// Bonfire
void main(){float i,t,d,a,v,n,w;vec3 p,q,k,o,K=vec3(9,3,1);for(d++;i++<5e1&&d>.001;o+=d>n?d=abs(n)*.4+.05,K/d:K*exp(-length(k)*.6)*20.,t+=d*.5)for(k=normalize(vec3(P+P-R,R.y))*t+vec3(0,6,-15),d=k.y,w=.0025,a-=a,n=.96*length(k.xz)+.27*k.y-5.34;a++<9.;w+=w)p=k,p.zx*=mat2(cos(a*2.4+vec4(0,33,11,0))),q=p,q.y-=a*T,n+=abs(dot(sin(q*.7/w),q-q+w)),p.z-=5.,p.yz*=mat2(1,v=a*.18,-v,1)/sqrt(v*v+1.),d=min(d,max(abs(p.z+5.)-5.,max(abs(p.x)*.9+p.y*.5,-p.y)-.3));O=vec4(tanh(o/5e2),1);}

#shader #demo