/**

* Arm.

*

* The angle of each segment is controlled with the mouseX and

* mouseY position. The transformations applied to the first segment

* are also applied to the second segment because they are inside

* the same pushMatrix() and popMatrix() group.

*/

float x, y;

float angle1 = 0.0;

float angle2 = 0.0;

float segLength = 100;

void setup() {

size(640, 360);

strokeWeight(30);

stroke(255, 160);

x = width * 0.3;

y = height * 0.5;

}

void draw() {

background(0);

angle1 = (mouseX / float(width) - 0.5) * -PI;

angle2 = (mouseY / float(height) - 0.5) * PI;

pushMatrix();

segment(x, y, angle1);

segment(segLength, 0, angle2);

popMatrix();

}

void segment(float x, float y, float a) {

translate(x, y);

rotate(a);

line(0, 0, segLength, 0);

}