| I had a chance to ship the first Tower Defense game for iOS. The OS X game I was porting had some crippling performance problems that were incredibly hard to track down. The problem was two-fold: 1. The relevant tools (Unity3D) were extremely immature and the problem was quite diffuse. No profiler, poor quality of generated code, tiny caches, etc. 2. A problem in string-handling code that was quite diffuse throughout the game. As near as I can tell, it was blowing out the tiny CPU cache hundreds of times per frame. On desktop, this code was a complete non-issue. On the puny little ARM on the iPhone? It was the difference between having dozens of towers and 50 enemies in play vs half a dozen towers and less than a dozen enemies in play. The impact on game dynamics, and need to re-balance everything by itself would add weeks to the shipping schedule. There were plenty of other things that needed to be scaled WAY back of course: Switching from 3D to 2D to get vertex count and draw call count down. Completely rebuilding the entire UI. Revamping the pathfinding and suffix caching to not play havoc with the CPU cache. Moving from a 24x24 grid to a 12x12 grid. All of that combined helped a LOT, but not nearly enough. The string manipulation was for a hierarchical property system that let me parameterize all sorts of attributes for enemies/spells/towers/projectiles in a set of text files. Ultimately, I had over-engineered on the assumption that I would be tweaking many more things -- with much greater frequency -- than I wound up actually tweaking. Had I ripped most of it out and just had local properties on each prefab that I assigned manually, I might've hit that market opportunity. Finding that that was the cause was a multi-month project because of how interwoven it was with everything else. Hell, it would've been fine, had a not over-generalized it into a shared component on each prefab that the other components inquired with to get property values. But I did. And it took me vastly too long to identify it was the major problem it was. Opportunity missed, and that was the final nail in the coffin for my fledgling game studio. |