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Posted: **Fri Aug 07, 2020 4:14 pm**

Does anyone know how to check for collisions and check for when not colliding with something in bump.lua?

I am making a platformer, and I've had problems with jumping, the player would always be levitating when not on the platform, and I've used the code from this: https://love2d.org/wiki/Tutorial:Baseline_2D_Platformer

Here's the .love file in case: https://drive.google.com/file/d/1jQ9J8M ... sp=sharing

Posted: **Fri Aug 07, 2020 5:53 pm**

I don't advise following that tutorial's recommendations regarding checking whether the player can jump. It has caused problems to others in past, like this guy: https://love2d.org/forums/viewtopic.php ... 35#p223735

Check the docs of Bump. It returns the collisions and the collision normals. The collision normals can help determining if your player can jump.

Posted: **Fri Aug 07, 2020 8:15 pm**

By default, bump.lua will report any and all collisions if you don't provide a filter to its functions.
Here's some crude, quick code example:

Code: Select all

local playerObj   = { isPlayer = true }
local pickup      = { isPickup = true }

-- populate the world
local playerX   = 0
local bumpWorld = bump.newWorld ()
bumpWorld:add ( playerObj,  playerX, 0, 10, 10 )
bumpWorld:add ( pickup,          20, 0,  5,  5 )

-- define filter for player to use
local playerFilter = function ( playerObj, otherObj )
  if otherObj.isPickup then return "cross" else return "slide" end
end

-- move player obj
playerX = playerX + 1
local actualX, actualY, cols, len = bumpWorld:move ( playerObj, playerX, 0, playerFilter )
playerX = actualX -- store the realized x coordinate

-- check collisions
for i = 1, len do
  if cols[i].other.isPickup then
    -- code to handle picking up the object
  else 
    -- do other things
  end
end

The main thing here is the playerFilter function, which will move over objects that are defined as pickups (but register the collision), and slide along the surfaces of other elements. For details on other collision responses (touch, bounce), check the documentation. Another thing worth pointing out that when using the "slide" response, if an object ends up or is spawned inside another, and the slide response is triggered, the object will 'zip' or 'warp' outside it.

Also please note that the objects that you insert to bump world can use just about any kind of structure you desire. As far as I know, they can be strings, numbers or tables.

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