/* October 2003
 * Brian J.Ross
 * Brock University, Dept of Computer Science
 * COSC 3P98 Midterm solution B
 *
 * A simple gradient renderer.
 */

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

#define MINDIM 0
#define MAXDIM 500


struct glob {
   float xmin;
   float xmax;
};
struct glob global = {0.0, 500.0};



void drawGradient(bot_x, bot_y, top_x, top_y, r1, g1, b1, r2, g2, b2 ) 
	float bot_x, bot_y, top_x, top_y;
	int  r1, g1, b1, r2, g2, b2; {

	glBegin(GL_POLYGON);
	   glColor3ub(r1, g1, b1);
	   glVertex2f(bot_x, bot_y);
	   glVertex2f(bot_x, top_y);
	   glColor3ub(r2, g2, b2);
	   glVertex2f(top_x, top_y);
	   glVertex2f(top_x, bot_y);
	glEnd();

}

void mydisplay(void) {

	glClear(GL_COLOR_BUFFER_BIT);
	drawGradient(30.0, 30.0, 250.0, 200.0, 50, 0, 20, 200, 200, 25);
	glFlush();
}

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

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

	glutDisplayFunc(mydisplay);

	glMatrixMode(GL_PROJECTION);
	gluOrtho2D(global.xmin, global.xmax, global.xmin, global.xmax);
	glClearColor (1.0, 1.0, 1.0, 1.0);

	glutMainLoop();
	return 0;
}