feat(soa): update SOAAttribSpec.buf to use ArrayBuffer w/ opt offset

- update aos() buffer handling - update SOA.initSpecs() - update tests
thi-ng · Oct 18, 2019 · 2759570 · 2759570
1 parent 21c1ef6
commit 2759570
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Showing 4 changed files with 18 additions and 13 deletions.
diff --git a/packages/soa/src/aos.ts b/packages/soa/src/aos.ts
@@ -64,12 +64,8 @@ export const aos = <K extends string>(
         const spec = soaSpecs[id];
         const tsize = SIZEOF[spec.type!];
         spec.stride = total / tsize;
-        spec.buf = typedArray(
-            spec.type!,
-            buf,
-            byteOffset + offsets[id],
-            (num * total - offsets[id]) / tsize
-        );
+        spec.buf = buf;
+        spec.byteOffset = byteOffset + offsets[id];
     }
     return new SOA<K>(num, soaSpecs);
 };
diff --git a/packages/soa/src/api.ts b/packages/soa/src/api.ts
@@ -21,7 +21,12 @@ export interface SOAAttribSpec extends AOSAttribSpec {
     /**
      * Optional user supplied backing buffer.
      */
-    buf: TypedArray;
+    buf: ArrayBuffer;
+    /**
+     * Optional start offset for mapped region in backing buffer. Only
+     * used if `buf` is given.
+     */
+    byteOffset: number;
     /**
      * Number of indices between each SOA value.
      * MUST be >= size

diff --git a/packages/soa/src/soa.ts b/packages/soa/src/soa.ts
@@ -165,7 +165,9 @@ export class SOA<K extends string> implements ILength {
             const spec = prepareSpec(specs[id]);
             this.validateSpec(id, spec);
             const { stride, default: defVal } = spec;
-            const buffer = spec.buf || typedArray(spec.type!, num * stride!);
+            const buffer = spec.buf
+                ? typedArray(spec.type!, spec.buf, spec.byteOffset || 0)
+                : typedArray(spec.type!, num * stride!);
             if (defVal) {
                 for (let i = 0; i < num; i++) {
                     buffer.set(defVal, i * stride!);
@@ -180,8 +182,9 @@ export class SOA<K extends string> implements ILength {
         assert(spec.stride! >= spec.size!, `${id} illegal stride`);
         assert(
             !spec.buf ||
-                spec.buf.length >=
-                    (this.length - 1) * spec.stride! + spec.size!,
+                spec.buf.byteLength >=
+                    ((this.length - 1) * spec.stride! + spec.size!) *
+                        SIZEOF[spec.type!],
             `${id} buffer too small`
         );
         assert(

diff --git a/packages/soa/test/aos.ts b/packages/soa/test/aos.ts
@@ -19,12 +19,13 @@ describe("aos", () => {
             struct.buffers.a.buffer === struct.buffers.b.buffer &&
                 struct.buffers.b.buffer === struct.buffers.c.buffer
         );
-        assert.equal(struct.buffers.a.byteOffset, 0x100);
-        assert.equal(struct.buffers.b.byteOffset, 0x104);
-        assert.equal(struct.buffers.c.byteOffset, 0x10c);
         assert.equal(struct.specs.a.stride, 8);
         assert.equal(struct.specs.b.stride, 4);
         assert.equal(struct.specs.c.stride, 16);
+        assert.equal(struct.buffers.a.byteOffset, 0x100);
+        assert.equal(struct.buffers.b.byteOffset, 0x104);
+        assert.equal(struct.buffers.c.byteOffset, 0x10c);
+        assert.equal(struct.buffers.a.buffer.byteLength, 0x100 + 0x20);
         struct.setValues({
             a: [[0x1001], [0x2002]],
             b: [[1, 2], [3, 4]],