/* October 1999
 * 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 <stdlib.h>

#define MINDIM 0
#define MAXDIM 200

struct glob {
   float v1r, v1g, v1b, v2r, v2g, v2b, v3r, v3g, v3b, v4r, v4g, v4b;
};
struct glob global;

void randomizeColors(void) {

	global.v1r = (float) rand()/RAND_MAX;
	global.v1g = (float) rand()/RAND_MAX;
	global.v1b = (float) rand()/RAND_MAX;
	global.v2r = (float) rand()/RAND_MAX;
	global.v2g = (float) rand()/RAND_MAX;
	global.v2b = (float) rand()/RAND_MAX;
	global.v3r = (float) rand()/RAND_MAX;
	global.v3g = (float) rand()/RAND_MAX;
	global.v3b = (float) rand()/RAND_MAX;
	global.v4r = (float) rand()/RAND_MAX;
	global.v4g = (float) rand()/RAND_MAX;
	global.v4b = (float) rand()/RAND_MAX;
}

void swapColors(void) {
	float tmp;

	tmp = global.v1r;
	global.v1r = global.v3r;
	global.v3r = tmp;

	tmp = global.v1g;
	global.v1g = global.v3g;
	global.v3g = tmp;

	tmp = global.v1b;
	global.v1b = global.v3b;
	global.v3b = tmp;

	tmp = global.v2r;
	global.v2r = global.v4r;
	global.v4r = tmp;

	tmp = global.v2g;
	global.v2g = global.v4g;
	global.v4g = tmp;

	tmp = global.v2b;
	global.v2b = global.v4b;
	global.v4b = tmp;
}

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

	switch (key) {

	case 'c':
	case 'C':
		randomizeColors();
		glutPostRedisplay();
		break;
	
	case 'e':
	case 'E':
		swapColors();
		glutPostRedisplay();
		break;
	
	case 'q':
	case 'Q':
		exit(0);
		break;
	}
}

void  poly(void) {

	glBegin(GL_POLYGON);
		glColor3f(global.v1r, global.v1g, global.v1b);
		glVertex2i(MINDIM, MINDIM);
		glColor3f(global.v2r, global.v2g, global.v2b);
		glVertex2i(MINDIM, MAXDIM);
		glColor3f(global.v3r, global.v3g, global.v3b);
		glVertex2i(MAXDIM, MAXDIM);
		glColor3f(global.v4r, global.v4g, global.v4b);
		glVertex2i(MAXDIM, MINDIM);
	glEnd();
	glFlush();
}

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

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

	gluOrtho2D(MINDIM, MAXDIM, MINDIM, MAXDIM);

	glutDisplayFunc(poly);
	glutKeyboardFunc(keybd);

	randomizeColors();
	glutMainLoop();

	return 0;
}