What does OOP stand for? When Object Oriented Programming(OOP) is taught so extensively, do computer programmers, specifically within games development, realise what it's possibly doing to productivity and performance? I explain my own view from experience in personal projects and professional work. This talk was given to the Edinburgh meet of IGDA Scotland, on 2011/07/27.

1. Object Oriented Programming What does OOP stand for? Colin Riley @domipheus

8. So what can OOP stand for? O OP O bfuscates P roductivity OOP

11. WTF

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26. More examples I retweeted a talk that Jonathan Blow of Braid fame gave to Berkeleys compsci group. He mentioned that he now does pretty much everything in simple flat arrays, no complicated data structures.

29. Need a system for handling the states of your things?

30. That does not mean you need a massive component system that is scalable and can handle any matter of things and things v2.0 and things v3.0

45. How do we get the data up to the code?

50. So what can OOP stand for? O OP O bliterates P erformance OOP (in high data throughput cases, which there are many in games) is basically

52. struct Details { int numShots; int numDeaths; int numTargets; int lifetime; int state; int priority; int health; int ammo; int friendThings[4]; }; // 48 bytes class Thing { Vector3 mPosition; Quat mOrientation; Colour mColour; Vector3 mVelocity; float mDecay; Details mDetails; }; // 96 bytes

53. OOP ish class ThingSystem { String mName; std::vector<Thing> mThings; .... }; void Thing :: UpdatePosition () { mPosition += mVelocity; mVelocity *= mDecay; } void ThingSystem :: UpdateThingPositions () { for( vector <int>:: iterator iter = mThings. begin (); iter != mThings. end (); iter++) { *iter. UpdatePosition (); } }

55. OOP fits 4 things.

57. Not great is it?

60. DOD ish class ThingSystem { Vector3 mThingPosition[MAX_THINGS]; Quat mThingOrientation[MAX_THINGS]; Colour mThingColour[MAX_THINGS]; Vector3 mThingVelocity[MAX_THINGS]; float mThingDecay[MAX_THINGS]; Details mThingDetails[MAX_THINGS]; int mNumThings; .... }; void ThingSystem :: UpdateThingPositions () { for(int i = 0; i< mNumThings; i++) { mThingPosition[i] += mThingVelocity[i]; mThingVelocity[i] *= mThingDecay[i]; } }

62. DOD fits 16 things.

64. So what keeps the OOP version lower on the performance scale?

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