Codea Net Sim

local part = class()

function part:init(x, y, l)
    --coords
    self.c = vec2(x, y)

    --original coords
    self.oc = vec2(x, y)

    --velocity
    self.v = vec2(0,0)

    self.l = l
end

local s, f, loss, el = 1, 0.99, 1.1, 0.01

function part:draw(pull, isMove)

    ---[[
    if isMove < ENDED then
        local d = self.c:dist(pull) * s
        self.v.x = (self.v.x + (pull.x - self.c.x) / (d^loss)) * f
        self.v.y = (self.v.y + (pull.y - self.c.y) / (d^loss)) * f
    end
    --]]

    d = math.max(1, self.c:dist(self.oc)) * s

    ---[[
    self.v.x = (self.v.x + (self.oc.x - self.c.x) / (d^loss)) * f
    self.v.y = (self.v.y + (self.oc.y - self.c.y) / (d^loss)) * f

    --]]

    self.c = self.c + self.v

    --point(self.c.x, self.c.y)
end

function part:pull(pull, str)

    local ov = self.v

    str = str or 1

    local d = math.max(1, self.l / math.abs(self.l - self.c:dist(pull)))

    local dir = (self.l - self.c:dist(pull)) > 0 and -1 or 1

    --print(d)

    ---[[
    self.v.x = (self.v.x + (pull.x - self.c.x) / ((d)^loss)*str*dir)
    self.v.y = (self.v.y + (pull.y - self.c.y) / ((d)^loss)*str*dir)
    --]]

    self.c = self.c + (self.v - ov)

    --point(self.c.x, self.c.y)
end

local net = {}

function makeNet(size)
    for y = 1, size do
        net[y] = {}
        for x = 1, size do
            net[y][x] = part(x * HEIGHT / size, y * HEIGHT / size, HEIGHT / size)
        end
    end
end

makeNet(10)

local nn = {}

local function pullToPart(py, px, x, nn, cx, cy)
    if nn[py-cy] and nn[py-cy][px-cx] then
        x:pull(vec2(nn[py-cy][px-cx].c.x, nn[py-cy][px-cx].c.y), el)
    end
end

function draw()

    background(255, 255, 255, 255)

    -- This sets the line thickness
    strokeWidth(5)
    stroke(0)
    --[[
    for i, v in pairs(net) do
        nn[i] = v
    end
    --]]
    nn = net
    local ct = vec2(CurrentTouch.x, CurrentTouch.y)
    for py, y in ipairs(net) do
        for px, x in ipairs(y) do
            x:draw(ct, CurrentTouch.state)
            ---[[
            pullToPart(py, px, x, nn, -1, 0)
            pullToPart(py, px, x, nn, 1, 0)
            pullToPart(py, px, x, nn, 0, -1)
            pullToPart(py, px, x, nn, 0, 1)
            --]]
            ---[[
            if px > 1 then
                line(x.c.x, x.c.y, net[py][px-1].c.x, net[py][px-1].c.y)
            end
            if py > 1 then
                line(x.c.x, x.c.y, net[py-1][px].c.x, net[py-1][px].c.y)
            end
            ---[[

            --]]
        end
    end
end