Chapter 420: GodraysNode

Core Idea

Post-Processing node for apply Screen-space raymarched godrays to a scene.

After the godrays have been computed, it's recommened to apply a Bilateral Blur to the result to mitigate raymarching and noise artifacts.

The composite with the scene pass is ideally done with depthAwareBlend(), which mitigates aliasing and light leaking.

Limitations:

• Only point and directional lights are currently supported.
• The effect requires a full shadow setup. Meaning shadows must be enabled in the renderer, 3D objects must cast and receive shadows and the main light must cast shadows.

Reference: This Node is a part of three-good-godrays.

Key Concepts

• density : UniformNode.<float>: The rate of accumulation for the godrays. Higher values roughly equate to more humid air/denser fog.
• depthNode : TextureNode: A node that represents the beauty pass's depth.
• distanceAttenuation : UniformNode.<float>: Higher values decrease the accumulation of godrays the further away they are from the light source.
• maxDensity : UniformNode.<float>: The maximum density of the godrays. Limits the maximum brightness of the godrays.
• raymarchSteps : UniformNode.<uint>: The number of raymarching steps
• resolutionScale : number: The resolution scale.
• updateBeforeType : string: The updateBeforeType is set to NodeUpdateType.FRAME since the node renders its effect once per frame in updateBefore().

Code Examples

const godraysPass = godrays( scenePassDepth, camera, light );
const blurPass = bilateralBlur( godraysPassColor ); // optional blur
const outputBlurred = depthAwareBlend( scenePassColor, blurPassColor, scenePassDepth, camera, { blendColor, edgeRadius, edgeStrength } ); // composite

• What it demonstrates: Typical usage of GodraysNode.

Reference Tables

Constructor

Signature
`new GodraysNode( depthNode : TextureNode, camera : Camera, light : DirectionalLight

Properties

Property	Description
.density : UniformNode.<float>	The rate of accumulation for the godrays. Higher values roughly equate to more humid air/denser fog.
.depthNode : TextureNode	A node that represents the beauty pass's depth.
.distanceAttenuation : UniformNode.<float>	Higher values decrease the accumulation of godrays the further away they are from the light source.
.maxDensity : UniformNode.<float>	The maximum density of the godrays. Limits the maximum brightness of the godrays.
.raymarchSteps : UniformNode.<uint>	The number of raymarching steps
.resolutionScale : number	The resolution scale.
.updateBeforeType : string	The updateBeforeType is set to NodeUpdateType.FRAME since the node renders its effect once per frame in updateBefore().

Methods

Method	Description
.dispose()	Frees internal resources. This method should be called when the effect is no longer required.
.getTextureNode() : PassTextureNode	Returns the result of the effect as a texture node.
.setSize( width : number, height : number )	Sets the size of the effect.
.setup( builder : NodeBuilder ) : PassTextureNode	This method is used to setup the effect's TSL code.
.updateBefore( frame : NodeFrame )	This method is used to render the effect once per frame.

Key Takeaways

1. GodraysNode extends: EventDispatcher → Node → TempNode
2. Most relevant properties: density, depthNode, distanceAttenuation, maxDensity.
3. Key methods: dispose, getTextureNode, setSize, setup.

Connects To

• EventDispatcher: parent class
• Node: parent class
• TempNode: parent class
• Source: examples/jsm/tsl/display/GodraysNode.js