fixed when low fps cannot play particle #19013

zhefengzhang · 2025-09-16T08:59:37Z

Re: https://github.com/cocos/3d-tasks/issues/19127

当粒子系统的播放时间与粒子可存活的总时间相差小于一帧时，允许在当前帧尝试播放粒子，避免游戏低帧率时粒子系统因为卡顿错过了可用于播放粒子的帧。
When the playback time of the particle system differs from the total survival time of the particles by less than one frame, it is allowed to attempt to play the particles in the current frame to prevent the particle system from missing the frames available for playing the particles due to lag when the game has a low frame rate.

此修改同时解决了以下类似情况的粒子播放问题:

设定可播放粒子时间为 2 s ，每秒播放粒子数量为 3，粒子存活时间为 1 s。在此设定下粒子只发射了 5 次。（当需要发射最后一个粒子时因为粒子剩余可播放时间不足一帧的间隔时间，所以无法发射）

This modification also resolves the particle playback issues in the following similar scenarios:

Set the playable particle time to 2 s, the number of particles played per second to 3, and the particle survival time to 1 s. Under this setting, particles were only emitted 5 times. (When the last particle needed to be emitted, it could not be emitted because the remaining playable time of the particle was less than the interval time of one frame.)

zhefengzhang · 2025-09-16T09:06:56Z

@cocos-robot run-test-cases-custom

github-actions · 2025-09-16T09:16:21Z

Code Size Check Report

Wechat (WASM)	Before	After	Diff
2D Empty (legacy pipeline)	1009805 bytes	1009805 bytes	✅ 0 bytes
2D All (legacy pipeline)	2675364 bytes	2675364 bytes	✅ 0 bytes
2D All (new pipeline)	2767100 bytes	2767100 bytes	✅ 0 bytes
(2D + 3D) All	10024070 bytes	10024098 bytes	⚠️ +28 bytes

Web (WASM + ASMJS)	Before	After	Diff
(2D + 3D) All	16843132 bytes	16843160 bytes	⚠️ +28 bytes

Interface Check Report

This pull request does not change any public interfaces !

star-e · 2025-09-17T02:41:01Z

@cocos-robot run test cases

zhefengzhang · 2025-09-22T01:56:02Z

@cocos-robot run test cases

star-e · 2025-09-23T07:13:49Z

@cocos-robot run test cases

zhefengzhang · 2025-09-24T06:55:04Z

@star-e

zhefengzhang · 2025-09-24T06:55:13Z

@cocos-robot run test cases

zhefengzhang · 2025-10-21T01:16:26Z

@cocos-robot run test cases

zhefengzhang · 2025-10-21T02:13:40Z

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sushanhong · 2025-10-22T09:22:30Z

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sushanhong · 2025-10-23T01:51:59Z

@cocos-robot run test cases

star-e · 2025-10-23T08:16:18Z

@cocos-robot run test cases

sushanhong · 2025-10-23T08:54:55Z

@cocos-robot run test cases

github-actions · 2025-10-23T10:21:09Z

@zhefengzhang, Please check the result of run test cases:

Test Platform: PR-Test
Editor Version: v3.8.8
Task Result: FAIL
Task URL: https://cctest.cocos.org/#/reportview/PR-TEST/cf634154-10b3-4f32-859a-fb7457939191/-1
GitHub Action: https://github.com/cocos/cocos-engine/actions/runs/18743023553

Task Details

Platform	build	boot	runned	FailScene
web-mobile	PASS	PASS	FAIL	particle-compare,particles-noise-test
ios	PASS	PASS	FAIL	particle-compare,particles-noise-test
mac	PASS	PASS	FAIL	particle-compare,particles-noise-test

github-actions · 2025-10-23T10:21:10Z

@zhefengzhang, Please check the result of run test cases:

Test Platform: PR-Test
Editor Version: v3.8.8
Task Result: FAIL
Task URL: https://cctest.cocos.org/#/reportview/PR-TEST/a03bb1f5-25b6-41e2-a186-ea0a193a0f73/-1
GitHub Action: https://github.com/cocos/cocos-engine/actions/runs/18743023553

Task Details

Platform	build	boot	runned	FailScene
windows	PASS	PASS	FAIL	particle-compare,particles-noise-test
android	PASS	PASS	FAIL	particle-compare,particles-noise-test
wechatgame	PASS	PASS	FAIL	particle-compare,particles-noise-test

zhefengzhang · 2025-10-24T01:39:10Z

@cocos-robot run test cases

zhefengzhang · 2025-10-24T06:15:58Z

@cocos-robot run test cases

sushanhong · 2025-10-24T07:51:33Z

@cocos-robot run test cases

zhefengzhang · 2025-10-24T09:39:11Z

@cocos-robot run test cases

zhefengzhang · 2025-10-27T02:08:08Z

@cocos-robot run test cases

github-actions · 2025-10-27T03:34:11Z

@zhefengzhang, Please check the result of run test cases:

Test Platform: PR-Test
Editor Version: v3.8.8
Task Result: FAIL
Task URL: https://cctest.cocos.org/#/reportview/PR-TEST/e75c8f32-06e8-457c-9cba-ba0837800b92/-1
GitHub Action: https://github.com/cocos/cocos-engine/actions/runs/18827579465

Task Details

Platform	build	boot	runned	FailScene
web-mobile	PASS	PASS	FAIL	particle-compare,particles-noise-test
ios	PASS	PASS	FAIL	particle-compare,particles-noise-test
mac	PASS	PASS	FAIL	particle-compare,particles-noise-test

github-actions · 2025-10-27T03:34:12Z

@zhefengzhang, Please check the result of run test cases:

Test Platform: PR-Test
Editor Version: v3.8.8
Task Result: FAIL
Task URL: https://cctest.cocos.org/#/reportview/PR-TEST/96a53a54-b6c9-4b4b-bca9-b670635b4a6a/-1
GitHub Action: https://github.com/cocos/cocos-engine/actions/runs/18827579465

Task Details

Platform	build	boot	runned	FailScene
windows	PASS	PASS	FAIL	particle-compare,particles-noise-test
android	PASS	PASS	FAIL	particle-compare,particles-noise-test
wechatgame	PASS	PASS	FAIL	particle-compare,particles-noise-test

zhefengzhang · 2025-10-27T09:11:41Z

@cocos-robot run test cases

zhefengzhang · 2025-10-27T09:12:38Z

cocos/particle/particle-system.ts

            // bursts
-            for (const burst of self.bursts) {
-                burst.update(self, dt);
+            if (timeLeft <= 0) {


对于 burst 中使用固定频率发射的粒子使用原来的逻辑

zhefengzhang · 2025-10-27T09:14:43Z

cocos/particle/particle-system.ts

        if (self._time > startDelay) {
-            if (self._time > (self.duration + startDelay)) {
+            const timeLeft = self._time - (self.duration + startDelay);
+            if (timeLeft > dt) {


对于粒子系统已激活时间减去粒子可活动时间与延迟播放时间之后剩余的时间不足一帧的，允许播放一次粒子。

zhefengzhang · 2025-10-27T10:39:05Z

@cocos-robot run test cases

zhefengzhang · 2025-10-28T01:23:40Z

@cocos-robot run test cases

github-actions · 2025-10-28T02:48:13Z

@zhefengzhang, Please check the result of run test cases:

Test Platform: PR-Test
Editor Version: v3.8.8
Task Result: FAIL
Task URL: https://cctest.cocos.org/#/reportview/PR-TEST/feb28e97-e863-460d-96a9-63b90e54141e/-1
GitHub Action: https://github.com/cocos/cocos-engine/actions/runs/18861038293

Task Details

Platform	build	boot	runned	FailScene
web-mobile	PASS	PASS	FAIL	particle-color,particle-compare,particle-size,particle-trail,
ios	PASS	PASS	FAIL	particle-color,particle-compare,particle-size,particle-trail
mac	PASS	PASS	FAIL	particle-color,particle-compare,particle-size,particle-trail

github-actions · 2025-10-28T02:48:14Z

@zhefengzhang, Please check the result of run test cases:

Test Platform: PR-Test
Editor Version: v3.8.8
Task Result: FAIL
Task URL: https://cctest.cocos.org/#/reportview/PR-TEST/94a4e616-590f-4b00-8d8c-86259f8b70ed/-1
GitHub Action: https://github.com/cocos/cocos-engine/actions/runs/18861038293

Task Details

Platform	build	boot	runned	FailScene
windows	PASS	PASS	FAIL	particle-color,particle-compare,particle-size,particle-trail
android	PASS	PASS	FAIL	particle-color,particle-compare,particle-size,particle-trail
wechatgame	PASS	PASS	FAIL	particle-color,particle-compare,particle-size,particle-trail

zhefengzhang · 2025-10-28T06:41:41Z

@cocos-robot run test cases

zhefengzhang · 2025-10-28T08:08:45Z

@cocos-robot run test cases

zhefengzhang · 2025-10-28T08:20:14Z

@cocos-robot run test cases

zhefengzhang · 2025-10-28T09:26:02Z

@cocos-robot run test cases

github-actions · 2025-10-28T11:00:03Z

@zhefengzhang, Please check the result of run test cases:

Test Platform: PR-Test
Editor Version: v3.8.8
Task Result: PASS
Task URL: https://cctest.cocos.org/#/reportview/PR-TEST/9bd92bc0-ca44-4591-9dfa-703804217ac0/-1
GitHub Action: https://github.com/cocos/cocos-engine/actions/runs/18868437983

Task Details

github-actions · 2025-10-28T11:00:04Z

@zhefengzhang, Please check the result of run test cases:

Test Platform: PR-Test
Editor Version: v3.8.8
Task Result: FAIL
Task URL: https://cctest.cocos.org/#/reportview/PR-TEST/542a8845-f97d-4827-bf63-3b2dffbf2416/-1
GitHub Action: https://github.com/cocos/cocos-engine/actions/runs/18868437983

Task Details

Platform	build	boot	runned	FailScene
windows	PASS	PASS	FAIL	particle-compare
android	PASS	PASS	PASS
wechatgame	PASS	PASS	PASS

github-actions · 2025-10-28T12:25:21Z

@zhefengzhang, Please check the result of run test cases:

Test Platform: PR-Test
Editor Version: v3.8.8
Task Result: PASS
Task URL: https://cctest.cocos.org/#/reportview/PR-TEST/852e6343-c611-40d2-8ee0-97338a5c12bd/-1
GitHub Action: https://github.com/cocos/cocos-engine/actions/runs/18870098729

Task Details

github-actions · 2025-10-28T12:25:22Z

@zhefengzhang, Please check the result of run test cases:

Test Platform: PR-Test
Editor Version: v3.8.8
Task Result: PASS
Task URL: https://cctest.cocos.org/#/reportview/PR-TEST/9e5f1683-9e8f-4651-9085-c0db8e4fabe1/-1
GitHub Action: https://github.com/cocos/cocos-engine/actions/runs/18870098729

Task Details

zhefengzhang · 2025-10-29T01:58:16Z

cocos/particle/particle-system.ts

            // bursts
-            for (const burst of self.bursts) {
-                burst.update(self, dt);
+            if (timeLeft <= 0 || self.loop) {


对于在 burst 中配置发射频率进行播放的粒子，使用原本的逻辑

fixed when low fps cannot play particle

cc51506

star-e self-requested a review September 17, 2025 02:38

star-e approved these changes Sep 17, 2025

View reviewed changes

Update particle-system.ts

9316e67

zhefengzhang commented Oct 27, 2025

View reviewed changes

Update particle-system.ts

bb7009a

zhefengzhang commented Oct 29, 2025

View reviewed changes

star-e approved these changes Oct 29, 2025

View reviewed changes

star-e merged commit 8c944a9 into cocos:v3.8.8 Oct 29, 2025
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fixed when low fps cannot play particle #19013

fixed when low fps cannot play particle #19013

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