stereoMultiplier = 0.1

function renderAsTris(obj,pos,size)

    local xt = 1

    local n = 1
    while(obj.f[n]) do
    n = n + 1
    end
    local numfaces = n

    while(xt < numfaces) do
        local vertex1ind = obj.f[xt][1]["v"] -- Gets the number in the list of the current vertex
        local vertex1 = Vertex.new(pos.x + size * obj.v[vertex1ind].x, pos.y + size * obj.v[vertex1ind].y, pos.z + size * obj.v[vertex1ind].z) -- creates vertex with position and size

        local vertex2ind = obj.f[xt][2]["v"]
        local vertex2 = Vertex.new(pos.x + size *  obj.v[vertex2ind].x, pos.y + size *  obj.v[vertex2ind].y, pos.z + size *  obj.v[vertex2ind].z)

        local vertex3ind = obj.f[xt][3]["v"]
        local vertex3 = Vertex.new(pos.x + size *  obj.v[vertex3ind].x, pos.y + size *  obj.v[vertex3ind].y, pos.z + size *  obj.v[vertex3ind].z)

        drawLine(vertex1,vertex2)
        drawLine(vertex2,vertex3)
        drawLine(vertex3,vertex1)

        xt = xt + 1

    end
end
-- OBJ LOADER LIBRARY --

local path ="."
local loader = {}
local fileString = ""

loader.version = "0.0.2"

function loader.load(file)
    local lines = {}
    fileStream = io.open(System.currentDirectory()..file,FREAD)
    size = io.size(fileStream)
    str = io.read(fileStream,0,size)
    io.close(fileStream)
     local x, a, b = 1;
      while x < string.len(str) do
        a, b = string.find(str, '.-\n', x);
        if not a then
            break;
        else
            if string.sub(str,a,b) then
                table.insert(lines,string.sub(str,a,b))
            end
        end;
        x = b + 1;
      end;
            --
    return loader.parse(lines)
end

function loader.parse(object)
    local obj = {
        v   = {}, -- List of vertices - x, y, z, [w]=1.0
        vt  = {}, -- Texture coordinates - u, v, [w]=0
        vn  = {}, -- Normals - x, y, z
        vp  = {}, -- Parameter space vertices - u, [v], [w]
        f   = {}, -- Faces
    }
    for _, line in ipairs(object) do
        local l = string_split(line, "%s+")
        if l[1] == "v" then
            local v = {
                x = tonumber(l[2]),
                y = tonumber(l[3]),
                z = tonumber(l[4]),
                w = tonumber(l[5]) or 1.0
            }
            table.insert(obj.v, v)
        elseif l[1] == "vt" then
            local vt = {
                u = tonumber(l[2]),
                v = tonumber(l[3]),
                w = tonumber(l[4]) or 0
            }
            table.insert(obj.vt, vt)
        elseif l[1] == "vn" then
            local vn = {
                x = tonumber(l[2]),
                y = tonumber(l[3]),
                z = tonumber(l[4]),
            }
            table.insert(obj.vn, vn)
        elseif l[1] == "vp" then
            local vp = {
                u = tonumber(l[2]),
                v = tonumber(l[3]),
                w = tonumber(l[4]),
            }
            table.insert(obj.vp, vp)
        elseif l[1] == "f" then
            local f = {}
            for i=2, #l do
                local split = string_split(l[i], "/")
                local v = {}
                v.v = tonumber(split[1])
                if split[2] ~= "" then v.vt = tonumber(split[2]) end
                v.vn = tonumber(split[3])
                table.insert(f, v)
            end
            table.insert(obj.f, f)
        end
    end
    return obj
end

-- http://wiki.interfaceware.com/534.html
function string_split(s, d)
    local t = {}
    local i = 0
    local f
    local match = '(.-)' .. d .. '()'
    if string.find(s, d) == nil then
        return {s}
    end
    for sub, j in string.gmatch(s, match) do
        i = i + 1
        t[i] = sub
        f = j
    end
    if i ~= 0 then
        t[i+1] = string.sub(s, f)
    end
    return t
end

function drawLine(vec1,vec2)

    Screen.drawLine(round(vec1.x-vec1.z*stereoMultiplier,0), round(vec2.x-vec2.z*stereoMultiplier,0), round(vec1.y,0),round(vec2.y,0), Color.new(255,255,255),TOP_SCREEN, LEFT_EYE)
    Screen.drawLine(round(vec1.x+vec1.z*stereoMultiplier,0), round(vec2.x+vec2.z*stereoMultiplier,0), round(vec1.y,0),round(vec2.y,0), Color.new(255,255,255),TOP_SCREEN, RIGHT_EYE)
end


function round(num, idp)
  local mult = 10^(idp or 0)
  return math.floor(num * mult + 0.5) / mult
end


function drawPoint(x,y,z)
    Screen.drawPixel(round(x-z*stereoMultiplier ,0), round(y,0), Color.new(255,0,0), TOP_SCREEN, LEFT_EYE)
    Screen.drawPixel(round(x+z*stereoMultiplier ,0), round(y,0), Color.new(255,0,0), TOP_SCREEN, RIGHT_EYE)
end

Vertex = {};
function Vertex.new(x,y,z)
    local self = {}
    self.x = x
    self.y = y
    self.z = z
    return self
end


local OBJModel = loader.load("/model.obj")
local objPos = Vertex.new(180,100,0)
Screen.enable3D() --Enabling 3D for the top screen
while(true) do

    Screen.waitVblankStart() -- Screen related stuff
    Screen.refresh() -- Other Screen related stuff
    Screen.clear(TOP_SCREEN) -- Clear top screen
    Screen.clear(BOTTOM_SCREEN) -- Clear bottom screen
    pad = Controls.read() -- Read Controls
    if(Controls.check(pad, KEY_START)) then-- check if start is pressed

        System.exit()-- Exit back to HBL

    end
    Screen.debugPrint(0,0,"Hello World",Color.new(255,255,255),BOTTOM_SCREEN) -- Print onto the bottom screen at (0,0), "Hello World" in white

    renderAsTris(OBJModel,objPos,50)
    Screen.flip() -- More screen related stuff

end