[SOLVED] ClosestRayResultCallback not working

[benelot]

Hello,

I found an issue in Bullet. It is in the btCollisionWorld::ClosestRayResultCallback. I tried to use that raytesting in my program but it did not work. Now I looked into the RaytestDemo and saw that btCollisionWorld::AllHitsRayResultCallback works properly and shows the hits.Then I commented the debug output from that segment and added a drawSphere to the code, which draws a red sphere at the raytest "from' position in case the btCollisionWorld::ClosestRayResultCallback does not hit anything. The red sphere is always there, I never get a hit anywhere. I appended the modified RaytestDemo.cpp file.

The only thing that I really modified is this segment:

Code: Select all

///all hits
		{
			btVector3 from(-30,1+up,0);
			btVector3 to(30,1,0);
			m_dynamicsWorld->getDebugDrawer()->drawLine(from,to,btVector4(0,0,0,1));
			btCollisionWorld::AllHitsRayResultCallback allResults(from,to);
			allResults.m_flags |= btTriangleRaycastCallback::kF_KeepUnflippedNormal;
			//kF_UseGjkConvexRaytest flag is now enabled by default, use the faster but more approximate algorithm
			//allResults.m_flags |= btTriangleRaycastCallback::kF_UseSubSimplexConvexCastRaytest;
			allResults.m_flags |= btTriangleRaycastCallback::kF_UseSubSimplexConvexCastRaytest;
			
			m_dynamicsWorld->rayTest(from,to,allResults);

			for (int i=0;i<allResults.m_hitFractions.size();i++)
			{
				btVector3 p = from.lerp(to,allResults.m_hitFractions[i]);
//				m_dynamicsWorld->getDebugDrawer()->drawSphere(p,0.1,red);
//				m_dynamicsWorld->getDebugDrawer()->drawLine(p,p+allResults.m_hitNormalWorld[i],red);
			}
		}

		///first hit
		{
			btVector3 from(-30,1.2,0);
			btVector3 to(30,1.2,0);
			m_dynamicsWorld->getDebugDrawer()->drawLine(from,to,btVector4(0,0,1,1));

			btCollisionWorld::ClosestRayResultCallback	closestResults(from,to);
//			closestResults.m_flags |= btTriangleRaycastCallback::kF_FilterBackfaces;



			if (closestResults.hasHit())
			{
				
				btVector3 p = from.lerp(to,closestResults.m_closestHitFraction);
				m_dynamicsWorld->getDebugDrawer()->drawSphere(p,0.1,blue);
				m_dynamicsWorld->getDebugDrawer()->drawLine(p,p+closestResults.m_hitNormalWorld,blue);

			}
			else{
				m_dynamicsWorld->getDebugDrawer()->drawSphere(to,0.1,red);
			}
		}

Is there something wrong with my compile I do here or is there a bug in bullet revision 5e956154ce04bb3052b4f474e71c3550303d2aee? (It might be from long before, but I just want to say that I look at the newest revision to date).

[benelot]

I could make my program work with ClosestRayResultCallback. But why does it look in my modified demo example as if it was not working?

[xexuxjy]

I could be missing something but it looks like in your first hit block of code you're not actually calling m_dynamicsWorld->rayTest ?

[benelot]

Oh wow, I did not see that. Interestingly that is precisely the problem in the bullet Raycast sample as well. Check it out, it does not do

Code: Select all

m_dynamicsWorld->rayTest(from,to,closestResults);

, so the

Code: Select all

if (closestResults.hasHit())

will never work.

[xexuxjy]

Hmm, just looked at my RayTestDemo.cpp from the svn repository(rev 2689( and it has the ray test in the first hit block :

Code: Select all

///first hit
		{
			btVector3 from(-30,1.2,0);
			btVector3 to(30,1.2,0);
			sDebugDraw.drawLine(from,to,btVector4(0,0,1,1));

			btCollisionWorld::ClosestRayResultCallback	closestResults(from,to);
			closestResults.m_flags |= btTriangleRaycastCallback::kF_FilterBackfaces;
			m_dynamicsWorld->rayTest(from,to,closestResults);


			if (closestResults.hasHit())
			{
				
				btVector3 p = from.lerp(to,closestResults.m_closestHitFraction);
				sDebugDraw.drawSphere(p,0.1,blue);
				sDebugDraw.drawLine(p,p+closestResults.m_hitNormalWorld,blue);

			}
		}

[benelot]

But it is not here:

https://github.com/bulletphysics/bullet ... stDemo.cpp

Am I wrong here? What SVN repository are you looking at? I thought the official repository is the one on github, is that incorrect?

[xexuxjy]

It used to be hosted at http://bullet.googlecode.com/svn/trunk and I guess I haven't updated for a while. It does look as though sometime during it's move over to GitHub that demo got broken slightly.

[benelot]

It is now fixed already, I opened an issue and it is fixed and closed again.