Difference between revisions of "AROT (MREA Section)"
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Octrees are a form of [[wikipedia:Binary Space Partitioning|BSP tree]] that subdivide an area in 3-dimensions. | Octrees are a form of [[wikipedia:Binary Space Partitioning|BSP tree]] that subdivide an area in 3-dimensions. | ||
They are structured recursively, starting with a ''root'' node and traversing their way to individual ''leaf'' nodes. | They are structured recursively, starting with a ''root'' node and traversing their way to individual ''leaf'' nodes. | ||
| − | A | + | A full-branch octant will split sub-octants across 3-tiers, one for each dimension of euclidean space. |
=== Header === | === Header === | ||
Revision as of 05:01, 10 April 2015
File:Octree2.svg
Left: Recursive subdivision of a cube into octants. Right: The corresponding octree.
Within MREA resources, the AROT section stores an octree which is used to accelerate rendering of areas in back-to-front order.
Octrees are a form of BSP tree that subdivide an area in 3-dimensions. They are structured recursively, starting with a root node and traversing their way to individual leaf nodes. A full-branch octant will split sub-octants across 3-tiers, one for each dimension of euclidean space.
Header
| Offset | Size | Data Type | Description | Notes |
|---|---|---|---|---|
| 0x0 | 4 | long | Magic | AROT
|
| 0x4 | 4 | long | Version | Always 0x1 |
| 0x8 | 4 | long | Mesh-Bitmap Count | Count of mesh-bitmaps |
| 0xC | 4 | long | Mesh-Bitmap Bit-Count | Count of bits in each mesh-bitmap (matches MREA's mesh count) |
| 0x10 | 4 | long | Node Count | Number of octant nodes |
| 0x14 | 24 | float2x3 | AABB | AABB that fully-encloses area and serves as the octree's root-shape |
