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The problem is in CStaticMulti::UpdateRenderModel. CStaticMulti is the class for seed-combined entities. I haven't followed the path all the way through to find out exactly how the heap corruption comes about, but the problem arises because of the re-use of a render model pointer for a newly-constructed combined model, which was probably done to avoid an allocation. When the native game code changes a model, it always calls gameRenderWorld->FreeEntityDef, and uses a fresh pointer for a different model. There are parts of the engine code that *rely* on hModel pointers always pointing to the same model, for example idRenderWorldLocal::UpdateEntityDef which compares the old and the new hModel pointers for an entity when deciding whether it can leave decals in place. The renderer's model code does look like you *should* be able to construct a new model using an existing pointer in this way, because it provides an InitEmpty() method that clears the surfaces of the model. But in the native code only dynamic models use that method, not statics, and for dynamic models there's no concept of consistency from frame to frame. Changing the code to clear the entity def and use a newly allocated pointer for the new model stops the problem. That's also what the (non-buggy) LOD code does. |
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At rev 6511 /trunk/game/StaticMulti.cpp /trunk/game/StaticMulti.h |
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Nice catch. |
- Anonymous
