import TempNode from '../core/TempNode.js';
import { uv } from '../accessors/UV.js';
import { normalView } from '../accessors/Normal.js';
import { positionView } from '../accessors/Position.js';
import { faceDirection } from './FrontFacingNode.js';
import { Fn, nodeProxy, float, vec2 } from '../tsl/TSLBase.js';
/** @module BumpMapNode **/
// Bump Mapping Unparametrized Surfaces on the GPU by Morten S. Mikkelsen
// https://mmikk.github.io/papers3d/mm_sfgrad_bump.pdf
const dHdxy_fwd = Fn( ( { 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 = Fn( ( 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();
} );
/**
* This class can be used for applying bump maps to materials.
*
* ```js
* material.normalNode = bumpMap( texture( bumpTex ) );
* ```
*
* @augments TempNode
*/
class BumpMapNode extends TempNode {
static get type() {
return 'BumpMapNode';
}
/**
* Constructs a new bump map node.
*
* @param {Node<float>} textureNode - Represents the bump map data.
* @param {Node<float>?} [scaleNode=null] - Controls the intensity of the bump effect.
*/
constructor( textureNode, scaleNode = null ) {
super( 'vec3' );
/**
* Represents the bump map data.
*
* @type {Node<float>}
*/
this.textureNode = textureNode;
/**
* Controls the intensity of the bump effect.
*
* @type {Node<float>?}
* @default null
*/
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;
/**
* TSL function for creating a bump map node.
*
* @function
* @param {Node<float>} textureNode - Represents the bump map data.
* @param {Node<float>?} [scaleNode=null] - Controls the intensity of the bump effect.
* @returns {BumpMapNode}
*/
export const bumpMap = /*@__PURE__*/ nodeProxy( BumpMapNode );