OBD:OTLF: Difference between revisions

:An octtree leaf (OTLF) stores its size and position and the gunk quads that intersect it. The first field contains an index/count pair that is used to access the first [[OBD:IDXA|IDXA]] field that is stored in the [[OBD:AKOT|AKOT]] that owns this leaf. This [[OBD:IDXA|IDXA]] contains the gunk quad numbers that intersect the leaf. In theory there can be at most 4096 gunk quads that intersect a leaf but in practice this number is much lower (max is 462). In addition the threshold limit used to build the octree seems to be 19 gunk quads per leaf. I.e., in Oni's levels, only the smallest leaves (with size 16x16x16) have more than 19 quads; larger leaves containing 20 and more quads are subdivided into "other, smaller boxes".

:If the 8192x8192x8192 environment is subdivided into 16x16x16 cubes in all three directions, the total number of leaves is 512x512x512 = 134,217,728. Theoretically the data structures allow for a densely packed level where each 16x16x16 volume has some quads inside it (theoretically up to 4096, i.e., a maximum of 549,755,813,888 quads per level!). In practice, the engine imposes much more modest limitations:

:*only up to 8192 environment triangles are expected to be ''visible'' (rendered) at any given time (they can be packed as 4096 quads, or as 8192 actual triangles, or any combination of tris and quads). If you attempt to view more geometry at once, Oni will ''not'' crash, but: it will complain with the dev-console message "Exceeded max visible GQs #", where # is the number of ''triangles'' in excess of 8192; it will start dropping random triangles from the rendering pipeline; collision will start to fail on the "dropped" triangles. The amount of other visible geometry (characters, particles etc) does not affect this limit.