如何用C语言画一个心形？

#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('\n'); } } 

参考：Heart Curve -- from Wolfram MathWorld

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更新1: 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'); } } 

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更新2: 「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'); } } 

参考：Heart Surface -- from Wolfram MathWorld

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更新4：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); } 

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更新5：通过空间的缩放变换实现 ASCII 心跳动画，需要改变光标位置，此版本仅支持Windows。录制视频不太顺畅，建议在本地测试。

ASCII心跳动画

http://v.youku.com/v_show/id_XODQ2MDc1NzYw.html

 

#include <stdio.h> #include <math.h> #include <windows.h> #include <tchar.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() { HANDLE o = GetStdHandle(STD_OUTPUT_HANDLE); _TCHAR buffer[25][80] = { _T(' ') }; _TCHAR ramp[] = _T(".:-=+*#%@"); for (float t = 0.0f;; t += 0.1f) { int sy = 0; float s = sinf(t); float a = s * s * s * s * 0.2f; for (float z = 1.3f; z > -1.2f; z -= 0.1f) { _TCHAR* p = &buffer[sy++][0]; float tz = z * (1.2f - a); for (float x = -1.5f; x < 1.5f; x += 0.05f) { float tx = x * (1.2f + a); float v = f(tx, 0.0f, tz); if (v <= 0.0f) { float y0 = h(tx, tz); float ny = 0.01f; float nx = h(tx + ny, tz) - y0; float nz = h(tx, tz + ny) - y0; float nd = 1.0f / sqrtf(nx * nx + ny * ny + nz * nz); float d = (nx + ny - nz) * nd * 0.5f + 0.5f; *p++ = ramp[(int)(d * 5.0f)]; } else *p++ = ' '; } } for (sy = 0; sy < 25; sy++) { COORD coord = { 0, sy }; SetConsoleCursorPosition(o, coord); WriteConsole(o, buffer[sy], 79, NULL, 0); } Sleep(33); } } 

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更新6：移植至 Shadertoy BETA 实现，加入高光和背景。

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