From e1452f9bdeadbed0ea7e15c2c48b577e36538b8e Mon Sep 17 00:00:00 2001
From: lealzhan <lealzhan@126.com>
Date: Tue, 19 Sep 2023 15:05:57 +0800
Subject: [PATCH] xx

---
 cocos/physics/utils/util.ts | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/cocos/physics/utils/util.ts b/cocos/physics/utils/util.ts
index ead93adcf0e..cd2c5c6c661 100644
--- a/cocos/physics/utils/util.ts
+++ b/cocos/physics/utils/util.ts
@@ -22,7 +22,7 @@
  THE SOFTWARE.
 */
 
-import { equals, Vec3, IVec3Like } from '../../core';
+import { equals, Vec3, IVec3Like, murmurhash2_32_gc } from '../../core';
 import { CharacterController, CharacterTriggerEventType, Collider, CollisionEventType, IContactEquation, TriggerEventType } from '../framework';
 
 export { cylinder } from '../../primitive';
@@ -69,23 +69,21 @@ export const CollisionEventObject = {
 
 export function shrinkPositions (buffer: Float32Array | number[]): number[] {
     const pos: number[] = [];
+    const posHashMap = {};
     if (buffer.length >= 3) {
-        // eslint-disable-next-line no-unused-expressions
-        pos[0] = buffer[0], pos[1] = buffer[1], pos[2] = buffer[2];
+        pos[0] = buffer[0];
+        pos[1] = buffer[1];
+        pos[2] = buffer[2];
         const len = buffer.length;
         for (let i = 3; i < len; i += 3) {
             const p0 = buffer[i];
             const p1 = buffer[i + 1];
             const p2 = buffer[i + 2];
-            const len2 = pos.length;
-            let isNew = true;
-            for (let j = 0; j < len2; j += 3) {
-                if (equals(p0, pos[j]) && equals(p1, pos[j + 1]) && equals(p2, pos[j + 2])) {
-                    isNew = false;
-                    break;
-                }
-            }
-            if (isNew) {
+            const str = String(p0) +  String(p1) + String(p2);
+            //todo: directly use buffer as input
+            const hash = murmurhash2_32_gc(str, 666);
+            if (posHashMap[hash] !== str) {
+                posHashMap[hash] = str;
                 pos.push(p0); pos.push(p1); pos.push(p2);
             }
         }