圣诞节的圣诞树

圣诞节特别篇

突然想起是圣诞节呀，想着能给同学们一些祝福。于是写了圣诞树的代码。
当然，其中不乏借鉴和参考。
感谢知乎Milo Yip的回答：https://www.zhihu.com/questio...，大神真的好棒。

#include "stdafx.h"
#include 
#include 
#include 
#include 
#define PI 3.14159265359
#define T px + scale * r * cosf(theta), py + scale * r * sin(theta)

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;
}

float f(float px, float py, float theta, float scale, int n) {
    float d = 0.0f;
    for (float r = 0.0f; r < 0.8f; 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 ribbon() {
    float x = (fmodf(sy, 0.1f) / 0.1f - 0.5f) * 0.5f;
    return sx >= x - 0.05f && sx <= x + 0.05f;
}
int main(int argc, char* argv[]) {
    int n = argc > 1 ? atoi(argv[1]) : 3;
    float zoom = argc > 2 ? atof(argv[2]) : 1.0f;
    for (sy = 0.8f; sy > 0.0f; sy -= 0.02f / zoom, putchar('\n'))
        for (sx = -0.35f; sx < 0.35f; sx += 0.01f / zoom) {
            if (f(0, 0, PI * 0.5f, 1.0f, n) < 0.0f) {
                if (sy < 0.1f) {
                    putchar('.');
                } else {
                    if (ribbon()) {
                        putchar('=');
                    } else {
                        putchar("............................#j&o"[rand() % 32]);
                    }
                }
            } else {
                putchar(' ');
            }
        }
    Sleep(1000);
    printf("\n\n\n");
    for (size_t i = 0; i < 40; i++) {
        putchar(' ');
    }
    //_sleep(5000);
    printf("Merry Christmas, Lavinia~!\n");
    Sleep(500);
    for (size_t i = 0; i < 40; i++) {
        putchar(' ');
    }
    printf("Never say die.\n");
    Sleep(500);
    for (size_t i = 0; i < 40; i++) {
        putchar(' ');
    }
    printf("2016/12/24, Zachariah.\n");
    getchar();
}