谢尔宾斯基三角(Sierpinski triangle)

#include<time.h>
#include<stdlib.h>
#include<stdio.h>
#include<GL/glut.h>
GLfloat v[3][2] = { { -1.0, -0.58 }, { 1.0, -0.58 }, { 0.0, 1.15 } };
int gCount = 1;
void triangle(GLfloat *a, GLfloat *b, GLfloat *c)
{
	glVertex2fv(a);
	glVertex2fv(b);
	glVertex2fv(c);
}
void divide_triangle(GLfloat *a, GLfloat *b, GLfloat *c, int m)
{
	GLfloat v0[2], v1[2], v2[2];
	int j;
	if (m > 0)
	{
		for (j = 0; j < 2; j++){
			v0[j] = (a[j] + b[j]) / 2;
		}
		for (j = 0; j < 2; j++){
			v1[j] = (a[j] + c[j]) / 2;
		}
		for (j = 0; j < 2; j++){
			v2[j] = (b[j] + c[j]) / 2;
		}
		divide_triangle(a, v0, v1, m - 1);
		divide_triangle(c, v1, v2, m - 1);
		divide_triangle(b, v2, v0, m - 1);
	}
	else
	{
		triangle(a, b, c);
	}
}
void init()
{
	glClearColor(1.0, 1.0, 1.0, 1.0);
	glColor3f(1.0, 0.0, 0.0);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(-2.0, 2.0, -2.0, 2.0);
	glMatrixMode(GL_MODELVIEW);
}

void increaseDisplay()
{
	while (gCount <= 5)
	{
		gCount++;
	}
	sleep(1);
	glutPostRedisplay();
}

void display()
{
	glClear(GL_COLOR_BUFFER_BIT);
	glBegin(GL_TRIANGLES);
	divide_triangle(v[0], v[1], v[2], gCount);
	glEnd();
	glutSwapBuffers();
}
int main(int argc, char *argv[])
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DOUBLE);
	glutInitWindowSize(640, 480);
	glutInitWindowPosition(200, 200);
	glutCreateWindow("三角形");
	init();
	glutDisplayFunc(display);
	glutIdleFunc(increaseDisplay);
	glutMainLoop();
	return 0;

}