Minimal Gamera Bound Love2d World

gamera_test.lua

-- print program output to ST console
io.stdout:setvbuf("no")

local gamera = require 'gamera'

local min, max = math.min, math.max

-- game variables (entities)
local world, player, target, cam1

-- auxiliary functions
local isDown = love.keyboard.isDown
local floor = math.floor

-- world functions
local function drawBackground(cl,ct,cw,ch)
  local w = world.w / world.columns
  local h = world.h / world.rows

  local minX = max(floor(cl/w), 0)
  local maxX = min(floor((cl+cw)/w), world.columns-1)
  local minY = max(floor(ct/h), 0)
  local maxY = min(floor((ct+ch)/h), world.rows-1)

  for y=minY, maxY do
    for x=minX, maxX do
      if (x + y) % 2 == 0 then
        love.graphics.setColor(155,155,155)
      else
        love.graphics.setColor(200,200,200)
      end
      love.graphics.rectangle("fill", x*w, y*h, w, h)
    end
  end
end

-- player functions
local function updatePlayer(dt)
  charSpeed = (550 * dt)

  -- player controls
  if isDown('left') and player.x > player.w / 2 then
    player.x = player.x - charSpeed
  elseif isDown('right') and player.x < (world.w - player.w / 2) then
    player.x = player.x + charSpeed
  end

  if isDown('up') and player.y > (player.h / 2) then
    player.y = player.y - charSpeed
  elseif isDown('down') and player.y < (world.h - player.h / 2) then
    player.y = player.y + charSpeed
  end
end

local function drawPlayer()
  love.graphics.setColor(0,255,0)
  love.graphics.rectangle('fill',
                          player.x - player.w / 2,
                          player.y - player.h / 2,
                          player.w,
                          player.h)
end

-- main love functions
function love.load()
  world  = { w = 5000, h = 3000, rows = 10, columns = 20 }
  target = { x = 500,  y = 500 }
  player = { x = 200,  y = 200, w = 100, h = 100 }

  cam1 = gamera.new(0, 0, world.w, world.h)
  cam1:setWindow(10,10,780,580)
end

function love.update(dt)
  updatePlayer(dt)
  -- Lock the camera to the player pos
  cam1:setPosition(player.x, player.y)
end

function love.draw()
  cam1:draw(function(l,t,w,h)
    drawBackground(l,t,w,h)
    drawPlayer()
  end)

  love.graphics.setColor(255,255,255)

end

-- exit with esc
function love.keypressed(key)
  if key == 'escape' then love.event.quit() end
end