From 8aa84c8c51caac0beaa483cb19b3cc089009c537 Mon Sep 17 00:00:00 2001
From: Don McCurdy <dm@donmccurdy.com>
Date: Fri, 11 Oct 2024 17:04:12 -0400
Subject: [PATCH] feat(extensions,functions): Allow encoding meshopt-compressed
 float32 accessors

---
 packages/cli/src/cli.ts                       |  6 ++---
 .../src/ext-meshopt-compression/constants.ts  |  1 +
 .../src/ext-meshopt-compression/encoder.ts    |  6 +++++
 .../meshopt-compression.ts                    |  6 ++++-
 packages/functions/src/meshopt.ts             | 26 +++++++++----------
 5 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/packages/cli/src/cli.ts b/packages/cli/src/cli.ts
index b0f0b552e..a87438416 100755
--- a/packages/cli/src/cli.ts
+++ b/packages/cli/src/cli.ts
@@ -254,7 +254,7 @@ commands or using the scripting API.
 		default: INSTANCE_DEFAULTS.min,
 	})
 	.option('--meshopt-level <level>', 'Meshopt compression level.', {
-		validator: ['medium', 'high'],
+		validator: ['low', 'medium', 'high'],
 		default: 'high',
 	})
 	.option('--palette <bool>', 'Creates palette textures and merges materials.', {
@@ -344,7 +344,7 @@ commands or using the scripting API.
 		const opts = options as {
 			instance: boolean;
 			instanceMin: number;
-			meshoptLevel: 'medium' | 'high';
+			meshoptLevel: 'low' | 'medium' | 'high';
 			palette: boolean;
 			paletteMin: number;
 			simplify: boolean;
@@ -859,7 +859,7 @@ ${underline('References')}
 	.argument('<input>', INPUT_DESC)
 	.argument('<output>', OUTPUT_DESC)
 	.option('--level <level>', 'Compression level.', {
-		validator: ['medium', 'high'],
+		validator: ['low', 'medium', 'high'],
 		default: 'high',
 	})
 	.option('--quantize-position <bits>', 'Precision for POSITION attributes.', {
diff --git a/packages/extensions/src/ext-meshopt-compression/constants.ts b/packages/extensions/src/ext-meshopt-compression/constants.ts
index 4f5b69536..e41146600 100644
--- a/packages/extensions/src/ext-meshopt-compression/constants.ts
+++ b/packages/extensions/src/ext-meshopt-compression/constants.ts
@@ -1,5 +1,6 @@
 import type { GLTF, TypedArray } from '@gltf-transform/core';
 
+/** @deprecated Use 'filter' boolean instead. */
 export enum EncoderMethod {
 	QUANTIZE = 'quantize',
 	FILTER = 'filter',
diff --git a/packages/extensions/src/ext-meshopt-compression/encoder.ts b/packages/extensions/src/ext-meshopt-compression/encoder.ts
index b7641dae4..f46074acd 100644
--- a/packages/extensions/src/ext-meshopt-compression/encoder.ts
+++ b/packages/extensions/src/ext-meshopt-compression/encoder.ts
@@ -139,6 +139,12 @@ export function getMeshoptFilter(accessor: Accessor, doc: Document): { filter: M
 		.listParentEdges(accessor)
 		.filter((edge) => !(edge.getParent() instanceof Root));
 
+	// If filtering is enabled but the attribute is not quantized, do not filter,
+	// which would change the attribute's component type.
+	if (accessor.getComponentSize() > 2) {
+		return { filter: MeshoptFilter.NONE };
+	}
+
 	for (const ref of refs) {
 		const refName = ref.getName();
 		const refKey = (ref.getAttributes().key || '') as string;
diff --git a/packages/extensions/src/ext-meshopt-compression/meshopt-compression.ts b/packages/extensions/src/ext-meshopt-compression/meshopt-compression.ts
index ddaa776a3..cb8067e47 100644
--- a/packages/extensions/src/ext-meshopt-compression/meshopt-compression.ts
+++ b/packages/extensions/src/ext-meshopt-compression/meshopt-compression.ts
@@ -19,10 +19,14 @@ import type { MeshoptEncoder, MeshoptDecoder } from 'meshoptimizer';
 const NAME = EXT_MESHOPT_COMPRESSION;
 
 interface EncoderOptions {
+	/** Whether to use meshopt filters, for more aggressive compression. Overrides 'method'. */
+	filter?: boolean;
+	/** @deprecated Use 'filter' instead. */
 	method?: EncoderMethod;
 }
 
 const DEFAULT_ENCODER_OPTIONS: Required<EncoderOptions> = {
+	filter: false,
 	method: EncoderMethod.QUANTIZE,
 };
 
@@ -313,7 +317,7 @@ export class EXTMeshoptCompression extends Extension {
 			const parentID = context.accessorUsageGroupedByParent.has(usage) ? getParentID(accessor) : null;
 			const mode = getMeshoptMode(accessor, usage);
 			const filter =
-				options.method === EncoderMethod.FILTER
+				(options.filter || options.method === EncoderMethod.FILTER)
 					? getMeshoptFilter(accessor, this.document)
 					: { filter: MeshoptFilter.NONE };
 			const preparedAccessor = prepareAccessor(accessor, encoder, mode, filter);
diff --git a/packages/functions/src/meshopt.ts b/packages/functions/src/meshopt.ts
index 9077603e8..b13497fbf 100644
--- a/packages/functions/src/meshopt.ts
+++ b/packages/functions/src/meshopt.ts
@@ -7,7 +7,7 @@ import { assignDefaults, createTransform } from './utils.js';
 
 export interface MeshoptOptions extends Omit<QuantizeOptions, 'pattern' | 'patternTargets'> {
 	encoder: unknown;
-	level?: 'medium' | 'high';
+	level?: 'low' | 'medium' | 'high';
 }
 
 export const MESHOPT_DEFAULTS: Required<Omit<MeshoptOptions, 'encoder'>> = {
@@ -78,22 +78,22 @@ export function meshopt(_options: MeshoptOptions): Transform {
 				encoder: encoder,
 				target: 'size',
 			}),
-			quantize({
-				...options,
-				pattern,
-				patternTargets,
-				quantizeNormal,
-			}),
 		);
 
+		if (options.level !== 'low') {
+			await document.transform(
+				quantize({
+					...options,
+					pattern,
+					patternTargets,
+					quantizeNormal,
+				}),
+			);
+		}
+
 		document
 			.createExtension(EXTMeshoptCompression)
 			.setRequired(true)
-			.setEncoderOptions({
-				method:
-					options.level === 'medium'
-						? EXTMeshoptCompression.EncoderMethod.QUANTIZE
-						: EXTMeshoptCompression.EncoderMethod.FILTER,
-			});
+			.setEncoderOptions({filter: options.level === 'high'});
 	});
 }