Assertion failed error

gyrosp

Hi,

I was 'playing' with some physics and stumbled about an Assertion failed error when I tried to start the app.
I just used the sample code 'Physics->Bridge' and removed the creation code of the bridge and the boxes.

This is the error message:

Mirosoft Visual C++ Runtime Library Assertion failed!   bla bla... b2Joint.cpp - Line 173   Expression: def->bodyA != def->bodyB

This is my code

--[[   This code is MIT licensed, see <a href="http://www.opensource.org/licenses/mit-license.php" rel="nofollow">http://www.opensource.org/licenses/mit-license.php</a> (C) 2010 - 2011 Gideros Mobile   ]]   require "box2d"   b2.setScale(10)   -- this table holds the dynamic bodies and their sprites local actors = {}   -- create world local world = b2.World.new(0, 9.8)   -- create ground body local ground = world:createBody({})   -- create an edge shape, and attach it to the ground body as a fixture local shape = b2.EdgeShape.new(0, 480, 320, 480) ground:createFixture({shape = shape, density = 0})   -- this box shape will be used while creating the bridge elements local shape = b2.PolygonShape.new() shape:setAsBox(11, 2)   -- and our fixture definition local fixtureDef = {shape = shape, density = 20, friction = 0.2}   -- start to create the bridge local prevBody = ground       -- attach last bridge element to the ground body local jointDef = b2.createRevoluteJointDef(prevBody, ground, 300, 250) world:createJoint(jointDef)       -- this box shape will be used while creating boxes falling down local shape = b2.PolygonShape.new() shape:setAsBox(10, 10)   local fixtureDef = {shape = shape, density = 2, restitution = 0.7}         -- step the world and then update the position and rotation of sprites local function onEnterFrame() world:step(1/60, 8, 3)   for body,sprite in pairs(actors) do sprite:setPosition(body:getPosition()) sprite:setRotation(body:getAngle() * 180 / math.pi) end end   stage:addEventListener(Event.ENTER_FRAME, onEnterFrame)

I know that my code makes no sense but it should not cause Gideros to crash .

Scouser

Interesting, this is just part of the bridge example with the bridge part missing. The problem here is you are trying to create a joint from a body (ground) to itself. The bridge code

for i=0,13 do local bodyDef = {type = b2.DYNAMIC_BODY, position = {x = 30 + i * 20, y = 250}} local body = world:createBody(bodyDef) body:createFixture(fixtureDef)   local bitmap = Bitmap.new(Texture.new("rect.png", true)) bitmap:setAnchorPoint(0.5, 0.5) stage:addChild(bitmap)   actors[body] = bitmap   -- attach each pair of bridge elements with revolute joint local jointDef = b2.createRevoluteJointDef(prevBody, body, 20 + i * 20, 250) world:createJoint(jointDef)   prevBody = body end

needs to be inserted before the line

-- attach last bridge element to the ground body

As far as I know, a joint must be attached to 2 separate bodies.

gyrosp

Yes, I know . As I mentioned the code makes no sense.
I wanted to modify the code and try somes things. I removed the parts I wanted to replace and just pressed run to test if the code still 'compiles' and then it crashed .

I just thought that it is not a wanted behaviour that gideros crashes like this, so I posted the error here.

Scouser

Ah, now I understand. This is just a simple oversight and can probably be fixed quite easily by checking the bodyA & bodyB are not the same when creating joints. I have just checked this on my Android phone and it didn't report any errors / problems so it would appear to only be the windows player.

Good catch