An Example of Code Optimization for Performance

I went through some old documents and found a some notes I wrote while optimizing a renderer written in AS3/Flash. I thought I'd post it here to show how performance optimizations usually proceed: Each one usually only raises the number of frames per second by a few percent, and none doubles it, but after 10 rounds of that the code is more than twice as fast.

Change and cumulative change in frames per second after each optimization. "RC" means a test with Release Configuration, for these tests all profiling and other instrumentation are turned off.
Note	Frames	ms	fps	Change	Index
Start	451	3002	150	-	100
Batch transform of vertices in `transformToScreen`	476	3005	158	5%	105
Better intersection code reusing vectors	547	3005	182	14%	121
Caching shared transformed vertices when generating subdivision face	614	3003	204	12%	136
Don't recalculate transform matrices unnecessarily. Some optimizations in `transformToScreen`	674	3002	224	9%	149
Better polygons / plane clipping	695	3003	231	3%	154
Inhibit event firing when there are no listeners	999	3002	332	43%	221
RC 1	1228	3002	409
Switch to using NumberBuffers	1200	3036	395	18%	263
RC 2	1550	3040	509
Precomputed index buffers	1250	3046	410	3%	273
Iterate with `NumberBuffer.next()`	1200	3004	399	-2%	265
RC 3	1600	3079	519

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