text: import { LinearEncoding } from 'three';
  
  import WebGPUNodeUniformsGroup from './WebGPUNodeUniformsGroup.js';
  import {
  	FloatNodeUniform, Vector2NodeUniform, Vector3NodeUniform, Vector4NodeUniform,
  	ColorNodeUniform, Matrix3NodeUniform, Matrix4NodeUniform
  } from './WebGPUNodeUniform.js';
  import WebGPUNodeSampler from './WebGPUNodeSampler.js';
  import { WebGPUNodeSampledTexture } from './WebGPUNodeSampledTexture.js';
  
  import WebGPUUniformBuffer from '../WebGPUUniformBuffer.js';
  import { getVectorLength, getStrideLength } from '../WebGPUBufferUtils.js';
  
  import VarNode from 'three-nodes/core/VarNode.js';
  import CodeNode from 'three-nodes/core/CodeNode.js';
  import BypassNode from 'three-nodes/core/BypassNode.js';
  import ExpressionNode from 'three-nodes/core/ExpressionNode.js';
  import NodeBuilder from 'three-nodes/core/NodeBuilder.js';
  import MaterialNode from 'three-nodes/accessors/MaterialNode.js';
  import PositionNode from 'three-nodes/accessors/PositionNode.js';
  import NormalNode from 'three-nodes/accessors/NormalNode.js';
  import ModelViewProjectionNode from 'three-nodes/accessors/ModelViewProjectionNode.js';
  import SkinningNode from 'three-nodes/accessors/SkinningNode.js';
  import ColorSpaceNode from 'three-nodes/display/ColorSpaceNode.js';
  import LightContextNode from 'three-nodes/lights/LightContextNode.js';
  import OperatorNode from 'three-nodes/math/OperatorNode.js';
  import WGSLNodeParser from 'three-nodes/parsers/WGSLNodeParser.js';
  import { vec3, add, join, mix, nodeObject } from 'three-nodes/ShaderNode.js';
  import { getRoughness } from 'three-nodes/functions/PhysicalMaterialFunctions.js';
  
  const wgslTypeLib = {
  	float: 'f32',
  	int: 'i32',
  	uint: 'u32',
  	bool: 'bool',
  	vec2: 'vec2<f32>',
  	vec3: 'vec3<f32>',
  	vec4: 'vec4<f32>',
  	uvec4: 'vec4<u32>',
  	bvec3: 'vec3<bool>',
  	mat3: 'mat3x3<f32>',
  	mat4: 'mat4x4<f32>'
  };
  
  const wgslMethods = {
  	dFdx: 'dpdx',
  	dFdy: 'dpdy'
  };
  
  const wgslPolyfill = {
  	lessThanEqual: new CodeNode( `
  fn lessThanEqual( a : vec3<f32>, b : vec3<f32> ) -> vec3<bool> {
  
  	return vec3<bool>( a.x <= b.x, a.y <= b.y, a.z <= b.z );
  
  }
  ` ),
  	mod: new CodeNode( `
  fn mod( x : f32, y : f32 ) -> f32 {
  
  	return x - y * floor( x / y );
  
  }
  ` ),
  
  	smoothstep: new CodeNode( `
  fn smoothstep( low : f32, high : f32, x : f32 ) -> f32 {
  
  	let t = clamp( ( x - low ) / ( high - low ), 0.0, 1.0 );
  
  	return t * t * ( 3.0 - 2.0 * t );
  
  }
  ` ),
  	repeatWrapping: new CodeNode( `
  fn repeatWrapping( uv : vec2<f32>, dimension : vec2<i32> ) -> vec2<i32> {
  
  	let uvScaled = vec2<i32>( uv * vec2<f32>( dimension ) );
  
  	return ( ( uvScaled % dimension ) + dimension ) % dimension;
  
  }
  ` ),
  	inversesqrt: new CodeNode( `
  fn inversesqrt( x : f32 ) -> f32 {
  
  	return 1.0 / sqrt( x );
  
  }
  ` )
  };
  
  class WebGPUNodeBuilder extends NodeBuilder {
  
  	constructor( object, renderer ) {
  
  		super( object, renderer, new WGSLNodeParser() );
  
  		this.lightNode = null;
  		this.fogNode = null;
  
  		this.bindings = { vertex: [], fragment: [] };
  		this.bindingsOffset = { vertex: 0, fragment: 0 };
  
  		this.uniformsGroup = {};
  
  	}
  
  	build() {
  
  		this._parseObject();
  
  		return super.build();
  
  	}
  
  	_parseObject() {
  
  		const object = this.object;
  		const material = this.material;
  
  		// parse inputs
  
  		if ( material.isMeshStandardMaterial || material.isMeshBasicMaterial || material.isPointsMaterial || material.isLineBasicMaterial ) {
  
  			let lightNode = material.lightNode;
  
  			// VERTEX STAGE
  
  			let vertex = new PositionNode( PositionNode.GEOMETRY );
  
  			if ( lightNode === null && this.lightNode && this.lightNode.hasLights === true ) {
  
  				lightNode = this.lightNode;
  
  			}
  
  			if ( material.positionNode && material.positionNode.isNode ) {
  
  				const assignPositionNode = new OperatorNode( '=', new PositionNode( PositionNode.LOCAL ), material.positionNode );
  
  				vertex = new BypassNode( vertex, assignPositionNode );
  
  			}
  
  			if ( object.isSkinnedMesh === true ) {
  
  				vertex = new BypassNode( vertex, new SkinningNode( object ) );
  
  			}
  
  			this.context.vertex = vertex;
  
  			this.addFlow( 'vertex', new VarNode( new ModelViewProjectionNode(), 'MVP', 'vec4' ) );
  
  			// COLOR
  
  			let colorNode = null;
  
  			if ( material.colorNode && material.colorNode.isNode ) {
  
  				colorNode = material.colorNode;
  
  			} else {
  
  				colorNode = new MaterialNode( MaterialNode.COLOR );
  
  			}
  
  			colorNode = this.addFlow( 'fragment', new VarNode( colorNode, 'Color', 'vec4' ) );
  
  			const diffuseColorNode = this.addFlow( 'fragment', new VarNode( colorNode, 'DiffuseColor', 'vec4' ) );
  
  			// OPACITY
  
  			let opacityNode = null;
  
  			if ( material.opacityNode && material.opacityNode.isNode ) {
  
  				opacityNode = material.opacityNode;
  
  			} else {
  
  				opacityNode = new VarNode( new MaterialNode( MaterialNode.OPACITY ) );
  
  			}
  
  			this.addFlow( 'fragment', new VarNode( opacityNode, 'OPACITY', 'float' ) );
  
  			this.addFlow( 'fragment', new ExpressionNode( 'DiffuseColor.a = DiffuseColor.a * OPACITY;' ) );
  
  			// ALPHA TEST
  
  			let alphaTest = null;
  
  			if ( material.alphaTestNode && material.alphaTestNode.isNode ) {
  
  				alphaTest = material.alphaTestNode;
  
  			} else if ( material.alphaTest > 0 ) {
  
  				alphaTest = new MaterialNode( MaterialNode.ALPHA_TEST );
  
  			}
  
  			if ( alphaTest !== null ) {
  
  				this.addFlow( 'fragment', new VarNode( alphaTest, 'AlphaTest', 'float' ) );
  
  				this.addFlow( 'fragment', new ExpressionNode( 'if ( DiffuseColor.a <= AlphaTest ) { discard; }' ) );
  
  			}
  
  			if ( material.isMeshStandardMaterial ) {
  
  				// METALNESS
  
  				let metalnessNode = null;
  
  				if ( material.metalnessNode && material.metalnessNode.isNode ) {
  
  					metalnessNode = material.metalnessNode;
  
  				} else {
  
  					metalnessNode = new MaterialNode( MaterialNode.METALNESS );
  
  				}
  
  				this.addFlow( 'fragment', new VarNode( metalnessNode, 'Metalness', 'float' ) );
  
  				this.addFlow( 'fragment', new ExpressionNode( 'DiffuseColor = vec4<f32>( DiffuseColor.rgb * ( 1.0 - Metalness ), DiffuseColor.a );' ) );
  
  				// ROUGHNESS
  
  				let roughnessNode = null;
  
  				if ( material.roughnessNode && material.roughnessNode.isNode ) {
  
  					roughnessNode = material.roughnessNode;
  
  				} else {
  
  					roughnessNode = new MaterialNode( MaterialNode.ROUGHNESS );
  
  				}
  
  				roughnessNode = getRoughness( { roughness: roughnessNode } );
  
  				this.addFlow( 'fragment', new VarNode( roughnessNode, 'Roughness', 'float' ) );
  
  				// SPECULAR_TINT
  
  				this.addFlow( 'fragment', new VarNode( new ExpressionNode( 'mix( vec3<f32>( 0.04 ), Color.rgb, Metalness )', 'vec3' ), 'SpecularColor', 'color' ) );
  
  				// NORMAL_VIEW
  
  				let normalNode = null;
  
  				if ( material.normalNode && material.normalNode.isNode ) {
  
  					normalNode = material.normalNode;
  
  				} else {
  
  					normalNode = new NormalNode( NormalNode.VIEW );
  
  				}
  
  				this.addFlow( 'fragment', new VarNode( normalNode, 'TransformedNormalView', 'vec3' ) );
  
  			}
  
  			// LIGHT
  
  			let outputNode = diffuseColorNode;
  
  			if ( lightNode && lightNode.isNode ) {
  
  				const lightContextNode = new LightContextNode( lightNode );
  
  				outputNode = this.addFlow( 'fragment', new VarNode( lightContextNode, 'Light', 'vec3' ) );
  
  			}
  
  			// OUTGOING LIGHT
  
  			let outgoingLightNode = vec3( outputNode );
  
  			// EMISSIVE
  
  			const emissiveNode = material.emissiveNode;
  
  			if ( emissiveNode && emissiveNode.isNode ) {
  
  				outgoingLightNode = add( emissiveNode, outgoingLightNode );
  
  			}
  
  			// OUTPUT
  
  			outputNode = join( vec3( outgoingLightNode ), nodeObject( diffuseColorNode ).w );
  
  			// ENCODING
  
  			const outputEncoding = this.renderer.outputEncoding;
  
  			if ( outputEncoding !== LinearEncoding ) {
  
  				outputNode = new ColorSpaceNode( ColorSpaceNode.LINEAR_TO_LINEAR, outputNode );
  				outputNode.fromEncoding( outputEncoding );
  
  			}
  
  			// FOG
  
  			const fogNode = this.fogNode;
  
  			if ( fogNode && fogNode.isFogNode ) {
  
  				outputNode = mix( outputNode, fogNode.colorNode, fogNode );
  
  			}
  
  			// RESULT
  
  			this.addFlow( 'fragment', new VarNode( outputNode, 'Output', 'vec4' ) );
  
  		}
  
  	}
  
  	addFlowCode( code ) {
  
  		if ( ! /;\s*$/.test( code ) ) {
  
  			code += ';';
  
  		}
  
  		super.addFlowCode( code + '\n\t' );
  
  	}
  
  	getTexture( textureProperty, uvSnippet, biasSnippet, shaderStage = this.shaderStage ) {
  
  		if ( shaderStage === 'fragment' ) {
  
  			return `textureSample( ${textureProperty}, ${textureProperty}_sampler, ${uvSnippet} )`;
  
  		} else {
  
  			this._include( 'repeatWrapping' );
  
  			const dimension = `textureDimensions( ${textureProperty}, 0 )`;
  
  			return `textureLoad( ${textureProperty}, repeatWrapping( ${uvSnippet}, ${dimension} ), 0 )`;
  
  		}
  
  	}
  
  	getPropertyName( node, shaderStage = this.shaderStage ) {
  
  		if ( node.isNodeVary === true ) {
  
  			if ( shaderStage === 'vertex' ) {
  
  				return `NodeVarys.${ node.name }`;
  
  			}
  
  		} else if ( node.isNodeUniform === true ) {
  
  			const name = node.name;
  			const type = node.type;
  
  			if ( type === 'texture' ) {
  
  				return name;
  
  			} else if ( type === 'buffer' ) {
  
  				return `NodeBuffer.${name}`;
  
  			} else {
  
  				return `NodeUniforms.${name}`;
  
  			}
  
  		}
  
  		return super.getPropertyName( node );
  
  	}
  
  	getBindings() {
  
  		const bindings = this.bindings;
  
  		return [ ...bindings.vertex, ...bindings.fragment ];
  
  	}
  
  	getUniformFromNode( node, shaderStage, type ) {
  
  		const uniformNode = super.getUniformFromNode( node, shaderStage, type );
  		const nodeData = this.getDataFromNode( node, shaderStage );
  
  		if ( nodeData.uniformGPU === undefined ) {
  
  			let uniformGPU;
  
  			const bindings = this.bindings[ shaderStage ];
  
  			if ( type === 'texture' ) {
  
  				const sampler = new WebGPUNodeSampler( `${uniformNode.name}_sampler`, uniformNode.node );
  				const texture = new WebGPUNodeSampledTexture( uniformNode.name, uniformNode.node );
  
  				// add first textures in sequence and group for last
  				const lastBinding = bindings[ bindings.length - 1 ];
  				const index = lastBinding && lastBinding.isUniformsGroup ? bindings.length - 1 : bindings.length;
  
  				if ( shaderStage === 'fragment' ) {
  
  					bindings.splice( index, 0, sampler, texture );
  
  					uniformGPU = [ sampler, texture ];
  
  				} else {
  
  					bindings.splice( index, 0, texture );
  
  					uniformGPU = [ texture ];
  
  
  				}
  
  
  			} else if ( type === 'buffer' ) {
  
  				const buffer = new WebGPUUniformBuffer( 'NodeBuffer', node.value );
  
  				// add first textures in sequence and group for last
  				const lastBinding = bindings[ bindings.length - 1 ];
  				const index = lastBinding && lastBinding.isUniformsGroup ? bindings.length - 1 : bindings.length;
  
  				bindings.splice( index, 0, buffer );
  
  				uniformGPU = buffer;
  
  			} else {
  
  				let uniformsGroup = this.uniformsGroup[ shaderStage ];
  
  				if ( uniformsGroup === undefined ) {
  
  					uniformsGroup = new WebGPUNodeUniformsGroup( shaderStage );
  
  					this.uniformsGroup[ shaderStage ] = uniformsGroup;
  
  					bindings.push( uniformsGroup );
  
  				}
  
  				if ( node.isArrayInputNode === true ) {
  
  					uniformGPU = [];
  
  					for ( const inputNode of node.nodes ) {
  
  						const uniformNodeGPU = this._getNodeUniform( inputNode, type );
  
  						// fit bounds to buffer
  						uniformNodeGPU.boundary = getVectorLength( uniformNodeGPU.itemSize );
  						uniformNodeGPU.itemSize = getStrideLength( uniformNodeGPU.itemSize );
  
  						uniformsGroup.addUniform( uniformNodeGPU );
  
  						uniformGPU.push( uniformNodeGPU );
  
  					}
  
  				} else {
  
  					uniformGPU = this._getNodeUniform( uniformNode, type );
  
  					uniformsGroup.addUniform( uniformGPU );
  
  				}
  
  			}
  
  			nodeData.uniformGPU = uniformGPU;
  
  			if ( shaderStage === 'vertex' ) {
  
  				this.bindingsOffset[ 'fragment' ] = bindings.length;
  
  			}
  
  		}
  
  		return uniformNode;
  
  	}
  
  	getAttributes( shaderStage ) {
  
  		let snippet = '';
  
  		if ( shaderStage === 'vertex' ) {
  
  			const attributes = this.attributes;
  			const length = attributes.length;
  
  			snippet += '\n';
  
  			for ( let index = 0; index < length; index ++ ) {
  
  				const attribute = attributes[ index ];
  				const name = attribute.name;
  				const type = this.getType( attribute.type );
  
  				snippet += `\t@location( ${index} ) ${ name } : ${ type }`;
  
  				if ( index + 1 < length ) {
  
  					snippet += ',\n';
  
  				}
  
  			}
  
  			snippet += '\n';
  
  		}
  
  		return snippet;
  
  	}
  
  	getVars( shaderStage ) {
  
  		let snippet = '';
  
  		const vars = this.vars[ shaderStage ];
  
  		for ( let index = 0; index < vars.length; index ++ ) {
  
  			const variable = vars[ index ];
  
  			const name = variable.name;
  			const type = this.getType( variable.type );
  
  			snippet += `var ${name} : ${type}; `;
  
  		}
  
  		return snippet;
  
  	}
  
  	getVarys( shaderStage ) {
  
  		let snippet = '';
  
  		if ( shaderStage === 'vertex' ) {
  
  			snippet += '\t@builtin( position ) Vertex: vec4<f32>;\n';
  
  			const varys = this.varys;
  
  			for ( let index = 0; index < varys.length; index ++ ) {
  
  				const vary = varys[ index ];
  
  				snippet += `\t@location( ${index} ) ${ vary.name } : ${ this.getType( vary.type ) };\n`;
  
  			}
  
  			snippet = this._getWGSLStruct( 'NodeVarysStruct', snippet );
  
  		} else if ( shaderStage === 'fragment' ) {
  
  			const varys = this.varys;
  
  			snippet += '\n';
  
  			for ( let index = 0; index < varys.length; index ++ ) {
  
  				const vary = varys[ index ];
  
  				snippet += `\t@location( ${index} ) ${ vary.name } : ${ this.getType( vary.type ) }`;
  
  				if ( index + 1 < varys.length ) {
  
  					snippet += ',\n';
  
  				}
  
  			}
  
  			snippet += '\n';
  
  		}
  
  		return snippet;
  
  	}
  
  	getUniforms( shaderStage ) {
  
  		const uniforms = this.uniforms[ shaderStage ];
  
  		let snippet = '';
  		let groupSnippet = '';
  
  		let index = this.bindingsOffset[ shaderStage ];
  
  		for ( const uniform of uniforms ) {
  
  			if ( uniform.type === 'texture' ) {
  
  				if ( shaderStage === 'fragment' ) {
  
  					snippet += `@group( 0 ) @binding( ${index ++} ) var ${uniform.name}_sampler : sampler; `;
  
  				}
  
  				snippet += `@group( 0 ) @binding( ${index ++} ) var ${uniform.name} : texture_2d<f32>; `;
  
  			} else if ( uniform.type === 'buffer' ) {
  
  				const bufferNode = uniform.node;
  				const bufferType = this.getType( bufferNode.bufferType );
  				const bufferCount = bufferNode.bufferCount;
  
  				const bufferSnippet = `\t${uniform.name} : array< ${bufferType}, ${bufferCount} >;\n`;
  
  				snippet += this._getWGSLUniforms( 'NodeBuffer', bufferSnippet, index ++ ) + '\n\n';
  
  			} else {
  
  				const vectorType = this.getType( this.getVectorType( uniform.type ) );
  
  				if ( Array.isArray( uniform.value ) === true ) {
  
  					const length = uniform.value.length;
  
  					groupSnippet += `uniform ${vectorType}[ ${length} ] ${uniform.name}; `;
  
  				} else {
  
  					groupSnippet += `\t${uniform.name} : ${ vectorType};\n`;
  
  				}
  
  			}
  
  		}
  
  		if ( groupSnippet ) {
  
  			snippet += this._getWGSLUniforms( 'NodeUniforms', groupSnippet, index ++ );
  
  		}
  
  		return snippet;
  
  	}
  
  	buildCode() {
  
  		const shadersData = { fragment: {}, vertex: {} };
  
  		for ( const shaderStage in shadersData ) {
  
  			let flow = '// code\n';
  			flow += `\t${ this.flowCode[ shaderStage ] }`;
  			flow += '\n';
  
  			const flowNodes = this.flowNodes[ shaderStage ];
  			const mainNode = flowNodes[ flowNodes.length - 1 ];
  
  			for ( const node of flowNodes ) {
  
  				const flowSlotData = this.getFlowData( shaderStage, node );
  				const slotName = node.name;
  
  				if ( slotName ) {
  
  					if ( flow.length > 0 ) flow += '\n';
  
  					flow += `\t// FLOW -> ${ slotName }\n\t`;
  
  				}
  
  				flow += `${ flowSlotData.code }\n\t`;
  
  				if ( node === mainNode ) {
  
  					flow += '// FLOW RESULT\n\t';
  
  					if ( shaderStage === 'vertex' ) {
  
  						flow += 'NodeVarys.Vertex = ';
  
  					} else if ( shaderStage === 'fragment' ) {
  
  						flow += 'return ';
  
  					}
  
  					flow += `${ flowSlotData.result };`;
  
  				}
  
  			}
  
  			const stageData = shadersData[ shaderStage ];
  
  			stageData.uniforms = this.getUniforms( shaderStage );
  			stageData.attributes = this.getAttributes( shaderStage );
  			stageData.varys = this.getVarys( shaderStage );
  			stageData.vars = this.getVars( shaderStage );
  			stageData.codes = this.getCodes( shaderStage );
  			stageData.flow = flow;
  
  		}
  
  		this.vertexShader = this._getWGSLVertexCode( shadersData.vertex );
  		this.fragmentShader = this._getWGSLFragmentCode( shadersData.fragment );
  
  	}
  
  	getMethod( method ) {
  
  		if ( wgslPolyfill[ method ] !== undefined ) {
  
  			this._include( method );
  
  		}
  
  		return wgslMethods[ method ] || method;
  
  	}
  
  	getType( type ) {
  
  		return wgslTypeLib[ type ] || type;
  
  	}
  
  	_include( name ) {
  
  		wgslPolyfill[ name ].build( this );
  
  	}
  
  	_getNodeUniform( uniformNode, type ) {
  
  		if ( type === 'float' ) return new FloatNodeUniform( uniformNode );
  		if ( type === 'vec2' ) return new Vector2NodeUniform( uniformNode );
  		if ( type === 'vec3' ) return new Vector3NodeUniform( uniformNode );
  		if ( type === 'vec4' ) return new Vector4NodeUniform( uniformNode );
  		if ( type === 'color' ) return new ColorNodeUniform( uniformNode );
  		if ( type === 'mat3' ) return new Matrix3NodeUniform( uniformNode );
  		if ( type === 'mat4' ) return new Matrix4NodeUniform( uniformNode );
  
  		throw new Error( `Uniform "${type}" not declared.` );
  
  	}
  
  	_getWGSLVertexCode( shaderData ) {
  
  		return `${ this.getSignature() }
  
  // uniforms
  ${shaderData.uniforms}
  
  // varys
  ${shaderData.varys}
  
  // codes
  ${shaderData.codes}
  
  @stage( vertex )
  fn main( ${shaderData.attributes} ) -> NodeVarysStruct {
  
  	// system
  	var NodeVarys: NodeVarysStruct;
  
  	// vars
  	${shaderData.vars}
  
  	// flow
  	${shaderData.flow}
  
  	return NodeVarys;
  
  }
  `;
  
  	}
  
  	_getWGSLFragmentCode( shaderData ) {
  
  		return `${ this.getSignature() }
  
  // uniforms
  ${shaderData.uniforms}
  
  // codes
  ${shaderData.codes}
  
  @stage( fragment )
  fn main( ${shaderData.varys} ) -> @location( 0 ) vec4<f32> {
  
  	// vars
  	${shaderData.vars}
  
  	// flow
  	${shaderData.flow}
  
  }
  `;
  
  	}
  
  	_getWGSLStruct( name, vars ) {
  
  		return `
  struct ${name} {
  \n${vars}
  };`;
  
  	}
  
  	_getWGSLUniforms( name, vars, binding = 0, group = 0 ) {
  
  		const structName = name + 'Struct';
  		const structSnippet = this._getWGSLStruct( structName, vars );
  
  		return `${structSnippet}
  @binding( ${binding} ) @group( ${group} )
  var<uniform> ${name} : ${structName};`;
  
  	}
  
  }
  
  export default WebGPUNodeBuilder;
  