TransitionTest.lua

local class = require "com.class"

---@class TransitionTest
---@overload fun():TransitionTest
local TransitionTest = class:derive("TransitionTest")

local Vec2 = require("Vector2")



---Constructs a Transition Test.
function TransitionTest:new()
    self.time = 0
    self.MAX_TIME = 3
    self.playing = false
    self.state = false

    self.SEGMENT_COUNT = Vec2(24, 13)
    self.SEGMENT_SIZE = _CANVAS.resolution / self.SEGMENT_COUNT
    self.DELAY_BETWEEN_SEGMENTS = 0.05
    self.SEGMENT_TIME = 0.2
end



---Starts the show animation (transition to dark).
function TransitionTest:show()
    self.time = 0
    self.state = true
    self.playing = true
end



---Starts the hide animation (transition from dark).
function TransitionTest:hide()
    self.time = 0
    self.state = false
    self.playing = true
end



---Updates the Transition Test.
---@param dt number Time delta, in seconds.
function TransitionTest:update(dt)
    if self.playing then
        if self.time < self.MAX_TIME then
            self.time = self.time + dt
            if self.time >= self.MAX_TIME then
                self.time = 0
                self.playing = false
            end
        end
    end
end



---Draws the Transition Test on the screen.
function TransitionTest:draw()
    love.graphics.setColor(0, 0, 0)
    if self.time == 0 then
        if self.state then
            love.graphics.rectangle("fill", 0, 0, _CANVAS.resolution.x, _CANVAS.resolution.y)
        end
    else
        for i = 1, self.SEGMENT_COUNT.x do
            for j = 1, self.SEGMENT_COUNT.y do
                local t = math.min(math.max((self.time - (i + j) * self.DELAY_BETWEEN_SEGMENTS) / self.SEGMENT_TIME, 0), 1)
                if not self.state then
                    t = 1 - t
                end
                local p = self.SEGMENT_SIZE * Vec2(i - 1, j - 1) + (self.SEGMENT_SIZE / 2 * (1 - t))
                love.graphics.rectangle("fill", p.x, p.y, self.SEGMENT_SIZE.x * t, self.SEGMENT_SIZE.y * t)
            end
        end
    end
end



return TransitionTest