Love2d / LUA grid locked movement NO DIAGONAL - lua

Question

I thought this would be a common problem but after days of research I can't find a solution. Very new to programming in general and LUA specifically. I'm building a SUPAPLEX clone as a CS50 personal project: the character moves along the grid based map and there's a code that everyone seems to suggest (attached). On release of arrow buttons the movement is continued until the end of a tile, smoothly. But if 2 movement buttons are pushed, it causes brief diagonal movement and that's the problem I'm unsuccessfully trying to solve.
Basically I'm trying to either ignore any input until the movement of the sprite is finished at the end of the grid tile or prevent updating until movement in one direction is complete. Seems like a simple thing but I'm about to give up this whole thing. Frustrating. Any input is hiiiighly appreciated and I'm sure this would be a lot of help for very many people...
function love.load()
love.keyboard.setKeyRepeat(true)
player = {
grid_x = 256,
grid_y = 256,
act_x = 256,
act_y = 256,
speed = 5,
}
map = {
{ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 },
{ 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1 },
{ 1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1 },
{ 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1 },
{ 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1 },
{ 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1 },
{ 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 },
{ 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 },
{ 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 },
{ 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 1 },
{ 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1 },
{ 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1 },
{ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 }
}
function testMap(x, y)
if map[(player.grid_y / 32) + y][(player.grid_x / 32) + x] == 1 then
return false
end
return true
end
function love.keypressed(key)
if key == "up" then
player.grid_y = player.grid_y - 32
elseif key == "down" then
player.grid_y = player.grid_y + 32
elseif key == "left" then
player.grid_x = player.grid_x - 32
elseif key == "right" then
player.grid_x = player.grid_x + 32
end
end
end
function love.update(dt)
player.act_y = player.act_y - ((player.act_y - player.grid_y) * player.speed * dt)
player.act_x = player.act_x - ((player.act_x - player.grid_x) * player.speed * dt)
end
function love.draw()
love.graphics.rectangle("fill", player.act_x, player.act_y, 32, 32)
for y=1, #map do
for x=1, #map[y] do
if map[y][x] == 1 then
love.graphics.rectangle("line", x * 32, y * 32, 32, 32)
end
end
end
end

Answer 1

you're trying to get it to only walk along grid-lines?
take out love.keyboard.setKeyRepeat(true)
and don't use love.keypressed(key)
that's for one-at-a-time keypresses, and it would be hard to use that
with love.keyreleased() to see if all the other keys are released.
use isDown instead, and if one of them isDown, then none of the other dir keys allow input. (along with the couple player.act lines you already have in your update)
player = {
grid_x = 256,
grid_y = 256,
act_x = 256,
act_y = 256,
speed = 5,
dir = ''
}
function love.update(dt)
if love.keyboard.isDown("up", "down", "left", "right") then
if love.keyboard.isDown("up") and ( player.dir == 'up' or player.dir == '' ) then
player.dir = 'up' -- only go up if currently held, or no other dir key being pressed
player.grid_y = player.grid_y - 32
elseif love.keyboard.isDown("down") and ( player.dir == 'down' or player.dir == '' ) then
player.dir = 'down' -- only go down if currently held...
player.grid_y = player.grid_y + 32
elseif key == "left" and ( player.dir == 'left' or player.dir == '' ) then
player.dir = 'left'
player.grid_x = player.grid_x - 32
elseif key == "right" and ( player.dir == 'right' or player.dir == '' ) then
player.dir = 'right'
player.grid_x = player.grid_x + 32
end
else -- none of those keys are being pressed, so player is idle
player.dir = ''
end -- isDown()
player.act_y = player.act_y - ((player.act_y - player.grid_y) * player.speed * dt)
player.act_x = player.act_x - ((player.act_x - player.grid_x) * player.speed * dt)
end -- update()