These changes seem to yield better results for the larger maps. The improvements are minimal however. This change is probably more noticable on tile cache.
In recastnavigation/recastnavigation@15ebb8bd25 the change was made to use detail polygons, but it appears that after this change, the bounding volume gets build under the polygons, especially if the polygons's Z are equal on all vertices. Flooring the mins and ceiling the maxs appears to yield correct behavior in all scenarios by making sure the bounding volume always encases its respective polygon.
Reverse engineered the last types that were mostly unused and unneeded by the navmesh. But to properly implement the destructor it had to go in. Cells and hints now get freed as well and we can now rely on our own destructor for the navmesh data allocated by the game.
If an off-mesh connection has a base link, but no land link, there will be an invalid link as we never process there. These links must be removed. Due to this change, the link flagging had to be moved to a separate loop as we would otherwise store the dead link in the file (it won't cause a crash as it has been unlinked, but there is no reason it should be stored). Also improved the detection of external off-mesh connections landing on our current tile, instead of doing a position lookup just decode the polyref and check if the index equals our current tile.
External references were never updated. Especially when the tile we process doesn't own an off-mesh connection, but does have one landing on it. After this patch, the navmesh passes all tests in game and all polygons appear to be remapped correctly when using all features of the Detour NavMesh (single step verification). Also no issues reported from address sanitizer after several tests on extremely large and complicated navmeshes.
- Off-mesh connections should always be linked to target poly's first. Also set the linked flag on titanfall navmeshes as this is necessary during the pruning stage.
- When connecting off-mesh links, we need to iterate over tiles using m_maxTiles, not m_tileCount as m_tileCount counts the number of added tiles, while m_maxTiles contains the maximum tiles in the lookup array, there can be empties in between.
- Radians to degrees and visa versa has been moved to a simple inline function, but during this, a regression was made where it was accidentally inverted in dtCalcOffMeshRefYaw and dtCalcOffMeshRefPos.
- rdCalcSubEdgeArea2D could return false when tmin > tmax, which prevents the link from being established, but tmin can be larger than tmax when the detail edge equals the main edge. The issue we wanted to prevent where the triangle had an inverted winding order has been fixed in commit 1e48d8abd9e604a384e65cf633b62f4e11737d35.
- In dtNavMesh::connectTraverseLinks, the extraneous dot product check has been removed; this is now handled by the user installed dtTraverseLinkConnectParams::getTraverseType and dtTraverseLinkConnectParams::getTraverseType.
- In dtNavMesh::connectTraverseLinks, when we ran out of links in the land tile, we would still continue the traversal of all its detail edges and polygons. We now break out of all loops to move on to the next tile as we can not establish any traverse link when there are no free ones available.
In commit a2d5d52dc4e571388b9b86f21e40a5110a69665e, the logic has been adjusted to build the polygon in the right order in the algorithm itself, but some indices are incorrect causing bad tesselation. The issue is somewhere in RecastMesh.cpp, writing polygon indices in the incorrect order '0, 3, 2, 1' instead of '3, 2, 1, 0'. Reverted to using "REVERSE_DIRECTION 0" for RecastMesh.cpp.
Additional notes, tesselation appears correct when building the mesh with the layered partitioner, monotone and watershed causes bad tesselation. The vertex order is however still incorrect.
Flood-fill assign instead to make sure all polygon islands are mapped to a contiguous range of group id's on the first pass. This is required as we will otherwise reach the DT_MAX_POLY_GROUP_COUNT limit on complex and large geometry before the prune pass while we don't have DT_MAX_POLY_GROUP_COUNT polygon islands inside the navmesh. Also implemented poly group overflow protection and simplified the API.
Polyrefs may become invalid as we remove dead polygons and reindex the remainders. If the polyref is invalid, skip the link as it will be thrown out anyways. Issue was found using address sanitizer on level mp_rr_desertlands_64k_x_64k.
The algorithm goes over each polygon in the tile and only keeps polygons and associated data if they don't originate from an unlinked polygon island (DT_UNLINKED_POLY_GROUP). The algorithm also drops all data associated to the polygons such as the detail meshes, cells, links, verts and detail (if not used by other polygons), off-mesh links that are dead (not having the DT_POLYFLAGS_JUMP_LINKED flag), and rebuilds the BVTree.
This algorithm reduced the file size of a navmesh generated for the map mp_rr_desertlands_64k_x_64k by over 50% (209mb to 97mb) while keeping it functionally identical.
Some additional updates that were required to make this work:
* dtCalcTraverseTableSize now return NULL if there are 2 or less polygroups.
* unionTraverseLinkedPolyGroups will not run if parameters instruct it to collapse groups, it will also not run if the disjoint set doesn't contain any poly groups.
* dtCreateTraverseTableData will not allocate traverse tables if there are 2 or less polygroups, as dtCalcTraverseTableSize will now always return 0 in this case. This is an enforcement of an optimization from the engine itself as there is no point in allocating and doing lookups on a table with only 2 groups (unlinked and linked), and linked will always be reachable and unlinked can't be reached in the first place.
The reason why the BVTree's appeared under the polygon was because we were rendering and calculating them incorrectly. After fixing this, they now appeared above the polygons. This offset is not necessary as it causes BVTree's to build incorrectly.
dtNavMesh::getTileCount returns the total number of added tiles, the issue with this is that if the navmesh gets pruned, that means disabling unlinked polygons and removing dead tiles, then some tile instances in the m_tiles array may become empty. Less tiles will be installed and since there are null tiles in between, we won't be traversing each tile.
Allows for parsing zipline positions from BSP entity partitions and placing them whilst also having it clamp the positions correctly to the polygon the zipliner will end up or start from.
Similar to the intersection test for cylindric volumes. The old convex hull intersection test in the raycast algorithm is inaccurate and also doesn't calculate the hit time, which prevents the editor from placing the cursor at the intersection. Raycast algorithm is pending a refactor and its convex hull isect test will be replaced with this.
'rdIntersectSegmentCylinder' is a new function that will be used for intersection tests on cylindric clip volumes.
'rdIntersectSegmentAABB' was already present in the library, but used and reimplemented across multiple source files (pending deduplication).
Instead of a box query, just take the position in the tile grid the land-side off-mesh vert is on. This vastly improves the query reliability for off-mesh links with a larger radius to the point it never fails if it is in a valid location. The box query isn't needed here as the off-mesh vert has to be on a tile, else the polygon box query will fail (unless its bounding box does happen to overlap with the point, but in this case the off-mesh connection is placed improperly causing the only factor to have its link established being luck).
