godotengine/godot

GPUParticles2D `finished` signal isn't affected by `speed_scale`

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#119675 opened on May 22, 2026

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buggood first issueneeds testingtopic:particles

Description

Tested versions

v4.7.beta1.official [1c8cc9e7e]

System information

Godot v4.7.beta1 - Windows 10 (build 19045) - Multi-window, 2 monitors - Direct3D 12 (Forward+) - dedicated NVIDIA GeForce GTX 1060 6GB (NVIDIA; 32.0.15.8157) - AMD Ryzen 7 2700X Eight-Core Processor (16 threads) - 15.94 Gio memory - WASAPI (48000 Hz, Stereo/mono)

Issue description

Changing the speed_scale of a GPUParticles2D doesn't affect the timing of the finished signal. So, if the speed_scale is set to 0.5, the signal will be emitted in the middle of the effect.

I don't know if this is intentional behavior, and I imagine it's complicated to track the speed_scale in real time. I'm wondering if the initial speed_scale could be used when calculating the duration?

Steps to reproduce

N/A

Minimal reproduction project (MRP)

particle-finished-signal.zip

Contributor guide

Tech stack
cpp
Domain
developer experience
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Godot node system basicssignal connectionsGPU particles
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50
Research direction
Investigate the implementation of the 'finished' signal in GPUParticles2D. The issue reports that changing speed scale does not affect the signal timing, suggesting that the initial speed scale could be used. Look at the source code in gpu particles 2d.cpp (or similar) to understand how the signal is emitted and how speed scale influences particle lifetime. Consider checking the engine's documentation or any related PRs.