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#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 = PI / 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)); } vec3
normalize3(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);
} mat3 rotationXY(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; } vec3 ray_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');
} }
If you need the source code, you can come to the small learning group 【669325409】 receive !
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