This tutorial assumes knowledge of:

• Corona SDK
• Tiled Map Editor

Here’s a short video of the game: In part 2 of the tutorial I showed how to load your map into a Corona project. In part 3 and 4 I’ll show you some elements of the game logic. I’m going to restrict the discussion to aspects of the game logic that are affected by the isometric perspective of the map.

Let’s firstly look at how to move the blocks on the isometric map. We’ll then discuss display ordering.

Here’s the function that handles block movement. In a nutshell, you provide the function with the angle the D-pad touch listener calculated, and which block was selected. The function will figure out where the block should end up (given the positions of the other blocks on the map), then transition the block from it’s current position to the new position.

``````--Moves a block. angle is the movement angle (sent from the D-pad)
--i is the selected block
function moveBlock(angle, i)
--i.e. if a block is indeed selected
if i > 0 then
--Variables
local deltaX, deltaY, newTilePosX, newTilePosY, iTileX, iTileY,
moveScreenPosX, moveScreenPosY, newScreenPosX, newScreenPosY,
deltaTilePosX, deltaTilePosY, timeScale

--Arrays
local jArr = {}

--Only move if the block is not already moving
--You don't want to interrupt a current movement
if not block[i].moving then

--Get directional change
--angleToDir function not shown, it returns the change
--in x and y axis represented by the angle argument
deltaX, deltaY = angleToDir(angle)

--Get tile position of current block
iTileX, iTileY = block[i].tileX, block[i].tileY

--Get tile position of the other blocks
for j = 1, #block do
if j ~= i then
table.insert(jArr, { tileX = block[j].tileX,
tileY = block[j].tileY})
end
end

--Calculate new block position
--newBlockPos (not shown) will calcalaute the new tile position
--of block i, given the positions of the other blocks
newTilePosX, newTilePosY = newBlockPos(iTileX, iTileY, jArr,
deltaX, deltaY)

--Change in block position
deltaTilePosX, deltaTilePosY = newTilePosX - iTileX,
newTilePosY - iTileY

--See if new position is viable i.e. on the map
if (newTilePosX >= 0 and newTilePosX < (mapWidth - 1)) and
(newTilePosY >= 0 and newTilePosY < (mapHeight - 1)) then                             --Update tile position
block[i].tileX, block[i].tileY = newTilePosX, newTilePosY                         --Calculate new screen position of block i
moveScreenPosX, moveScreenPosY = (deltaTilePosX - deltaTilePosY) *                tileWidth/2, (deltaTilePosX + deltaTilePosY) * tileHeight/2                       newScreenPosX, newScreenPosY = block[i].x + moveScreenPosX,
block[i].y + moveScreenPosY
--Set the block to moving
block[i].moving = true
--Update screen position with a transition
local function listener (event)
block[i].moving = false
if moveScreenPosX == 0 and moveScreenPosY == 0 then
else
audio.play(blockClick)
end
--Check if the game's been won
checkWon()
end
if math.abs(deltaX) > math.abs(deltaY) then
timeScale = math.abs(deltaTilePosX)
else
timeScale = math.abs(deltaTilePosY)
end

transition.to(block[i], {time=timeScale*100,