302 lines
6.9 KiB
Lua
302 lines
6.9 KiB
Lua
-- Localize globals
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local read_int, read_single = mtul.binary.read_int, mtul.binary.read_single
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--+ Reads a single BB3D chunk from a stream
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--+ Doing `assert(stream:read(1) == nil)` afterwards is recommended
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--+ See `b3d_specification.txt` as well as https://github.com/blitz-research/blitz3d/blob/master/blitz3d/loader_b3d.cpp
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--> B3D model
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function mtul.b3d.read(stream)
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local left = 8
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local function byte()
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left = left - 1
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return assert(stream:read(1):byte())
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end
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local function int()
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return read_int(byte, 4)
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end
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local function id()
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return int() + 1
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end
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local function optional_id()
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local id = int()
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if id == -1 then
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return
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end
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return id + 1
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end
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local function string()
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local rope = {}
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while true do
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left = left - 1
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local char = assert(stream:read(1))
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if char == "\0" then
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return table.concat(rope)
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end
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table.insert(rope, char)
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end
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end
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local function float()
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return read_single(byte)
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end
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local function float_array(length)
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local list = {}
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for index = 1, length do
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list[index] = float()
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end
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return list
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end
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local function color()
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local ret = {}
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ret.r = float()
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ret.g = float()
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ret.b = float()
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ret.a = float()
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return ret
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end
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local function vector3()
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return float_array(3)
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end
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local function quaternion()
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local w = float()
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local x = float()
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local y = float()
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local z = float()
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return {x, y, z, w}
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end
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local function content()
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if left < 0 then
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error(("unexpected EOF at position %d"):format(stream:seek()))
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end
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return left ~= 0
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end
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local chunk
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local chunks = {
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TEXS = function()
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local textures = {}
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while content() do
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local tex = {}
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tex.file = string()
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tex.flags = int()
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tex.blend = int()
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tex.pos = float_array(2)
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tex.scale = float_array(2)
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tex.rotation = float()
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table.insert(textures, tex)
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end
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return textures
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end,
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BRUS = function()
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local brushes = {}
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local n_texs = int()
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assert(n_texs <= 8)
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while content() do
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local brush = {}
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brush.name = string()
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brush.color = color()
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brush.shininess = float()
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brush.blend = int()
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brush.fx = int()
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brush.texture_id = {}
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for index = 1, n_texs do
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brush.texture_id[index] = optional_id()
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end
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table.insert(brushes, brush)
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end
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return brushes
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end,
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VRTS = function()
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local vertices = {}
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vertices.flags = int()
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vertices.tex_coord_sets = int()
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vertices.tex_coord_set_size = int()
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assert(vertices.tex_coord_sets <= 8 and vertices.tex_coord_set_size <= 4)
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local has_normal = (vertices.flags % 2 == 1) or nil
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local has_color = (math.floor(vertices.flags / 2) % 2 == 1) or nil
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while content() do
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local vertex = {}
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vertex.pos = vector3()
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vertex.normal = has_normal and vector3()
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vertex.color = has_color and color()
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vertex.tex_coords = {}
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for tex_coord_set = 1, vertices.tex_coord_sets do
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local tex_coords = {}
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for tex_coord = 1, vertices.tex_coord_set_size do
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tex_coords[tex_coord] = float()
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end
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vertex.tex_coords[tex_coord_set] = tex_coords
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end
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table.insert(vertices, vertex)
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end
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return vertices
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end,
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TRIS = function()
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local tris = {}
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tris.brush_id = id()
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tris.vertex_ids = {}
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while content() do
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local i = id()
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local j = id()
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local k = id()
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table.insert(tris.vertex_ids, {i, j, k})
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end
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return tris
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end,
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MESH = function()
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local mesh = {}
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mesh.brush_id = optional_id()
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mesh.vertices = chunk{VRTS = true}
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mesh.triangle_sets = {}
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repeat
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local tris = chunk{TRIS = true}
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table.insert(mesh.triangle_sets, tris)
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until not content()
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return mesh
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end,
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BONE = function()
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local bone = {}
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while content() do
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local vertex_id = id()
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assert(not bone[vertex_id], "duplicate vertex weight")
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local weight = float()
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if weight > 0 then
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-- Many exporters include unneeded zero weights
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bone[vertex_id] = weight
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end
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end
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return bone
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end,
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KEYS = function()
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local flags = int()
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local _flags = flags % 8
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local rotation, scale, position
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if _flags >= 4 then
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rotation = true
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_flags = _flags - 4
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end
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if _flags >= 2 then
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scale = true
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_flags = _flags - 2
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end
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position = _flags >= 1
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local bone = {
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flags = flags
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}
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while content() do
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local frame = {}
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frame.frame = int()
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if position then
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frame.position = vector3()
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end
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if scale then
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frame.scale = vector3()
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end
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if rotation then
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frame.rotation = quaternion()
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end
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table.insert(bone, frame)
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end
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return bone
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end,
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ANIM = function()
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local ret = {}
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ret.flags = int() -- flags are unused
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ret.frames = int()
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ret.fps = float()
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return ret
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end,
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NODE = function()
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local node = {}
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node.name = string()
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node.position = vector3()
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node.scale = vector3()
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node.keys = {}
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node.rotation = quaternion()
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node.children = {}
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local node_type
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-- See https://github.com/blitz-research/blitz3d/blob/master/blitz3d/loader_b3d.cpp#L263
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-- Order is not validated; double occurrences of mutually exclusive node def are
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while content() do
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local elem, type = chunk()
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if type == "MESH" then
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assert(not node_type)
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node_type = "mesh"
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node.mesh = elem
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elseif type == "BONE" then
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assert(not node_type)
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node_type = "bone"
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node.bone = elem
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elseif type == "KEYS" then
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mtul.tbl.append(node.keys, elem)
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elseif type == "NODE" then
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table.insert(node.children, elem)
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elseif type == "ANIM" then
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node.animation = elem
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else
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assert(not node_type)
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node_type = "pivot"
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end
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end
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-- Ensure frames are sorted ascendingly
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table.sort(node.keys, function(a, b)
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assert(a.frame ~= b.frame, "duplicate frame")
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return a.frame < b.frame
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end)
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return node
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end,
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BB3D = function()
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local version = int()
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local self = {
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version = {
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major = math.floor(version / 100),
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minor = version % 100,
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},
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textures = {},
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brushes = {}
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}
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assert(self.version.major <= 2, "unsupported version: " .. self.version.major)
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while content() do
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local field, type = chunk{TEXS = true, BRUS = true, NODE = true}
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if type == "TEXS" then
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mtul.tbl.append(self.textures, field)
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elseif type == "BRUS" then
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mtul.tbl.append(self.brushes, field)
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else
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self.node = field
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end
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end
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return self
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end
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}
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local function chunk_header()
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left = left - 4
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return stream:read(4), int()
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end
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function chunk(possible_chunks)
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local type, new_left = chunk_header()
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local parent_left
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left, parent_left = new_left, left
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if possible_chunks and not possible_chunks[type] then
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error("expected one of " .. table.concat(mtul.tbl.keys(possible_chunks), ", ") .. ", found " .. type)
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end
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local res = assert(chunks[type])()
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assert(left == 0)
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left = parent_left - new_left
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return res, type
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end
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local self = chunk{BB3D = true}
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return setmetatable(self, mtul.b3d)
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end |