support normalizing external buffer

visgl · Nov 18, 2019 · 24285eb · 24285eb
1 parent 161e2de
commit 24285eb
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Showing 3 changed files with 47 additions and 18 deletions.
diff --git a/modules/core/src/lib/attribute/attribute.js b/modules/core/src/lib/attribute/attribute.js
@@ -250,11 +250,14 @@ export default class Attribute extends DataColumn {
         buffer = {value: buffer};
       }
       assert(ArrayBuffer.isView(buffer.value), `invalid ${settings.accessor}`);
+      const needsNormalize = buffer.size && buffer.size !== this.size;
 
       state.logicalAccessor = getAccessorFromBuffer(buffer.value, {
-        ...settings,
-        ...buffer,
-        startIndices
+        size: buffer.size || this.size,
+        stride: buffer.stride,
+        offset: buffer.offset,
+        startIndices,
+        nested: needsNormalize
       });
       // Fall through to auto updater
       return false;
@@ -285,6 +288,7 @@ export default class Attribute extends DataColumn {
     return shaderAttributes;
   }
 
+  /* eslint-disable max-depth, max-statements */
   _autoUpdater(attribute, {data, startRow, endRow, props, numInstances}) {
     const {settings, state, value, size, startIndices} = attribute;
 

diff --git a/modules/core/src/utils/iterable-utils.js b/modules/core/src/utils/iterable-utils.js
@@ -64,30 +64,45 @@ export function isAsyncIterable(data) {
 /*
  * Create an accessor function from a flat buffer that yields the value at each object index
  */
-export function getAccessorFromBuffer(typedArray, opts) {
-  const {size, stride, offset, vertexStarts} = opts;
+export function getAccessorFromBuffer(typedArray, {size, stride, offset, startIndices, nested}) {
   const bytesPerElement = typedArray.BYTES_PER_ELEMENT;
   const elementStride = stride ? stride / bytesPerElement : size;
   const elementOffset = offset ? offset / bytesPerElement : 0;
   const vertexCount = Math.floor((typedArray.length - elementOffset) / elementStride);
 
   return (_, {index, target}) => {
-    if (vertexStarts) {
-      const startVertex = vertexStarts[index];
-      const endVertex = vertexStarts[index + 1] || vertexCount;
-      const result = new typedArray.constructor((endVertex - startVertex) * size);
-      for (let i = startVertex, targetIndex = 0; i < endVertex; i++) {
+    if (!startIndices) {
+      const sourceIndex = index * elementStride + elementOffset;
+      for (let j = 0; j < size; j++) {
+        target[j] = typedArray[sourceIndex + j];
+      }
+      return target;
+    }
+    const startIndex = startIndices[index];
+    const endIndex = startIndices[index + 1] || vertexCount;
+    let result;
+
+    if (nested) {
+      result = new Array(endIndex - startIndex);
+      for (let i = startIndex; i < endIndex; i++) {
+        const sourceIndex = i * elementStride + elementOffset;
+        target = new Array(size);
+        for (let j = 0; j < size; j++) {
+          target[j] = typedArray[sourceIndex + j];
+        }
+        result[i - startIndex] = target;
+      }
+    } else {
+      result = new typedArray.constructor((endIndex - startIndex) * size);
+      let targetIndex = 0;
+      for (let i = startIndex; i < endIndex; i++) {
         const sourceIndex = i * elementStride + elementOffset;
         for (let j = 0; j < size; j++) {
           result[targetIndex++] = typedArray[sourceIndex + j];
         }
       }
-      return result;
     }
-    const sourceIndex = index * elementStride + elementOffset;
-    for (let j = 0; j < size; j++) {
-      target[j] = typedArray[sourceIndex + j];
-    }
-    return target;
+
+    return result;
   };
 }
diff --git a/test/modules/core/utils/iterable-utils.spec.js b/test/modules/core/utils/iterable-utils.spec.js
@@ -133,7 +133,7 @@ test('getAccessorFromBuffer', t => {
       input: {
         value: new Float32Array([1, 1, 0, 2, 2, 0, 3, 3, 0]),
         size: 3,
-        vertexStarts: [0, 2]
+        startIndices: [0, 2]
       },
       output: [[1, 1, 0, 2, 2, 0], [3, 3, 0]]
     },
@@ -144,9 +144,19 @@ test('getAccessorFromBuffer', t => {
         size: 2,
         stride: 12,
         offset: 12,
-        vertexStarts: [0, 2]
+        startIndices: [0, 2]
       },
       output: [[1, 1, 2, 2], [3, 3]]
+    },
+    {
+      title: 'variable-width buffer nested',
+      input: {
+        value: new Float32Array([1, 1, 0, 2, 2, 0, 3, 3, 0]),
+        size: 3,
+        startIndices: [0, 2],
+        nested: true
+      },
+      output: [[[1, 1, 0], [2, 2, 0]], [[3, 3, 0]]]
     }
   ];