Optimizing Spine Animations for Qt/QML Mobile Game – Performance Issues & APK

mimi001

I'm currently integrating Spine animations into a 2D mobile game developed with Qt/QML (Qt Quick), targeting Android devices. I’ve exported the character rigs and animations using the official Spine runtime for Qt, and everything looks great — but I’m running into some issues on real devices.

Key Issues I'm Facing:

FPS drops when multiple Spine characters are on screen, especially during fast transitions or when animations overlap.
Memory usage spikes when switching scenes or reloading skeletons dynamically.
Animation blending sometimes stutters, even though timelines are separated cleanly.

I’ve followed the optimization tips from the Spine docs (e.g., atlas packing, skeleton caching), but it still feels heavy on mid-range Android devices.

Questions:

Is there a preferred way to reuse Spine skeleton instances across multiple QML scenes without reloading them from JSON every time?
Should I consider moving to native OpenGL rendering instead of Qt’s SceneGraph for better animation performance?
Any tips from devs who have used Spine in real-world mobile games and faced similar bottlenecks?

This project is a side passion of mine and I’d love to polish it further for release. If anyone's curious to try the demo APK, just let me know happy to share a link.

Thanks a lot in advance, and I really appreciate this awesome community!

Spinebot

To reuse Spine skeleton instances across multiple QML scenes without reloading them from JSON every time, you can consider caching the skeleton data in memory. This way, you can instantiate new skeletons from the cached data rather than reloading from JSON, which can help reduce memory usage spikes and improve performance.
Moving to native OpenGL rendering could potentially improve animation performance, especially if you are experiencing bottlenecks with Qt’s SceneGraph. OpenGL allows for more direct control over rendering, which can be optimized for specific use cases like Spine animations. However, this approach requires more in-depth knowledge of OpenGL and may increase the complexity of your project.
Developers who have used Spine in real-world mobile games often emphasize the importance of profiling to identify specific bottlenecks. Ensure that you are using a texture atlas to minimize texture binds and reduce draw calls. Additionally, consider simplifying your skeletons and animations where possible, and ensure that you are not overusing bones or vertices. Profiling tools can help you pinpoint whether CPU usage, fill rate, or draw calls are the main issues, allowing you to focus your optimization efforts effectively.

Mario

We do not have an official Qt/QML runtime. Could you point me to what you are using?