Add DougalBinaryLoader Deck.gl loader

lib/www/client/source/src/lib/deck.gl/DougalBinaryLoader.js

@@ -0,0 +1,146 @@
+// src/lib/deck.gl/DougalBinaryLoader.js
+import { LoaderObject } from '@loaders.gl/core';
+import { DougalBinaryBundle } from '@dougal/binary';
+
+async function cachedFetch(url, init, opts = {}) {
+    let res; // The response
+    let cache; // Potentially, a Cache API cache name
+    let isCached;
+
+    if (opts?.cache === true) {
+      opts.cache = { name: "dougal" };
+    } else if (typeof opts?.cache === "string") {
+      opts.cache = { name: opts.cache };
+    } else if (opts?.cache) {
+      if (!(opts.cache instanceof Object)) {
+        opts.cache = { name: "dougal" }
+      } else if (!(opts.cache.name)) {
+        opts.cache.name = "dougal";
+      }
+    }
+
+    if (opts?.cache) {
+      cache = await caches.open(opts.cache.name);
+      res = await cache.match(url);
+      isCached = !!res;
+    }
+
+    if (!res) {
+      res = await fetch(url, init);
+    }
+
+    if (cache && !isCached) {
+      cache.put(url, res.clone());
+    }
+
+    return res;
+}
+
+const DougalBinaryLoader = {
+  name: 'DougalBinaryBundle Loader',
+  extensions: ['dbb'],
+  mimeTypes: ['application/vnd.aaltronav.dougal+octet-stream'],
+  parse: async (input, options) => {
+    let arrayBuffer;
+    if (typeof input === 'string') {
+      // Input is URL, fetch with caching
+      const response = await cachedFetch(input, options?.fetch, options);
+      if (!response.ok) {
+        throw new Error(`Failed to fetch: ${response.statusText}`);
+      }
+      arrayBuffer = await response.arrayBuffer();
+    } else if (input instanceof ArrayBuffer) {
+      arrayBuffer = input;
+    } else {
+      throw new Error('Invalid input: Expected URL string or ArrayBuffer');
+    }
+
+    const bundle = DougalBinaryBundle.clone(arrayBuffer);
+
+    // Calculate total points
+    const totalCount = bundle.chunks().reduce((acc, chunk) => acc + chunk.jCount, 0);
+
+    // Prepare positions (Float32Array: [lon1, lat1, lon2, lat2, ...])
+    const positions = new Float32Array(totalCount * 2);
+
+    // Extract udv (assume constant across chunks)
+    const udv = bundle.chunks()[0].udv;
+
+    // Prepare values as an array of TypedArrays
+    const ΔelemCount = bundle.chunks()[0].ΔelemCount;
+    const elemCount = bundle.chunks()[0].elemCount;
+    const values = new Array(ΔelemCount + elemCount + 2);
+
+    // Initialize values arrays with correct types
+    if (udv == 0) {
+      for (let k = 0; k < values.length; k++) {
+        values[k] = new (k === 0 ? Uint16Array : k === 1 ? Uint32Array : Uint8Array)(totalCount);
+      }
+    } else if (udv == 1) {
+      for (let k = 0; k < values.length; k++) {
+        values[k] = new (k === 0 ? Uint16Array : k === 1 ? Uint32Array : k === 2 ? Uint8Array : Uint16Array)(totalCount);
+      }
+    } else if (udv == 2) {
+      for (let k = 0; k < values.length; k++) {
+        values[k] = new (k === 0 ? Uint16Array : k === 1 ? Uint32Array : k === 2 ? BigUint64Array : Float32Array)(totalCount);
+      }
+    } else {
+      throw new Error(`Invalid udv: Expected 0, 1, or 2; found ${udv}`);
+    }
+
+    let offset = 0;
+    for (const chunk of bundle.chunks()) {
+      const λarray = chunk.elem(0);
+      const φarray = chunk.elem(1);
+      for (let i = 0; i < λarray.length; i++) {
+        positions[offset * 2 + i * 2] = λarray[i];
+        positions[offset * 2 + i * 2 + 1] = φarray[i];
+      }
+
+      values[0].set(new Uint16Array(chunk.jCount).fill(chunk.i), offset);
+      values[1].set(Uint32Array.from({ length: chunk.jCount }, (_, i) => chunk.j0 + i * chunk.Δj), offset);
+
+      for (let j = 0; j < ΔelemCount; j++) {
+        values[2 + j].set(chunk.Δelem(j), offset);
+      }
+      for (let j = 2; j < elemCount; j++) {
+        values[2 + ΔelemCount + j - 2].set(chunk.elem(j), offset);
+      }
+
+      offset += chunk.jCount;
+    }
+
+    console.log(`Parsed ${totalCount} points, ${values.length} value arrays`);
+
+    const attributes = {
+      getPosition: {
+        value: positions,
+        type: 'float32',
+        size: 2
+      },
+      udv
+    };
+
+    values.forEach((valArray, k) => {
+      let value = valArray;
+      if (valArray instanceof BigUint64Array) {
+        value = Float64Array.from(valArray, v => Number(v));
+      }
+      attributes[`value${k}`] = {
+        value,
+        type: value instanceof Float64Array ? 'float64' :
+              value instanceof Uint16Array ? 'uint16' :
+              value instanceof Uint32Array ? 'uint32' : 'float32',
+        size: 1
+      };
+    });
+
+    return {
+      length: totalCount,
+      attributes
+    };
+  },
+  options: {} // Optional: Add custom options if needed
+};
+
+export default DougalBinaryLoader;