Paid For With Blood
The Starwind lock-on implementation is useful because its history shows performance maturity in layers.
An early fix, commit f90baec, corrected a bug where the lock-on texture resource was effectively recreated continuously because the cached value and compared value used different representations.
That is a valid micro-level fix: stop rebuilding a resource whose configuration did not change.
But the larger targeting system still had a much more expensive layer: geometry and engine queries.
By the later T4rg3t5 implementation, commit de85472b was explicitly a major refactor to minimize raycasts and runtime operations.
From the St4sh
The T4rg3t5 targeting API is the public surface. The lock-on manager source is the implementation worth studying: target state, camera work, and presentation are not the same operation.
It changed the shape of the work rather than polishing one Lua expression.
Among other things, the refactor:
- stopped evaluating both shoulder-camera candidates unconditionally;
- checked the current side first and only evaluated the alternate side when needed;
- compared squared distances where normalization/length was unnecessary;
- removed redundant vector normalization before angle calculations;
- cached marker visibility as ordinary state instead of rereading UI layout state;
- avoided UI updates when visibility did not change.
What changed in the engineering question
The early question was:
Why are we recreating this texture?
The later question was:
Why are we asking the engine all of these geometry questions every frame?
Both are correct questions at different stages.
The second usually matters more.
The rule
When profiling engine-bound code, rank work by semantic cost, not by how complicated the Lua expression looks.
A table lookup may look busy and cost almost nothing beside:
- a raycast;
- a bounding-box query;
- a world/object scan;
- a UI rebuild;
- a binding that constructs temporary userdata.
Optimize the layer the profiler says is expensive.
See Engine Boundaries, Hot Paths, and Every Frame Is a Budget, Not an Invitation.