Distorted Android

  vec2 force = vUniforms[effect].xy;    // force = vec(MM')

  vec2 vert_vec, horz_vec; 

  vec2 signXY = sign(center-v.xy);

  vec2 time = (u_objD.xy+signXY*v.xy)/(u_objD.xy+signXY*center);

  vec2 factorV = vec2(0.5,0.5) + (center*v.xy)/(4.0*u_objD.xy*u_objD.xy);

  vec2 factorD = (u_objD.xy-signXY*center)/(2.0*u_objD.xy);

  vec2 vert_d = factorD.x*force;

  vec2 horz_d = factorD.y*force;

  float dot = dot(force,force);

  vec2 corr = 0.33 * (center+force+signXY*u_objD.xy) * dot / ( dot + (4.0*u_objD.x*u_objD.x) ); // .x = the vector tangent to X(t) at Fl = 0.3*vec(LM')  (or vec(RM') if signXY.x=-1).

                                                                                                // .y = the vector tangent to X(t) at Fb = 0.3*vec(BM')  (or vec(TM') if signXY.y=-1)

                                                                                                // the scalar: make the length of the speed vectors at Fl and Fr be 0 when force vector 'force' is zero

  vert_vec.x = ( force.x-vert_d.x-corr.x )*time.x*time.x + corr.x*time.x + vert_d.x;

  horz_vec.y = (-force.y+horz_d.y+corr.y )*time.y*time.y - corr.y*time.y - horz_d.y;

  vert_vec.y = (-3.0*vert_d.y+2.0*force.y )*time.x*time.x*time.x + (-3.0*force.y+5.0*vert_d.y )*time.x*time.x - vert_d.y*time.x - vert_d.y;

  horz_vec.x = ( 3.0*horz_d.x-2.0*force.x )*time.y*time.y*time.y + ( 3.0*force.x-5.0*horz_d.x )*time.y*time.y + horz_d.x*time.y + horz_d.x;

  v.xy += (factorV.y*vert_vec + factorV.x*horz_vec);