Cache scene node depth

[nongio]

Summary

• cache node depth in SceneNode
• track depth during node insertion and reparenting
• use cached depth to group updates

Testing

• cargo check
• cargo test --no-run (fails: cannot find -lGLESv2)

---

https://chatgpt.com/codex/tasks/task_e_6845603f3e88832db4687866ea8a6971

[github-actions]

Benchmark for 82fe804

Click to view benchmark

Test	Base	PR	%
engine::append/1	47.3±23.27µs	48.0±23.80µs	+1.48%
engine::append/10	47.3±23.14µs	48.0±23.57µs	+1.48%
engine::append/100	47.3±23.25µs	47.9±23.52µs	+1.27%
engine::append/1000	47.5±23.17µs	47.9±23.56µs	+0.84%
engine::remove/1	0.3±0.01ns	0.3±0.01ns	0.00%
engine::remove/10	0.3±0.01ns	0.3±0.00ns	0.00%
engine::remove/100	0.3±0.04ns	0.3±0.04ns	0.00%
engine::remove/1000	995.8±2245.67ns	1906.8±4334.67ns	+91.48%
engine::update/1	27.0±0.93µs	26.9±0.80µs	-0.37%
engine::update/10	88.1±3.02µs	87.9±2.56µs	-0.23%
engine::update/100	267.4±3.60µs	268.1±3.19µs	+0.26%
engine::update/1000	1947.9±128.12µs	1962.3±133.57µs	+0.74%

[github-actions]

Benchmark for b0475bd

Click to view benchmark

Test	Base	PR	%
engine::append/1	47.5±23.31µs	47.7±23.41µs	+0.42%
engine::append/10	47.6±23.33µs	48.0±23.33µs	+0.84%
engine::append/100	47.5±23.27µs	47.9±23.42µs	+0.84%
engine::append/1000	47.7±23.33µs	47.7±23.38µs	0.00%
engine::remove/1	0.3±0.00ns	0.3±0.01ns	0.00%
engine::remove/10	0.3±0.01ns	0.3±0.01ns	0.00%
engine::remove/100	0.3±0.04ns	0.3±0.05ns	0.00%
engine::remove/1000	1010.4±2283.98ns	1024.1±2313.20ns	+1.36%
engine::update/1	26.5±0.77µs	27.1±0.94µs	+2.26%
engine::update/10	87.1±2.25µs	87.9±3.05µs	+0.92%
engine::update/100	266.3±4.07µs	267.8±3.34µs	+0.56%
engine::update/1000	1944.9±126.62µs	1938.0±124.60µs	-0.35%

[github-actions]

Benchmark for 2d71966

Click to view benchmark

Test	Base	PR	%
engine::append/1	47.3±23.07µs	48.9±24.11µs	+3.38%
engine::append/10	47.5±23.26µs	48.7±23.78µs	+2.53%
engine::append/100	47.3±23.23µs	49.0±24.04µs	+3.59%
engine::append/1000	47.8±23.19µs	48.8±23.96µs	+2.09%
engine::remove/1	0.3±0.01ns	0.3±0.00ns	0.00%
engine::remove/10	0.3±0.00ns	0.3±0.01ns	0.00%
engine::remove/100	0.3±0.04ns	0.3±0.04ns	0.00%
engine::remove/1000	1007.9±2274.63ns	1031.1±2341.40ns	+2.30%
engine::update/1	26.4±0.93µs	26.7±1.01µs	+1.14%
engine::update/10	85.9±3.41µs	89.0±3.30µs	+3.61%
engine::update/100	266.3±3.41µs	269.6±4.69µs	+1.24%
engine::update/1000	1950.4±137.45µs	1937.4±123.18µs	-0.67%