Engine Architecture Overview

Multithreaded ECS Pipeline

AnKi employs a job-based execution model with a heavily multithreaded ECS system. While this architecture ensures high scalability, debugging race conditions and synchronization issues becomes complex without robust tracing.

Vulkan-First Rendering Pipeline

Its Vulkan backend introduces low-level control and performance benefits, but also demands precise resource lifecycle management. Improper sync primitives or descriptor mismanagement often result in GPU crashes or undefined behavior.

Common Enterprise-Level Issues

1. GPU Memory Leaks and Resource Starvation

Large-scale asset streaming (e.g., high-res textures, instancing) can silently exhaust GPU memory. AnKi's allocator system may not immediately reflect leaks, requiring external validation tools.

// GPU crash on frame N
[Vulkan] vkAllocateMemory failed: VK_ERROR_OUT_OF_DEVICE_MEMORY

2. Pipeline Barrier Misuse

Improper synchronization between compute and graphics queues may cause rendering glitches, especially during GBuffer generation or shadow mapping phases.

3. Asset Import and Loader Stalls

Large GLTF or FBX assets processed via AnKi's pipeline may fail silently due to incorrect scene graph hierarchy or malformed data in skeletal animation rigs.

4. Untracked Descriptor Set Overwrites

Improperly updating dynamic uniform buffers without syncing frame indices leads to flickering, garbage data, or shader binding errors.

Diagnostics and Debugging Strategy

1. Use Vulkan Validation Layers

Enable all Vulkan validation layers to catch resource misuse:

VK_INSTANCE_LAYERS=VK_LAYER_KHRONOS_validation ./AnKi

2. Memory Profiling with RenderDoc and Nsight

Visualize buffer lifetime, pipeline usage, and overdraw hotspots using external profilers.

3. Log and Trace Job Graphs

Enable internal job graph debug logs to trace ECS execution order and thread workload distribution. Look for job starvation or deadlocks:

[JobSystem] Warning: Job graph node 'GBufferPass' delayed due to barrier sync

Step-by-Step Fixes

1. Implement Descriptor Set Versioning

Introduce per-frame descriptor versioning to avoid race conditions in uniform updates.

if (descriptor.version != currentFrame) {
  updateDescriptor(descriptor);
  descriptor.version = currentFrame;
}

2. Split Resource Upload Queues

Dedicate queues for streaming and rendering. Use semaphores to explicitly sync:

vkQueueSubmit(streamingQueue, ...);
vkQueueWaitIdle(streamingQueue);

3. Normalize Asset Importers

Patch import pipeline to validate skeleton nodes, ensure consistent up-axis conversion, and re-bake normals where necessary.

4. Modularize Render Graph

Break monolithic render passes into modular nodes with explicit barriers. This improves readability and debugging surface.

5. Enhance Thread Debugging

Integrate thread tracing macros inside core jobs to track execution and contention:

ANKI_TRACE_START("ShadowPass");
// work
ANKI_TRACE_END();

Best Practices for Large Projects

• Use offline baking for lights, probes, and reflection captures
• Prefer immutable GPU buffers for static geometry
• Batch material switches to reduce pipeline state churn
• Adopt asset tagging to enable selective LOD and memory budgeting
• Enforce per-frame memory recycling to avoid leaks

Conclusion

AnKi Engine's powerful, low-level design unlocks unmatched control but demands strict discipline in memory, synchronization, and asset workflows. Troubleshooting issues such as descriptor overwrites, GPU memory starvation, or import failures requires a structured diagnostic approach and an understanding of Vulkan intricacies. By modularizing the render graph, enforcing ECS synchronization rules, and validating every asset path, teams can build stable and high-performance 3D applications using AnKi.

FAQs

1. Why does AnKi crash after loading large scenes?

Likely due to GPU memory exhaustion or stale descriptor sets. Profile memory usage with RenderDoc or Vulkan info layers.

2. How do I debug flickering in shadow maps?

This usually stems from unflushed barriers or inconsistent depth formats. Review render pass transitions and descriptor bindings.

3. Can I use AnKi for VR development?

Yes, but expect to customize stereo rendering paths. Low latency sync and fixed foveated rendering are not built-in.

4. How do I trace ECS performance bottlenecks?

Enable job graph tracing and correlate ECS job durations with system loads. Use custom job markers to isolate slow nodes.

5. Is AnKi production-ready for commercial games?

It's stable and powerful but lacks tooling and documentation found in Unity or Unreal. Suitable for advanced teams with graphics programming expertise.