Lesson 5 of 10 · Forces in a shader
Vortex
Triangles in orbit. The vortex pulls.
Convert to polar coordinates, add T to the angle, convert back. The entire space rotates. The warp coils like water going down the drain.
Water when you pull the plug.
atan() + T
atan(p.y, p.x) gives you the angle. Add T * 0.1 and rebuild with cos/sin. Everything rotates. Low speed = contemplative. High = centrifuge.Change
0.15 to 0.5, spin cycle. To 0.02, so slow you barely notice. Flip sign to -T * 0.15, spins the other way.The code
void main(){
vec2 p = (2.*gl_FragCoord.xy - R) / min(R.x, R.y);
float spin = T * 0.15;
vec3 col = vec3(0.04, 0.02, 0.1);
for(int i = 0; i < 5; i++){
float fi = float(i);
float a = spin + fi * 1.2566;
float dist = 0.4 + fi * 0.08;
vec2 c = vec2(cos(a),sin(a)) * dist;
float rot = a*2.; float ca=cos(rot),sa=sin(rot);
vec2 q = p-c; q = vec2(q.x*ca-q.y*sa, q.x*sa+q.y*ca);
vec2 aq = abs(q);
float d = max(aq.x*.866+q.y*.5, -q.y) - 0.1;
vec2 sq=q+vec2(.03,-.05); vec2 asq=abs(sq);
col *= smoothstep(-.01,.1,max(asq.x*.866+sq.y*.5,-sq.y)-.1);
col += vec3(.85,.45,.05) * smoothstep(.01,-.01,d) * (.5+fi*.1);
}
col += vec3(.95,.85,.4) * exp(-length(p)*2.) * .2;
col = hueShift(col, 0.0);
gl_FragColor = vec4(col, 1.);
}