如何用C语言画一个高逼格的"心形"？

来源：互联网发布：李钟硕李敏镐网络剧编辑：程序博客网时间：2024/06/05 17:24

本文转自知乎：http://www.zhihu.com/question/20187195                Milo Yip大神的回答

#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('\n');    }}

再来个有花纹的。（这其实是该函数的Level set）

#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('\n');    }}

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('\n');    }}

「3D」版，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('\n');    }}

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。

#ifdef _MSC_VER#define _CRT_SECURE_NO_WARNINGS#endif#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() {    FILE* fp = fopen("heart.ppm", "w");    int sw = 512, sh = 512;    fprintf(fp, "P3\n%d %d\n255\n", sw, sh);    for (int sy = 0; sy < sh; sy++) {        float z = 1.5f - sy * 3.0f / sh;        for (int sx = 0; sx < sw; sx++) {            float x = sx * 3.0f / sw - 1.5f;            float v = f(x, 0.0f, z);            int r = 0;            if (v <= 0.0f) {                float y0 = h(x, z);                float ny = 0.001f;                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) / sqrtf(3) * nd * 0.5f + 0.5f;                r = (int)(d * 255.0f);            }            fprintf(fp, "%d 0 0 ", r);        }        fputc('\n', fp);    }    fclose(fp);}原文出处：http://www.zhihu.com/question/20187195

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