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效果展示：
#include <stdio.h> #include <math.h> const int max_iterations = 128; const
float stop_threshold = 0.01f; const float grad_step = 0.01f; const float
clip_far= 10.0f; const float PI = 3.14159265359f; const float PI2 =
6.28318530718f; const float DEG_TO_RAD = 3.14159265359f / 180.0f; typedef struct
{ float x, y; } vec2; typedef struct { float x, y, z; } vec3; typedef struct {
float m[9]; } mat3; const vec3 light_pos = { 20.0f, 50.0f, 20.0f }; float min(
float a, float b) { return a < b ? a : b; } float max(float a, float b) { return
a> b ? a : b; } float clamp(float f, float a, float b) { return max(min(f, b),
a); } vec2 make2(float x, float y) { vec2 r = { x, y }; return r; } vec2 add2(
vec2 a, vec2 b) { vec2 r = { a.x + b.x, a.y + b.y }; return r; } vec2 sub2(vec2
a, vec2 b) { vec2 r = { a.x - b.x, a.y - b.y }; return r; } float dot2(vec2 a,
vec2 b) { return a.x * b.x + a.y * b.y; } float length2(vec2 v) { return sqrt(
dot2(v, v)); } vec3 make3(float x, float y, float z) { vec3 r = { x, y, z };
return r; } vec3 add3(vec3 a, vec3 b) { vec3 r = { a.x + b.x, a.y + b.y, a.z + b
.z }; return r; } vec3 sub3(vec3 a, vec3 b) { vec3 r = { a.x - b.x, a.y - b.y, a
.z - b.z }; return r; } vec3 mul3(vec3 a, vec3 b) { vec3 r = { a.x * b.x, a.y *
b.y, a.z * b.z }; return r; } vec3 scale3(vec3 v, float s) { vec3 r = { v.x * s,
v.y * s, v.z * s }; return r; } float dot3(vec3 a, vec3 b) { return a.x * b.x +
a.y * b.y + a.z * b.z; } float length3(vec3 v) { return sqrt(dot3(v, v)); }
vec3normalize3(vec3 v) { return scale3(v, 1.0f / length3(v)); } vec3 mul(mat3 m,
vec3 v) { return make3( m.m[0] * v.x + m.m[3] * v.y + m.m[6] * v.z, m.m[1] * v.
x+ m.m[4] * v.y + m.m[7] * v.z, m.m[2] * v.x + m.m[5] * v.y + m.m[8] * v.z); }
mat3rotationXY(float x, float y) { vec2 c = { cos(x), cos(y) }, s = { sin(x),
sin(y) }; mat3 m = { c.y , 0.0f, -s.y, s.y * s.x, c.x, c.y * s.x, s.y * c.x, -s.
x, c.y * c.x }; return m; } float opI(float d1, float d2) { return max(d1, d2);
} float opU(float d1, float d2) { return min(d1, d2); } float opS(float d1,
float d2) { return max(-d1, d2); } float sdPetal(vec3 p, float s) { p = add3(
mul3(p, make3(0.8f, 1.5f, 0.8f)), make3(0.1f, 0.0f, 0.0f)); vec2 q = make2(
length2(make2(p.x, p.z)), p.y); float lower = length2(q) - 1.0f; lower = opS(
length2(q) - 0.97f, lower); lower = opI(lower, q.y); float upper = length2(sub2(
q, make2(s, 0.0f))) + 1.0f - s; upper = opS(upper, length2(sub2(q, make2(s, 0.0f
))) + 0.97f - s); upper = opI(upper, -q.y); upper = opI(upper, q.x - 2.0f);
float region = length3(sub3(p, make3(1.0f, 0.0f, 0.0f))) - 1.0f; return opI(opU(
upper, lower), region); } float map(vec3 p) { float d = 1000.0f, s = 2.0f; mat3
r= rotationXY(0.1f, PI2 * 0.618034f); r.m[0] *= 1.08f; r.m[1] *= 1.08f; r.m[2]
*= 1.08f; r.m[3] *= 0.995f; r.m[4] *= 0.995f; r.m[5] *= 0.995f; r.m[6] *= 1.08f;
r.m[7] *= 1.08f; r.m[8] *= 1.08f; for (int i = 0; i < 21; i++) { d = opU(d,
sdPetal(p, s)); p = mul(r, p); p = add3(p, make3(0.0, -0.02, 0.0)); s *= 1.05f;
} return d; } vec3 gradient(vec3 pos) { const vec3 dx = { grad_step, 0.0, 0.0 };
const vec3 dy = { 0.0, grad_step, 0.0 }; const vec3 dz = { 0.0, 0.0, grad_step }
; return normalize3(make3( map(add3(pos, dx)) - map(sub3(pos, dx)), map(add3(pos
, dy)) - map(sub3(pos, dy)), map(add3(pos, dz)) - map(sub3(pos, dz)))); } float
ray_marching(vec3 origin, vec3 dir, float start, float end) { float depth =
start; for (int i = 0; i < max_iterations; i++) { float dist = map(add3(origin,
scale3(dir, depth))); if (dist < stop_threshold) return depth; depth += dist *
0.3; if (depth >= end) return end; } return end; } float shading(vec3 v, vec3 n,
vec3 eye) { vec3 ev = normalize3(sub3(v, eye)); vec3 vl = normalize3(sub3(
light_pos, v)); float diffuse = dot3(vl, n) * 0.5f + 0.5f; vec3 h = normalize3(
sub3(vl, ev)); float rim = pow(1.0f - max(-dot3(n, ev), 0.0f), 2.0f) * 0.15f;
float ao = clamp(v.y * 0.5f + 0.5f, 0.0f, 1.0f); return (diffuse + rim) * ao; }
vec3ray_dir(float fov, vec2 pos) { vec3 r = { pos.x, pos.y, -tan((90.0f - fov *
0.5f) * DEG_TO_RAD) }; return normalize3(r); } float f(vec2 fragCoord) { vec3
dir= ray_dir(45.0f, fragCoord); vec3 eye = { 0.0f, 0.0f, 4.5f }; mat3 rot =
rotationXY(-1.0f, 1.0f); dir = mul(rot, dir); eye = mul(rot, eye); float depth =
ray_marching(eye, dir, 0.0f, clip_far); vec3 pos = add3(eye, scale3(dir, depth))
; if (depth >= clip_far) return 0.0f; else return shading(pos, gradient(pos),
eye); } int main() { puts("\033[91m"); for (int y = 0; y < 80; y++) { for (int x
= 0; x < 160; x++) putchar(" .,-:;+=*#@"[(int)(f(make2((x / 160.0f - 0.5f) *
2.0f, (y / 80.0f - 0.5f) * -2.0f)) * 12.0f)]); putchar('\n'); } }
效果展示：
#include <stdio.h> int main(int argc, char* argv[]) { float x, y, a; for (y =
1.5; y > -1.5; y -= 0.1) { for (x = -1.5; x < 1.5; x += 0.05) { a = x * x + y *
y- 1; putchar(a * a * a - x * x * y * y * y <= 0.0 ? '*' : ' '); } system(
"color 0c"); putchar('\n'); } printf(" 玲珑骰子安红豆"); printf("\n\n"); return 0; }