Indiana Jones: 24% Faster Path Tracing

What happened

MachineGames and NVIDIA cut GPU time on the main path-tracing pass in Indiana Jones and the Great Circle by 24%. They shrank ray-tracing live state from 222 to 84 bytes per thread by removing one redundant loop and demoting a float4 to half4, guided by Nsight GPU Trace and Shader Execution Reordering.

Why it worked

• Measurement came first: GPU trace data pointed at live state as the bottleneck.
• The fix was small and targeted, not a rewrite.
• Lower precision was used only where it did not show on screen.

What we'd take into a client project

• Profile with a GPU trace tool before optimising; guesses about shader cost are often wrong.
• Check register pressure and live state in heavy shaders, not only instruction counts.
• Keep before and after captures for every optimisation so gains can be checked after later changes.

Related

• Game development services
• Pixel Streaming case study
• DOOM: The Dark Ages path tracing

Note: Feative Studios was not involved in this project. This breakdown summarises what the developers have shared publicly; the takeaways are our own.