public class Limb {

//Set color, points and scale variables

color col = color(255, 255, 255);

PVector point1, point2, midPoint, polar;

float scaleFactorY, scaleFactorZ;

//Constructor takes in two pvectors for start and end point fo limb

//and scale factors. factor of 1.0 will give a circle, 0.3 will be closer to limb

public Limb(PVector p1, PVector p2, float _scaleFactorY, float _scaleFactorZ ) {

point1 = p1;

point2 = p2;

scaleFactorY = _scaleFactorY;

scaleFactorZ = _scaleFactorZ;

//Calculates the midpoint between point 1 and point 2 x, y and z values

midPoint = new PVector( (point1.x+point2.x)/2.f, (point1.y+point2.y)/2.f, (point1.z+point2.z)/2.f );

//Vecotr is the direction away from midpoint to point2

PVector vector = new PVector();

vector.set(point2);

vector.sub(midPoint);

polar = cartesianToPolar( vector );

}

public float draw() {

//Save style and rotation matrix

pushStyle();

pushMatrix();

noStroke();

//fill only

fill(col);

//Move origin to centre of sphere

translate(midPoint.x, midPoint.y, midPoint.z);

//Rorate so x axis points along polar coordinate vector

rotateY( polar.y );

rotateZ( polar.z );

//Squash sphere by scale factors

scale(1, scaleFactorY, scaleFactorZ);

//draw shpere according to radius of polar coordinates

sphere(polar.x);

//restore style and rotation matrix

popMatrix();

popStyle();

//return radius for use in joint drawing

return polar.x;

}

//converts from cartesian (x,y,z component) to polar (radius, rotation, z rotation) coordinates.

PVector cartesianToPolar(PVector v) {

PVector res = new PVector();

res.x = v.mag();

if (res.x > 0) {

res.y = -atan2(v.z, v.x);

res.z = asin(v.y / res.x);

}

else {

res.y = 0;

res.z = 0;

}

return res;

}

}