This example is for Processing 3+. If you have a previous version, use the examples included with your software. If you see any errors or have suggestions, please let us know.

Spot.

Move the mouse the change the position and concentation of a blue spot light.

 
int concentration = 600; // Try values 1 -> 10000

void setup() {
  size(640, 360, P3D);
  noStroke();
  fill(204);
  sphereDetail(60);
}

void draw() {
  background(0); 
  
  // Light the bottom of the sphere
  directionalLight(51, 102, 126, 0, -1, 0);
  
  // Orange light on the upper-right of the sphere
  spotLight(204, 153, 0, 360, 160, 600, 0, 0, -1, PI/2, 600); 
  
  // Moving spotlight that follows the mouse
  spotLight(102, 153, 204, 360, mouseY, 600, 0, 0, -1, PI/2, 600); 
  
  translate(width/2, height/2, 0); 
  sphere(120); 
}