if( typeof document != "undefined" ) {

	document.shaders	= new Array();

	document.bufferMap 	= {};

}


export default class Shader {

	sampleCount			= 1;

	device;

	path;

	wgslSource;

	bindGroupLayout;

	bindGroupLayouts 			= new Map();

	vertexBuffersDescriptors 	= new Map();

	textures 					= new Map();

	pipeline;

	bindGroups 					= new Map();

	entryPoint					= "main";

	bindings 					= new Array();

    buffers      				= new Map();

    bufferUsages 				= new Map();

    bufferSizes  				= new Map();

	attributeBuffers			;

	bufferUsages 				= new Map();  // store usage per buffer to recreate correctly

	_externalBindGroupLayout 	= null;

	hasLoaded					= false;

	stage						= GPUShaderStage.COMPUTE;

	isInWorker 					= typeof document === "undefined";

	topologyValue				= "triangle-strip";	

	binded 						= false;

	clearOnRender				= true;


	textures 					= new Map();

	samplers 					= new Map();



	constructor( device, path = false ) {

		if( !this.isInWorker ) {

			document.shaders.push( this );

		}

		console.log("\n\n \n Creating New Shader", path, "\n\n");

		console.log("device", typeof device);

		this.device = device;

		if( path ) {

			this.path = path;

		}

	}

	set topology(value) {
		
		if (this.binded) {

			console.error("Define topology before setup", this);
		}

		this.topologyValue = value;

	}

	get topology() {

		return this.topologyValue;

	}
_createAllBuffers() {

    for (const b of this.bindings) {

        if (this.buffers.has(b.varName)) continue;

        let size;

        if (b.type === "uniform") {
            size = 256;                  // uniforms must be 256 bytes
        }
        else if (b.type === "read-only-storage" || b.type === "storage") {
            size = 16;                   // minimum valid storage buffer size
        }
        else {
            size = 16;                   // safe fallback
        }

        let usage;

        switch (b.type) {
            case "uniform":
                usage = GPUBufferUsage.UNIFORM | GPUBufferUsage.COPY_DST;
                break;

            case "read-only-storage":
                usage = GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_DST | GPUBufferUsage.COPY_SRC;
                break;

            case "storage":
            default:
                usage = GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_DST | GPUBufferUsage.COPY_SRC;
                break;
        }

        const buffer = this.device.createBuffer({
            size,
            usage,
            label: b.varName
        });

        this.buffers.set(b.varName, buffer);
        this.bufferUsages.set(b.varName, usage);
        this.bufferSizes.set(b.varName, size);
    }
}

_parseStructs(wgsl) {

    this.structs = {};

    const structRegex =
        /struct\s+(\w+)\s*\{([^}]+)\}/g;

    let match;

    while ((match = structRegex.exec(wgsl)) !== null) {

        const structName = match[1];
        const body       = match[2].trim();

        const fields = [];

        const fieldRegex =
            /(\w+)\s*:\s*([\w<>\[\]]+)\s*,?/g;

        let f;

        while ((f = fieldRegex.exec(body)) !== null) {

            const fieldName = f[1];
            const fieldType = f[2];

            fields.push({
                name:  fieldName,
                type:  fieldType
            });
        }

        this.structs[structName] = {
            name:   structName,
            fields: fields,
            size:   0   // computed later
        };
    }

	for (const name of Object.keys(this.structs)) {
		
		this._computeStructSize(name);

	}

    console.log("structs reflection created:", this.structs);
}

_computeStructSize(structName) {

    const struct = this.structs[structName];
    if (!struct) return 0;

    let offset = 0;

    for (const f of struct.fields) {

        const align = 4;
        const size  = 4;

        // align field offset
        offset = Math.ceil(offset / align) * align;

        f.offset = offset;
        f.size   = size;
        f.align  = align;

        offset += size;
    }

    struct.size = offset;

    return offset;
}


_computeTypeSize(wgslType) {

    if (wgslType === "f32" || wgslType === "i32" || wgslType === "u32") {
        return 4;
    }

    // vecN<T>
    const vecMatch = wgslType.match(/vec(\d+)<(\w+)>/);
    if (vecMatch) {
        const n        = Number(vecMatch[1]);
        const elemType = vecMatch[2];
        return n * this._computeTypeSize(elemType);
    }

    // matCxR<T> (e.g. mat4x4<f32>)
    const matMatch = wgslType.match(/mat(\d+)x(\d+)<(\w+)>/);
    if (matMatch) {
        const c        = Number(matMatch[1]);
        const r        = Number(matMatch[2]);
        const elemType = matMatch[3];
        return c * r * this._computeTypeSize(elemType);
    }

    // array<T, N>
    const arrFix = wgslType.match(/array<(\w+),\s*(\d+)>/);
    if (arrFix) {
        const element = arrFix[1];
        const count   = Number(arrFix[2]);
        return this._computeTypeSize(element) * count;
    }

    // array<T> runtime sized
    const arrDyn = wgslType.match(/array<(\w+)>/);
    if (arrDyn) {
        return 4;
    }

    // struct
    if (this.structs[wgslType]) {
        return this.structs[wgslType].size;
    }

    return 4;
}

_computeBindingSizes() {

    for (const b of this.bindings) {

        const t = b.varType;

        // -----------------------------------------
        // 1. Struct?
        // -----------------------------------------
        if (this.structs[t]) {
            b.size = this.structs[t].size;
            continue;
        }

        // -----------------------------------------
        // 4. Texture / sampler (no buffer)
        // -----------------------------------------
        if (b.type === "texture" || b.type === "sampler") {
            b.size = 0;
            continue;
        }

        // -----------------------------------------
        // 5. Use computed WGSL type size (scalars, vectors, matrices, arrays)
        // -----------------------------------------
        b.size = this._computeTypeSize(t);
    }
}




_createAllBuffers() {

    for (const b of this.bindings) {

        if (this.buffers.has(b.varName))
            continue;

        let size = b.size;
        if (size < 4) size = 4;

        let usage;
        switch (b.type) {
            case "uniform":
                usage = GPUBufferUsage.UNIFORM | GPUBufferUsage.COPY_DST;
                break;
            case "read-only-storage":
                usage = GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_DST | GPUBufferUsage.COPY_SRC;
                break;
            default:
                usage = GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_DST | GPUBufferUsage.COPY_SRC;
        }

        const buffer = this.device.createBuffer({
            size,
            usage,
            label: b.varName
        });

        this.buffers.set(b.varName, buffer);
        this.bufferSizes.set(b.varName, size);
        this.bufferUsages.set(b.varName, usage);
    }
}


_createDefaultTexturesAndSamplers() {

	for ( const b of this.bindings ) {

		if ( b.type === "texture" && !this.textures.has( b.varName ) ) {

			// Detect if the type is a texture array
			const isTextureArray = b.varType.startsWith("texture_2d_array");

			// Create 1x1 texture with 1 layer (depthOrArrayLayers = 1)
			const defaultTexture = this.device.createTexture({

				size: isTextureArray ? [1, 1, 2] : [1, 1, 1],

				format: "rgba8unorm",

				usage: GPUTextureUsage.TEXTURE_BINDING | GPUTextureUsage.COPY_DST,

				label: b.varName + "_defaultTexture"

			});

			
			console.log("create texture ", isTextureArray, isTextureArray ? "2d-array" : "2d");
			// Create texture view with correct dimension
			const defaultTextureView = defaultTexture.createView({

				dimension: isTextureArray ? "2d-array" : "2d"

			});

			console.log("create default texture?", b, defaultTextureView, isTextureArray ? "2d-array" : "2d");

			this.textures.set(b.varName, defaultTextureView);

		} else if ( b.type === "sampler" && !this.samplers.has( b.varName ) ) {

			// Create default sampler

			const defaultSampler = this.device.createSampler( {

				magFilter: "linear",

				minFilter: "linear",

				label: b.varName + "_defaultSampler"

			} );

			this.samplers.set( b.varName, defaultSampler );

		}

	}

}


createBindGroups() {

	this.bindGroups = new Map();

	for ( const [ group, layout ] of this.bindGroupLayouts.entries() ) {

		const bindings = this.bindings.filter( b => b.group === group );

		const entries = new Array( bindings.length );

		for ( let i = 0; i < bindings.length; i++ ) {

			const b = bindings[ i ];

			let resource;

			if ( b.type === "uniform" || b.type === "read-only-storage" || b.type === "storage" ) {

				const gpuBuffer = this.buffers.get( b.varName );

				if ( !gpuBuffer ) {

					throw new Error( `Buffer missing for ${b.varName} when creating bind group.` );

				}

				resource = { buffer: gpuBuffer };

			} else if ( b.type === "texture" ) {

				const gpuTextureView = this.textures.get( b.varName );

				//console.log("this.textures", this.textures);

				if ( !gpuTextureView ) {

					console.warn( `Texture missing for ${b.varName} when creating bind group.` );

				} else {

					//console.log( `Binding texture ${b.varName} with dimension:`, gpuTextureView.dimension );

				}

				resource = gpuTextureView;

			} else if ( b.type === "sampler" ) {

				const gpuSampler = this.samplers.get( b.varName );

				if ( !gpuSampler ) {

					//throw new Error( `Sampler missing for ${b.varName} when creating bind group.` );

				}

				resource = gpuSampler;

			} else {

				throw new Error( `Unknown binding type '${b.type}' for ${b.varName}` );

			}

			entries[ i ] = {

				binding: b.binding,

				resource: resource

			};

		}

		const bindGroup = this.device.createBindGroup( {

			layout: layout,

			entries: entries

		} );

		this.bindGroups.set( group, bindGroup );

	}

}
	extractEntryPoints( wgslCode ) {
		const entryPoints = [];

		// Regex to match lines like: @vertex fn functionName(...) { ... }
const regex =
	/@(\w+)(?:\s*@[\w_]+(?:\([^)]*\))?)*\s*fn\s+([\w_]+)\s*\(/gm;

				let match;

		while ((match = regex.exec(wgslCode)) !== null) {


			const stage = match[1];
			const name  = match[2];

			let type;

			switch (stage) {
				case "vertex":
					type =  GPUShaderStage.VERTEX;
				break;
				case "fragment":
					type =  GPUShaderStage.FRAGMENT;
				break;
				case "compute":
					type = GPUShaderStage.COMPUTE;
					break;
				default:
					type = "Unknown";
			}

			entryPoints.push({ name: name, type: type });
		}

		return entryPoints;
		
	}

	async setup( path ) {



		this.path  = path;

		this.wgslSource 	= await this._loadShaderSource( this.path );

	    // 2. Parse metadata from WGSL
	    this._parseVertexAttributes(this.wgslSource);
	    this._parseBindings(this.wgslSource);
	    this._parseStructs(this.wgslSource);

	    // 3. Compute struct sizes BEFORE creating buffers
	    this._computeBindingSizes();  // if you implemented this

	    // ----------------------------------------------------------
	    // 4. CREATE BUFFERS BEFORE EVERYTHING ELSE
	    // ----------------------------------------------------------
	    this._createAllBuffers();


		//console.log(this.wgslSource);
		var entryPoints	= this.extractEntryPoints( this.wgslSource );
		console.log(entryPoints);


		for (var i = 0; i < entryPoints.length; i++) {

			var entryPoint = entryPoints[i];

			await this.addStage( entryPoint.name, entryPoint.type );

		}





		//await this.addStage("computeMain", 4 );

		//console.log( "load shader", this.wgslSource, entryPoints )

	}

	async _loadShaderSource( pathName ) {

		const response = await fetch( pathName );

		if ( !response.ok ) throw new Error( `Failed to load shader: ${ pathName }` );

		return await response.text();

	}

	setVertexBuffer( name, dataArray ) {

		const buffer = this.device.createBuffer({
			size: dataArray.byteLength,
			usage: GPUBufferUsage.VERTEX | GPUBufferUsage.COPY_DST,
			mappedAtCreation: true
		});

		const mapping = new Float32Array( buffer.getMappedRange() );

		mapping.set( dataArray );

		buffer.unmap();



		this.buffers.set( name, buffer );

	}

	extractVertexFunctionParameters(wgsl) {

		let vertexFnIndex = wgsl.indexOf('@vertex');

		if (vertexFnIndex === -1) return '';

		let fnIndex = wgsl.indexOf('fn', vertexFnIndex);

		if (fnIndex === -1) return '';

		let parenStart = wgsl.indexOf('(', fnIndex);

		if (parenStart === -1) return '';

		let parenCount = 1;
		let i = parenStart + 1;

		while (i < wgsl.length && parenCount > 0) {
			const c = wgsl[i];

			if (c === '(') parenCount++;

			else if (c === ')') parenCount--;

			i++;
		}

		if (parenCount !== 0) {
			// unbalanced parentheses
			return '';
		}

		// Extract parameter substring between parenStart+1 and i-1
		let paramsStr = wgsl.substring(parenStart + 1, i - 1);

		return paramsStr.trim();
	}

	 extractVertexParamsLocations(wgsl) {

		const paramsStr 	= this.extractVertexFunctionParameters(wgsl)

		const paramRegex 	= /@location\s*\(\s*(\d+)\s*\)\s+(\w+)\s*:\s*([\w<>\d]+(\s*<[^>]+>)?)/g;

		const results 		= new Array();

		let paramMatch;

		while ((paramMatch = paramRegex.exec(paramsStr)) !== null) {

			const location 	= Number(paramMatch[1]);

			const varName 	= paramMatch[2];

			const type 		= paramMatch[3].trim();

			results.push({ location, varName, type });
		}



		return results;
	}

	getFormatSize( format ) {

		switch ( format ) {

			case "float32":   return 4;

			case "float32x2": return 8;

			case "float32x3": return 12;

			case "float32x4": return 16;

			case "uint32":    return 4;

			case "sint32":    return 4;

			default: throw new Error("Unsupported format size for: " + format);

		}

	}

	mapTypeToVertexFormat( type ) {

		// Map WGSL types to GPUVertexFormat strings (example subset)

		switch ( type ) {

			case "f32": return "float32";

			case "vec2<f32>": return "float32x2";

			case "vec3<f32>": return "float32x3";

			case "vec4<f32>": return "float32x4";

			case "u32": return "uint32";

			case "i32": return "sint32";

			default: throw new Error("Unsupported vertex attribute type: " + type);

		}

	}

	_parseVertexAttributes( wgsl ) {

		const locations = this.extractVertexParamsLocations( wgsl );


		if (locations.length === 0) {
			// No vertex attributes = no vertex buffer descriptors needed
			return;
		}

		let offset = 0;

		const attributes = new Array();

		for ( let attr of locations ) {

			const format = this.mapTypeToVertexFormat( attr.type );

			attributes.push({
				shaderLocation : attr.location,
				offset         : offset,
				format         : format
			});

			offset += this.getFormatSize( format );

		}

		const vertexBufferDescriptor = {
			arrayStride: offset,
			attributes: attributes,
			stepMode: "vertex"
		};

		console.log("vertexBufferDescriptor", vertexBufferDescriptor);


		this.vertexBuffersDescriptors.set("vertexBuffer0", vertexBufferDescriptor);

		console.log("vertex buffer descriptors updated:", this.vertexBuffersDescriptors);

	}

	_parseBindings( wgsl ) {

		console.log("parse bindings");

	this.bindings = [];

	// Make the `<...>` part optional by wrapping it in a non-capturing group with `?`
	const regex = /@group\((\d+)\)\s+@binding\((\d+)\)\s+var(?:<(\w+)(?:,\s*(\w+))?>)?\s+(\w+)\s*:\s*([^;]+);/g;

	let match;

	while ((match = regex.exec(wgsl)) !== null) {

		const group        = Number(match[1]);

		const binding      = Number(match[2]);

		const storageClass = match[3];   // e.g. "uniform", "storage", or undefined for textures/samplers

		const access       = match[4];   // e.g. "read", "write", or undefined

		const varName      = match[5];

		const varType      = match[6];   // WGSL type string like "mat4x4<f32>", "texture_2d<f32>", "sampler", etc.

		let type;

		if (storageClass === "storage") {

			type = access === "read" ? "read-only-storage" : "storage";

		} else if (storageClass === "uniform") {

			type = "uniform";

		} else if (varType.startsWith("texture_")) {

			type = "texture";

		} else if (varType === "sampler" || varType === "sampler_comparison") {

			type = "sampler";

		} else {

			type = "uniform";  // fallback

		}

		this.bindings.push({ group, binding, type, varName, varType });

	}

	console.log("bindings", this.bindings);

	this.bindings.sort((a, b) => a.binding - b.binding);

}

_createBindGroupLayoutsFromBindings() {

	const groups = new Map();

	for ( let i = 0; i < this.bindings.length; i++ ) {

		const b = this.bindings[ i ];

		if ( !groups.has( b.group ) ) groups.set( b.group, [] );

		groups.get( b.group ).push( b );

	}

	const layouts = new Map();

	for ( const groupEntry of groups.entries() ) {

		const group = groupEntry[ 0 ];

		const bindings = groupEntry[ 1 ];

		let visibility;

		if ( this.stage === GPUShaderStage.COMPUTE ) {

			visibility = GPUShaderStage.COMPUTE;

		} else {

			visibility = GPUShaderStage.VERTEX | GPUShaderStage.FRAGMENT;

		}

		const entries = new Array( bindings.length );

		for ( let j = 0; j < bindings.length; j++ ) {

			const b = bindings[ j ];

			let entry;

			if ( b.type === "uniform" || b.type === "read-only-storage" || b.type === "storage" ) {

				entry = {

					binding: b.binding,

					visibility: visibility,

					buffer: { type: b.type }

				};

			} else if ( b.type === "texture" ) {


				let viewDimension = "2d";  // default

				if ( b.varType.startsWith("texture_2d_array") ) {

					viewDimension = "2d-array";

				} else if ( b.varType.startsWith("texture_cube") ) {

					viewDimension = "cube";

				} else if ( b.varType.startsWith("texture_3d") ) {

					viewDimension = "3d";

				}

				console.log("viewDimension", viewDimension);

				entry = {
					binding: b.binding,
					visibility: visibility,
					texture: {
						sampleType: "float",
						viewDimension: viewDimension,
						multisampled: false
					}
				};

			} else if ( b.type === "sampler" ) {

				entry = {

					binding: b.binding,

					visibility: visibility,

					sampler: { type: "filtering" }

				};

			} else {

				entry = {

					binding: b.binding,

					visibility: visibility,

					buffer: { type: "uniform" }

				};

			}

			entries[ j ] = entry;

		}

		console.log("createBindGroupLayout ", entries);

		const layout = this.device.createBindGroupLayout( { entries } );

		layouts.set( group, layout );

	}

	return layouts;

}

	async _createPipeline() {

		const layoutsArray = 	this.bindGroupLayouts && this.bindGroupLayouts.size > 0

								? Array.from( this.bindGroupLayouts.values() )

								: [ this.bindGroupLayout ];

		const shaderModule = this.device.createShaderModule( { 
																code: this.wgslSource,

																label: this.path,

															} );

		const info = await shaderModule.compilationInfo();

		if (info.messages.length > 0) {
			for (const msg of info.messages) {
				console[msg.type === "error" ? "error" : "warn"](
					`[${msg.lineNum}:${msg.linePos}] ${msg.message}`
				);
			}
		}

		//console.log("this.bindGroupLayouts.values()", this.bindGroupLayouts.values());

		this.pipeline = this.device.createComputePipeline({

			layout: this.device.createPipelineLayout({

				bindGroupLayouts: Array.from( this.bindGroupLayouts.values() )

			}),

			compute: {

				module: shaderModule,

				entryPoint: this.entryPoint,

			},

		} );

	}

	setBindingGroupLayout( bindGroupLayout ) {

		this._externalBindGroupLayout = bindGroupLayout;

	}

	getBindingGroupLayout( bindingGroupIndex = 0 ) {

		if ( this.bindGroupLayouts ) {

			return this.bindGroupLayouts.get( bindingGroupIndex );

		}

		return this.bindGroupLayout;

	}

	getTypedArrayByVariableName( name, flatData ) {

		let typedArray;

		const bindingInfo = this.bindings.find( b => b.varName === name );

		if ( bindingInfo ) {

			const wgslType = bindingInfo.varType;

			switch( wgslType ) {

				case "vec3<f32>":

				//	flatData.push( 0 );

				break;

			}

			switch ( wgslType ) {

				case "f32":
				case "vec2<f32>":
				case "vec3<f32>":
				case "vec4<f32>":
				case "array<f32>":

					typedArray = new Float32Array( flatData );

				break;

				case "u32":
				case "vec2<u32>":
				case "vec3<u32>":
				case "vec4<u32>":
				case "array<u32>":

					typedArray = new Uint32Array( flatData );

				break;

				case "i32":
				case "vec2<i32>":
				case "vec3<i32>":
				case "vec4<i32>":
				case "array<i32>":

					typedArray = new Int32Array( flatData );

				break;

				default:

					// find struct and then the datatype
					typedArray = new Float32Array( flatData );
					//console.error( "Unknown WGSL type in setVariable: " + wgslType );
			}

			//console.log("wgslType", wgslType);

		}

		return typedArray;

	}

	createTextureFromData(width, height, data = null) {

		// 1. Infer format based on TypedArray
		let format;
		let bytesPerComponent;

		if (data instanceof Float32Array) {
			format = "rgba32float";
			bytesPerComponent = 4;
		}
		else if (data instanceof Uint8Array) {
			format = "rgba8unorm";
			bytesPerComponent = 1;
		}
		else if (data instanceof Uint32Array) {
			format = "rgba32uint";
			bytesPerComponent = 4;
		}
		else if (data instanceof Int32Array) {
			format = "rgba32sint";
			bytesPerComponent = 4;
		}
		else {
			throw new Error("Unsupported texture data type");
		}

		// 2. Compute expected size
		const channels = 4;
		const expected = width * height * channels;

		if (data && data.length !== expected) {
			throw new Error(
				`Texture data length mismatch. Expected ${expected}, got ${data.length}`
			);
		}

		// 3. Create texture
		const texture = this.device.createTexture({
			size: { width, height, depthOrArrayLayers: 1 },
			format,
			usage:
				GPUTextureUsage.TEXTURE_BINDING |
				GPUTextureUsage.STORAGE_BINDING |
				GPUTextureUsage.COPY_DST
		});

		// 4. Upload if data provided
		if (data) {

			this.device.queue.writeTexture(
				{
					texture: texture
				},
				data,
				{
					bytesPerRow: width * channels * bytesPerComponent
				},
				{
					width,
					height,
					depthOrArrayLayers: 1
				}
			);
		}

		return texture;
	}


setVariable( name, dataObject ) {


	if (dataObject instanceof GPUBuffer) {
		// Direct buffer binding – do NOT recreate, resize, or write.
		this.setBuffer( name, dataObject );
		return;
	}


	// TEXTURES -----------------------------------------------------
	if (dataObject instanceof GPUTexture) {
		this.textures.set(name, dataObject.createView());
		this._invalidateBindGroups();
		return;
	}

	// SAMPLERS -----------------------------------------------------
	if (dataObject instanceof GPUSampler) {
		this.samplers.set(name, dataObject);
		this._invalidateBindGroups();
		return;
	}

	// STRUCT CHECK -------------------------------------------------
	const binding    = this.bindings.find(b => b.varName === name);
	const structInfo = binding ? this.structs[binding.varType] : undefined;

	let typed;

	// --------------------------------------------------------------
	// 1. WGSL STRUCT → Uint32Array (using struct reflection)
	// --------------------------------------------------------------
	if (structInfo) {

		const out = new Uint32Array(structInfo.size / 4); // aligned struct size in bytes

		for (let i = 0; i < structInfo.fields.length; i++) {

			const f = structInfo.fields[i];
			let v   = dataObject[f.name];

			if (v === undefined) {
				v = 0;
			}

			// only scalar u32/f32 fields for now
			out[f.offset / 4] = v >>> 0;
		}

		typed = out;
	}

	// --------------------------------------------------------------
	// 2. Already typed arrays
	// --------------------------------------------------------------
	else if (
		dataObject instanceof Float32Array ||
		dataObject instanceof Uint32Array ||
		dataObject instanceof Int32Array
	) {
		typed = dataObject;
	}

	// --------------------------------------------------------------
	// 3. Number or JS array → detect type
	// --------------------------------------------------------------
	else if (typeof dataObject === "number" || Array.isArray(dataObject)) {
		const flat = this.flattenStructure(dataObject);
		typed = this.getTypedArrayByVariableName(name, flat);
	}

	// --------------------------------------------------------------
	// 4. Raw ArrayBuffer
	// --------------------------------------------------------------
	else if (dataObject instanceof ArrayBuffer) {
		typed = new Float32Array(dataObject);
	}

	// --------------------------------------------------------------
	// 5. Fallback
	// --------------------------------------------------------------
	else {
		const flat = this.flattenStructure(dataObject);
		typed = new Float32Array(flat);
	}

	// BUFFER CREATION / RESIZE -------------------------------------
	const bytes     = typed.byteLength;
	const oldBuffer = this.buffers.get(name);
	const oldUsage  = this.bufferUsages.get(name);
	const oldSize   = oldBuffer ? oldBuffer.size : 0;

	if (typeof oldUsage !== "number") {
		throw new Error("Invalid buffer usage for '" + name + "'");
	}

	let buffer = oldBuffer;

	// Resize if needed
	if (!buffer || oldSize !== bytes) {

		buffer = this.device.createBuffer({
			label: name,
			size: bytes,
			usage: oldUsage,
			mappedAtCreation: false
		});

		this.buffers.set(name, buffer);
		this.bufferSizes.set(name, bytes);

		this._invalidateBindGroups();   // <— IMPORTANT FIX
	}

	// BUFFER UPLOAD -------------------------------------------------
	this.device.queue.writeBuffer(
		buffer,
		0,
		typed.buffer,
		typed.byteOffset,
		typed.byteLength
	);
}


_invalidateBindGroups() {
    this.bindGroups = false;
}



computeUsage(name) {

    const binding = this.bindings.find(b => b.varName === name);

    if (!binding) {
        // No binding found → use safe fallback
        return GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_DST | GPUBufferUsage.COPY_SRC;
    }

    switch (binding.type) {

        case "uniform":
            return GPUBufferUsage.UNIFORM | GPUBufferUsage.COPY_DST;

        case "read-only-storage":
            return GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_DST ;

        case "storage":
            return GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_DST | GPUBufferUsage.COPY_SRC;

        default:
            return GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_DST | GPUBufferUsage.COPY_SRC;
    }
}


	flattenStructure( input, output = [] ) {

		if ( Array.isArray( input ) ) {

			for ( const element of input ) {

				this.flattenStructure( element, output );

			}

		} else if ( typeof input === "object" && input !== null ) {

			for ( const key of Object.keys( input ) ) {

				this.flattenStructure( input[ key ], output );

			}

		} else if ( typeof input === "number" ) {

			output.push( input );

		} else if ( typeof input === "boolean" ) {

			output.push( input ? 1 : 0 );

		} else {

			throw new Error( "Unsupported data type in shader variable: " + typeof input );

		}

		return output;

	}

	copyBuffersFromShader( sourceShader ) {

		for ( const [ name, buffer ] of sourceShader.buffers.entries() ) {

			this.buffers.set( name, buffer );

		}

	}

	updateUniforms( data ) {
		const arrayBuffer = new ArrayBuffer(12); // 3 x u32 = 3 * 4 bytes
		const dataView = new DataView(arrayBuffer);

		dataView.setUint32(0, data.k, true);           // offset 0
		dataView.setUint32(4, data.j, true);           // offset 4
		dataView.setUint32(8, data.totalCount, true);  // offset 8

		this.device.queue.writeBuffer(
			this.uniformBuffer,   // your GPUBuffer holding uniforms
			0,                   // offset in buffer
			arrayBuffer
		);
	}

	createCommandEncoder( x, y, z ) {

  // AUTO-REBUILD BIND GROUPS IF NEEDED
  if (!this.bindGroups || this.bindGroups.size === 0) {
       this.createBindGroups();
  }


		const commandEncoder 	= this.device.createCommandEncoder({
			label: this.path
		});

		const passEncoder 		= commandEncoder.beginComputePass({
			label: this.path
		});


		if( !this.pipeline ) {

			console.log("Pipeline missing, Maybe you forget to call addStage( ) ", this);

		}

		passEncoder.setPipeline( this.pipeline );

		for ( const [bindingGroupIndex, bindGroup] of this.bindGroups.entries() ) {

			passEncoder.setBindGroup( bindingGroupIndex, bindGroup );

		}

		passEncoder.dispatchWorkgroups( x, y, z );

		passEncoder.end();

		return commandEncoder;

	}

	async execute( x = 1, y = 1, z = 1 ) {

		const commandEncoder = this.createCommandEncoder( x, y, z );

		const commandBuffer = commandEncoder.finish();

		this.device.queue.submit( [ commandBuffer ] );

		await this.device.queue.onSubmittedWorkDone(); // critical!

	}

	registerBuffer( buffer, name, type ) {

		if( !this.isInWorker ) {

			if( !document.bufferMap[name] ) {

				document.bufferMap[name] = new Array();

			}

			var bufferHistoryPoint = { buffer: buffer, shader: this, label : buffer.label, type: type };

			document.bufferMap[name].push( bufferHistoryPoint );

		}

	}

	getBuffer( name ) {


		// If no bind groups yet, create them now
		if (!this.bindGroups || this.bindGroups.size === 0) {
			this.createBindGroups();
		}

		var buffer = this.buffers.get( name );

		this.registerBuffer( buffer, name, "get" );

		return buffer;

	}

	async setBuffer( name, buffer ) {

		this.registerBuffer( buffer, name, "set" );

		if( !this.isInWorker ) {

			//var bufferOwner 	= document.bufferOwners.get( buffer );

			//console.log("setBuffer Origin:", bufferOwner, " this shader", this);


		}



		const bindingInfo 	= this.bindings.find( b => b.varName === name );

		if( !bindingInfo ) {

			console.error("No binding to buffer ", name, " in shader ", this );

		}

		//console.log("set buffer", name, buffer);

		this.buffers.set(name, buffer);

		await this.createBindGroups(); // always refresh bindings

	}



	async addStage( entryPoint, stage ) {

		if ( !this.path ) {

			throw new Error("Shader path is not set");

		}
		this.entryPoint = entryPoint;

		if( stage != GPUShaderStage.COMPUTE ) {

			this.stage = GPUShaderStage.VERTEX | GPUShaderStage.FRAGMENT;

		}


		if ( !this.binded ) {

			if( stage != GPUShaderStage.COMPUTE ) {

				if( this.sampleCount == 1 ) {

					this.depthTexture = this.device.createTexture({
						size: {
							width: 	this.canvas.width,
							height: this.canvas.height,
							depthOrArrayLayers: 1
						},
						sampleCount: 1, // Must be 1 for non-multisampled rendering
						format: "depth24plus", // Or "depth24plus-stencil8" if stencil is needed
						usage: GPUTextureUsage.RENDER_ATTACHMENT
					});

				} else {

					this.multisampledColorTexture = this.device.createTexture({
					    size: [this.canvas.width, this.canvas.height],
					    sampleCount: this.sampleCount,
					    format: "bgra8unorm",
					    usage: GPUTextureUsage.RENDER_ATTACHMENT,
					});

					this.multisampledDepthTexture = this.device.createTexture({
						size: [this.canvas.width, this.canvas.height],
						sampleCount: this.sampleCount, // must match multisample count of color texture and pipeline
						format: "depth24plus", // or "depth24plus-stencil8" if you need stencil
						usage: GPUTextureUsage.RENDER_ATTACHMENT,
					});		

				}
			}	

			this.wgslSource = await this._loadShaderSource( this.path );

			//this._parseVertexAttributes( this.wgslSource );

			//this._parseBindings( this.wgslSource );

			//this._parseStructs( this.wgslSource );

			if ( this._externalBindGroupLayout ) {

				this.bindGroupLayouts.set( 0, this._externalBindGroupLayout );

			} else {

				this.bindGroupLayouts = this._createBindGroupLayoutsFromBindings();

			}


			this._createDefaultTexturesAndSamplers();

			await this.createBindGroups();

			this.binded = true;

		}

		const shaderModule = this.device.createShaderModule( {

			code: this.wgslSource,

			label: this.path

		} );

		if ( stage === GPUShaderStage.COMPUTE ) {

			//console.log("this.bindGroupLayouts", this.bindGroupLayouts);

			//console.log("create compute shader pipeline.");

			this.computeStage = { module: shaderModule, entryPoint: this.entryPoint };

			this.pipeline = this.device.createComputePipeline( {

				layout: this.device.createPipelineLayout( {

					bindGroupLayouts: Array.from( this.bindGroupLayouts.values() )

				} ),

				compute: this.computeStage

			} );

			await this.finalizeShader();

		} else if ( stage === GPUShaderStage.VERTEX ) {

			//this.vertexStage = { module: shaderModule, entryPoint: this.entryPoint };
console.log("Vertex buffers descriptors:", Array.from(this.vertexBuffersDescriptors.values()));
			
			const vertexBuffers = this.vertexBuffersDescriptors.size > 0
			? [...this.vertexBuffersDescriptors.values()]
			: [];

			this.vertexStage = {
				module: shaderModule,
				entryPoint: this.entryPoint,
				buffers: vertexBuffers
			};

		} else if ( stage === GPUShaderStage.FRAGMENT ) {

			this.fragmentStage = { module: shaderModule, entryPoint: this.entryPoint };

		}

		// If both vertex and fragment stages exist, create render pipeline
		if ( this.vertexStage && this.fragmentStage ) {

			this._createAllBuffers();

			console.log( this.device );

			console.log("create fragment and vertex shader pipeline.");

			console.log("setup createRenderPipeline", this.vertexStage);

			console.log("this.device.createPipelineLayout", this.bindGroupLayouts.get(0)  );




			this.pipeline = this.device.createRenderPipeline( {

				layout: this.device.createPipelineLayout( {

							bindGroupLayouts: Array.from( this.bindGroupLayouts.values() )
						
						} ),

						vertex: this.vertexStage,

						fragment: {
							...this.fragmentStage,

							targets:  [
					            {
					                format: "bgra8unorm",
					                // No blending here for opaque rendering
					                blend: undefined,
					                writeMask: GPUColorWrite.ALL
					            }
					        ] // Specify the color target format here
						

						},
						multisample: {

							count: this.sampleCount, // number of samples per pixel, typical values: 4 or 8

						},
						primitive: {

							topology: 	this.topologyValue,
					
						    frontFace: 	'ccw' ,

						    cullMode: 	'none',

						},    

						depthStencil: {

							format: "depth24plus",     // <-- Add this to match render pass depthStencil

							depthWriteEnabled: true,

							depthCompare: "less",

						},
						    
					

			} );

			this._createAllBuffers();

			await this.finalizeShader();

		}

	}

	convertToTypedArrayWithPadding(array, preferredType = null) {

		const isTypedArray = (
			array instanceof Uint16Array ||
			array instanceof Uint32Array ||
			array instanceof Float32Array
		);

		let typedArray;
		let arrayType = preferredType;

		if (isTypedArray) {
			if (preferredType === null) {
				if (array instanceof Uint16Array) arrayType = "uint16";
				else if (array instanceof Uint32Array) arrayType = "uint32";
				else if (array instanceof Float32Array) arrayType = "float32";
			}

			const remainder = array.byteLength % 4;

			if (remainder !== 0) {
				const elementSize = (arrayType === "uint16") ? 2 : 4;
				const paddedByteLength = array.byteLength + (4 - remainder);
				const paddedElementCount = paddedByteLength / elementSize;

				if (arrayType === "uint16") {
					const paddedArray = new Uint16Array(paddedElementCount);
					paddedArray.set(array);
					typedArray = paddedArray;
				} else if (arrayType === "uint32") {
					const paddedArray = new Uint32Array(paddedElementCount);
					paddedArray.set(array);
					typedArray = paddedArray;
				} else if (arrayType === "float32") {
					const paddedArray = new Float32Array(paddedElementCount);
					paddedArray.set(array);
					typedArray = paddedArray;
				} else {
					throw new Error("Unsupported typed array type for padding");
				}
			} else {
				typedArray = array;
			}
		} else if (Array.isArray(array)) {
			if (preferredType === null) {
				// Default to Float32Array if no preferred type
				arrayType = "float32";
			} else {
				arrayType = preferredType;
			}

			if (arrayType === "uint16") {
				typedArray = new Uint16Array(array);
			} else if (arrayType === "uint32") {
				typedArray = new Uint32Array(array);
			} else if (arrayType === "float32") {
				typedArray = new Float32Array(array);
			} else {
				throw new Error("Unsupported preferred type");
			}

			const remainder = typedArray.byteLength % 4;

			if (remainder !== 0) {
				const elementSize = (arrayType === "uint16") ? 2 : 4;
				const paddedByteLength = typedArray.byteLength + (4 - remainder);
				const paddedElementCount = paddedByteLength / elementSize;

				if (arrayType === "uint16") {
					const paddedArray = new Uint16Array(paddedElementCount);
					paddedArray.set(typedArray);
					typedArray = paddedArray;
				} else if (arrayType === "uint32") {
					const paddedArray = new Uint32Array(paddedElementCount);
					paddedArray.set(typedArray);
					typedArray = paddedArray;
				} else if (arrayType === "float32") {
					const paddedArray = new Float32Array(paddedElementCount);
					paddedArray.set(typedArray);
					typedArray = paddedArray;
				} else {
					throw new Error("Unsupported typed array type for padding");
				}
			}
		} else {
			throw new Error("Input must be a TypedArray or Array of numbers");
		}

		return { typedArray, arrayType };
	}

	setIndices( indices ) {
console.log("indices", indices);
		const isTypedArray = indices instanceof Uint16Array || indices instanceof Uint32Array;

		let typedArray;
		let arrayType;
		
		console.log("isTypedArray", isTypedArray);

		if ( isTypedArray ) {

			arrayType = (indices instanceof Uint16Array) ? "uint16" : "uint32";

			({ typedArray } = this.convertToTypedArrayWithPadding( indices, arrayType ) );

		} else if (Array.isArray(indices)) {

			let maxIndex = 0;

			for (let i = 0; i < indices.length; i++) {
				if (indices[i] > maxIndex) maxIndex = indices[i];
			}

			arrayType = (maxIndex < 65536) ? "uint16" : "uint32";


			({ typedArray } = this.convertToTypedArrayWithPadding(indices, arrayType));


		} else {

			throw new Error("Indices must be Uint16Array, Uint32Array, or Array of numbers");

		}

		this.indexFormat 		= arrayType;

		this.indexBufferData 	= typedArray;

		if (this.indexBuffer) {

			this.indexBuffer.destroy();

		}

		this.indexBuffer = this.device.createBuffer({
			size: this.indexBufferData.byteLength,
			usage: GPUBufferUsage.INDEX | GPUBufferUsage.COPY_DST,
		});

		this.device.queue.writeBuffer(
			this.indexBuffer,
			0,
			this.indexBufferData.buffer,
			this.indexBufferData.byteOffset,
			this.indexBufferData.byteLength
		);

		this.indexCount = this.indexBufferData.length;


	}

	setAttribute( name, array ) {

		if ( this.attributeArrays === undefined ) {

			this.attributeArrays = new Map();

		}

		const { typedArray, arrayType } 	= this.convertToTypedArrayWithPadding( array );

		let attributeSize = 3; // Default size (vec3)

		// this is not proper
		if ( name === "uv" ) {

			attributeSize = 2;

		} else if ( name === "position" || name === "normal" ) {

			attributeSize = 3;

		} else {

			// You can add more attribute names and sizes here

		}

		this.attributeArrays.set( name, { typedArray: typedArray, size: attributeSize } );

	}

	getAllAttributeBuffers() {

		if ( !this.attributeBuffers ) {

			return new Map();

		}

		return this.attributeBuffers;

	}

	vertexBuffers( passEncoder ) {

		if ( this.attributeArrays === undefined ) {

			console.warn("No attribute arrays to bind.");

			return;

		}

		if ( this.mergedAttributeBuffer === undefined ) {

			const attributeNames = Array.from( this.attributeArrays.keys() );

			const arrays = attributeNames.map( name => this.attributeArrays.get( name ).typedArray );

			const attributeSizes = attributeNames.map( name => (name === "uv") ? 2 : 3 );

			const vertexCount = arrays[0].length / attributeSizes[0];

			const strideFloats = attributeSizes.reduce( (sum, size) => sum + size, 0 );

			const mergedArray = new Float32Array( vertexCount * strideFloats );

		
			for ( let i = 0; i < vertexCount; i++ ) {

				let offset = i * strideFloats;

				for ( let attrIndex = 0; attrIndex < arrays.length; attrIndex++ ) {

					const arr = arrays[attrIndex];

					const size = attributeSizes[attrIndex];

					const baseIndex = i * size;

					for ( let c = 0; c < size; c++ ) {

						mergedArray[ offset++ ] = arr[ baseIndex + c ];

					}

				}

			}

			const byteLength = mergedArray.byteLength;

			const buffer = this.device.createBuffer({

				size             : byteLength,

				usage            : GPUBufferUsage.VERTEX | GPUBufferUsage.COPY_DST,

				mappedAtCreation : true,

				label            : "mergedAttributes"

			});

			const mapping = new Float32Array( buffer.getMappedRange() );

			mapping.set( mergedArray );

			buffer.unmap();

			this.device.queue.writeBuffer(

				buffer,

				0,

				mergedArray.buffer,

				mergedArray.byteOffset,

				mergedArray.byteLength

			);

			this.mergedAttributeBuffer = buffer;

			// Store for pipeline setup
			this.attributeStrideFloats = strideFloats;

			this.attributeSizes = attributeSizes;

			this.attributeNames = attributeNames;

		}

		// Bind the merged buffer at slot 0

		passEncoder.setVertexBuffer( 0, this.mergedAttributeBuffer );

	}

	setCanvas( canvas ) {

		this.canvas 	= canvas;

	}


	encodeRender( passEncoder, x, y = 0, z = 0 ) {

		if ( !this.bindGroups || this.bindGroups.size === 0 ) {
			this.createBindGroups();
		}

		passEncoder.setPipeline( this.pipeline );

		this.vertexBuffers( passEncoder );

		for ( const [ bindingGroupIndex, bindGroup ] of this.bindGroups.entries() ) {

			passEncoder.setBindGroup( bindingGroupIndex, bindGroup );

		}

		if ( this.indexBuffer ) {

			passEncoder.setIndexBuffer( this.indexBuffer, this.indexFormat );

			passEncoder.drawIndexed( this.indexCount, y, z );

		} else {

			passEncoder.draw( x, y, z );

		}

	}

	async renderToCanvas( x, y = 0, z = 0 ) {

		// AUTO-REBUILD BIND GROUPS IF NEEDED
		if ( !this.bindGroups || this.bindGroups.size === 0 ) {
			this.createBindGroups();
		}

		const canvas 		= this.canvas;

		const context 		= canvas.getContext( "webgpu" );

		const format 		= navigator.gpu.getPreferredCanvasFormat();

		const depthTexture = this.device.createTexture( {
			size: [ this.canvas.width, this.canvas.height, 1 ],
			sampleCount: this.sampleCount,
			format: "depth24plus",
			usage: GPUTextureUsage.RENDER_ATTACHMENT
		} );

		const commandEncoder = this.device.createCommandEncoder();

		let renderPassDescriptor;

		const colorLoadOp 	= this.clearOnRender ? "clear" : "load";
		const depthLoadOp 	= this.clearOnRender ? "clear" : "load";
		const clearColor   	= { r: 0.3, g: 0.3, b: 0.3, a: 1 };

		if ( this.sampleCount === 1 ) {

			renderPassDescriptor = {
				colorAttachments: [ {
					view: context.getCurrentTexture().createView(),
					loadOp: colorLoadOp,
					storeOp: "store",
					clearValue: clearColor
				} ],
				depthStencilAttachment: {
					view: this.depthTexture.createView(),
					depthLoadOp: depthLoadOp,
					depthStoreOp: "store",
					depthClearValue: 1.0
				}
			};

		} else {

			renderPassDescriptor = {
				colorAttachments: [ {
					view: this.multisampledColorTexture.createView(),
					resolveTarget: context.getCurrentTexture().createView(),
					loadOp: colorLoadOp,
					storeOp: "store",
					clearValue: { r: 0, g: 0, b: 0, a: 1 }
				} ],
				depthStencilAttachment: {
					view: this.multisampledDepthTexture.createView(),
					depthLoadOp: depthLoadOp,
					depthStoreOp: "store",
					depthClearValue: 1.0
				}
			};
		}

		const passEncoder = commandEncoder.beginRenderPass( renderPassDescriptor );

		this.encodeRender( passEncoder, x, y, z );

		passEncoder.end();

		this.device.queue.submit( [ commandEncoder.finish() ] );

	}

	async finalizeShader() {

		//await this._createPipeline();

		await this.createBindGroups();

	}

	async debugBuffer( bufferName, bufferType ) {



		const buffer			= this.getBuffer( bufferName );

		const dataSize			= buffer.size;

		const debugReadBuffer	= this.device.createBuffer( {
			size: dataSize,
			usage: GPUBufferUsage.COPY_DST | GPUBufferUsage.MAP_READ
		} );

		const debugEncoder		= this.device.createCommandEncoder();

		//console.log( "print buffer", buffer );

		debugEncoder.copyBufferToBuffer(
			buffer,
			0,
			debugReadBuffer,
			0,
			dataSize
		);

		this.device.queue.submit( [ debugEncoder.finish() ] );

		await this.device.queue.onSubmittedWorkDone();

		await debugReadBuffer.mapAsync( GPUMapMode.READ );

		const copyArrayBuffer	= debugReadBuffer.getMappedRange();

		let result;

		const bindingInfo = this.bindings.find( b => b.varName === bufferName );

		if ( bindingInfo ) {

			const wgslType = bindingInfo.varType;

			//console.log("wgslType", bindingInfo, wgslType, bufferName);

			// === STRUCT SUPPORT ========================================================
			if (this.structs && this.structs[wgslType]) {

			    const structInfo = this.structs[wgslType];
			    const view = new DataView(copyArrayBuffer);
			    const resultObj = {};

			    for (const field of structInfo.fields) {

			        const off = field.offset;

			        switch (field.type) {
			            case "u32":
			                resultObj[field.name] = view.getUint32(off, true);
			                break;
			            case "i32":
			                resultObj[field.name] = view.getInt32(off, true);
			                break;
			            case "f32":
			                resultObj[field.name] = view.getFloat32(off, true);
			                break;

			            default:
			                console.warn("Unhandled struct field type:", field.type);
			                resultObj[field.name] = null;
			                break;
			        }
			    }

			    debugReadBuffer.unmap();
			    return resultObj;
			}



			switch ( wgslType ) {

				case "array<f32>":
					result = new Float32Array( copyArrayBuffer );
				break;
				case "array<u32>":
					result = new Uint32Array( copyArrayBuffer );
				break;
				case "vec3<f32>":

				break;
				case "vec4<f32>":
					result = new Float32Array( copyArrayBuffer );
				break;
				case "u32":
				case "vec2<u32>":
				case "vec3<u32>":
				case "vec4<u32>":
					result = new Uint32Array( copyArrayBuffer );
				break;
				case "Tensor":
				    result = new Float32Array(copyArrayBuffer);
				break;

				case "array<vec4<f32>>":
				case "array<Vector>":
				case "array<array<f32, 64>>":
				case "array<vec3<f32>>":
					result = new Float32Array( copyArrayBuffer );
				break;
				case "vec3<i32>":
				case "vec4<i32>":
					result = new Int32Array( copyArrayBuffer );
				break;

				default:
					console.error( "Unknown WGSL type in setVariable: " + wgslType, "Using Float32Array as fallback." );

					result = new Float32Array( copyArrayBuffer );
			}

			// use wgslType here to determine appropriate TypedArray
		}
		const length = result.length;
		var regularArray = new Array();

		for (var i = 0; i < length; i++) {

			regularArray.push(result[i]);

		}
		
/*
		console.log("Debugging array");
		console.log("");
		console.log("Shader:				", this.path);
		console.log("Variable Name:		", bufferName);

		console.log( "Buffer Size:		", this.getBuffer(bufferName).size );
		console.log( "TypedArray Size:	", length );
*/

		if ( bindingInfo ) {

			const wgslType = bindingInfo.varType;

			//console.log( "type:				", wgslType );

		}

		//console.log(regularArray);

		debugReadBuffer.unmap();

		return regularArray;

	}


}