Playdate 7

After a bit of a break to update some code for Make America Kittens Again and submit that to the Mac App Store, back to the little Pacman game.

Today: time to put the ghost back in motion. The key thing here is a function to check whether a given direction is a possible way to travel:

function checkForOpenPath(mapRefX,mapRefY,requestedDir) 
    -- calculate the grid ref targeted by the requested direction
    -- then check if it is possible to move into that space
    local targetRefX = mapRefX
    local targetRefY = mapRefY
    if requestedDir == "l" then
        targetRefX = targetRefX - 1
    elseif requestedDir == "r" then
        targetRefX = targetRefX + 1
    elseif requestedDir == "u" then
        targetRefY = targetRefY - 1
    elseif requestedDir == "d" then
        targetRefY = targetRefY + 1
    end
    -- check for edge of grid
    if (targetRefX < 1 or targetRefX > 15 or targetRefY < 1 or targetRefY > 15) then
        -- target out of bounds
        return false
    end    
    -- check for wall
    if map:getTileAtPosition(targetRefX,targetRefY) == 1 then
        -- target is a wall
        return false
    end      
    return true
end

This gets called regularly to check for “ghost bumps into wall”, and also when the user tries to change direction.

The other things I learned: “not equals to” is checked using ~= rather than the != that I’m more used to, and I struggled to do a “is this value false” check, so need to look into that. For the moment I had to do this, which is clunky AF:

-- check for collision with wall on current path
                if checkForOpenPath(mapRefX,mapRefY,playerDirection) then
                    -- nothing to see here
                else    
                    -- stop!
                    playerDirection = "n"
                end   

I also took out the timer as, at the moment, it just doesn’t seem needed.

And here’s the result:

.. look at the little guy go. Full code here.