​​Navigation Meshes with Recast and Detour
​​Jotting down some notes on this from GSoC discussions before I (Mitchell) forget them.
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​​Classes:
  • ​​NavMeshBuilder - requires recast, returns a NavMesh, a separate builder allows not needing recast at runtime if loading from BAM
  • ​​NavMeshNode - anchor the navmesh in the scene graph (ie. make the position of other things relative to it meaningful), and also to allow us to display a visual representation, the way one can visualize collision nodes
  • ​​NavMesh - stores the navmesh, not sure what else it actually does
  • ​​NavMeshQuery - queries a navmesh and follows Detour’s API (dtNavMeshQuery) (maybe gets merged into either NavMesh or NavMeshNode)
  • ​​Start with find_path() and find_straight_path()
  • ​​Skip sliced pathfinding and Dijkstra functions to start
  • ​​Look into local query options
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​​Options for building a navmesh:
  • ​​Geom
  • ​​Heightfield
  • ​​Collision Mesh
  • ​​EGG
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​​Rough outline of implementation:
  • ​​Review Recast demo for how to build a navigation mesh and Detour demo for how to query a navigation mesh
  • ​​Modify build systems to be able to build against Recast and Detour
  • ​​Includes CMake and makepanda systems
  • ​​These should be as two different libraries/plugins so we don’t have to include Recast in deployed applications
  • ​​NavMeshBuilder and Recast in one Panda library/plugin and NavMesh, NavMeshNode, NavMeshQuery, and Detour in the other
  • ​​Support building a nav mesh from a Geom
  • ​​Need to implement this in a way that can be expanded to other sources later
  • ​​Probably helps to get the NavMeshNode and debug visualization going at this point to be able to visualize the results of nav mesh building
  • ​​Implement NavMeshQuery with support for find_path() and find_straight_path()
  • ​​Support serialization of NavMeshes to/from BAM (this is important to avoid needing to build nav meshes at runtime)
  • ​​Should be usable at this point, collect feedback, fix some bugs, look toward expanding functionality
  • ​​Add more NavMeshBuilder sources (Heightfield may be the next most important source)
  • ​​Add more query options
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