Background and Architectural Context

How GDevelop Executes Logic

GDevelop compiles event sheets into JavaScript under the hood. Every frame, conditions are evaluated, and actions are executed when conditions are met. As event complexity grows, especially with nested structures, evaluation costs can spike dramatically, impacting framerates.

Enterprise-Scale Considerations

In large commercial projects, multiple contributors may work on the same scenes and event sheets. Without enforced architectural patterns, duplication and unused logic accumulate. Combined with unoptimized assets (large textures, unused sounds), the result is exponential growth in runtime and build size.

Root Cause Analysis

Common Triggers

  • Duplicated events across multiple scenes instead of shared external events
  • Global variables with excessive scope checks in every scene
  • Large, uncompressed textures or sounds loaded at startup
  • Physics and pathfinding behaviors applied unnecessarily to many objects
  • Complex collision checks on every frame

Architectural Implications

Poorly optimized events and assets create runtime CPU and GPU bottlenecks. On mobile and web builds, these bottlenecks manifest as frame drops, input lag, and battery drain, reducing user retention and harming reviews.

Diagnostics

Profiling Event Performance

Use GDevelop's built-in Profiler (Debug Mode) to measure event execution time per frame. Identify events consuming the highest milliseconds and prioritize refactoring those first.

# Steps
1. Launch Preview with Debug Mode.
2. Open Profiler tab.
3. Sort by execution time.
4. Note top event groups and their average frame cost.

Asset Audit

Review the Resources panel for unused assets. Use external tools (e.g., TexturePacker, Audacity) to optimize formats and compress sizes without visible/audio quality loss.

Scene Complexity Check

Count object instances per scene and remove off-screen or unused ones. For large maps, use object groups and spawn/despawn logic instead of loading all at once.

Pitfalls in Troubleshooting

One pitfall is over-optimizing early and breaking functional logic. Another is replacing visual assets with lower quality ones without user experience testing, which can hurt perceived quality. Avoid profiling on powerful desktop hardware alone—issues often emerge only on low-end devices.

Step-by-Step Fixes

1. Modularize with External Events and Functions

Refactor repeated event blocks into external events or functions. This reduces duplication and centralizes logic for easier optimization.

# Example: Replacing duplicated player input events
Create External Event: handlePlayerInput
Link external event in all scenes with player character

2. Optimize Collision Checks

Restrict collision conditions to relevant object groups and run them less frequently (e.g., every few frames instead of every frame).

// Use a timer variable to space out checks
Conditions: timer > 0.1 seconds
Actions: check collisions, reset timer

3. Manage Asset Loading

Lazy-load large textures or sounds only when needed. Split assets across scenes to avoid loading everything at startup.

4. Reduce Behavior Overhead

Remove unused behaviors from objects. Physics and pathfinding calculations are expensive when applied at scale.

5. Texture and Audio Compression

Use compressed formats (WebP for images, OGG for audio) and power-of-two texture dimensions for GPU efficiency.

Best Practices for Long-Term Stability

  • Enforce coding patterns for event reuse
  • Set asset size and format guidelines in project documentation
  • Regularly run profiler on mid-to-low hardware targets
  • Integrate version control to manage scene and event changes
  • Maintain a cleanup checklist for unused assets and events

Conclusion

GDevelop's accessibility makes it easy to start but also easy to accumulate inefficiencies in large projects. By profiling regularly, modularizing logic, optimizing asset usage, and following architectural discipline, senior developers and leads can ensure stable performance across all platforms, protecting both user experience and delivery timelines.

FAQs

1. How often should I run the GDevelop profiler?

In active development, run it at least once per major feature addition, and always before beta or release builds.

2. Can too many external events slow down performance?

Not inherently—performance depends on event complexity, not the number of external events. Modularization usually improves maintainability and optimization potential.

3. What's the best image format for mobile builds?

WebP is recommended for its high compression ratio and quality balance. Ensure fallback formats for platforms that lack full WebP support.

4. How can I debug performance issues specific to exported builds?

Export in debug mode with logs enabled, or wrap exported builds in browser DevTools for web targets and platform profiling tools for native targets.

5. Are object groups better for performance?

Yes, grouping reduces redundant conditions and makes collision checks more efficient by limiting scope to relevant objects.