Forum de FilmDeCulte

cw = false;
upper = false;
upperLimb = "cuisse";
lowerLimb = "jambe";
extremity = "pied";
effector = "control";

function getWorldPos(theLayerName){
  L = thisComp.layer(theLayerName);
  return L.toWorld(L.anchorPoint);
}

A = getWorldPos(upperLimb);
B = getWorldPos(lowerLimb);
C = getWorldPos(extremity);
E = getWorldPos(effector);

a = length(B,C);
b = length(E,A);
c = length(A,B);

x = (b*b + c*c - a*a )/(2*b);
alpha = Math.acos(clamp(x/c,-1,1));
if (upper){
  D = E - A;
  delta = Math.atan2(D[1],D[0]);
  result = radiansToDegrees(delta - (cw ? 1 : -1)*alpha);
  V = B - A;
  adj1 = radiansToDegrees(Math.atan2(V[1],V[0]));
  result - adj1 + value;
}else{
  y = b - x;
  gamma = Math.acos(clamp(y/a,-1,1));
  result = (cw ? 1 : -1)*radiansToDegrees(gamma + alpha);
  V1 = B - A;
  adj1 = radiansToDegrees(Math.atan2(V1[1],V1[0]));
  V2 = C - B;
  adj2 = radiansToDegrees(Math.atan2(V2[1],V2[0]));
  result +  adj1 - adj2 + value;
}