Lights and Custom Shaders - Three.js - page 230

1. The first thing to do is create a THREE.PointLight instance:
var pointLight = new THREE.PointLight();
pointLight.color = new
THREE.Color(0xff0000);
pointLight.intensity = 3;
pointLight.distance = 60;
pointLight.name = 'pointLight';
With the color property, we set the color THREE.PointLight object emits,
and the intensity allows us to set how much light is emitted. Finally, the dis-
tance property is used to calculate how much the intensity decreases the
farther away the lit object is from the light. In this case, the intensity will be 0
when the distance to the light is 60 .
2. THREE.PointLight emits lights in all directions, so we need to set the po-
sition property and then we can add the light to the scene:
pointLight.position = new
THREE.Vector3(-30,0,0);
scene.add(pointLight);
3. The last thing we need to do for this recipe is move THREE.PointLight
through the scene. Like all animations, we do this in the render loop by
adding the following to the render function:
var light =
scene.getObjectByName('pointLight');
light.position.y = 15 *
Math.sin(count+=0.005);
In this small code snippet, we first get a reference to our
THREE.PointLight object and then update its position.y property. For
this to work, we also need to define a global count property at the top of our
JavaScript like this:
var count = 0;