adding new files
diff --git a/webgl/ktx2_studio/encode-worker.js b/webgl/ktx2_studio/encode-worker.js
new file mode 100644
index 0000000..07a8c3e
--- /dev/null
+++ b/webgl/ktx2_studio/encode-worker.js
@@ -0,0 +1,190 @@
+// encode-worker.js
+//
+// Step 2 of moving encoding off the UI thread: load the (threaded) BasisEncoder
+// module in a Web Worker (proven working), then on demand apply a DTO and run a
+// real encode -- reporting the resulting size/PSNR/time back to the page. Uses its
+// OWN independent module instance; the page keeps its own instance for transcode.
+//
+// Protocol (page -> worker):
+//   { type: 'init',      scriptSrc }   load + initialize the module ONCE
+//   { type: 'encode',    dto }         applyEncodeDTO(dto) + encode(); report result (.basis/.KTX2)
+//   { type: 'encodeDDS', dto }         applyEncodeDTO(dto) + applyDDSEncodeDTO(dto) + encodeToDDS(); report .DDS
+// Protocol (worker -> page):
+//   { type: 'log',        text }   informational
+//   { type: 'loaded',     text }   module loaded + initializeBasis() succeeded
+//   { type: 'encoded',    text }   encode finished (size / PSNR / time)
+//   { type: 'encodedDDS', text }   DDS encode finished (size / time)
+//   { type: 'error',      text }   something failed
+
+importScripts('encode_dto_apply.js'); // defines applyEncodeDTO()/applyDDSEncodeDTO() -- shared with the page
+
+let g_module = null;
+
+function post(type, text) { self.postMessage({ type: type, text: text }); }
+
+self.onmessage = function (e)
+{
+   const msg = e.data || {};
+
+   if (msg.type === 'init')
+   {
+      if (g_module)
+      {
+         post('loaded', 'worker: module already loaded (reusing instance)');
+         return;
+      }
+
+      try
+      {
+         post('log', 'worker: importScripts(' + msg.scriptSrc + ')');
+         importScripts(msg.scriptSrc); // defines the global BASIS() factory (EXPORT_NAME=BASIS)
+
+         if (typeof BASIS !== 'function')
+         {
+            post('error', 'worker: BASIS factory not defined after importScripts');
+            return;
+         }
+
+         // Absolute URL to the encoder .js (relative to this worker's location).
+         const absMainUrl = new URL(msg.scriptSrc, self.location.href).href;
+         post('log', 'worker: mainScriptUrlOrBlob=' + absMainUrl);
+
+         BASIS({
+            // REQUIRED when loaded via importScripts inside a worker: emscripten
+            // spawns its pthread sub-workers from this URL. Without it the thread
+            // pool never comes up and BASIS() hangs silently.
+            mainScriptUrlOrBlob: absMainUrl,
+            locateFile: function (path) { return new URL('../encoder/build/' + path, self.location.href).href; },
+            // Forward the encoder's stdout/stderr to the page line-by-line. Because
+            // encode() blocks the WORKER (not the main thread), these stream LIVE to
+            // the page during the encode -- the modal log updates in real time.
+            print: function (t) { self.postMessage({ type: 'print', text: t }); },
+            printErr: function (t) { self.postMessage({ type: 'print', text: t }); },
+            onRuntimeInitialized: function () { post('log', 'worker: onRuntimeInitialized'); }
+         })
+         .then(function (module)
+         {
+            g_module = module;
+
+            if (module.initializeBasis)
+            {
+               module.initializeBasis();
+               post('loaded', 'worker: module loaded + initializeBasis() OK (threaded module live in worker)');
+            }
+            else
+            {
+               post('error', 'worker: module loaded but initializeBasis() is missing');
+            }
+         })
+         .catch(function (err)
+         {
+            post('error', 'worker: BASIS() instantiation failed: ' + err);
+         });
+      }
+      catch (err)
+      {
+         post('error', 'worker: init exception: ' + err);
+      }
+   }
+   else if (msg.type === 'encode')
+   {
+      if (!g_module)
+      {
+         post('error', 'worker: encode requested before module is loaded');
+         return;
+      }
+
+      let enc = null;
+      try
+      {
+         enc = new g_module.BasisEncoder();         // embind class lives on the module instance
+         applyEncodeDTO(enc, msg.dto);              // shared with the page; pure (encoder, dto)
+
+         // destination buffer -- matches the legacy page (new Uint8Array(1024*1024*24))
+         const out = new Uint8Array(1024 * 1024 * 24);
+
+         // time JUST the encode() call, like the main-thread path (startTime/elapsed)
+         const encT0 = performance.now();
+         const len = enc.encode(out);
+         const encodeMs = performance.now() - encT0;
+
+         const psnr = (typeof enc.getLastEncodeMip0RGBAPSNR === 'function') ? enc.getLastEncodeMip0RGBAPSNR() : -1;
+
+         if (len > 0)
+         {
+            // exact-size copy (its own ArrayBuffer) so we can transfer it back zero-copy
+            const result = out.slice(0, len);
+            self.postMessage({
+               type: 'encoded',
+               text: 'worker: ENCODE OK -> ' + len + ' bytes, mip0 RGBA PSNR ' + psnr.toFixed(3) + ', ' + encodeMs.toFixed(2) + ' ms',
+               bytes: result.buffer,
+               len: len,
+               psnr: psnr,         // number: mip0 RGBA PSNR (-> g_lastEncodeMip0RGBAPSNR)
+               encodeMs: encodeMs  // number: encode() wall time (-> g_lastEncodeTime)
+            }, [result.buffer]); // transfer the buffer (no copy)
+         }
+         else
+            post('error', 'worker: encode returned 0 bytes (failed)');
+      }
+      catch (err)
+      {
+         post('error', 'worker: encode exception: ' + err);
+      }
+      finally
+      {
+         // Free the WASM encoder even on exception -- the worker is never terminated, so a leak here
+         // would permanently consume WASM heap.
+         if (enc) enc.delete();
+      }
+   }
+   else if (msg.type === 'encodeDDS')
+   {
+      if (!g_module)
+      {
+         post('error', 'worker: DDS encode requested before module is loaded');
+         return;
+      }
+
+      let enc = null;
+      try
+      {
+         enc = new g_module.BasisEncoder();         // embind class lives on the module instance
+         applyEncodeDTO(enc, msg.dto);              // shared source/sRGB/mip/weights setup (same as KTX2)
+         applyDDSEncodeDTO(enc, msg.dto);           // DDS-specific output format + BC7 options
+
+         // Destination buffer: sized by the page (worst case 32bpp + full mip chain, bounded by the
+         // encoder's source-pixel cap). If somehow too small, encodeToDDS() returns 0 (clean failure).
+         const out = new Uint8Array(msg.dto.ddsBufferSize);
+
+         // Time JUST the encode, like the .basis/.KTX2 path.
+         const encT0 = performance.now();
+         const len = enc.encodeToDDS(out);
+         const encodeMs = performance.now() - encT0;
+
+         if (len > 0)
+         {
+            // exact-size copy (its own ArrayBuffer) so we can transfer it back zero-copy
+            const result = out.slice(0, len);
+            self.postMessage({
+               type: 'encodedDDS',
+               text: 'worker: DDS ENCODE OK -> ' + len + ' bytes, ' + encodeMs.toFixed(2) + ' ms',
+               bytes: result.buffer,
+               len: len,
+               encodeMs: encodeMs  // number: encodeToDDS() wall time (-> g_lastEncodeTime)
+            }, [result.buffer]); // transfer the buffer (no copy)
+         }
+         else
+            post('error', 'worker: encodeToDDS returned 0 bytes (failed)');
+      }
+      catch (err)
+      {
+         post('error', 'worker: DDS encode exception: ' + err);
+      }
+      finally
+      {
+         // Free the WASM encoder even on exception -- the worker is never terminated, so a leak here
+         // would permanently consume WASM heap.
+         if (enc) enc.delete();
+      }
+   }
+};
diff --git a/webgl/ktx2_studio/encode_dto_apply.js b/webgl/ktx2_studio/encode_dto_apply.js
new file mode 100644
index 0000000..9307e93
--- /dev/null
+++ b/webgl/ktx2_studio/encode_dto_apply.js
@@ -0,0 +1,129 @@
+// encode_dto_apply.js
+//
+// applyEncodeDTO(encoder, dto): applies an encode DTO (built by buildEncodeDTO in
+// index.html) to a BasisEncoder instance, in the SAME ORDER as the legacy inline
+// encode path; the caller then calls encoder.encode().
+//
+// PURE: depends only on (encoder, dto) -- no Module, no DOM. That's why it can run
+// unchanged on the main thread (non-worker DTO path) AND inside the encode worker
+// (which importScripts() this file). All enum values in dto are already ints.
+//
+// Loaded on the page via <script src> and in the worker via importScripts(), so it
+// is the single source of truth for both modes (no duplication / drift).
+
+function applyEncodeDTO(encoder, dto)
+{
+   // container / threading
+   encoder.controlThreading(dto.multithreaded, dto.numWorkerThreads);
+   encoder.setCreateKTX2File(dto.createKTX2);
+   encoder.setKTX2UASTCSupercompression(dto.ktx2UASTCSupercompression);
+
+   // color / transfer
+   encoder.setPerceptual(dto.sRGB);
+   if (!dto.isHDRSourceFile)
+      encoder.setKTX2AndBasisSRGBTransferFunc(dto.sRGB);
+   encoder.setMipSRGB(dto.sRGB);
+
+   // source image (the DTO normalized the 3 legacy cases into one shape:
+   // pre-decoded RGBA has real dims; raw file bytes use 0,0 + an img_type)
+   const s = dto.source;
+   if (s.isHDRTarget)
+      encoder.setSliceSourceImageHDR(0, s.bytes, s.width, s.height, s.imgType, s.convertLDRToLinear, s.nitMultiplier);
+   else
+      encoder.setSliceSourceImage(0, s.bytes, s.width, s.height, s.imgType);
+
+   encoder.setFormatMode(dto.formatMode);
+   encoder.setRec2020(dto.rec2020);
+   encoder.setDebug(dto.debug);
+   encoder.setComputeStats(dto.computeStats);
+   encoder.setPrintStats(dto.printStats);
+   encoder.setStatusOutput(true);
+
+   // low-level codec opts -- run when the unified checkbox is OFF (legacy).
+   // NOTE this can run even for XUBC7 (when checkbox is off); applyUnified then
+   // overrides quality/effort afterward, exactly as the legacy path does.
+   if (dto.lowLevelOptsEnabled)
+   {
+      encoder.setUASTCHDRQualityLevel(dto.uastcHDRQuality);
+      encoder.setASTC_HDR_6x6_Level(dto.astcHDR6x6Level);
+      encoder.setLambda(dto.astc6x6Lambda);
+
+      // three-way quality branch (mirrors legacy): XUBC7 defers to the unified
+      // call (no setQualityLevel here); XUASTC uses DCT; everything else ETC1S.
+      if (dto.isXUBC7Target)
+      {
+         // intentionally nothing -- applyUnified handles XUBC7 quality/effort
+      }
+      else if (dto.isXUASTCLDRTarget)
+      {
+         if (dto.xuastcDCTQuality < 100)
+         {
+            encoder.setQualityLevel(dto.xuastcDCTQuality);
+            encoder.setXUASTCLDRUseDCT(true);
+         }
+      }
+      else
+      {
+         encoder.setQualityLevel(dto.etc1sQuality);
+      }
+
+      encoder.setXUASTCLDRUseLossySupercompression(dto.xuastcLossySupercompression);
+      encoder.setASTCOrXUASTCLDREffortLevel(dto.astcXuastcEffortLevel);
+      encoder.setRDOUASTC(dto.rdoUASTC);
+      encoder.setRDOUASTCQualityScalar(dto.rdoUASTCQualityScalar);
+      encoder.setPackUASTCFlags(dto.packUASTCFlags);
+      encoder.setETC1SCompressionLevel(dto.etc1sCompLevel);
+   }
+
+   // always-applied opts (available even when the unified path is used)
+   for (let i = 0; i < 6; i++)
+      encoder.setXUASTCLDRBoundedRDOParam(i, dto.xuastcBoundedRDO[i]);
+
+   encoder.setXUASTCLDRForceDisableRGBDualPlane(dto.xuastcDisableRGBDualPlane);
+   encoder.setXUASTCLDRForceDisableSubsets(dto.xuastcDisableSubsets);
+   encoder.setXUASTCLDRUseBlurring(dto.xuastcUseBlur);
+   encoder.setXUASTCLDRSelectCompressor(dto.xuastcSelectCompressor);
+   encoder.setXUASTCLDRHeavySubsetUsage(dto.xuastcHeavySubsetUsage);
+   encoder.setXUASTCLDRSharpenMode(dto.xuastcSharpenMode);
+   encoder.setXUASTCLDRSharpenAmount(dto.xuastcSharpenAmount);
+   encoder.setXUASTCLDRDeblockingMode(dto.xuastcDeblockingMode);
+   encoder.setXUASTCLDRNumDeblockingPasses(dto.xuastcNumDeblockingPasses);
+   encoder.setASTCOrXUASTCLDRWeights(dto.weights[0], dto.weights[1], dto.weights[2], dto.weights[3]);
+   encoder.setSwizzle(dto.swizzle[0], dto.swizzle[1], dto.swizzle[2], dto.swizzle[3]);
+   encoder.setXUASTCLDRSyntax(dto.xuastcSyntax);
+   encoder.setXUBC7RDOLevel(dto.xubc7RDOLevel);
+   encoder.setXUBC7NumStripes(dto.xubc7NumStripes);
+   encoder.setXUBC7Encoder(dto.xubc7Encoder);
+   encoder.setXUBC7BC7EScalarLevel(dto.xubc7BC7EScalarLevel);
+
+   // mipmaps
+   encoder.setMipGen(dto.mipGen);
+   encoder.setMipFilter(dto.mipFilter);
+   encoder.setMipScale(dto.mipScale);
+   encoder.setMipSmallestDimension(dto.mipSmallestDim);
+   encoder.setMipRenormalize(dto.mipRenormalize);
+   encoder.setMipWrapping(dto.mipWrapping);
+   encoder.setYFlip(dto.yFlip);
+
+   // unified quality/effort LAST -- it intentionally overrides some of the
+   // codec-specific low-level options set above (matches the legacy path)
+   if (dto.applyUnified)
+      encoder.setFormatModeAndQualityEffort(dto.formatMode, dto.unifiedQuality, dto.unifiedEffort, true);
+}
+
+// applyDDSEncodeDTO(encoder, dto): applies ONLY the DDS-export-specific options on top of a
+// BasisEncoder that has ALREADY had applyEncodeDTO() run on it. The caller then calls
+// encoder.encodeToDDS(buffer). Used by the DDS-export path (worker 'encodeDDS' message).
+//
+// PURE: depends only on (encoder, dto) -- no Module, no DOM (same contract as applyEncodeDTO).
+//
+// Everything DDS shares with KTX2 (source image, sRGB transfer func, perceptual, channel weights,
+// mips, etc.) was already set by applyEncodeDTO() and is consumed by encodeToDDS()/build_dds()
+// unchanged -- so we only set the genuinely NEW things here: the output format + BC7 packer knobs.
+function applyDDSEncodeDTO(encoder, dto)
+{
+   encoder.setDDSFormatEnum(dto.ddsFormat);
+   encoder.setDDSBC7Encoder(dto.ddsBC7Encoder);
+   encoder.setDDSBC7FLevel(dto.ddsBC7FLevel);
+   encoder.setDDSBC7EScalarLevel(dto.ddsBC7EScalarLevel);
+}
diff --git a/webgl/ktx2_studio/wasm-feature-detect.js b/webgl/ktx2_studio/wasm-feature-detect.js
new file mode 100644
index 0000000..a915f39
--- /dev/null
+++ b/webgl/ktx2_studio/wasm-feature-detect.js
@@ -0,0 +1 @@
+!function(e,n){"object"==typeof exports&&"undefined"!=typeof module?module.exports=n():"function"==typeof define&&define.amd?define(n):(e="undefined"!=typeof globalThis?globalThis:e||self).wasmFeatureDetect=n()}(this,(function(){"use strict";return{bigInt:()=>(async e=>{try{return(await WebAssembly.instantiate(e)).instance.exports.b(BigInt(0))===BigInt(0)}catch(e){return!1}})(new Uint8Array([0,97,115,109,1,0,0,0,1,6,1,96,1,126,1,126,3,2,1,0,7,5,1,1,98,0,0,10,6,1,4,0,32,0,11])),bulkMemory:async()=>WebAssembly.validate(new Uint8Array([0,97,115,109,1,0,0,0,1,4,1,96,0,0,3,2,1,0,5,3,1,0,1,10,14,1,12,0,65,0,65,0,65,0,252,10,0,0,11])),exceptions:async()=>WebAssembly.validate(new Uint8Array([0,97,115,109,1,0,0,0,1,4,1,96,0,0,3,2,1,0,10,8,1,6,0,6,64,25,11,11])),exceptionsFinal:()=>(async()=>{try{return new WebAssembly.Module(Uint8Array.from(atob("AGFzbQEAAAABBAFgAAADAgEAChABDgACaR9AAQMAAAsACxoL"),(e=>e.codePointAt(0)))),!0}catch(e){return!1}})(),extendedConst:async()=>WebAssembly.validate(new Uint8Array([0,97,115,109,1,0,0,0,5,3,1,0,1,11,9,1,0,65,1,65,2,106,11,0])),gc:()=>(async()=>WebAssembly.validate(new Uint8Array([0,97,115,109,1,0,0,0,1,5,1,95,1,120,0])))(),jsStringBuiltins:()=>(async()=>{try{return await WebAssembly.instantiate(Uint8Array.from(atob("AGFzbQEAAAABBgFgAW8BfwIXAQ53YXNtOmpzLXN0cmluZwR0ZXN0AAA="),(e=>e.codePointAt(0))),{},{builtins:["js-string"]}),!0}catch(e){return!1}})(),jspi:()=>(async()=>"Suspending"in WebAssembly)(),memory64:async()=>WebAssembly.validate(new Uint8Array([0,97,115,109,1,0,0,0,5,3,1,4,1])),multiMemory:()=>(async()=>{try{return new WebAssembly.Module(new Uint8Array([0,97,115,109,1,0,0,0,5,5,2,0,0,0,0])),!0}catch(e){return!1}})(),multiValue:async()=>WebAssembly.validate(new Uint8Array([0,97,115,109,1,0,0,0,1,6,1,96,0,2,127,127,3,2,1,0,10,8,1,6,0,65,0,65,0,11])),mutableGlobals:async()=>WebAssembly.validate(new Uint8Array([0,97,115,109,1,0,0,0,2,8,1,1,97,1,98,3,127,1,6,6,1,127,1,65,0,11,7,5,1,1,97,3,1])),referenceTypes:async()=>WebAssembly.validate(new Uint8Array([0,97,115,109,1,0,0,0,1,4,1,96,0,0,3,2,1,0,10,7,1,5,0,208,112,26,11])),relaxedSimd:async()=>WebAssembly.validate(new Uint8Array([0,97,115,109,1,0,0,0,1,5,1,96,0,1,123,3,2,1,0,10,15,1,13,0,65,1,253,15,65,2,253,15,253,128,2,11])),saturatedFloatToInt:async()=>WebAssembly.validate(new Uint8Array([0,97,115,109,1,0,0,0,1,4,1,96,0,0,3,2,1,0,10,12,1,10,0,67,0,0,0,0,252,0,26,11])),signExtensions:async()=>WebAssembly.validate(new Uint8Array([0,97,115,109,1,0,0,0,1,4,1,96,0,0,3,2,1,0,10,8,1,6,0,65,0,192,26,11])),simd:async()=>WebAssembly.validate(new Uint8Array([0,97,115,109,1,0,0,0,1,5,1,96,0,1,123,3,2,1,0,10,10,1,8,0,65,0,253,15,253,98,11])),streamingCompilation:()=>(async()=>"compileStreaming"in WebAssembly)(),tailCall:async()=>WebAssembly.validate(new Uint8Array([0,97,115,109,1,0,0,0,1,4,1,96,0,0,3,2,1,0,10,6,1,4,0,18,0,11])),threads:()=>(async e=>{try{return"undefined"!=typeof MessageChannel&&(new MessageChannel).port1.postMessage(new SharedArrayBuffer(1)),WebAssembly.validate(e)}catch(e){return!1}})(new Uint8Array([0,97,115,109,1,0,0,0,1,4,1,96,0,0,3,2,1,0,5,4,1,3,1,1,10,11,1,9,0,65,0,254,16,2,0,26,11])),typeReflection:()=>(async()=>"Function"in WebAssembly)(),typedFunctionReferences:()=>(async()=>{try{return new WebAssembly.Module(Uint8Array.from(atob("AGFzbQEAAAABEANgAX8Bf2ABZAABf2AAAX8DBAMBAAIJBQEDAAEBChwDCwBBCkEqIAAUAGoLBwAgAEEBagsGANIBEAAL"),(e=>e.codePointAt(0)))),!0}catch(e){return!1}})()}}));