如何用C语言画一个高逼格的"心形"？

#include <stdio.h>

int main() {
    for (float y = 1.5f; y > -1.5f; y -= 0.1f) {
        for (float x = -1.5f; x < 1.5f; x += 0.05f) {
            float a = x * x + y * y - 1;
            putchar(a * a * a - x * x * y * y * y <= 0.0f ? * :  );
        }
        putchar(
);
    }
}

#include <stdio.h>

int main() {
    for (float y = 1.5f; y > -1.5f; y -= 0.1f) {
        for (float x = -1.5f; x < 1.5f; x += 0.05f) {
            float z = x * x + y * y - 1;
            float f = z * z * z - x * x * y * y * y;
            putchar(f <= 0.0f ? ".:-=+*#%@"[(int)(f * -8.0f)] :  );
        }
        putchar(
);
    }
}

简单使用迭代法求解，用Finite difference求法矢量，用wrapped diffuse着色。

#include <stdio.h>
#include <math.h>

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(
);
    }
}

「3D」版，简单使用迭代法求解，用求法矢量，用wrapped diffuse着色。

#include <stdio.h>
#include <math.h>

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(
);
    }
}

把「3D版」输出至PPM文件，可以用Photoshop打开。另外降低了ny的值导致有超有趣的pattern，就保留下来吧。