IPhysics - Newton/Irrlicht framework

[RapchikProgrammer]

Monkey cracks, in the old version just set the update mode to:

physics->setUpdateMode(UM_EVERY_FRAME);

and youll see alot of improvement.

[monkeycracks]

Didn't help at all.

[RapchikProgrammer]

Well i might be mixing up with something else so sorry! But in the new release it will be a lot better tho.

[Nargil]

Hi. How is your work going ? I must say IPhysics is the only irrlicht based physics engine I managed to run in my linux project. Although I have a problem with the 1.2 (RP edit) release: I have a terrain

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#include <iostream.h>

#include <IPhysics.h>

#include <Irrlicht.h>
#include <Newton.h>

#pragma comment(lib, "Irrlicht.lib")
#pragma comment(lib, "Newton.lib")
#pragma comment(lib, "IPhysics.lib")

using namespace irr;
using namespace core;
using namespace scene;
using namespace video;
using namespace io;
using namespace gui;

CPhysicsCamera* camEntity = new CPhysicsCamera;
CPhysics* physics;

ICameraSceneNode* cam;

int ground;
int rubber;
int metal;

stringw solver;

class CEventReceiver_eg2 : public IEventReceiver
{
public:
	CEventReceiver_eg2(ISceneManager* sceneManager, ICameraSceneNode* camera)
	{
		m_sceneManager = sceneManager;
	}
	~CEventReceiver_eg2()
	{
	}
	bool OnEvent(SEvent event)
	{
		if (event.EventType == EET_KEY_INPUT_EVENT&&
			!event.KeyInput.PressedDown)
		{
			switch(event.KeyInput.Key)
			{
			case KEY_KEY_0:
					physics->setSolverModel(0);
					solver = "Exact";
			case KEY_KEY_1:
					physics->setSolverModel(1);
					solver = "Adaptive";
			case KEY_KEY_2:
					physics->setSolverModel(2);
					solver = "Linear";

				return true;
			}
		}

		if(event.EventType == EET_MOUSE_INPUT_EVENT)
		{
			if(event.MouseInput.Event == EMIE_LMOUSE_PRESSED_DOWN)
			{
				vector3df camvec = (cam->getTarget() - camEntity->getPosition()).normalize() * 500;
				// drop test cube from camera's position
				physics->dropTestCube(m_sceneManager, camEntity->getPosition(), 2.0f, 25.0f);
			}
			else if(event.MouseInput.Event == EMIE_RMOUSE_PRESSED_DOWN)
			{
				// drop test sphere from camera's position
				physics->dropTestSphere(m_sceneManager, camEntity->getPosition(), 2.0f, 5.0f);
			}
		}

		camEntity->onEvent(event);

		return false;
	}
protected:
	ISceneManager* m_sceneManager;

	ICameraSceneNode* m_camera;
};

int main()
{
	// start Irrlicht
	IrrlichtDevice* device = createDevice(EDT_OPENGL);


	// pointers to driver, scenemanager
	IVideoDriver* driver = device->getVideoDriver();
	ISceneManager* smgr = device->getSceneManager();

	// create an FPS camera
	cam = smgr->addCameraSceneNode();

	// start iphysics
	physics = new CPhysics;
	physics->init(device);
	physics->setUpdateMode(UM_EVERY_FRAME);

	// create our custom event receiver, set it as the active one
	CEventReceiver_eg2 receiver(smgr, cam);
	device->setEventReceiver(&receiver);

	// get pointer to material manager
	CMaterialManager* mm = physics->getMaterialManager();

	// create materials
	ground = mm->createMaterial();
	rubber = mm->createMaterial();
	metal = mm->createMaterial();

	mm->setFriction(ground,ground,0.8f, 0.4f);
	mm->setElasticity(ground,ground,0.3f);
	mm->setSoftness(ground,ground,0.05f);

	mm->setFriction(ground,rubber,0.5f,0.2f);
	mm->setElasticity(ground,rubber,0.6f);
	mm->setSoftness(ground,rubber,0.15f);

	mm->setFriction(ground,metal,1.0f,0.6f);
	mm->setElasticity(ground,metal,0.1f);
	mm->setSoftness(ground, metal,0.01f);

    IAnimatedMesh* levelmesh = smgr->getMesh("teren.3DS");
	IAnimatedMeshSceneNode* levelnode = smgr->addAnimatedMeshSceneNode(levelmesh);
	levelnode->setMaterialFlag(EMF_LIGHTING, false);
	levelnode->setMaterialTexture(0,driver->getTexture("terrain-texture.jpg"));

	SPhysicsStaticMesh level;
	level.mesh = levelmesh;
	level.meshnode = levelnode;
	level.meshScale = vector3df(1.1f, 1.1f, 1.1f);
	level.meshnode->setScale(level.meshScale);

	IPhysicsEntity* levelEntity = physics->addEntity(&level);
	levelEntity->setPosition(vector3df(0,0,0)*level.meshScale);
	levelEntity->setMaterial(ground);

	SPhysicsCamera* camera = new SPhysicsCamera;
	camera->cam = cam;
	camera->bodySize = vector3df(3.5f,3.5f,3.5f);
	camera->mass = 20.0f;
	camera->moveSpeed = 15.0f;
	camera->sensitivity = 100.0f;

	camEntity = physics->addEntity(camera);
	camEntity->setPosition(vector3df(3.0f,30.0f, 3.0f));;

	//physics->debug(true);

	stringw caption;

	while(device->run())
	{
		driver->beginScene(true, true, SColor(0,100,100,100));

		caption = driver->getFPS();
		caption += " ";
		caption += solver;

		device->setWindowCaption(caption.c_str());

		smgr->drawAll();

		driver->endScene();

		physics->update();

	}
	return 0;
}

Now dropping a test sphere makes the sphere roll on the terrain (what is fine) but after a few seconds it begins to fall down through the terrain.

[RapchikProgrammer]

Thank you nargil, work is going pretty gud and i hope i can bring out the 2.0 release soon. Ya about your problem this has been reported by other people too and i am seeing it myself in terrain example! I am trying to go through this tho, so this shud be released by v2.0!

edit: I just got a weird idea and amazingly it worked! Just increase the terrain size from

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vector3df terrainScale(10.0f, 1.0f, 10.0f);

to

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vector3df terrainScale(20.0f, 2.0f, 20.0f);

and increase the cube and sphere size from

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// drop test cube from camera's position
physics->dropTestCube(m_sceneManager, camEntity->getPosition(), 2.0f, 25.0f);

and

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// drop test sphere from camera's position
physics->dropTestSphere(m_sceneManager, camEntity->getPosition(), 2.0f, 5.0f);

to

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// drop test cube from camera's position
physics->dropTestCube(m_sceneManager, camEntity->getPosition(), 20.0f, 25.0f);

and

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// drop test sphere from camera's position
physics->dropTestSphere(m_sceneManager, camEntity->getPosition(), 20.0f, 5.0f);

That means just blow up the scale of all the objects to some pretty big numbers and youll see that the objects dont go through the floor! Its a problem in newton, maybe its rounding up the values because they are too small and hence causing penetration, not sure why it wud be solved after this!

[Nargil]

This does not help me, and i tried it before posting. In addition scaling the values 10times makes the camera move pretty unsmooth. I didn't experience the problem using an earlier version of iPhysics from Nick_Japan

[RapchikProgrammer]

You do set the update mode to:

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physics->setUpdateMode(UM_EVERY_FRAME);

rit?
This could be the solution to the jerky cam issue! BTW Nick_Japan did not implement one major constant, which makes the size and position you set of newton objects the same in newtonian terms! So thats why if you set size 1000 in nick_japan version it will be like multiplied by 0.3somethig constant hence decreasing the size! Hope you get the point!

[monkeycracks]

@RP, how would you make a node move when a key is pressed.

By node I mean the node's IPhysics structure thing.

[RapchikProgrammer]

You can use the set position command in iphysicsentity.

[kburkhart84]

@RP, how would you make a node move when a key is pressed.

By node I mean the node's IPhysics structure thing.

Maybe I'm mistaken here, but why would you want to set the position yourself. The point of a physics library is so that it sets the positions for you. You should apply a force to the object/node upon keypresses, but not set the position yourself. If I'm mistaken though, feel free to let me know anybody.

[monkeycracks]

I have a 3rd person style RPG. I was testing some things and I don't think I'll need physics in this project but if it comes down to it, I will be using IPhysics

[Baiame]

Maybe I'm mistaken here, but why would you want to set the position yourself. The point of a physics library is so that it sets the positions for you. You should apply a force to the object/node upon keypresses, but not set the position yourself. If I'm mistaken though, feel free to let me know anybody.

That's what I was thinking (I've used Newton before, in a totally different engine and language). Only ever set positions upon a rigid body's creation.

By the way, Rapchik Programmer, I don't see any functions in the IPhysics doco (I know it's outdated) for manually applying forces to objects. Is that in the new version?

[RapchikProgrammer]

Forces have been implemented in the newer version, it will be there in the next release but currently you cant work with forces, sorry!

@monkeycracks: Hey thanks, it feels gr8 to know that the amount of time i spent on iphysics is never gonna go down the drain!

[monkeycracks]

Forces have been implemented in the newer version, it will be there in the next release but currently you cant work with forces, sorry!

@monkeycracks: Hey thanks, it feels gr8 to know that the amount of time i spent on iphysics is never gonna go down the drain!

No problem, I'm actually working on a game that uses it.

However, this code :

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levelMesh[1] = smgr->getMesh("media/level one fps.x");
//levelMesh[2] = smgr->getMesh("media/level two fps.x");

levelNode[1] = smgr->addAnimatedMeshSceneNode(levelMesh[1]);
//levelNode[2] = smgr->addAnimatedMeshSceneNode(levelMesh[2]);

levelNode[1]->setMaterialFlag(EMF_LIGHTING, false);
//levelNode[2]->setMaterialFlag(EMF_LIGHTING, false);

level1.mesh = levelMesh[1];
level1.meshnode = levelNode[1];
level1.meshScale = vector3df(1.0f, 1.0f, 1.0f);
level1.meshnode->setScale(level1.meshScale);

levelEntity1 = physics->addEntity(&level1);
levelEntity1->setPosition(vector3df(0,0,0)*level1.meshScale);

cam = smgr->addCameraSceneNodeFPS();

camera = new SPhysicsCamera;
camera->cam = cam;
camera->bodySize = vector3df(3.5f,3.5f,3.5f);
camera->mass = 10.0f;
camera->moveSpeed = 3.0f;
camera->sensitivity = 100.0f;

camEntity = physics->addEntity(camera);
camEntity->setPosition(vector3df(10,85,10));
camEntity->setGround(levelEntity1->getBody());

causes a crash when update() is called.
I have narrowed it down to be in here somewhere :

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cam = smgr->addCameraSceneNodeFPS();

camera = new SPhysicsCamera;
camera->cam = cam;
camera->bodySize = vector3df(3.5f,3.5f,3.5f);
camera->mass = 10.0f;
camera->moveSpeed = 3.0f;
camera->sensitivity = 100.0f;

camEntity = physics->addEntity(camera);
camEntity->setPosition(vector3df(10,85,10));
camEntity->setGround(levelEntity1->getBody());

I do have the camEntity->onEvent(event); in my event receiver.

Here are all the pointers just in case you need them :

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        IAnimatedMeshSceneNode* levelNode[2];
        IAnimatedMesh* levelMesh[2];
        SPhysicsStaticMesh level1;
        IPhysicsEntity* levelEntity1;
        
        CPhysicsCamera* camEntity;
        SPhysicsCamera* camera;
        ICameraSceneNode* cam;

Sorry for the long post, thanks though

[monkeycracks]

I changed smgr->addCameraSceneNodeFPS to smgr->addCameraSceneNode and it didn't crash but there was no mouse input and the keyboard commands didn't work.