;;-*-Lisp-*-
(in-package goal)
(bundles "ENGINE.CGO" "GAME.CGO")
(require "engine/draw/drawable-inline-array-h.gc")

;; DECOMP BEGINS

;; A "draw-node" is a way to group together a bunch of drawables (possibly other draw-nodes) in a BVH
;; This BVH is used for sphere-in-view culling and the broad phase collision detection.
;; _most_ uses of draw-node are in a special tree with these properties:
;; - between 1 and 8 roots.
;; - each child has between 1 and 8 children
;; - all leaves are stored at the same depth
;; - all nodes and leaves have visibility IDs

;; shrub does not have these properties - it supports arbitrary children counts, leaves
;; may occur at any depth, and nothing has visibility ids.

(deftype draw-node (drawable)
  ((child-count uint8 :offset 6)
   (flags       uint8 :offset 7)
   (child       drawable :offset 8)
   (distance    float :offset 12)))

;; for non-shrub uses of draw-node, this is used to store all the draw-nodes at a given depth.
(deftype drawable-inline-array-node (drawable-inline-array)
  ((data draw-node 1 :inline)
   (pad  uint32)))

;; the types of these fields are a guess for now.
;; used for draw-node-cull function
(deftype draw-node-dma (structure)
  ((banka draw-node 32 :inline)
   (bankb draw-node 32 :inline)))
