Bullet crash with debug viewer in debugDrawWorld()

[TKotze]

Hi there

I am having trouble getting the debug viewer to play nice. I have done the following :

Code: Select all

class CBulletDebugDraw : public btIDebugDraw
{
	virtual void drawLine(const btVector3& from,const btVector3& to,const btVector3& color);
	virtual void drawLine(const btVector3& from,const btVector3& to, const btVector3& fromColor, const btVector3& toColor);
	virtual void drawTriangle(const btVector3& v0,const btVector3& v1,const btVector3& v2,const btVector3& color, btScalar alpha ) { }

	virtual void	drawContactPoint(const btVector3& PointOnB,const btVector3& normalOnB,btScalar distance,int lifeTime,const btVector3& color) {};

	virtual void	reportErrorWarning(const char* warningString);

	virtual void	draw3dText(const btVector3& location,const char* textString) { };

	virtual void	setDebugMode(int debugMode) { };

	virtual int		getDebugMode() const ;
};

...

void CBulletDebugDraw::drawLine(const btVector3& from,const btVector3& to,const btVector3& color)
{
	Vec3d vFrom(from.m_floats[0],from.m_floats[1],from.m_floats[2]);
	Vec3d vTo(to.m_floats[0],to.m_floats[1],to.m_floats[2]);
	g_Renderer.AddDebugLine(vFrom,vTo);
}

void CBulletDebugDraw::drawLine(const btVector3& from,const btVector3& to, const btVector3& fromColor, const btVector3& toColor)
{
	drawLine(from,to,fromColor);
}

int CBulletDebugDraw::getDebugMode() const
{
	return DBG_DrawWireframe; 
}

void CBulletDebugDraw::reportErrorWarning( const char* warningString )
{
	... logging code ...
}

I then create btDynamicsWorld, initialize all the necessary stuff, set an instance of the above class as my debug viewer and
add 3 rigid bodies with different kinds of shapes.
However, this causes an access violation in btCollisionWorld.cpp in the method debugDrawWorld(), line 1444 (not too sure how reliable that is).
I know this isn't too much to go on, but does anyone have an idea what could be causing this? Is there anything obvious I am missing, or something
I do not know regarding the debug viewer?
When I do not add the rigid bodies to the world the program runs fine. The physics also seems to be working fine when I do not use the debug viewer.

Any help would be much appreciated!
Thanks

[dphil]

Everything looks ok to me. Can you check your Bullet source and see what line 1444 is (if there is one)?

[TKotze]

Yea I marked the line here at the bottom

Code: Select all

void	btCollisionWorld::debugDrawWorld()
{
	if (getDebugDrawer() && getDebugDrawer()->getDebugMode() & btIDebugDraw::DBG_DrawContactPoints)
	{
		int numManifolds = getDispatcher()->getNumManifolds();
		btVector3 color(0,0,0);
		for (int i=0;i<numManifolds;i++)
		{
			btPersistentManifold* contactManifold = getDispatcher()->getManifoldByIndexInternal(i);
			//btCollisionObject* obA = static_cast<btCollisionObject*>(contactManifold->getBody0());
			//btCollisionObject* obB = static_cast<btCollisionObject*>(contactManifold->getBody1());

			int numContacts = contactManifold->getNumContacts();
			for (int j=0;j<numContacts;j++)
			{
				btManifoldPoint& cp = contactManifold->getContactPoint(j);
				getDebugDrawer()->drawContactPoint(cp.m_positionWorldOnB,cp.m_normalWorldOnB,cp.getDistance(),cp.getLifeTime(),color);
			}
		}
	}

	if (getDebugDrawer() && getDebugDrawer()->getDebugMode() & (btIDebugDraw::DBG_DrawWireframe | btIDebugDraw::DBG_DrawAabb))
	{
		int i;

		for (  i=0;i<m_collisionObjects.size();i++)
		{
			btCollisionObject* colObj = m_collisionObjects[i];
			if ((colObj->getCollisionFlags() & btCollisionObject::CF_DISABLE_VISUALIZE_OBJECT)==0)
			{
				if (getDebugDrawer() && getDebugDrawer()->getDebugMode() & btIDebugDraw::DBG_DrawWireframe)
				{
					btVector3 color(btScalar(1.),btScalar(1.),btScalar(1.));
					switch(colObj->getActivationState())
					{
					case  ACTIVE_TAG:
						color = btVector3(btScalar(1.),btScalar(1.),btScalar(1.)); break;
					case ISLAND_SLEEPING:
						color =  btVector3(btScalar(0.),btScalar(1.),btScalar(0.));break;
					case WANTS_DEACTIVATION:
						color = btVector3(btScalar(0.),btScalar(1.),btScalar(1.));break;
					case DISABLE_DEACTIVATION:
						color = btVector3(btScalar(1.),btScalar(0.),btScalar(0.));break;
					case DISABLE_SIMULATION:
						color = btVector3(btScalar(1.),btScalar(1.),btScalar(0.));break;
					default:
						{
							color = btVector3(btScalar(1),btScalar(0.),btScalar(0.));
						}
					};

					debugDrawObject(colObj->getWorldTransform(),colObj->getCollisionShape(),color);
				}
1444:				if (m_debugDrawer && (m_debugDrawer->getDebugMode() & btIDebugDraw::DBG_DrawAabb))
				{
					btVector3 minAabb,maxAabb;
					btVector3 colorvec(1,0,0);
					colObj->getCollisionShape()->getAabb(colObj->getWorldTransform(), minAabb,maxAabb);
					btVector3 contactThreshold(gContactBreakingThreshold,gContactBreakingThreshold,gContactBreakingThreshold);
					minAabb -= contactThreshold;
					maxAabb += contactThreshold;

					btVector3 minAabb2,maxAabb2;

					if(colObj->getInternalType()==btCollisionObject::CO_RIGID_BODY)
					{
						colObj->getCollisionShape()->getAabb(colObj->getInterpolationWorldTransform(),minAabb2,maxAabb2);
						minAabb2 -= contactThreshold;
						maxAabb2 += contactThreshold;
						minAabb.setMin(minAabb2);
						maxAabb.setMax(maxAabb2);
					}

					m_debugDrawer->drawAabb(minAabb,maxAabb,colorvec);
				}
			}

		}
	}
}

Soo I'm guessing it breaks in the method debugDrawObject(colObj->getWorldTransform(),colObj->getCollisionShape(),color);.
It does call my line drawing code before it breaks.

Thanks for the reply

[xexuxjy]

clutching at straws, but have you checked that m_debugDraw is a valid pointer at that point? It's interesting that the code above that line uses getDebugDraw() rather then m_debugDraw directly.

[TKotze]

Ahhhh so I solved the issue. I was linking with a version of the bullet lib using double's, however
in my application #define BT_USE_DOUBLE_PRECISION was not defined. So on debugDrawObject's return
it was writing over the stack.

Thanks for the help though