     // castRay(ro, rd)
     float tmin = .2;
     float mat = -1.;
-    for( float i=0.; i<64.; i++ ) { // 64 = maxIterations
+    for( float i=-32.; i<32.; i++ ) { // 64 = maxIterations
       vec2 rayRes = map( ro+rd*tmin );
       //float precis = .000001*tmin;
       //if( rayRes.x<precis) break; // TODO: nice optimisation, but eats space

}
*/

float calcPlasma(vec3 p) {
  return sin(5. *
    // horizontal sinusoid

    // return vec2(sdPlasmaSphere(p, 0.5), hue);
    vec2(length(p)-.5 + plasma * sin(a / 100.0), sin(plasma) * 100. + a),
    // plane
    vec2(p.y + 1., 0.)
  );

  /* ---------- DEBUGGING ---------- */
