91 lines
2.3 KiB
JavaScript
91 lines
2.3 KiB
JavaScript
import TempNode from '../core/TempNode.js';
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import ModelNode from '../accessors/ModelNode.js';
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import ShaderNode from '../shadernode/ShaderNode.js';
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import { positionView, normalView, uv, join, cond, add, sub, mul, dFdx, dFdy, cross, max, dot, normalize, inversesqrt, equal } from '../shadernode/ShaderNodeElements.js';
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import { TangentSpaceNormalMap, ObjectSpaceNormalMap } from 'three';
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// Normal Mapping Without Precomputed Tangents
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// http://www.thetenthplanet.de/archives/1180
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const perturbNormal2ArbNode = new ShaderNode( ( inputs ) => {
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const { eye_pos, surf_norm, mapN, faceDirection, uv } = inputs;
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const q0 = dFdx( eye_pos.xyz );
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const q1 = dFdy( eye_pos.xyz );
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const st0 = dFdx( uv.st );
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const st1 = dFdy( uv.st );
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const N = surf_norm; // normalized
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const q1perp = cross( q1, N );
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const q0perp = cross( N, q0 );
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const T = add( mul( q1perp, st0.x ), mul( q0perp, st1.x ) );
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const B = add( mul( q1perp, st0.y ), mul( q0perp, st1.y ) );
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const det = max( dot( T, T ), dot( B, B ) );
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const scale = cond( equal( det, 0 ), 0, mul( faceDirection, inversesqrt( det ) ) );
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return normalize( add( mul( T, mul( mapN.x, scale ) ), mul( B, mul( mapN.y, scale ) ), mul( N, mapN.z ) ) );
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} );
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class NormalMapNode extends TempNode {
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constructor( node, scaleNode = null ) {
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super( 'vec3' );
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this.node = node;
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this.scaleNode = scaleNode;
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this.normalMapType = TangentSpaceNormalMap;
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}
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generate( builder ) {
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const type = this.getNodeType( builder );
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const { normalMapType, scaleNode } = this;
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const normalOP = mul( this.node, 2.0 );
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let normalMap = sub( normalOP, 1.0 );
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if ( scaleNode !== null ) {
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const normalMapScale = mul( normalMap.xy, scaleNode );
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normalMap = join( normalMapScale, normalMap.z );
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}
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if ( normalMapType === ObjectSpaceNormalMap ) {
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const vertexNormalNode = mul( new ModelNode( ModelNode.NORMAL_MATRIX ), normalMap );
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const normal = normalize( vertexNormalNode );
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return normal.build( builder, type );
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} else if ( normalMapType === TangentSpaceNormalMap ) {
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const perturbNormal2ArbCall = perturbNormal2ArbNode( {
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eye_pos: positionView,
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surf_norm: normalView,
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mapN: normalMap,
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faceDirection: 1.0,
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uv: uv()
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} );
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return perturbNormal2ArbCall.build( builder, type );
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}
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}
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}
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export default NormalMapNode;
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