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JamesDeRaja/README.md

James De Raja

Senior Real-Time Performance Engineer

Unity • Rendering • Frame Pacing • XR Optimization

I build deterministic performance systems for real-time applications — focusing on stable frame delivery, GPU/CPU bottleneck isolation, and reproducible profiling workflows.


What I Do

  • Diagnose CPU vs GPU bottlenecks using profiler-backed experiments
  • Design controlled stress environments to reproduce performance issues
  • Optimize rendering pipelines for mobile and XR constraints
  • Maintain stable frame budgets (11ms / 16.6ms) under load
  • Build telemetry-driven systems to monitor runtime health

The goal is simple: consistent frame delivery under real-world stress — not just high FPS in ideal conditions.


Core Approach

Performance problems are not random. They are measurable, reproducible, and isolatable.

My workflow:

  • Establish baseline → apply controlled stress → measure delta
  • Separate CPU vs GPU cost using profiler evidence
  • Eliminate variance before applying optimizations
  • Validate improvements with repeatable scenarios

If it cannot be reproduced, it cannot be fixed reliably.


Featured Work

XR Performance Lab

Deterministic stress framework for analyzing rendering cost in XR.

Focus areas:

  • Stereo rendering overhead
  • Overdraw amplification (200+ transparent layers)
  • MSAA cost scaling
  • Fragment workload vs submission cost

Key finding:

  • Single rendering factor produced +7ms GPU cost under stereo load while CPU remained stable → clear GPU-bound scenario

🔗 https://github.com/JamesDeRaja/XRPerformanceLab


SoftMaskPro – UI Rendering Study

Performance breakdown of Unity UI masking under layered transparency.

Focus areas:

  • Mask pass cost in UI pipelines
  • Overdraw amplification in stacked elements
  • Canvas rebuild CPU impact
  • Tradeoffs between visual fidelity and performance

Result:

  • Clear identification of GPU-heavy UI scenarios caused by layered transparency and masking

🔗 https://github.com/JamesDeRaja/SoftMaskPro-Performance-Study


ECS Performance Improvement Study

Comparison of update architectures under scale.

Variants:

  • A — Per-object Update (baseline)
  • B — Prefab-based Update
  • C — Central Manager
  • D — ECS (DOTS + Burst)

Focus areas:

  • CPU scaling to 10,000+ entities
  • GC elimination
  • Update cost distribution
  • Deterministic simulation control

Outcome:

  • Measurable reduction in CPU overhead and improved scalability with ECS-based systems

🔗 https://github.com/JamesDeRaja/ECS-Performance-Improvement


Engineering Philosophy

Performance is a systems problem.

  • Define budgets in milliseconds, not FPS
  • Measure before optimizing
  • Remove non-determinism
  • Validate under stress, not ideal conditions

Architecture drives performance more than micro-optimizations.


Experience Snapshot

  • 13+ years in real-time systems and Unity development
  • Worked with publishers: Voodoo, Lion Studios, Supersonic
  • Built and optimized systems for hundreds of live game features
  • Improved retention and performance metrics through optimization-driven design

Portfolio & Contact

🌐 https://james.alphaden.club 🔗 https://www.linkedin.com/in/james-de-raja/

Pinned Loading

  1. XRPerformanceLab XRPerformanceLab Public

    Deterministic XR rendering stress framework for isolating GPU bottlenecks, overdraw amplification, and frame-time instability under controlled load.

    ShaderLab

  2. SoftMaskPro-Performance-Study SoftMaskPro-Performance-Study Public

    Unity UI rendering performance study focused on soft masking cost, overdraw amplification, and deterministic CPU/GPU bottleneck isolation using Profiler and Frame Debugger.

    C#

  3. ECS-Performance-Improvement ECS-Performance-Improvement Public

    Unity performance study comparing MonoBehaviour, manager, and ECS update patterns at 10,000+ entities under identical conditions.

    C#

  4. risk-gated-execution-engine risk-gated-execution-engine Public

    Deterministic execution engine with risk gating, telemetry streaming, and state-machine control loop architecture.

    JavaScript