#include <stdio.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glx.h>
#include <GL/glut.h>

float spin = 0.0;
float angle = 0.0;      /* Spin increment angle */
float rb,gb,bb;		/* Background R G B color */
float rs,gs,bs;		/* Foreground (Square) R G B color */
float px;		/* Horizontal position of the mouse cursor */

float colorr[91];	/* R Color Values of Rainbow Gradient */
float colorg[91];	/* G Color Values of Rainbow Gradient */
float colorb[91];	/* B Color Values of Rainbow Gradient */

int xindex = 0;		/* Horizontal Mouse position relative to window origin as Rainbow Gradient index */
int yindex = 0;		/* Vertical Mouse position relative to window origin as Rainbow Gradient index */

void display(void) {	/* OpenGL Rendering Function */
	/* Reset all pixels in buffer to clear color */
	glClearColor(colorr[yindex], colorg[yindex], colorb[yindex], 1.0);
	glClear(GL_COLOR_BUFFER_BIT);

	glPushMatrix();

	/* Rotate buffer x y z relative to horizontal mouse position */
	glRotatef(spin, 0.0, 0.0, 1.0);

	/* Draw rectangle by coordinate pairs x1,y1 x2,y2 */
	glColor3f(colorr[xindex], colorg[xindex], colorb[xindex]);
	glRectf(-25.0, -25.0, 25.0, 25.0);

	glPopMatrix();

	/* Switch buffers displaying rendering to the screen */
	glutSwapBuffers(); 
}

void spinDisplay(void) {        /* Increase the rotation angle and render */
        spin += angle;
        if (spin >= 360.0) {    /* Limit the rotation angle to [0,360) */
                spin -= 360;
        }
        if (spin <= -360.0) {   /* Limit the rotation angle to (-360,0] */
                spin += 360;
        }
        display();
}

void keyboard(unsigned char key, int x, int y) {        /* Keyboard Event Handler */
        switch (key) {
                case 'q':
                        exit(0);       			/* Exit if 'q' is pressed */
                        break;
		case '+':
			angle += 1.0;
			break;
		case '-':
			angle -= 1.0;
			break;
        }

}

void motion(int x, int y) {					/* Mouse Event Handler */
	xindex = (int) (91.0 * (float) x / (float) 400.0);	/* Map Horizontal Mouse Movement to Rainbow Gradient */
	yindex = (int) (91.0 * (float) y / (float) 400.0);	/* Map Vertical Mouse Movement to Rainbow Gradient */

        printf("The mouse is at %d and %d (indicies at %d and %d)\n",x,y,xindex,yindex);	/* Print x,y coordinates of mouse location relative to window origin */
}

void myinit(void) {	/* Initialize OpenGL default values */
	int w,h;
	int i;
        FILE *fp;

	/* Window geometry - Width, Height */
	w = 400;	
	h = 400;

	/* Initial Forground and Background R G B Colors */
	rb = 1.0;
        gb = 1.0;
        bb = 1.0;

        rs = 0.0;
        gs = 0.0;
        bs = 0.0;

	px = 0.0;

	/* Read R G B Color Values From File (Rainbow Gradient) */
	fp = fopen("COLOR_PATTERNS","r");
	for (i=0;i<91;i++) {
		fscanf(fp, "%f%f%f", &colorr[i],  &colorg[i],  &colorb[i]);
	}
	fclose(fp);

	/* OpenGL defaults */
	glClearColor(rb,gb,bb, 1.0);	/* Background Color */
        glColor3f(rs,gs,bs);		/* Foreground Color */
	glViewport(0,0,w,h);	/* Viewable area includes entire window geometry */

	/* Default orientation */
	glOrtho(-50.0, 50.0, -50.0*(float)h/(float)w, 50.0*(float)h/(float)w, -1.0, 1.0);
}

int main(int argc, char** argv) {
	/* Initialize GLUT and processes any command line arguments */
        glutInit(&argc, argv); 

	/* Create a double buffer using the RGB color scheme */
        glutInitDisplayMode( GLUT_DOUBLE | GLUT_RGB ); 

	/* Define Window Geometry */
        glutInitWindowSize(400, 400); 

	/* Create window with string argument as title */
        glutCreateWindow("My Box"); 

	/* Initialize OpenGL */
	myinit();

        /* Register the spinDisplay function to run while idle (continuously) */
        glutIdleFunc(spinDisplay);

	/* Register Rendering function */
        glutDisplayFunc(display); 

        /* Register Keyboard Event Handler function */
        glutKeyboardFunc(keyboard);

	/* Register Mouse Event Handler function */
	glutMotionFunc(motion);

	/* Initialize GLUT Event Handler */
        glutMainLoop();
}