Adminotech - Implement Ogre Instancing

[jonnenauha]

Implements Ogre instancing support for Tundra in EC_Mesh and OgreWorld.

Implemented now

• New useInstancing attribute for EC_Mesh.
  • Handles toggling instancing on/off during runtime.
  • No other visible changes to external code, except OgreEntity() may return null if instancing is used. Created new OgreInstancedEntity() for these situations. I've checked all core c++ code that nothing blindly uses the OgreEntity() ptr.
  • EC_Placeable attaching and EC_Mesh node transform keep working just like before instancing.
• OgreWorld implements CreateInstance() and DestroyInstances() functions that must be used by eg. EC_Mesh in pair to keep OgreWorld internal state in sync.
  • Implements automatically injecting VS and PS programs into the input materials if they are not already defined. This logic will not modify the existing material but clone it and put changes there, so non instanced meshes can use the material at the same time. It will also replace shaders if there already are existing shaders, in this case it will prints a helpful warning log line that tells the author what we should do to fix the situation.
  • Implements visual debugging on instance batch bounding boxes (utilizes an existing Ogre feature) via IsDebugInstancingEnabled() and SetDebugInstancingEnabled(enabled) and a qt property (just like PhysicsWorld does).
  • Enables script logic to define static instancing for a particular mesh ref via IsInstancingStatic(meshRef) and SetInstancingStatic(meshRef, static). This can make the rendering dramatically faster in cases where the instances are not moved. This must be decided by a inworld script, it is too bug prone to automate in OgreWorld. If you know a) you have huge amount of instances b) you are not going to move them via EC_Mesh transform or EC_Placeacble, either for scripts or via clients, you should go ahead and set static to true.
• Example scene bin/scenes/Instancing/scene.txml
  • Test instanced and non-instanced runs with your own instance row/column count.
  • UI can toggle static/non-static intancing.
  • UI can toggle instancing debugging.

Needs work!?

• Test all kinds of input materials and how they will behave. Also test multi submesh meshes.
• Integrate instancing VS part to Tundra super shader?
• EC_Highlight wont work on instanced entities as their submesh materials cannot be replaced that easily. We might need to make a instanced version of the highlight material and apply that. Afaik EC_Highlight calls SetMaterial that does currently nothing for instanced meshes, and it would probably be a bit slow to destroy the current material ones and recreate with "hightlight" material.

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I've sent this pull request in good time so people have time to review it before merging talk becomes relevant. Any feedback on the code in general and API in OgreWorld would be appreciated!

[jonnenauha]

https://github.com/Adminotech/tundra/commit/b3f72500e7f828f4e2f495bc5d1aaacab823bc04 Makes a bit of overhaul to my OgreWorld internals. Fixes things with multiple submeshes and should speed up DestroyInstance() a bit, less things to loop around.

Hopefully this will get cleanly merged to lasses work that is making all (most at least) our super shaders available for instancing, which is a super exiting feature for artists! My thing was kind of restricted demo phase in terms of shaders :)

[cadaver]

Multi-submesh support looks solid now. Draw distance & draw shadows settings are not being used in instanced entities though.

[jonnenauha]

https://github.com/realXtend/naali/pull/680/files#L13R966 Hmm, I did implement and even test it by selecting a bunch of ents in the instancing test scene, setting their draw distance to 10 and they dissapeared. Came back when a high enough distance was used, or set to 0. It should sync that in both creation and any time the attribute changes.

[cadaver]

Sorry, when retesting, draw distance worked correctly. Shadow casting is only changeable per instance batch, so it is now locked on.

[jonnenauha]

Thanks @cadaver for the quick work and great job on cloning the super shaders with instancing support! This is huge plus for maintainability of the super shader.