Nodes: Cache linear depth and viewZ of depth textures in PassNode

[cmhhelgeson]

Description

Following on from some work I'm doing porting the outline pass, this PR allows the user to access the linear depth and viewZ of multiple relevant depth textures within any class that extends PassNode. This can be helpful for debugging or accessing the linear depth of relevant depth passes to be forwarded to other post-processing steps.

Example usage below:

// Create a class that extends PassNodee
class PostPassNode extends PassNode {

	constructor( scene, camera ) {

		super( 'color', scene, camera );

		// Create Render Target Pass with color and depth
		let passName;

		this._prePassRT = new RenderTarget();
		passName = 'PostPassNode.prePassColor';
		this._prePassRT.texture.name = passName;
		this._textures[ passName ] = this._prePassRT.texture;

	        const prePassDepth = new DepthTexture();
	        passName = 'PostPassNode.prePassDepth';
		prePassDepth.name = passName;
	        prePassDepth.isRenderTargetTexture = true;
		this._prePassRT.depthTexture = prePassDepth;
		this._textures[ passName ] = this._prePassRT.depthTexture;

	}

	updateBefore( frame ) {

		const { renderer } = frame;
		const { scene, camera } = this;

		// Random configuration

		// Render to any number of render targets
		renderer.setRenderTarget( this._prePassRT );
		renderer.setMRT( null );
		renderer.render( scene, camera );

		// Render to final output
		renderer.setRenderTarget( this.renderTarget );
		renderer.setMRT( this._mrt );
		renderer.render( scene, camera );

	}

	setup() {

		// # Use Case 1: Debug depth output of texture

		return super.getLinearDepthNode(  'PostPassNode.prePassDepth'  );
                // return postProcess( ..... )

		// # Use Case 2: Apply depth or linear depth to shader post process node

		const color = super.getTextureNode( 'output' );
		const depth = super.getTextureNode( 'depth' ); 
                const linearDepth = super.getLinearDepth(); // 
		const prePassDepth = super.getTextureNode(  this._prePassRT.depthTexture.name );
		const prePassLinearDepth = super.getLinearDepthNode( this._prePassRT.depthTexture.name );

		return postProcess( color, depth, linearDepth, prePassDepth, prePassLinearDepth, uniformX, ...etc );

	}

}

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

Filesize dev	Filesize PR	Diff
684 kB (169.4 kB)	684 kB (169.4 kB)	+0 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

Filesize dev	Filesize PR	Diff
460.9 kB (111.2 kB)	460.9 kB (111.2 kB)	+0 B