From 1d1cfaa34c2705bcabc33be0cde63241ca4de33d Mon Sep 17 00:00:00 2001
From: wangzhihao <492187276@qq.com>
Date: Thu, 6 Aug 2026 15:03:43 +0800
Subject: [PATCH] fix(particle): handle floating-point precision in burst
 triggers

Particle Burst determines whether the current frame crosses a trigger point using floating-point time. Account for precision errors during the comparison.

Reference: https://forum.cocos.org/t/topic/176928
---
 cocos/particle/burst.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/cocos/particle/burst.ts b/cocos/particle/burst.ts
index 3148a9e1c25..581cc9d83fe 100644
--- a/cocos/particle/burst.ts
+++ b/cocos/particle/burst.ts
@@ -23,7 +23,7 @@
 */
 
 import { ccclass, type, serializable, editable, range } from 'cc.decorator';
-import { repeat } from '../core/math';
+import { EPSILON, repeat } from '../core/math';
 import CurveRange from './animator/curve-range';
 import type { ParticleSystem } from './particle-system';
 
@@ -108,7 +108,7 @@ export default class Burst {
             let preFrameTime = repeat(psys.time - psys.startDelay.evaluate(0, 1), psys.duration) - dt;
             preFrameTime = (preFrameTime > 0.0) ? preFrameTime : 0.0;
             const curFrameTime = repeat(psys.time - psys.startDelay.evaluate(0, 1), psys.duration);
-            if (this._curTime >= preFrameTime && this._curTime < curFrameTime) {
+            if (this._curTime >= preFrameTime - EPSILON && this._curTime < curFrameTime) {
                 psys.emit(this.count.evaluate(this._curTime / psys.duration, 1), dt - (curFrameTime - this._curTime));
                 this._curTime += this.repeatInterval;
                 --this._remainingCount;