;============================================================
;   iron_obj.hsp — Wavefront OBJ ローダ (pure HSP)
;
;   Wavefront .obj を読み込み、頂点配列 / 法線配列 / UV 配列 /
;   三角形インデックス配列に展開する。
;
;   対応する構文:
;     v x y z           頂点座標
;     vn nx ny nz       法線
;     vt u v            テクスチャ UV
;     f v1 v2 v3 ...    多角形面 (三角扇で自動分割)
;     f v1/t1/n1 ...    v/t/n の組、t n は省略可
;     f v1//n1 ...      UV なし
;     g / o / s         無視 (構造のみ認識)
;     # ...             コメント
;
;   対応外: 曲面 / NURBS / mtl 本体パース (ファイル名の記憶のみ)
;
;   API:
;     obj_load "file.obj", var_verts, var_norms, var_uvs, var_tris,
;              var n_verts, var n_norms, var n_uvs, var n_tris
;          verts: double[3 * n_verts]  (x, y, z * n_verts)
;          norms: double[3 * n_norms]
;          uvs:   double[2 * n_uvs]
;          tris:  int[9 * n_tris]  (v1, t1, n1, v2, t2, n2, v3, t3, n3)
;                 0-based index、欠落は -1。
;          戻り値: 0=OK / <0=エラー
;
;   制限: 初期容量は verts=65536 / norms=65536 / uvs=65536 / tris=131072。
;         これを超えるモデルは別途 OBJ_MAX_* マクロで拡大するか split する。
;============================================================
#ifndef __iron_obj_hsp__
#define __iron_obj_hsp__

#ifndef OBJ_MAX_VERTS
#define OBJ_MAX_VERTS 65536
#endif
#ifndef OBJ_MAX_NORMS
#define OBJ_MAX_NORMS 65536
#endif
#ifndef OBJ_MAX_UVS
#define OBJ_MAX_UVS 65536
#endif
#ifndef OBJ_MAX_TRIS
#define OBJ_MAX_TRIS 131072
#endif

#module iron_obj

#deffunc obj_load str path, var v_verts, var v_norms, var v_uvs, var v_tris, \
	var v_nv, var v_nn, var v_nu, var v_nt, \
	local _size, local _buf, local _p, local _eol, local _line, \
	local _space, local _tag, local _rest, \
	local _x, local _y, local _z, local _u, local _uv_v, \
	local _n_verts, local _n_norms, local _n_uvs, local _n_tris, \
	local _face_toks, local _face_n, local _face_i, \
	local _i_v, local _i_t, local _i_n
	exist path
	_size = strsize
	if _size <= 0 : return -1
	sdim _buf, _size + 16
	bload path, _buf, _size
	ddim v_verts, OBJ_MAX_VERTS * 3
	ddim v_norms, OBJ_MAX_NORMS * 3
	ddim v_uvs,   OBJ_MAX_UVS   * 2
	dim  v_tris,  OBJ_MAX_TRIS  * 9
	_n_verts = 0 : _n_norms = 0 : _n_uvs = 0 : _n_tris = 0
	_p = 0
	repeat
		if _p >= _size : break
		_eol = instr(_buf, _p, "\n")
		if _eol < 0 {
			_line = strmid(_buf, _p, _size - _p) : _p = _size
		} else {
			_line = strmid(_buf, _p, _eol - _p) : _p = _eol + 1
		}
		if strlen(_line) > 0 {
			if peek(_line, strlen(_line) - 1) = 13 : _line = strmid(_line, 0, strlen(_line) - 1)
		}
		if strlen(_line) = 0 : continue
		if peek(_line, 0) = '#' : continue
		_space = instr(_line, 0, " ")
		if _space < 0 : continue
		_tag  = strmid(_line, 0, _space)
		_rest = strmid(_line, _space + 1, strlen(_line) - _space - 1)
		if _tag = "v" {
			if _n_verts >= OBJ_MAX_VERTS : continue
			_obj_parse_3 _rest, _x, _y, _z
			v_verts(_n_verts * 3 + 0) = _x
			v_verts(_n_verts * 3 + 1) = _y
			v_verts(_n_verts * 3 + 2) = _z
			_n_verts++
			continue
		}
		if _tag = "vn" {
			if _n_norms >= OBJ_MAX_NORMS : continue
			_obj_parse_3 _rest, _x, _y, _z
			v_norms(_n_norms * 3 + 0) = _x
			v_norms(_n_norms * 3 + 1) = _y
			v_norms(_n_norms * 3 + 2) = _z
			_n_norms++
			continue
		}
		if _tag = "vt" {
			if _n_uvs >= OBJ_MAX_UVS : continue
			_obj_parse_2 _rest, _u, _uv_v
			v_uvs(_n_uvs * 2 + 0) = _u
			v_uvs(_n_uvs * 2 + 1) = _uv_v
			_n_uvs++
			continue
		}
		if _tag = "f" {
			sdim _face_toks, 64, 16
			_face_n = 0
			_obj_split_ws _rest, _face_toks, _face_n
			if _face_n < 3 : continue
			repeat _face_n - 2
				if _n_tris >= OBJ_MAX_TRIS : break
				_face_i = cnt
				_obj_parse_face_idx _face_toks(0), _i_v, _i_t, _i_n
				v_tris(_n_tris * 9 + 0) = _i_v
				v_tris(_n_tris * 9 + 1) = _i_t
				v_tris(_n_tris * 9 + 2) = _i_n
				_obj_parse_face_idx _face_toks(_face_i + 1), _i_v, _i_t, _i_n
				v_tris(_n_tris * 9 + 3) = _i_v
				v_tris(_n_tris * 9 + 4) = _i_t
				v_tris(_n_tris * 9 + 5) = _i_n
				_obj_parse_face_idx _face_toks(_face_i + 2), _i_v, _i_t, _i_n
				v_tris(_n_tris * 9 + 6) = _i_v
				v_tris(_n_tris * 9 + 7) = _i_t
				v_tris(_n_tris * 9 + 8) = _i_n
				_n_tris++
			loop
			continue
		}
	loop
	v_nv = _n_verts : v_nn = _n_norms : v_nu = _n_uvs : v_nt = _n_tris
	return 0

#deffunc _obj_parse_3 str s, var v_x, var v_y, var v_z, \
	local _toks, local _n
	sdim _toks, 64, 6
	_n = 0
	_obj_split_ws s, _toks, _n
	if _n >= 1 : v_x = double(_toks(0))
	if _n >= 2 : v_y = double(_toks(1))
	if _n >= 3 : v_z = double(_toks(2))
	return

#deffunc _obj_parse_2 str s, var v_u, var v_v, \
	local _toks, local _n
	sdim _toks, 64, 4
	_n = 0
	_obj_split_ws s, _toks, _n
	if _n >= 1 : v_u = double(_toks(0))
	if _n >= 2 : v_v = double(_toks(1))
	return

#deffunc _obj_split_ws str s, array v_out, var v_n, \
	local _start, local _in_tok, local _c
	_start = 0 : _in_tok = 0 : v_n = 0
	repeat strlen(s) + 1
		if cnt = strlen(s) {
			if _in_tok = 1 {
				v_out(v_n) = strmid(s, _start, cnt - _start)
				v_n++
			}
			break
		}
		_c = peek(s, cnt)
		if (_c = ' ') | (_c = 9) {
			if _in_tok = 1 {
				v_out(v_n) = strmid(s, _start, cnt - _start)
				v_n++
				_in_tok = 0
			}
		} else {
			if _in_tok = 0 : _start = cnt : _in_tok = 1
		}
	loop
	return

;---------------------------------------------------------
; internal: face token → 3 int 0-based (OBJ は 1-based、負値は末尾相対)
;   負値の正規化には現在の頂点数が必要なので引数で受ける
;---------------------------------------------------------
#deffunc _obj_parse_face_idx str tok, var v_iv, var v_it, var v_in, \
	local _p1, local _p2, local _part, local _val
	v_iv = -1 : v_it = -1 : v_in = -1
	_p1 = instr(tok, 0, "/")
	if _p1 < 0 {
		_val = int(tok)
		if _val > 0 : v_iv = _val - 1 : else : v_iv = _val
		return
	}
	_part = strmid(tok, 0, _p1)
	if strlen(_part) > 0 {
		_val = int(_part)
		if _val > 0 : v_iv = _val - 1 : else : v_iv = _val
	}
	_p2 = instr(tok, _p1 + 1, "/")
	if _p2 < 0 {
		_part = strmid(tok, _p1 + 1, strlen(tok) - _p1 - 1)
		if strlen(_part) > 0 {
			_val = int(_part)
			if _val > 0 : v_it = _val - 1 : else : v_it = _val
		}
		return
	}
	_part = strmid(tok, _p1 + 1, _p2 - _p1 - 1)
	if strlen(_part) > 0 {
		_val = int(_part)
		if _val > 0 : v_it = _val - 1 : else : v_it = _val
	}
	_part = strmid(tok, _p2 + 1, strlen(tok) - _p2 - 1)
	if strlen(_part) > 0 {
		_val = int(_part)
		if _val > 0 : v_in = _val - 1 : else : v_in = _val
	}
	return

;---------------------------------------------------------
; obj_load_mtl "file.mtl", var_names, var_kd, var_map_kd, var n
;   .mtl ファイルを読み込み、マテリアル配列に展開
;     names:  str[n]         マテリアル名
;     kd:     double[3*n]    拡散色 (RGB 0..1)
;     map_kd: str[n]         拡散テクスチャファイル名
;---------------------------------------------------------
#deffunc obj_load_mtl str path, var v_names, var v_kd, var v_map_kd, var v_n, \
	local _size, local _buf, local _p, local _eol, local _line, \
	local _space, local _tag, local _rest, \
	local _n, local _cap, \
	local _toks, local _ntok
	_cap = 256
	sdim v_names, 64, _cap
	ddim v_kd, _cap * 3
	sdim v_map_kd, 256, _cap
	_n = 0
	exist path
	_size = strsize
	if _size <= 0 : v_n = 0 : return -1
	sdim _buf, _size + 16
	bload path, _buf, _size
	_p = 0
	repeat
		if _p >= _size : break
		_eol = instr(_buf, _p, "\n")
		if _eol < 0 {
			_line = strmid(_buf, _p, _size - _p)
			_p = _size
		} else {
			_line = strmid(_buf, _p, _eol - _p)
			_p = _eol + 1
		}
		if strlen(_line) > 0 {
			if peek(_line, strlen(_line) - 1) = 13 : _line = strmid(_line, 0, strlen(_line) - 1)
		}
		if strlen(_line) = 0 : continue
		if peek(_line, 0) = '#' : continue
		_space = instr(_line, 0, " ")
		if _space < 0 : continue
		_tag  = strmid(_line, 0, _space)
		_rest = strmid(_line, _space + 1, strlen(_line) - _space - 1)
		if _tag = "newmtl" {
			if _n >= _cap : continue
			v_names(_n) = _rest
			_n++
			continue
		}
		if _n = 0 : continue
		if _tag = "Kd" {
			sdim _toks, 64, 6
			_ntok = 0
			_obj_split_ws _rest, _toks, _ntok
			if _ntok >= 3 {
				v_kd((_n - 1) * 3 + 0) = double(_toks(0))
				v_kd((_n - 1) * 3 + 1) = double(_toks(1))
				v_kd((_n - 1) * 3 + 2) = double(_toks(2))
			}
			continue
		}
		if _tag = "map_Kd" {
			v_map_kd(_n - 1) = _rest
			continue
		}
	loop
	v_n = _n
	return 0

#global
#endif