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- import TempNode from '../core/TempNode.js';
- import { addNodeClass } from '../core/Node.js';
- import { uv } from '../accessors/UVNode.js';
- import { normalView } from '../accessors/NormalNode.js';
- import { positionView } from '../accessors/PositionNode.js';
- import { faceDirection } from './FrontFacingNode.js';
- import { addNodeElement, tslFn, nodeProxy, float, vec2 } from '../shadernode/ShaderNode.js';
- // Bump Mapping Unparametrized Surfaces on the GPU by Morten S. Mikkelsen
- // https://mmikk.github.io/papers3d/mm_sfgrad_bump.pdf
- const dHdxy_fwd = tslFn( ( { textureNode, bumpScale } ) => {
- // It's used to preserve the same TextureNode instance
- const sampleTexture = ( callback ) => textureNode.cache().context( { getUV: ( texNode ) => callback( texNode.uvNode || uv() ), forceUVContext: true } );
- const Hll = float( sampleTexture( ( uvNode ) => uvNode ) );
- return vec2(
- float( sampleTexture( ( uvNode ) => uvNode.add( uvNode.dFdx() ) ) ).sub( Hll ),
- float( sampleTexture( ( uvNode ) => uvNode.add( uvNode.dFdy() ) ) ).sub( Hll )
- ).mul( bumpScale );
- } );
- // Evaluate the derivative of the height w.r.t. screen-space using forward differencing (listing 2)
- const perturbNormalArb = tslFn( ( inputs ) => {
- const { surf_pos, surf_norm, dHdxy } = inputs;
- // normalize is done to ensure that the bump map looks the same regardless of the texture's scale
- const vSigmaX = surf_pos.dFdx().normalize();
- const vSigmaY = surf_pos.dFdy().normalize();
- const vN = surf_norm; // normalized
- const R1 = vSigmaY.cross( vN );
- const R2 = vN.cross( vSigmaX );
- const fDet = vSigmaX.dot( R1 ).mul( faceDirection );
- const vGrad = fDet.sign().mul( dHdxy.x.mul( R1 ).add( dHdxy.y.mul( R2 ) ) );
- return fDet.abs().mul( surf_norm ).sub( vGrad ).normalize();
- } );
- class BumpMapNode extends TempNode {
- constructor( textureNode, scaleNode = null ) {
- super( 'vec3' );
- this.textureNode = textureNode;
- this.scaleNode = scaleNode;
- }
- setup() {
- const bumpScale = this.scaleNode !== null ? this.scaleNode : 1;
- const dHdxy = dHdxy_fwd( { textureNode: this.textureNode, bumpScale } );
- return perturbNormalArb( {
- surf_pos: positionView,
- surf_norm: normalView,
- dHdxy
- } );
- }
- }
- export default BumpMapNode;
- export const bumpMap = nodeProxy( BumpMapNode );
- addNodeElement( 'bumpMap', bumpMap );
- addNodeClass( 'BumpMapNode', BumpMapNode );
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