/* November 2000
 * Brian J.Ross
 * Brock University, Dept of Computer Science
 * COSC 3P98 Midterm solution 			*/

#if !defined(Linux)
  #include <windows.h>           //Not Linux must be windows
#endif
#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glut.h>

//#include <gl.h>
//#include <glu.h>
//#include <glut.h>


#include <stdlib.h>

#define MINDIM 0
#define MAXDIM 500
#define MYRANDOM ((float) rand()/RAND_MAX)

struct glob {
   int x, y, mode;
};
struct glob global = {250, 250, 0};

void my_clear(void) {	

	glClear(GL_COLOR_BUFFER_BIT);
	glFlush();
}

void keybd(unsigned char key, int x, int y) {

	switch (key) {

		case 'q':
		case 'Q':
		   exit(0);
		   break;
	}
}

void  scribble(void) {
	int x2, y2;

	x2 = global.x;
	y2 = global.y;

	switch (global.mode) {

		case 0:  // blue right
		   x2 += (int) (MYRANDOM * (MAXDIM-x2));
		   glColor3f(0.0, 0.0, 1.0);
		   break;

		case 1:  // red up
		   y2 += (int) (MYRANDOM * (MAXDIM-y2));
		   glColor3f(1.0, 0.0, 0.0);
		   break;

		case 2:  // green left
		   x2 -= (int) (MYRANDOM * (x2 - MINDIM));
		   glColor3f(0.0, 1.0, 0.0);
		   break;

		case 3:  // black down
		   y2 = (int) (MYRANDOM * (y2-MINDIM));
		   glColor3f(0.0, 0.0, 0.0);
		   break;
	}

	glBegin(GL_LINES);
		glVertex2i(global.x, global.y);
		glVertex2i(x2, y2); 
	glEnd();

	if (++global.mode > 3) global.mode=0;
	global.x = x2;  // save for next time around
	global.y = y2;
}

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

	glutInit(&argc, argv);
	glutInitWindowSize(MAXDIM, MAXDIM);
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
	glutCreateWindow("window");

	glutDisplayFunc(my_clear);
	glutIdleFunc(scribble);
	glutKeyboardFunc(keybd);

	glMatrixMode(GL_PROJECTION);
	gluOrtho2D(MINDIM, MAXDIM, MINDIM, MAXDIM);
	glClearColor (1.0, 1.0, 1.0, 1.0);

	glutMainLoop();
	return 0;
}