125 lines
2.9 KiB
Lua
125 lines
2.9 KiB
Lua
---@class Obj
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---@field model string
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---@field texture string
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---@field texture_size integer
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---@field position Vector3
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---@field triangles table
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local Obj = {}
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local Vector3 = require "types.vector3"
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Obj.__index = Obj
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local function string_split(str, delimiter)
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local res = {}
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local i = 0
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local f
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local match = '(.-)' .. delimiter .. '()'
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if string.find(str, delimiter) == nil then
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return {str}
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end
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for sub, j in string.gmatch(str, match) do
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i = i + 1
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res[i] = sub
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f = j
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end
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if i ~= 0 then
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res[i+1] = string.sub(str, f)
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end
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return res
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end
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---parses the obj file and triangulates it for drawing
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---@param model string path to obj model
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---@param texture {file: string, size: number}
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---@param position Vector3?
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---@return Obj
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function Obj.create(model, texture, position)
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local pos
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if position ~= nil then
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pos = position
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else
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pos = Vector3()
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end
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local obj = {
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model = model,
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texture = texture.file,
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texture_size = texture.size,
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position = pos:copy(),
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triangles = {}
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}
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obj.position = obj.position:copy()
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setmetatable(obj, Obj)
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-- adapted from https://github.com/karai17/lua-obj/blob/master/obj_loader.lua
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-- Copyright (c) 2014 Landon Manning - LManning17@gmail.com - LandonManning.com
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-- MIT
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local file = file_read{file = obj.model}
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local lines = string_split(file, "\r?\n")
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local obj_data = {
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v = {},
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vt = {},
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f = {},
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}
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for _, line in ipairs(lines) do
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local l = string_split(line, "%s+")
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if l[1] == "v" then
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local v = {
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x = tonumber(l[2]),
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y = tonumber(l[3]),
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z = tonumber(l[4]),
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}
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table.insert(obj_data.v, v)
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elseif l[1] == "vt" then
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local vt = {
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x = tonumber(l[2]) * obj.texture_size,
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y = tonumber(l[3]) * obj.texture_size,
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}
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table.insert(obj_data.vt, vt)
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elseif l[1] == "f" then
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local f = {}
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for i = 2, #l do
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local split = string_split(l[i], "/")
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local v = {}
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v.v = tonumber(split[1])
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if split[2] ~= "" then v.vt = tonumber(split[2]) end
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-- v.vn = tonumber(split[3])
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table.insert(f, v)
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end
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table.insert(obj_data.f, f)
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end
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end
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for _, face in ipairs(obj_data.f) do
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for i = 2, #face - 1 do
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local triangle = {
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v0 = obj_data.v[face[1].v],
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v1 = obj_data.v[face[i].v],
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v2 = obj_data.v[face[i + 1].v],
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uv0 = obj_data.vt[face[1].vt],
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uv1 = obj_data.vt[face[i].vt],
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uv2 = obj_data.vt[face[i + 1].vt],
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texture = obj.texture
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}
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table.insert(obj.triangles, triangle)
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end
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end
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return obj
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end
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function Obj:draw()
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for _, triangle in ipairs(self.triangles) do
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local newt = util.shallow_copy(triangle)
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newt.v0 = Vector3(triangle.v0) + self.position
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newt.v1 = Vector3(triangle.v1) + self.position
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newt.v2 = Vector3(triangle.v2) + self.position
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draw_triangle(newt)
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end
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end
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return Obj |