i(-320, 0);
    glVertex2i(319, 0);
    glVertex2i(0, -240);
    glVertex2i(0, 239);
    glEnd();
    glBegin(GL_POINTS);
    //glColor3d(.4,.6,.8);
    if(cnt == 2){
        cnt = 0;
    }
    else{
        lineDraw(cx0,cy0,cx1,cy1);
    }
    glEnd();
    glutSwapBuffers();
}


static void key(unsigned char key, int x, int y)
{
    switch (key)
    {
    case 27 :
    case 'q':
        exit(0);
        break;

    case '+':
        slices++;
        stacks++;
        break;

    case '-':
        if (slices>3 && stacks>3)
        {
            slices--;
            stacks--;
        }
        break;
    }

    glutPostRedisplay();
}

static void idle(void)
{
    glutPostRedisplay();
}

/* Program entry point */

int main(int argc, char *argv[])
{
    glutInit(&argc, argv);
    glutInitWindowSize(640,480);
    glutInitWindowPosition(10,10);
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);

    glutCreateWindow("Experiment 01");

    glutReshapeFunc(resize);
    glutDisplayFunc(display);
    glutKeyboardFunc(key);
    glutMouseFunc(mouse);
    glutIdleFunc(idle);

    glutMainLoop();

    return EXIT_SUCCESS;
}