feat: LOD 网格分级——meshopt 解析期简化 + 按距离/级联选级

vendored meshoptimizer 1.2（submodule 环境故障改直接 vendor）。Mesh 多 LOD：各级索引连续拼进同一 index buffer（共享顶点，LodRange 区间选择），解析期 meshopt_simplify 生成链（LOD0=原始，每级目标减半，相对误差 1e-2，小网格复用上级）；都在 worker 线程，加载零额外卡顿。 SceneRenderer 按 (mesh, LOD) 聚合 batch（lookup key = 指针<<8|lod）：主视图按屏占比近似 radius/dist 选级（阈值 10/20 倍半径）；阴影级联按级联序降级（越远越简）。Draw 按 batch.lod 选索引区间。 A/B 对比（100 背包 10×10，RTX 5060 Laptop，vsync off）： - 纯背包：LOD 开 93-95 fps / 关 90-107 fps —— 无显著差异 - 加 SunTemple：LOD 开 52-56 / 关 51-55 —— 无显著差异结论：当前场景瓶颈不在顶点数（5060 顶点吞吐富余），LOD 基础设施保留（几何复杂资产/低端 GPU/更大场景生效），帧率问题转向 Tracy GPU 时间线定位真实瓶颈。坑：LodRange 记录"LOD 不足复用最后一级"时 first 不得继续累加（buffer 无重复数据，累加必越界——VUID-08798 抓的）。
2026-09-24 20:53:19 +08:00
parent 34b593f734
commit 5bdfb53566
125 changed files with 67608 additions and 29 deletions
@@ -0,0 +1,69 @@
+// This file is part of meshoptimizer library and is distributed under the terms of MIT License.
+// Copyright (C) 2016-2026, by Arseny Kapoulkine (arseny.kapoulkine@gmail.com)
+
+export class Bounds {
+	centerX: number;
+	centerY: number;
+	centerZ: number;
+	radius: number;
+	coneApexX: number;
+	coneApexY: number;
+	coneApexZ: number;
+	coneAxisX: number;
+	coneAxisY: number;
+	coneAxisZ: number;
+	coneCutoff: number;
+}
+
+export class MeshletBuffers {
+	meshlets: Uint32Array;
+	vertices: Uint32Array;
+	triangles: Uint8Array;
+	meshletCount: number;
+}
+
+export class Meshlet {
+	vertices: Uint32Array;
+	triangles: Uint8Array;
+}
+
+export const MeshoptClusterizer: {
+	supported: boolean;
+	ready: Promise<void>;
+
+	buildMeshlets: (
+		indices: Uint32Array,
+		vertex_positions: Float32Array,
+		vertex_positions_stride: number,
+		max_vertices: number,
+		max_triangles: number,
+		cone_weight?: number
+	) => MeshletBuffers;
+
+	buildMeshletsFlex: (
+		indices: Uint32Array,
+		vertex_positions: Float32Array,
+		vertex_positions_stride: number,
+		max_vertices: number,
+		min_triangles: number,
+		max_triangles: number,
+		cone_weight?: number,
+		split_factor?: number
+	) => MeshletBuffers;
+
+	buildMeshletsSpatial: (
+		indices: Uint32Array,
+		vertex_positions: Float32Array,
+		vertex_positions_stride: number,
+		max_vertices: number,
+		min_triangles: number,
+		max_triangles: number,
+		fill_weight?: number
+	) => MeshletBuffers;
+
+	extractMeshlet: (buffers: MeshletBuffers, index: number) => Meshlet;
+
+	computeClusterBounds: (indices: Uint32Array, vertex_positions: Float32Array, vertex_positions_stride: number) => Bounds;
+	computeMeshletBounds: (buffers: MeshletBuffers, vertex_positions: Float32Array, vertex_positions_stride: number) => Bounds[];
+	computeSphereBounds: (positions: Float32Array, positions_stride: number, radii?: Float32Array, radii_stride?: number) => Bounds;
+};