GTA:SA Streaming Garbage Collection

The GTA:SA Streaming Garbage Collection system monitors the usage of game memory. It maintains the streaming memory limit for the entire game engine. Streaming memory is calculated by adding up the resource file chunk size of every loaded game resource. When the limit is reached, the system will attempt to free space by destroying resources from game instances. If this process fails, the game engine will hang (by design). This limit can be adjusted by setting the video memory setting in your MTA video settings.

Active Streaming Entities

Full potencial of GTA:SA streaming.

Objects, buildings and dummies that have their RenderWare resources loaded are added into the active entity garbage collector. Once it runs, it will destroy the RenderWare objects of all registered entities that are out of sight and far away. If the model reference count has reached 0, the system will free the model resource. Natively, the engine can handle 1000 entities in its sorted container (CRenderChainInterface <streamingChainInfo>). If allocation of a container node fails, the requesting entity does destroy its RenderWare data. Hence, natively, only 1000 objects, buildings or dummies can be rendered at a time. The failure to allocate container nodes has often been seen at high draw distances (a.k.a. the blinking building bug).

The MTA developer ccw is the person who first found the blinking building bug.

Implementation differences between MTA versions

MTA:BLUE

The draw distance bug has been decimated in MTA:BLUE. The maximum number of managed streaming entities has been increased to 2500 to compensate for large drawing distances. That increases the engine performance a lot, as more streaming memory can be allocated by game entities.

MTA:Eir

In MTA:Eir, the drawing distance bug has been fixed, too. While the hardcoded maximum has been left at 1000 entities inside of the garbage collection system, when the limit has been reached, the system allocates new nodes into the sorted container. There is theoretically no limit to object, dummy and building streaming this way.

Multiple options have been added through scripting functions to change the streaming node allocation behavior. The flickering is no longer a bug, but a feature that can be disabled. Using scripting functions Lua scripts can retrieve the amount of nodes allocated and free to be allocated.

References

• http://gtaforums.com/topic/573478-iiivcsa-project-2dfx/page-25 - pioneers of draw distance fixing