Fixture Destroy 0.8.0

[acp0112]

Creating a fixture and then immediately destroying it seems to cause love to crash during the subsequent call to World:update.

[Boolsheet]

I don't see it crashing with something simple like this.

Code: Select all

local step = 1 / 60
W = love.physics.newWorld(0, 1000)

W:update(step)

B = love.physics.newBody(W, 400, 0, "dynamic")
S = love.physics.newCircleShape(10)
F = love.physics.newFixture(B, S, 1)

W:update(step)
W:update(step)
W:update(step)

B2 = love.physics.newBody(W, 400, 0, "dynamic")
S2 = love.physics.newCircleShape(10)
F2 = love.physics.newFixture(B2, S2, 1)

F2:destroy()

W:update(step)

B2:destroy()

W:update(step)
W:update(step)

W:destroy()

Do you create the Fixture in a callback? Box2D assumes that you do not alter the physics world during the timestep and may throw (currently uncaught) exceptions or crash horribly. Adding new bodies and fixtures should be done after the timestep. The destruction of objects is queued by LÖVE as a convenience, but I recommend to do it after the timestep as well because it might make debugging more difficult.

[acp0112]

thanks for the response. i probably should have stated that i am using coroutines. i have included an example.

Code: Select all

function love.load()
  w = love.physics.newWorld(0, 1000)
end

function love.update(dt)
  b = love.physics.newBody(w, 400, 0, "dynamic")
  s = love.physics.newCircleShape(10)
  co = coroutine.create(function()
    while true do
      f = love.physics.newFixture(b, s, 1)
      f:setFilterData(1,65535,-1)
      coroutine.yield()
    end
  end)
  coroutine.resume(co)
  coroutine.resume(co)

  f:destroy()

  w:update(dt)
end

[Boolsheet]

Aha. It's not the coroutines, but an actual bug in Box2D. setFilterData will refilter the contacts and the destroy call doesn't remove all proxies properly. I don't think you can do anything about it from the Lua side.

[acp0112]

you are correct it is not the coroutine. well thanks for the help.