;;-*-Lisp-*-
(in-package goal)

;; name: matrix-h.gc
;; name in dgo: matrix-h
;; dgos: ENGINE, GAME

;; DECOMP BEGINS

;; A 4x4 matrix, stored in row-major order
;; some, but not all, functions assume that a matrix is an affine transform.
;; others assume that the rotation has no scale or shear (and that its inverse is its transpose)
(deftype matrix (structure)
  ((data    float    16)
   (vector  vector   4 :inline :overlay-at (-> data 0))
   (quad    uint128  4         :overlay-at (-> data 0))
   (trans   vector   :inline   :overlay-at (-> data 12))
   )
  (:methods
    (transform-vectors! (_type_ (inline-array vector) (inline-array vector) int) none)
    )
  )

;; A 3x3 matrix, stored in row-major order.
;; NOTE: the rows each have an extra 4-bytes of padding
;;  so this is really a 3x4 matrix.
;; this type is rarely used
(deftype matrix3 (structure)
  ((data    float    12)
   (vector  vector   3 :inline :overlay-at (-> data 0))
   (quad    uint128  3         :overlay-at (-> data 0))
   )
  )

;; a matrix stored using 16-bit integers.
;; note that these usually have different scaling for the 4th row which
;; contains the translation in an affine transform.
;; so you generally should not unpack these to floats without knowing where they came from
;; and how they were originally packed (for example, in tie/shrub)
(deftype matrix4h (structure)
  ((data      int16     16)
   (vector4h  vector4h  4 :inline :overlay-at (-> data 0))
   (long      int64     4         :overlay-at (-> data 0))
   )
  )


(defun matrix-copy! ((arg0 matrix) (arg1 matrix))
  "Copy arg1 to arg0"
  (declare (inline))
  (let ((v1-0 (-> arg1 quad 0))
        (a2-0 (-> arg1 quad 1))
        (a3-0 (-> arg1 quad 2))
        (a1-1 (-> arg1 trans quad))
        )
    (set! (-> arg0 quad 0) v1-0)
    (set! (-> arg0 quad 1) a2-0)
    (set! (-> arg0 quad 2) a3-0)
    (set! (-> arg0 trans quad) a1-1)
    )
  arg0
  )

(defmacro new-stack-matrix0 ()
  "Get a new matrix on the stack that's set to zero."
  `(let ((mat (new 'stack-no-clear 'matrix)))
     (set! (-> mat quad 0) (the-as uint128 0))
     (set! (-> mat quad 1) (the-as uint128 0))
     (set! (-> mat quad 2) (the-as uint128 0))
     (set! (-> mat quad 3) (the-as uint128 0))
     mat
     )
  )