#include <stdio.h>
#include <math.h>
#include <iostream>
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');
}
}
