C++圣诞树代码

效果图

代码

#include<stdio.h>
#include<math.h>
#include<stdlib.h>
using namespace std;

#define PI 3.14159265359

float sx, sy;

float sdCircle(float px, float py, float r)
{
	float dx = px - sx, dy = py - sy;
	return sqrtf(dx * dx + dy * dy) - r;
}

float opUnion(float d1, float d2)
{
	return d1 < d2 ? d1 : d2;
}

#define T px + scale *  r * cosf(theta), py + scale * r * sin(theta)

float f(float px, float py, float theta, float scale, int n)
{
	float d = 0.0f;
	for (float r = 0.0f; r < 0.8; r += 0.02f)
		d = opUnion(d, sdCircle(T, 0.05f * scale * (0.95f - r)));
	if (n>0)
		for (int t = -1; t <= 1; t += 2)
		{
			float tt = theta + t * 1.8f;
			float ss = scale * 0.9f;
			for (float r = 0.2f; r < 0.8f; r +=0.1f)
			{
				d = opUnion(d, f(T, tt, ss * 0.5f, n - 1));
				ss *= 0.8f;
			}
		}
	return d;
}

int main(int argc, char* argv[])
{
	int n = argc > 1 ? atoi(argv[1]) : 3;
	for (sy = 0.8f; sy > 0.0f; sy -= 0.02f, putchar('\n'))
		for (sx = -0.35f; sx < 0.35f; sx += 0.01f)
				putchar(f(0, 0, PI * 0.5f, 1.0f, n) < 0 ? '*' : ' ');	
}