From 5bdb9e405fa035e949a1381c5db8c51e912580b3 Mon Sep 17 00:00:00 2001
From: andyhall <andy@fenomas.com>
Date: Fri, 28 Apr 2023 14:50:28 +0900
Subject: [PATCH] Hopefully avoids more GC churn by giving BJS typed arrays
 (which shouldn't be copied?)

---
 src/lib/terrainMesher.js | 33 ++++++++++++---------------------
 1 file changed, 12 insertions(+), 21 deletions(-)

diff --git a/src/lib/terrainMesher.js b/src/lib/terrainMesher.js
index a04f3d9..fa6d66d 100644
--- a/src/lib/terrainMesher.js
+++ b/src/lib/terrainMesher.js
@@ -594,12 +594,6 @@ var faceDataPool = (() => {
 /** @param {import('../index').Engine} noa  */
 function MeshBuilder(noa, terrainMatManager) {
 
-    var cache_arr_positions = []
-    var cache_arr_normals = []
-    var cache_arr_colors = []
-    var cache_arr_uvs = []
-    var cache_arr_atlasIndexes = []
-
     /** 
      * Consume the intermediate FaceData struct and produce
      * actual mesehes the 3D engine can render
@@ -634,22 +628,14 @@ function MeshBuilder(noa, terrainMatManager) {
             }
 
             // build the necessary arrays
-            var indices = []
-            var positions = cache_arr_positions
-            var normals = cache_arr_normals
-            var colors = cache_arr_colors
-            var uvs = cache_arr_uvs
-            var atlasIndexes = cache_arr_atlasIndexes
-
-            // trim size of reused arrays if needed
             var nf = faceData.numFaces
-            if (positions.length > nf * 12) {
-                positions.length = nf * 12
-                normals.length = nf * 12
-                colors.length = nf * 16
-                uvs.length = nf * 8
-                if (usesAtlas) atlasIndexes.length = nf * 4
-            }
+            var indices = new Uint16Array(nf * 6)
+            var positions = new Float32Array(nf * 12)
+            var normals = new Float32Array(nf * 12)
+            var colors = new Float32Array(nf * 16)
+            var uvs = new Float32Array(nf * 8)
+            var atlasIndexes
+            if (usesAtlas) atlasIndexes = new Float32Array(nf * 4)
 
             // scan all faces in the struct, creating data for each
             for (var f = 0; f < faceData.numFaces; f++) {
@@ -700,6 +686,11 @@ function MeshBuilder(noa, terrainMatManager) {
             var mesh = new Mesh(name, scene)
             var vdat = new VertexData()
 
+            // clobber babylon's bounding internals
+            mesh.doNotSyncBoundingInfo = true
+            mesh._updateBoundingInfo = () => mesh
+            mesh._refreshBoundingInfo = () => mesh
+
             vdat.positions = positions
             vdat.indices = indices
             vdat.normals = normals