Panda3D Forums

by **enn0x** » Sun Apr 03, 2011 2:27 pm

Sorry for the slow response - I have been away for the weeend.

You are right, the shapeDesc going out of scope is causing the problem. When call actorDesc.addShape is just reads the NxShapeDesc pointer and hands it over to the NxActorDesc. PhysxActorDesc does not retain a PT of the PhysxShapeDesc.

The descriptors are not meant to be kept for a longer time, and they do not inhierit e. g. from TypedReferenceCount. As a general rule you should keep around all descriptors until the actual object is created, and then throw them away.

The actual objects (PhysxActor, PhysxMaterial, PhysxShape, ...) are reference counted, and I store a reference to these objects in whatever other object owns them, so e. g. a PhysxActor instance can go out of scope without the instance being deleted.

by **enn0x** » Fri May 06, 2011 2:01 am

The PhysX SDK 3.0 is out now.

I had a quick glance at the documentation, and it seems quite interesting. However, it is also a full rerwrite of the API. Not only the names for all the classes have changed, but also the object hierarchies and several other details.

For now there is only a Windows SDK available. Linux and OSX will follow several months later. At least for far it has been like this.

The huge change in the PhysX API makes it unreasonable to just "upgrade" the existing Panda3D PhysX module. I think a full rewrite based on the lessons learned with the current PhysX integration and the emergin Bullet integration is the way to go.

Don't try to compile the current Panda3D source code using the PhysX SDK 3.0. It won't compile.

by **claudio** » Wed Jul 27, 2011 3:41 pm

Hello! I'm having troubles with groups and groups masks.

Code: Select all: import direct.ffi.panda3d import direct.directbase.DirectStart from panda3d.core import Vec3 from panda3d.core import Point3 from panda3d.physx import PhysxManager from panda3d.physx import PhysxScene from panda3d.physx import PhysxSceneDesc from panda3d.physx import PhysxBodyDesc from panda3d.physx import PhysxActorDesc from panda3d.physx import PhysxBoxShapeDesc from panda3d.physx import PhysxPlaneShapeDesc from panda3d.physx import PhysxRay from panda3d.physx import PhysxMask from panda3d.physx import PhysxGroupsMask from base import BaseWorld class World(BaseWorld): def __init__(self): BaseWorld.__init__(self) def setup(self): # Scene sceneDesc = PhysxSceneDesc() sceneDesc.setGravity(Vec3(0, 0, -9.81)) self.scene = PhysxManager.getGlobalPtr().createScene(sceneDesc) # Plane shapeDesc = PhysxPlaneShapeDesc() shapeDesc.setPlane(Vec3(0, 0, 1), -2) actorDesc = PhysxActorDesc() actorDesc.addShape(shapeDesc) self.planeActor = self.scene.createActor(actorDesc) # Box self.boxNP = loader.loadModel('models/box.egg') self.boxNP.reparentTo(render) shapeDesc = PhysxBoxShapeDesc() shapeDesc.setDimensions(Vec3(0.5, 0.5, 0.5)) bodyDesc = PhysxBodyDesc() bodyDesc.setMass(10.0) actorDesc = PhysxActorDesc() actorDesc.setBody(bodyDesc) actorDesc.setName('Box') actorDesc.addShape(shapeDesc) actorDesc.setGlobalPos(Point3(0, 0, -1.5)) self.boxActor = self.scene.createActor(actorDesc) self.boxActor.attachNodePath(self.boxNP) # Scene collision filtering expression: (G0 & G1) == True. self.scene.setFilterConstant0(PhysxGroupsMask.allOff()) self.scene.setFilterConstant1(PhysxGroupsMask.allOff() self.scene.setFilterOps(op0 = self.scene.FOOr ,op1 = self.scene.FOOr ,op2 = self.scene.FOAnd) self.scene.setFilterBool(True) # Main groups mask. GROUPSMASK1 = PhysxGroupsMask().allOff() GROUPSMASK1.setBits0(1) # Another groups mask. GROUPSMASK2 = PhysxGroupsMask().allOff() GROUPSMASK2.setBits0(2) # Box in group 0. self.boxActor.setGroup(0) # Box and plane in groups mask 1. self.boxActor.getShape(0).setGroupsMask(GROUPSMASK1) self.planeActor.getShape(0).setGroupsMask(GROUPSMASK1) # Ray ray = PhysxRay() ray.setOrigin(Point3(0, -1, -1.5)) ray.setDirection(Vec3(0, 1, 0)) ray.setLength(5.0) # Raycast 1. group0 = PhysxMask.allOff() rayhit = self.scene.raycastClosestShape(ray ,shapesType=PhysxScene.STAll ,mask=group0 ,groups=GROUPSMASK1) print "raycast 1 hit? ", not rayhit.isEmpty() # Raycast 2. group0 = PhysxMask.allOff() group0.setBit(0) rayhit = self.scene.raycastClosestShape(ray ,shapesType=PhysxScene.STAll ,mask=group0 ,groups=GROUPSMASK1) print "raycast 2 hit? ", not rayhit.isEmpty() # Raycast 3. group0 = PhysxMask.allOff() group0.setBit(0) rayhit = self.scene.raycastClosestShape(ray ,shapesType=PhysxScene.STAll ,mask=group0 ,groups=GROUPSMASK2) print "raycast 2 hit? ", not rayhit.isEmpty() def update(self, task): dt = globalClock.getDt() self.scene.simulate(dt) self.scene.fetchResults() return task.cont def cleanup(self): self.boxNP.removeNode() self.scene.release() render.ls() if __name__ == '__main__': world = World() run()

I was expecting an opposite outcome for any of the three ray casts. What am I doing wrong? Thanks!

by **enn0x** » Thu Jul 28, 2011 4:27 pm

I would expect False, True, True.
Let's have a look at the first one. You print out the boolean value rayhit.isEmpty(). So getting a hit will print 'False'.

You set the custom filter expression like this

Code: Select all: self.scene.setFilterConstant0(PhysxGroupsMask.allOff()) self.scene.setFilterConstant1(PhysxGroupsMask.allOff()) self.scene.setFilterOps(op0 = self.scene.FOOr, op1 = self.scene.FOOr, op2 = self.scene.FOAnd) self.scene.setFilterBool(True)

From the NVIDIA docs:

(G0 op0 K0) op2 (G1 op1 K1) == b
with

G0 = NxGroupsMask for shape S0. See setGroupsMask
G1 = NxGroupsMask for shape S1. See setGroupsMask
K0 = filtering constant 0. See setFilterConstant0
K1 = filtering constant 1. See setFilterConstant1
b = filtering boolean. See setFilterBool
op0, op1, op2 = filtering operations.

Now, using your setting, you have:

Code: Select all: (G0 or 0000...) and (G1 or 0000...) = True

For the box you set GROUPSMASK1, which is '100000000000...',
and for the ray you also set GROUPSMAKS1. Inserting these values for G0 and G1 gives:

Code: Select all: (1000.. or 0000...) and (1000... or 0000...) = True

or

Code: Select all: true and true = true

This is true, so your ray scores a hit for the box. And raycase.isEmpty() will return 'False'
This is what I get when running your script.

by **cla** » Tue Aug 02, 2011 1:17 pm

Hey thanks for replying! I'm actually printing "not rayhit.isEmpty()".. so the first ray cast doesn't hit even though box and ray have same group and groups mask.

by **enn0x** » Tue Aug 02, 2011 2:45 pm

Ok, didn't notice the "not".
Something else I didn't notice is that you use the 128-bit masks filtering (groupsMasks), but you don't provide 1111111 for the mask itself. You use

Code: Select all: group0 = PhysxMask.allOff()

If using 128-bit masks this should be the default value for the "mask" parameter

Code: Select all: group0 = PhysxMask.allOn()

You can cose between two methods when raycasting:
(1) Use actor.getShape(i).setGroup() and use the "group" parameter of the raycast to pass a mask of groups.
(2) Use actor.getShape(i).setGroupsMask() and use the "groupsMask" parameter of the raycast. Leave the parameter group at it's default value PhysxMask.allOn.

By the way:

Code: Select all: self.boxActor.setGroup(0)

This sets the "actor group", which is not related to shape group (first option above) or shape groupsMask (second option above). I know this might be a bit confusing since PhysX offers four or five different mechanisms to filter collisions.

by **cla** » Thu Aug 04, 2011 12:46 pm

Yeah that's pretty confusing! I changed the code by removing the actor group and setting PhysxMask.allOn() for every ray cast. There two ray casts now, the first with GROUPSMASK1 and the second with GROUPSMASKS2. They both hit the box but the second shouldn't. What else am I doing wrong? Thanks!

Code: Select all: import direct.ffi.panda3d import direct.directbase.DirectStart from panda3d.core import Vec3 from panda3d.core import Point3 from panda3d.physx import PhysxManager from panda3d.physx import PhysxScene from panda3d.physx import PhysxSceneDesc from panda3d.physx import PhysxBodyDesc from panda3d.physx import PhysxActorDesc from panda3d.physx import PhysxBoxShapeDesc from panda3d.physx import PhysxPlaneShapeDesc from panda3d.physx import PhysxRay from panda3d.physx import PhysxMask from panda3d.physx import PhysxGroupsMask from base import BaseWorld class World(BaseWorld): def __init__(self): BaseWorld.__init__(self) def setup(self): # Scene sceneDesc = PhysxSceneDesc() sceneDesc.setGravity(Vec3(0, 0, -9.81)) self.scene = PhysxManager.getGlobalPtr().createScene(sceneDesc) # Plane shapeDesc = PhysxPlaneShapeDesc() shapeDesc.setPlane(Vec3(0, 0, 1), -2) actorDesc = PhysxActorDesc() actorDesc.addShape(shapeDesc) self.planeActor = self.scene.createActor(actorDesc) # Box self.boxNP = loader.loadModel('models/box.egg') self.boxNP.reparentTo(render) shapeDesc = PhysxBoxShapeDesc() shapeDesc.setDimensions(Vec3(0.5, 0.5, 0.5)) bodyDesc = PhysxBodyDesc() bodyDesc.setMass(10.0) actorDesc = PhysxActorDesc() actorDesc.setBody(bodyDesc) actorDesc.setName('Box') actorDesc.addShape(shapeDesc) actorDesc.setGlobalPos(Point3(0, 0, -1.5)) self.boxActor = self.scene.createActor(actorDesc) self.boxActor.attachNodePath(self.boxNP) # Scene collision filtering expression: (G0 & G1) == True. self.scene.setFilterConstant0(PhysxGroupsMask.allOff()) self.scene.setFilterConstant1(PhysxGroupsMask.allOff()) self.scene.setFilterOps(op0=self.scene.FOOr ,op1=self.scene.FOOr ,op2=self.scene.FOAnd) self.scene.setFilterBool(True) # Main groups mask. GROUPSMASK1 = PhysxGroupsMask().allOff() GROUPSMASK1.setBits0(1) # Another groups mask. GROUPSMASK2 = PhysxGroupsMask().allOff() GROUPSMASK2.setBits0(2) # Box and plane in groups mask 1. self.boxActor.getShape(0).setGroupsMask(GROUPSMASK1) self.planeActor.getShape(0).setGroupsMask(GROUPSMASK1) # Ray ray = PhysxRay() ray.setOrigin(Point3(0, -1, -1.5)) ray.setDirection(Vec3(0, 1, 0)) ray.setLength(5.0) # Raycast 1. rayhit = self.scene.raycastClosestShape(ray ,shapesType=PhysxScene.STAll ,mask=PhysxMask.allOn() ,groups=GROUPSMASK1) print "raycast 1, same groups mask, hit? ", not rayhit.isEmpty() # Raycast 2. rayhit = self.scene.raycastClosestShape(ray ,shapesType=PhysxScene.STAll ,mask=PhysxMask.allOn() ,groups=GROUPSMASK2) print "raycast 2, different groups mask, hit? ", not rayhit.isEmpty() def update(self, task): dt = globalClock.getDt() self.scene.simulate(dt) self.scene.fetchResults() return task.cont def cleanup(self): self.boxNP.removeNode() self.scene.release() render.ls() if __name__ == '__main__': world = World() run()

by **enn0x** » Thu Aug 04, 2011 4:58 pm

Now I would expect True for the first raycast and False for the second. I get True and True.

You found a bug. I evaluated the groupsMask parameter for all of the raycast* methods, but I forgot to pass the evaluated groupsMask to PhysX. A fix is checked in already. Please try your sample again with the next snapshot build.

by **cla** » Mon Aug 08, 2011 9:54 am

I tried with the last spanshot and now works fine. Thanks for fixing it!!

by **martburg** » Mon Aug 29, 2011 1:38 pm

Hi Enn0x,

Which horse to bet on?

Bullet or PhysX?

I have to update a panda3D 1.6.2 program I use to visualize a real world stage where we fly a camera.
At the moment we use the native panda collision control which seems to be a little bit unstable so we are looking into upgrading.

please advice

with kind regards

Martin

by **enn0x** » Mon Aug 29, 2011 4:03 pm

martburg wrote:Which horse to bet on?

Bullet or PhysX?

I have to update a panda3D 1.6.2 program I use to visualize a real world stage where we fly a camera.
At the moment we use the native panda collision control which seems to be a little bit unstable so we are looking into upgrading.

I'm afraid that I can not answer this question, at least not based on any hard facts.

It seems you don't need physics, but only collision detection. I assume you do collision response yourself. Neither Bullet nor PhysX have been designed with this in mind. PhysX probably has more function you might find useful, but current development focus is on Bullet. This is why I would go for Bullet.

Or probably stick with the native Panda3D collision system until you find something that definitely can not be handled by this system. Often it is just not being familiar enough with something that leads to the (false) impression that something is unstable.

Sorry, but it is impossible to give solid advice here.

by **wraithix** » Sun Mar 25, 2012 3:05 am

Hi enn0x,

I know you're primarily developing Bullet integration at the moment, but I was wondering if you have any plans to develop the PhysX integration up to a more recent SDK version. I'm guessing probably not V3 because of the API changes, but maybe 2.8.4.6?

If not, I don't suppose you have a copy of the 2.8.4.4 SDK saved off somewhere that you could rehost? The PhysX site doesn't appear to have it available anymore.

Thanks for any help.

by **enn0x** » Sun Mar 25, 2012 9:13 am

Actually (now that Bullet is out) my current focus is on PhysX 3.2 and Havok 2011.3.0. Because of the huge changes in the PhysX API with 3.x it won't be an upgrade, but a complete rewrite from scratch.

I am currently playing around with different ways to integrate, utilising the lessons learned with Bullet and trying out other, new concepts. The bad news is that it will be quite some time (half a year?) before any code will be moved into the Panda3D SDK builds.

As far as I know it is possible to build using the 2.8.4.6 SDK. This is the only version I have found in my archives, and I used this version when I did compile Panda3D with PhysX the last time.

by **wraithix** » Mon Mar 26, 2012 1:53 am

That's great to hear, and as always, thanks for the quick reply. =)

I've tried to get 2.8.4.6 working. By copying the deployment files into the root of my panda application it compiles fine, but python crashes upon execution. I'm running Panda 1.8.0. I recall having any issue running 2.8.4.5 a few months back too, where you recommended that I needed to use 2.8.4.4, hence my thinking that's the issue.

You can verify this yourself if you like by running the following code segment:

Code: Select all: from panda3d.physx import * scene = PhysxManager.getGlobalPtr().createScene(PhysxSceneDesc())

by **enn0x** » Mon Mar 26, 2012 8:20 am

I've tried to get 2.8.4.6 working. By copying the deployment files into the root of my panda application it compiles fine, but python crashes upon execution

Just to make sure: You did compile the Panda3D SDK source code (aprox. 30-60 minutes) by executing makepanda/makepanda.py? Because you don't have to copy anything in oder to compile. Makepanda automatically detects the location of the PhysX SDK if installed in default locations.

by **wraithix** » Wed Mar 28, 2012 6:22 am

Ah apologies, I misunderstood what you were suggesting. I've rebuilt from source now and it runs against 2.8.4.6 fine, thanks for your help. I feel like it might be worthwhile hosting the recompiled libpandaphysx.dll somewhere so that other people who want to use PhysX don't need do a build from source in order to use it. Is there an appropriate place it can be hosted?

by **enn0x** » Wed Mar 28, 2012 2:28 pm

Panda3D Projects might be a possible place. But you could also try and push rdb into upgrading the build machines.

by **wraithix** » Fri Mar 30, 2012 3:44 am

I've asked rdb if he could update the build machine SDK to 2.8.4.6, he said he'll do it when he gets a chance. Thanks for your help enn0x. =)

by **rdb** » Fri Mar 30, 2012 1:42 pm

Done. Try the latest build. I have only upgraded the Windows buildbot. The OSX SDK for 2.8.4 was not newer than the one I already had installed, and the Linux SDKs were only available for PhysX 3.

by **wraithix** » Fri Mar 30, 2012 9:36 pm

I've tried the latest Windows build snapshot (#544) and it still crashes when launching. The libpandaphysx.dll file looks to have been updated however, so I'm not sure what's wrong. No error message, python just crashes (which is the problem I had before when using a the newer SDK with the older library).

The working libpandaphysx.dll I've been using is slightly larger than the packaged one, so maybe it's not linking to the PhysX SDK 2.8.4.6 properly?

by **rdb** » Sat Mar 31, 2012 2:39 am

I'm not sure. Is there something I'm supposed to do besides remove the old SDK build and install the new one for makepanda to link properly?

by **enn0x** » Sat Mar 31, 2012 2:52 pm

No, I don't think there is anything else to do.

I installed the PhysX 2.8.4.6 SDK and did a full build using the current CVS head. It compiled fine, and I did not see any warnings/errors regarding PhysX. After copying the required PhysX dlls to my samples folder I have been able to run my samples without any problems.

Then I downloaded the Panda3D SDK (Panda3D-2012.03.31-545) and using this verison of libpandaphysx I get crashes too. Not when creating a world, but when creating the first actor. Anyway.

Comparing the two libpandaphysx.dll files:

Code: Select all: -> my own build: 2.925.568 bytes -> snapshot build 545: 2.911.232 bytes

So what is going on? I downloaded the 2.8.4.6 SDK a few months ago. Maybe NVIDIA replaced it, with a new SDK without changing the version number. We had this once, and it caused lots of confusion. Can you check your versions/sizes of the following dlls:

Code: Select all: cudart32_30_9.dll 6.14.11.3000 290.408 NxCharacter.dll 2.8.4.6 107.872 PhysXCooking.dll 2.8.4.6 383.840 PhysXCore.dll 2.8.4.6 3.567.456 physxcudart_20.dll -/- 197.912 PhysXDevice.dll 11.2.25.0 65.536 PhysXLoader.dll 2.8.4.6 64.352

by **enn0x** » Mon Apr 02, 2012 3:29 pm

Try the latest Panda3D SDK (547 or later). I guess the 545 build has been started before the PhysX SDK has been replace.

by **wraithix** » Wed Apr 04, 2012 7:52 am

Hey enn0x, just two quick questions regarding documentation:

1). Are there any plans to add PhysX to the manual? I don't need it personally, but I imagine other people might find it hard to pick up PhysX at the moment because there's not really any documentation around for it. Even just adding the samples zip file to the manual would probably be useful.

2). I can't seem to find any API doc. Am I just missing it, or will I just need to read the code itself for the moment?

by **enn0x** » Wed Apr 04, 2012 8:18 am

Well, first I'd like to know if the above problem is solved now, i. e. does the 547 snapshot (or later) work for you?

wraithix wrote:Are there any plans to add PhysX to the manual?

Nope. It's 20-30 hours of work to write such a documentation, and since we are going to rewrite the PhysX module for PhysX 3.2 (or later) I don't think it's worth the effort. But of course we are very happy if someone likes to contribute some pages.

wraithix wrote:Even just adding the samples zip file to the manual would probably be useful.

Good idea.

wraithix wrote:I can't seem to find any API doc.

Hmm, this is probably a doxygen configuration problem. It's just the Python docs which are missing. The C++ API docs have pages for the various PhysX classes.

by **wraithix** » Thu Apr 05, 2012 4:51 am

I've tested with #550 and verified that it's not working. Oddly, the DLL size is still different than mine, but I guess that doesn't matter.

I'd be happy to help with the documentation, but as you said it's probably not worth the effort at the moment as you're rewriting the module. Once Physx 3.2 implementation is ready to go (or almost ready) I'm more than willing to help test/document.

Hmm, this is probably a doxygen configuration problem. It's just the Python docs which are missing. The C++ API docs have pages for the various PhysX classes.

The C++ API will suit me fine, thanks.

by **enn0x** » Fri Apr 06, 2012 7:59 pm

wraithix wrote:I've tested with #550 and verified that it's not working.

This is strange, because it works here. I wonder where the difference is.

by **wraithix** » Fri Apr 06, 2012 9:18 pm

Oops, that was a typo. It was supposed to be "now." =p

by **Pataua101** » Mon May 14, 2012 10:53 pm

The samples download isnt working could you please put some up somewhere thanks.

by **wraithix** » Tue May 15, 2012 3:01 am

Pataua101 wrote:The samples download isnt working could you please put some up somewhere thanks.

You can download the samples here: http://enn0x.p3dp.com/physx-samples.zip

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