98 lines
2.7 KiB
JavaScript
98 lines
2.7 KiB
JavaScript
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import Node, { addNodeClass } from '../core/Node.js';
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import { nodeImmutable, nodeProxy } from '../shadernode/ShaderNode.js';
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import { cameraNear, cameraFar } from '../accessors/CameraNode.js';
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import { positionView } from '../accessors/PositionNode.js';
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import { viewportDepthTexture } from './ViewportDepthTextureNode.js';
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class ViewportDepthNode extends Node {
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constructor( scope, valueNode = null ) {
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super( 'float' );
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this.scope = scope;
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this.valueNode = valueNode;
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this.isViewportDepthNode = true;
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}
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generate( builder ) {
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const { scope } = this;
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if ( scope === ViewportDepthNode.DEPTH_PIXEL ) {
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return builder.getFragDepth();
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}
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return super.generate( builder );
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}
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setup( /*builder*/ ) {
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const { scope } = this;
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let node = null;
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if ( scope === ViewportDepthNode.DEPTH ) {
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node = viewZToOrthographicDepth( positionView.z, cameraNear, cameraFar );
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} else if ( scope === ViewportDepthNode.DEPTH_TEXTURE ) {
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const texture = this.valueNode || viewportDepthTexture();
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const viewZ = perspectiveDepthToViewZ( texture, cameraNear, cameraFar );
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node = viewZToOrthographicDepth( viewZ, cameraNear, cameraFar );
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} else if ( scope === ViewportDepthNode.DEPTH_PIXEL ) {
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if ( this.valueNode !== null ) {
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node = depthPixelBase().assign( this.valueNode );
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}
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}
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return node;
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}
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}
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// NOTE: viewZ, the z-coordinate in camera space, is negative for points in front of the camera
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// -near maps to 0; -far maps to 1
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export const viewZToOrthographicDepth = ( viewZ, near, far ) => viewZ.add( near ).div( near.sub( far ) );
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// maps orthographic depth in [ 0, 1 ] to viewZ
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export const orthographicDepthToViewZ = ( depth, near, far ) => near.sub( far ).mul( depth ).sub( near );
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// NOTE: https://twitter.com/gonnavis/status/1377183786949959682
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// -near maps to 0; -far maps to 1
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export const viewZToPerspectiveDepth = ( viewZ, near, far ) => near.add( viewZ ).mul( far ).div( far.sub( near ).mul( viewZ ) );
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// maps perspective depth in [ 0, 1 ] to viewZ
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export const perspectiveDepthToViewZ = ( depth, near, far ) => near.mul( far ).div( far.sub( near ).mul( depth ).sub( far ) );
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ViewportDepthNode.DEPTH = 'depth';
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ViewportDepthNode.DEPTH_TEXTURE = 'depthTexture';
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ViewportDepthNode.DEPTH_PIXEL = 'depthPixel';
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export default ViewportDepthNode;
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const depthPixelBase = nodeProxy( ViewportDepthNode, ViewportDepthNode.DEPTH_PIXEL );
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export const depth = nodeImmutable( ViewportDepthNode, ViewportDepthNode.DEPTH );
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export const depthTexture = nodeProxy( ViewportDepthNode, ViewportDepthNode.DEPTH_TEXTURE );
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export const depthPixel = nodeImmutable( ViewportDepthNode, ViewportDepthNode.DEPTH_PIXEL );
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depthPixel.assign = ( value ) => depthPixelBase( value );
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addNodeClass( 'ViewportDepthNode', ViewportDepthNode );
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