干货!用C语言画一个小猪佩奇(附源码),针不戳! | 您所在的位置:网站首页 › 用c语言画滚动的圆怎么画 › 干货!用C语言画一个小猪佩奇(附源码),针不戳! |
分享下如何用 C 语言画小猪佩奇使用带符号距离场(signed distance field, SDF)表示圆形:file:///C:\Users\Administrator.WIN- STED6B9V5UI\AppData\Local\Temp\ksohtml9656\wps19.png 沿用这个方法表示形状,但这次我们想利用 ASCII 字符|/=\画出形状的外框,并填充内部,类似这样: ===== //.....\\ ||.......|| \\.....// =====SDF 的梯度(gradient)代表 SDF 变化最大的方向,可用这个方向去决定用哪一个字符。file:///C:\Users\Administrator.WIN- STED6B9V5UI\AppData\Local\Temp\ksohtml9656\wps20.png 我们通过差分求 SDF 的梯度近似值,然后用atan2()求出梯度的角度:file:///C:\Users\Administrator.WIN- STED6B9V5UI\AppData\Local\Temp\ksohtml9656\wps21.jpg 用 C 语言简单实现,在画布中画一个半径 0.8 并带有 0.1 寛度外框的圆形:file:///C:\Users\Administrator.WIN- \AppData\Local\Temp\ksohtml9656\wps22.jpg #include #include #define T doubleT f(T x, T y) { return sqrt(x * x + y * y) - 0.8f;}char outline(T x, T y) { T delta = 0.001; if (fabs(f(x, y)) < 0.05) { T dx = f(x + delta, y) - f(x - delta, y); T dy = f(x, y + delta) - f(x, y - delta); return "|/=\\|/=\\|"[(int)((atan2(dy, dx) / 6.2831853072 + 0.5) * 8 + 0.5)]; } else if (f(x, y) < 0) return '.'; else return ' ';}int main() { for (T y = -1; y < 1; y += 0.05, putchar('\n')) for (T x = -1; x < 1; x += 0.025) putchar(outline(x, y));}代码可以左右移动!▲ file:///C:\Users\Administrator.WIN-STED6B9V5UI\AppData\Local\Temp\ksohtml9656\wps23.png 然后,我们就可以画多个圆形, 把它们适当地旋转和缩放,用构造实体几何比它们组合起来,那么用 19 行代码就可以画出小猪佩奇了:代码可以左右移动! ▼// ASCII Peppa Pig by Milo Yip#include #include #include #define T double T c(T x,T y,T r){return sqrt(x*x+y*y)-r;} T u(T x,T y,T t){return x*cos(t)+y*sin(t);} T v(T x,T y,T t){return y*cos(t)-x*sin(t);} T fa(T x,T y){return fmin(c(x,y,0.5),c(x*0.47+0.15,y+0.25,0.3));} T no(T x,T y){return c(x*1.2+0.97,y+0.25,0.2);} T nh(T x,T y){return fmin(c(x+0.9,y+0.25,0.03),c(x+0.75,y+0.25,0.03));} T ea(T x,T y){return fmin(c(x*1.7+0.3,y+0.7,0.15),c(u(x,y,0.25)*1.7,v(x,y,0.25)+0.65,0.15));} T ey(T x,T y){return fmin(c(x+0.4,y+0.35,0.1),c(x+0.15,y+0.35,0.1));} T pu(T x,T y){return fmin(c(x+0.38,y+0.33,0.03),c(x+0.13,y+0.33,0.03));} T fr(T x,T y){return c(x*1.1-0.3,y+0.1,0.15);} T mo(T x,T y){return fmax(c(x+0.15,y-0.05,0.2),-c(x+0.15,y,0.25));} T o(T x,T y,T(*f)(T,T),T i){T r=f(x,y);return fabs(r) |
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