Gift for GS5

//

//  main.cpp

//  生日快乐

//

//  Created by wasdns on 16/11/21.

//  Copyright © 2016年 wasdns. All rights reserved.

//

#include <stdio.h>

#include <math.h>

#include <iostream>

using namespace std;

float f(float x, float y, float z) {

    float a = x * x + 9.0f / 4.0f * y * y + z * z - 1;

    return a * a * a - x * x * z * z * z - 9.0f / 80.0f * y * y * z * z * z;

}

float h(float x, float z) {

    for (float y = 1.0f; y >= 0.0f; y -= 0.001f)

        if (f(x, y, z) <= 0.0f)

            return y;

    return 0.0f;

}

int main() {

    for (float z = 1.5f; z > -1.5f; z -= 0.05f) {

        for (float x = -1.5f; x < 1.5f; x += 0.025f) {

            float v = f(x, 0.0f, z);

            if (v <= 0.0f) {

                float y0 = h(x, z);

                float ny = 0.01f;

                float nx = h(x + ny, z) - y0;

                float nz = h(x, z + ny) - y0;

                float nd = 1.0f / sqrtf(nx * nx + ny * ny + nz * nz);

                float d = (nx + ny - nz) * nd * 0.5f + 0.5f;

                putchar(".:-=+*#%@"[(int)(d * 5.0f)]);

            }

            else

                putchar(' ');

        }

        putchar('\n');

    }

}

注：源码来自网络。使用DevC++编译器进行编译，一般终端可能过小，无法完全显示。