LÖVE

Posted: **Thu Apr 26, 2018 6:35 pm**

Hi can anyone help me please, i'm studyin Love2D framework and getting stucked by checking collision between two classes using rxi/classic - library (Ball and Paddle).
I know how check collision between singe object and objects in table. Like:

function love.update(dt)
for _, v in ipairs(tablename) do
v:update(dt)
-- collision
if AABB(p.x, p.y, p.w, p.h, v.x, v.y, v.w, v.h) then
-- do something
end
end

but dunno how check collision between "two kind of objects in one table" (ball and paddle)

mayble looking my code have better explanation, here my example.

game.love: (12.17 KiB) Downloaded 104 times

Posted: **Fri Jun 29, 2018 3:34 am**

I started by adding an object identifier variable in the constructor of each class.

Code: Select all

function Ball:new(x, y)
       -- ...
        self.type = "ball"

end

Here is how you would check collisions

Code: Select all


checkCollision = 
local function(x1,y1,w1,h1,x2,y2,w2,h2)

    return (x1 + w1 > x2) and (x1 < x2 + w2) and (y1 + h1 > y2) and (y1 < y2 + y2)

end

function love.update(dt)
    for i, v in ipairs(objects) do
        v:update(dt)  
        if(v.type == "paddle") then
          for i = 1,#objects do -- Not good for lots of objects
            if(objects[i].type == "ball") then
              if(checkCollision(v.x,v.y,v.w,v.h,objects[i].x,objects[i].y,objects[i].w,objects[i].h)) then
                objects[i].xv = objects[i].xv * -1 
              end
            end 
          end
        end
    end
end

Here is the working project.

Posted: **Fri Jun 29, 2018 6:16 am**

You're almost there, a few things that could be improved:

Check every pair of objects only once:

Code: Select all

for i = 1, #objects do
  for j = i + 1, #objects do
    objects[i]:overlaps(objects[j])
  end
end

For classes, try to pass as few parameters as possible:

Code: Select all

function object:overlaps(b)
  local a = self
  if a.x + a.w < b.x or a.x > b.x + b.w then
    return false
  end
  if a.y + a.h < b.y or a.y > b.y + b.h then
    return false
  end
  return true
end

Posted: **Sun Jul 01, 2018 1:22 am**

ivan wrote: ↑Fri Jun 29, 2018 6:16 am You're almost there, a few things that could be improved:

Check every pair of objects only once:
Code: Select all
for i = 1, #objects do
  for j = i + 1, #objects do
    objects[i]:overlaps(objects[j])
  end
end
For classes, try to pass as few parameters as possible:
Code: Select all
function object:overlaps(b)
  local a = self
  if a.x + a.w < b.x or a.x > b.x + b.w then
    return false
  end
  if a.y + a.h < b.y or a.y > b.y + b.h then
    return false
  end
  return true
end

Time to clean up some of my stuff

Thank you!

LÖVE

how check AABB between 2 classes?

how check AABB between 2 classes?

Re: how check AABB between 2 classes?

Re: how check AABB between 2 classes?

Re: how check AABB between 2 classes?