Hi!
I think I found a bug in Box2D. I was using 2.1.2 versión, I updated it to 2.2.1 and the bug continues there.
I will try to cut the specific code by copying them from my big program. I apologize if anything is missing.
First I make a box to limit a 'rectangular world' with 4 edges:
Code:
void
_CreateFrame()
{
b2BodyDef groundBodyDef;
b2EdgeShape groundEdge;
b2FixtureDef boxShapeDef;
float width, height;
float margin;
margin = 32;
width = (IDevice::GetWindowManager()->GetWidth() + margin) * gPixelsToMeters;
height = (IDevice::GetWindowManager()->GetHeight() + margin) * gPixelsToMeters;
groundBodyDef.position.Set(0, 0);
mpGroundBody = mPhisicWorld.CreateBody(&groundBodyDef);
boxShapeDef.shape = &groundEdge;
margin *= -gPixelsToMeters;
groundEdge.Set(b2Vec2(margin, margin), b2Vec2(width, margin));
mpGroundBody->CreateFixture(&boxShapeDef);
groundEdge.Set(b2Vec2(margin, margin), b2Vec2(margin, width));
mpGroundBody->CreateFixture(&boxShapeDef);
groundEdge.Set(b2Vec2(margin, height), b2Vec2(width, height));
mpGroundBody->CreateFixture(&boxShapeDef);
groundEdge.Set(b2Vec2(width, height), b2Vec2(width, margin));
mpGroundBody->CreateFixture(&boxShapeDef);
}
Then I create a ball:
Code:
void
_CreateBall(b2Vec2 _position;)
{
b2BodyDef ballBodyDef;
b2CircleShape circle;
b2FixtureDef ballShapeDef;
ballBodyDef.type = b2_dynamicBody;
ballShapeDef.shape = &circle;
ballShapeDef.density = 2.0f;
ballShapeDef.friction = 0.4f;
ballShapeDef.restitution = 0.2f;
circle.m_radius = 128;
mpBall = mPhisicWorld.CreateBody(&ballBodyDef);
mpBall->CreateFixture(&ballShapeDef);
mpBall->SetTransform(position, angle);
}
BUG: If the ball hits the top or the left edge my program crash because I'm getting NaN in the position and rotation of the ball.Note that I initialize the world without gravity and update the world every frame in this way:
Code:
// Init
mPhisicWorld(b2Vec2(0, 0))
Code:
// on every frame
mPhisicWorld.Step(1.0f/30.0f, 10, 10);
Furthermore, if I put
margin = 0 in the function
_CreateFrame all works fine.
Could someone reproduce the bug, please?
Any suggestions for prevent it?
Thanks!
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