smoke vs structure - shadertoy version! (Fell^RiFT)

precision lowp float;
#define f float
#define n normalize
#define v vec3

uniform vec2 resolution;
uniform f time;
f t=time/10.;

f b(v p,v b){
        v q=abs(p)-b;
        return min(max(q.x,max(q.y,q.z)),length(max(q,0.)));
}

f h(v p){
        v q=v(2.5),a,r,k=v(1e2,1,0);
        p=mod(p,q)-q/2.;
        f d=b(p,v(1)),s=1.;
        for(int i=0;i<3;i++){
                a=mod(p*s,2.)-1.;
                s*=(2.+t)/3.;
                r=1.5-3.0*abs(a);
                d=max(d,-min(b(r,k.xyy),min(b(r.yzx,k.yxy),b(r.zxy,k.yyx)))/s);
        }
        return d;
}

void main(){
        vec2 q=-1.+2.*gl_FragCoord.xy/resolution;
        q.x*=resolution.x/resolution.y;
        f d=0.;
        v p=v(.1*sin(t),.5,6.*t),
        w=n(-p),u=n(cross(v(cos(6.*t),sin(6.*t),0),w)),
        r=n(q.x*u+q.y*n(cross(w,u))+w);
        for(int i=0;i<64;i++){
                d=h(p)-.001;
                if(d<.001)break;
                p+=r*d/4.;
        }

        d=0.;
        for(f i=0.;i<9.;i++)
                d+=h(p+v(cos(i),sin(i),-cos(i))/4.);

        t<1.?d*=t:d;
        gl_FragColor=vec4(h(p+.1)*v(1,.4,.2)*d*d,1);
}