a Love2D 11.x simple wrapper library for rendering games with a fixed update rate and chunky pixels

canvas.lua

local floor = math.floor

local canvas = {}
canvas._version = "0.1.0"
canvas.frame, canvas.time = 0, 0
canvas.width = 240
canvas.height = floor(canvas.width / (16 / 9))
canvas.pixelPerfect = true
canvas.backgroundColor = { 0, 0, 0, 1 }
canvas.xOffset, canvas.yOffset = 0, 0

local lag, msPerUpdate = 0, 0
local width, height, xScale, yScale, topLeftX, topLeftY

function canvas.framerate(n)
  if n then
    canvas._framerate = n
    msPerUpdate = 1 / n
  end
  return canvas._framerate
end

canvas.framerate(60)

local function scaleX(x) return (x-topLeftX)/xScale end
local function scaleY(y) return (y-topLeftY)/yScale end

function canvas.getMouseX() return scaleX(love.mouse.getX()) end

function canvas.getMouseY() return scaleY(love.mouse.getY()) end

function canvas.getMousePosition() return canvas.getMouseX(), canvas.getMouseY() end

local function applyIf(f, ...) if f then return f(...) end return end

function love.mousepressed(x, y, ...) applyIf(canvas.mousepressed, scaleX(x), scaleY(y), ...) end
function love.mousemoved(x, y, dx, dy, ...) applyIf(canvas.mousemoved, scaleX(x), scaleY(y), scaleX(dx), scaleY(dy), ...) end
function love.mousereleased(x, y, ...) applyIf(canvas.mousereleased, scaleX(x), scaleY(y), ...) end

local function resize(w, h)
  width, height = w, h
  xScale, yScale = w / canvas.width, h / canvas.height
  if xScale < yScale then yScale = xScale else xScale = yScale end
  if canvas.pixelPerfect then
    xScale, yScale = floor(xScale), floor(yScale)
  end
  topLeftX, topLeftY = (width - canvas.width * xScale) / 2, (height - canvas.height * yScale) / 2
end

function love.load(...)
  canvas._canvas = love.graphics.newCanvas(canvas.width, canvas.height)
  ---@diagnostic disable-next-line: missing-parameter
  canvas._canvas:setFilter "nearest"
  resize(love.graphics.getDimensions())
  love.window.updateMode(width, height, {
    minwidth = canvas.width, minheight = canvas.height,
  })
  applyIf(canvas.load, ...)
end

love.resize = resize

local delta = 0
function love.update(dt)
  delta = dt
  lag = lag + dt
  while lag >= msPerUpdate do
    applyIf(canvas.update)
    lag = lag - msPerUpdate
  end
end

function love.draw()
  if canvas.draw then
    love.graphics.push "all"
    love.graphics.setCanvas(canvas._canvas)
    love.graphics.clear(love.graphics.getBackgroundColor())
    canvas.draw(lag / msPerUpdate)
    love.graphics.setCanvas()
    love.graphics.pop()
  end

  love.graphics.clear(canvas.backgroundColor)
  love.graphics.translate(canvas.xOffset, canvas.yOffset)
  love.graphics.draw(canvas._canvas, topLeftX, topLeftY, 0, xScale, yScale)

  canvas.time = canvas.time + delta
  canvas.frame = canvas.frame + 1
end

return canvas

-- Copyright (c) 2024 @thacuber2a03
--
-- Permission is hereby granted, free of charge, to any person obtaining a copy
-- of this software and associated documentation files (the "Software"), to deal
-- in the Software without restriction, including without limitation the rights
-- to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-- copies of the Software, and to permit persons to whom the Software is
-- furnished to do so, subject to the following conditions:
--
-- The above copyright notice and this permission notice shall be included in all
-- copies or substantial portions of the Software.
--
-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-- SOFTWARE.

changelog

format: dd/mm/yyyy

10/11/2024:

• override love.mouse* callbacks

08/11/2024:

• initial release
• limit the maximum size of the window to the maximum size of the virtual canvas
• add getMouseX(), getMouseY(), getMousePosition(), canvas.xOffset and canvas.yOffset
• optimize getMouse*() and virtual canvas drawing