I am currently diving deeper into lights and ThreeJS. Much to my surprise I found the code shown below in FBXLoader.js. Can someone explain to me why the FBX loader has a function for creating lights (createLight()) as part of its FBX model loading code? None of the other model loaders (e.g. - GLTF, etc.) seem to have light related, or light creating code in them. At least not what I can see. Why does the FBX format code have this?
I’m asking this because my current project is to attach a PointLight to the lens of an animated camera drone model and have it project a light beam.
// Here is the createLight code found in FBXLoader.js:
// Create a THREE.DirectionalLight, THREE.PointLight or THREE.SpotLight
createLight: function ( relationships ) {
var model;
var lightAttribute;
relationships.children.forEach( function ( child ) {
var attr = fbxTree.Objects.NodeAttribute[ child.ID ];
if ( attr !== undefined ) {
lightAttribute = attr;
}
} );
if ( lightAttribute === undefined ) {
model = new THREE.Object3D();
} else {
var type;
// LightType can be undefined for Point lights
if ( lightAttribute.LightType === undefined ) {
type = 0;
} else {
type = lightAttribute.LightType.value;
}
var color = 0xffffff;
if ( lightAttribute.Color !== undefined ) {
color = new THREE.Color().fromArray( lightAttribute.Color.value );
}
var intensity = ( lightAttribute.Intensity === undefined ) ? 1 : lightAttribute.Intensity.value / 100;
// light disabled
if ( lightAttribute.CastLightOnObject !== undefined && lightAttribute.CastLightOnObject.value === 0 ) {
intensity = 0;
}
var distance = 0;
if ( lightAttribute.FarAttenuationEnd !== undefined ) {
if ( lightAttribute.EnableFarAttenuation !== undefined && lightAttribute.EnableFarAttenuation.value === 0 ) {
distance = 0;
} else {
distance = lightAttribute.FarAttenuationEnd.value;
}
}
// TODO: could this be calculated linearly from FarAttenuationStart to FarAttenuationEnd?
var decay = 1;
switch ( type ) {
case 0: // Point
model = new THREE.PointLight( color, intensity, distance, decay );
break;
case 1: // Directional
model = new THREE.DirectionalLight( color, intensity );
break;
case 2: // Spot
var angle = Math.PI / 3;
if ( lightAttribute.InnerAngle !== undefined ) {
angle = THREE.MathUtils.degToRad( lightAttribute.InnerAngle.value );
}
var penumbra = 0;
if ( lightAttribute.OuterAngle !== undefined ) {
// TODO: this is not correct - FBX calculates outer and inner angle in degrees
// with OuterAngle > InnerAngle && OuterAngle <= Math.PI
// while three.js uses a penumbra between (0, 1) to attenuate the inner angle
penumbra = THREE.MathUtils.degToRad( lightAttribute.OuterAngle.value );
penumbra = Math.max( penumbra, 1 );
}
model = new THREE.SpotLight( color, intensity, distance, angle, penumbra, decay );
break;
default:
console.warn( 'THREE.FBXLoader: Unknown light type ' + lightAttribute.LightType.value + ', defaulting to a THREE.PointLight.' );
model = new THREE.PointLight( color, intensity );
break;
}
if ( lightAttribute.CastShadows !== undefined && lightAttribute.CastShadows.value === 1 ) {
model.castShadow = true;
}
}
return model;
},
