```module Data.Glome.Box (box) where
import Data.Glome.Vec
import Data.Glome.Solid

-- Simple, axis-aligned bounding box defined with two points at opposing corners.

data Box = Box !Bbox deriving Show

box :: Vec -> Vec -> SolidItem
box (Vec x1 y1 z1) (Vec x2 y2 z2) =
SolidItem (Box (Bbox (Vec (fmin x1 x2) (fmin y1 y2) (fmin z1 z2))
(Vec (fmax x1 x2) (fmax y1 y2) (fmax z1 z2))))

-- this could be optimized a bit more
rayint_box :: Box -> Ray -> Flt -> Texture -> Rayint
rayint_box (Box (Bbox (Vec p1x p1y p1z) (Vec p2x p2y p2z))) r@(Ray orig@(Vec ox oy oz) dir@(Vec dx dy dz)) d t =
let dxrcp = 1/dx
dyrcp = 1/dy
dzrcp = 1/dz
Interval inx outx = if dx > 0
then Interval ((p1x-ox)*dxrcp) ((p2x-ox)*dxrcp)
else Interval ((p2x-ox)*dxrcp) ((p1x-ox)*dxrcp)
Interval iny outy = if dy > 0
then Interval ((p1y-oy)*dyrcp) ((p2y-oy)*dyrcp)
else Interval ((p2y-oy)*dyrcp) ((p1y-oy)*dyrcp)
Interval inz outz = if dz > 0
then Interval ((p1z-oz)*dzrcp) ((p2z-oz)*dzrcp)
else Interval ((p2z-oz)*dzrcp) ((p1z-oz)*dzrcp)
lastin   = (fmax3 inx iny inz)
firstout = (fmin3 outx outy outz)
in if lastin > firstout || firstout < 0 || lastin > d
then RayMiss
else
let n = if inx == lastin
then if dx > 0 then nvx else vx
else if iny == lastin
then if dy > 0 then nvy else vy
else if dz > 0 then nvz else vz
norm = if lastin > 0 then n else vinvert n
hitdepth = fmax 0 lastin
in
RayHit hitdepth (vscaleadd orig dir hitdepth) norm t

shadow_box :: Box -> Ray -> Flt -> Bool
shadow_box (Box box) r d =
let Interval near far = bbclip r box
in
if (near > far) || far <= 0 || far > d
then False
else True

inside_box :: Box -> Vec -> Bool
inside_box (Box (Bbox (Vec x1 y1 z1) (Vec x2 y2 z2))) (Vec x y z) =
x > x1 && x < x2 &&
y > y1 && y < y2 &&
z > z1 && z < z2

bound_box :: Box -> Bbox
bound_box (Box box) = box

instance Solid Box where
rayint = rayint_box