Newton Dynamic Physics Integration

[fps]

i found an interesting video that shows weapon physcis in use i watched it without sound (broken speakers) so i dont know for sure if its appropriate but i didnt see anything wrong with it. watch the shotgun flip off the arm of the small couch. now i you could have snatched that out of the air and blown someone away that would have been an incredible game experience.

also i dont know if the video will show. the video is called "RagDoll Physics: Artform. Chapter One"
i foud it while looking through rag doll physics vids on you tube.

thanks,
fps

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[kikosmalltalk]

Hi Federico

Thank you again.

The that more it interests me at this time, it is the form that you use to Newton update.

Newton uses callback, that return the position of my actor. Something like that:

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  void  PhysicsSetTransform (const NewtonBody* body, const dFloat* matrix)
{
	RenderPrimitive* primitive;

	// get the graphic object form the rigid body
	primitive = (RenderPrimitive*) NewtonBodyGetUserData (body);

	// set the transformation matrix for this rigid body
	dMatrix& mat = *((dMatrix*)matrix);
	primitive->SetMatrix (mat);
}
  

I update newton this way:

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  float t = 0.0f;
    const float dt = 0.01f;

    float currentTime = 0.0f;
    float accumulator = 0.0f;

    State previous;
    State current;

    while (!quit)
    {
         float newTime = time();
         float deltaTime = newTime - currentTime;
         currentTime = newTime;

         accumulator += deltaTime;

         while (accumulator>=dt)
         {
              previousState = currentState;
              integrate(currentState, t, dt);
              t += dt;
              accumulator -= dt;
         }

         const float alpha = accumulator / dt;

         State state = currentState*alpha + previousState*(1.0f-alpha);

         render(state);
    }

That it uses the same concept that their form of update Newton. Right ?.

you wrote:
UpdateLoop is defined in the physicsSystem entity and force the phsycisengine to run multiple update in the same frame.

The problem is that NewtonUpdate is executed 3 times and the frame 1 time, for example. When I relocate the actors I will have a stutterer problem.

As it describes the article that I commented him.

Do you understand? .

Now. Tokamak uses callback as Newton, but I don't find as Nout it solved the problem.


Did he use INTERPOLATION? .
This is the code:

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	//Run now the real physics simulation
	dwTicks = (float)(TimeTicks)/IterationTime;
	geVec3d Pos;
	//Calculate the new positions for all rigid bodies
	//If the engine is slow, run multiple physics loops
	for (int p = 0; p <(1 + dwTicks); p++) 
	{
	    gSim->Advance(AdvanceTime*0.001f);
		for (int nr = 0; nr<sizeInfo.rigidBodiesCount; nr++)
	    {
			//Calculate the new positions for all rigid bodies
			neT3 trans = rBody[nr]->GetTransform();
			geXForm3d M;
			geXForm3d_SetIdentity(&M);
			geVec3d Angles;
			neGeometry *geom;
			rBody[nr]->BeginIterateGeometry(); //get the corresponding actor index number
			int s=0;
			while (geom = rBody[nr]->GetNextGeometry())
			{
				if (s>0)
				{
					neT3 gtrans = geom->GetTransform();
					neT3 gmt = trans * gtrans;
					M.AX = gmt.rot[0][0];
					M.BX = gmt.rot[0][1];
					M.CX = gmt.rot[0][2];
					M.AY = gmt.rot[1][0];
					M.BY = gmt.rot[1][1];
					M.CY = gmt.rot[1][2];
					M.AZ = gmt.rot[2][0];
					M.BZ = gmt.rot[2][1];
					M.CZ = gmt.rot[2][2];
					M.Translation.X = gmt.pos[0];
					M.Translation.Y = gmt.pos[1];
					M.Translation.Z = gmt.pos[2];
					Pos.X = gmt.pos[0];
					Pos.Y = gmt.pos[1];
					Pos.Z = gmt.pos[2];
				}
				else
				{
					M.AX = trans.rot[0][0];
					M.BX = trans.rot[0][1];
					M.CX = trans.rot[0][2];
					M.AY = trans.rot[1][0];
					M.BY = trans.rot[1][1];
					M.CY = trans.rot[1][2];
					M.AZ = trans.rot[2][0];
					M.BZ = trans.rot[2][1];
					M.CZ = trans.rot[2][2];
					M.Translation.X = trans.pos[0];
					M.Translation.Y = trans.pos[1];
					M.Translation.Z = trans.pos[2];
					Pos.X = trans.pos[0];
					Pos.Y = trans.pos[1];
					Pos.Z = trans.pos[2];
				}
				int rgNr = geom->GetUserData();
				CCD->ActorManager()->Position(PhActor[rgNr], Pos);
				geXForm3d_GetEulerAngles(&M, &Angles);
				CCD->ActorManager()->Rotate(PhActor[rgNr], Angles);
				s++;
			}
		}
	}

Best regards, KIKO

PD: I hope you understand what I mean

[federico]

@fps
http://www.youtube.com/watch?v=gFwUrcGzLZ4

The attribute entity is now physics driven, QoD added the ability to add entities at runtime. I think could be possible... theorically.
___
@kiko

yes I think it's an interpolation process. Your method and the Nout's one aren't different.

Nout on tokamak:

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//Run now the real physics simulation
   dwTicks = (float)(TimeTicks)/IterationTime;
  
   //Calculate the new positions for all rigid bodies
   //If the engine is slow, run multiple physics loops
   for (int p = 0; p <(1 + dwTicks); p++)
   {
       //Update Physics
       
   }

TimeTicks is time sliced by RealityFactory. Where? in CCommonData.cpp. Look at the RF code.

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        dwTicksGoneBy = CCD->GetTimePassed_F();

	if(dwTicksGoneBy <= 0.0f)
		return RGF_SUCCESS;					// No time passed?  Ignore call!
	
// ...
        thePhysicsManager->Tick(dwTicksGoneBy);

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/* ------------------------------------------------------------------------------------ */
//	Get the amount of time passed since the last call, in milliseconds.
//	..Return the result as a floating-point value.
/* ------------------------------------------------------------------------------------ */
geFloat CCommonData::GetTimePassed_F()
{

	geFloat DeltaTime;

	DeltaTime = (geFloat)TimeCounter - (geFloat)LastTimePoll;

	LastTimePoll = TimeCounter;
	
	LastTimePassed_D = (DWORD)DeltaTime;		// Last elapsed time as DWORD
	LastTimePassed_F = DeltaTime;						// Need in both places
	
	return DeltaTime;
}

so TimeTicks is the time sliced as in your code. My problem is that I don't unterstand exactly in your code where's the newtonupdate...
In my code is the PhysicsManager class in the Tick(TimeStep) method, as shown above.

Code: Select all

void CPhysicsManager::Tick(geFloat TimeTicks)
{
        float dwTicks = 0.0f;
	dwTicks = (float)(TimeTicks)*IterationTime;

	for (int p = 0; p <(1 + dwTicks); p++) 
	{
                //update your entities etc...

	        float theTick = dwTicks*AdvanceTime;	
		NewtonUpdate (nWorld, theTick);	
	}	
}

IterationTime is a user defined value that tells the engine how to loop the physics against the graphics loop. In my case it is a value between 0.1 and 1 and I arranged to define this value in the world editor (0.4 is my default value).

a) 1 = results in a higher update
b) 0.1 = in lower update

a) bigger physics step = the physics sim is faster = more calculations needed to draw a frame = worse graphics framerate
b) smaller physics step = the physics sim is slower = less calculations needed to draw a frame = better graphics framerate

________________

Kiko I really need help on vehicles. I know you got it working, please share your code.

Federico

[fps]

you have got to see the celfactor revolution videos.
check them out.

[kikosmalltalk]

Hi Fediro

Did you see the code of example of Newton vehicleJoint?

and the code of StuntPlayground_2_0_source?.

My vehicle works, but I have problems with the control of Side Sleep.

What problem do you have with the vehicleJoint?.

Perhaps I can help.

you wrote:
My problem is that I don't unterstand exactly in your code where's the newtonupdate...



I update Newton this way in a called class NewtonSpaceManager:

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timer tick.                 
elapsed := timer elapsedTime .
 
(elapsed > 0.25) ifTrue:[elapsed:=0.25]   .
accumulatedTime:=accumulatedTime + elapsed.        
 [accumulatedTime >= 0.016] whileTrue:[newtonWorld 
                                     update: 0.016.  
                                     accumulatedTime:=accumulatedTime - 0.016.                                                            
                                      ]. 

you wrote:
yes I think it's an interpolation process. Your method and the Nout's one aren't different.

The problem is that I cannot see where Nout makes the interpolation.

Federico you have their private mail, perhaps the one can clarify like it works



Best regards kiko

PD: Please, if you have some problem with the vehicleJoint, ask and I will try to help him

[fps]

is there going to be a community release of the physics engine and jays release anytime soon?

[federico]

as soon as I release the source, I think that Jay can easily integrate his features, so he can release an a community release of Realityfactory NGD. Anyway I hope that physics could actually be integrated in the RF stable release. I have to set up some things to release the alpha2. I've tried some experiment on cars, but I don't think I will go on in this way. Probably I will try a better solution to refine wet zones (instead of defining a water height) and something different in the update code to avoid the growing time paradox.

[fps]

a time paradox!!!
could this possibly be the solution to all of mankinds problems?
Just kidding.
what it the matter with the time? (daylight saving, im up an hour early ).
So i should be asking jay that question.

thanks,
fps

[Jay]

yes it's perfectly right with me if federico first finishes his work to an extent where he is content with it. Otherwise i will be working on the merging and he migth be working on new features at the same time, and then i release it and federico releases it 2 weeks later, and i have got to do the whole work again. (i think that's what you meant, federico?)

[fps]

your right,
it wouldent make any sence to itergrate it before fredrico is happy with it.
just keep up the good work, both of you.

[fps]

why is it that when i make a copy of demo6 and copy the ragpawn and its working parts, rename everything ragpawn3. then shoot it.
both ragpawns that are the same guy die?

[federico]

Please be specific. Write the names of your entities (pawns and Ragdoll entities) with parameters.
What's 'ragpawn3'? Is it the szEntityname of the Pawn entity?

both ragpawns that are the same guy die?

I don't understand the question, sorry. You have two pawn entities and when the first dies, also the second one dies? Is that the issue?

[fps]

the die at the exact same time.
it must be a naming problem because the both go ragdoll at he exact same time. like the bullet hits both of them.
that might be usefull for somthing intentional.
but now im just trying to but some more guys in the level.

[federico]

please post the parameters of the ragdoll and pawn entities.
As a starting suggest, consider to check if the names are correctly setup.
the pawn has name 'XXX' so the RagdollEntity parameter in the ragdoll entity should be the same and the ActivationTrigger should be 'XXX_Die' according to my script.
In my script:

Code: Select all

 if(in_pain)
    {
          SetEventState(EntityName#"_Die",true);
    }

[kikosmalltalk]

Hi Federico

Aaaaaaa!!!!. You send a private mail.

Excuse, I don't habitually look at the private mail of RF.

This is my code:

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VehicleDemo>>initializeVehicleJoint
          
         "Initialize the receiver's vehicle joint" 

vehicleJoint:= NewtonVehicleJoint world: self newtonWorld
                                         upDirection: (GeVec3D x:0.0 y:1.0 z:0.0 )
                                                  body:  self chassis body. 
                                          
vehicleJoint tireCallback:( GenesisVehicle methodAddressAt:#tirePhysicsUpdate:);
userData: self .

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VehicleDemo>>initializeTires

       "  Initialize the receiver's tires. "
     
     |tire1 tire2 tire3 tire4|   
     
     
tires:=OrderedCollection new.   
                       
tire1:=FrontWheel for: self .
tire1 setupIn: (D3DXVECTOR3 x:-0.90  y:-0.75 z:-1.3).   
self addTire: tire1.      

tire2:=FrontWheel  for: self .
tire2 setupIn: (D3DXVECTOR3 x:0.87 y:-0.75 z:-1.3).  
self addTire: tire2 .

tire3:=RearWheel  for: self .
tire3 setupIn: (D3DXVECTOR3 x:-0.87  y:-0.75 z:1.35).
self addTire: tire3 .

tire4:=RearWheel  for: self .
tire4 setupIn: (D3DXVECTOR3 x:0.87 y:-0.75 z:1.35).
self addTire: tire4  .  

self tires do:[:each | each setupActor]

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VehicleChassis>>initializeBody

         |world inertia origin mass|
         
world:=self parent newtonWorld .             
body:=NewtonRigidBody world: world
                  collision: self bodyCollision.   
                  
body autoFreeze: 0.     
world  unFreezeBody: body . 

body userData: self; 
     transformCallback:(VehicleChassis _methodAddressAt: #transform:from:);
     forceAndTorqueCallback:(VehicleChassis _methodAddressAt:#applyGravityForce:).
                                             
	

inertia:=bodyCollision  calculeInertiaMatrix .                                         
mass:=1000.0.
body massMatrix: mass 
                  inertiaX: (inertia x * mass)
                  inertiaY: (inertia y * mass)
                  inertiaZ: (inertia z * mass).
      	                               
      
origin:=GeVec3D x:0.0 y:0.2 z:0.0.
body centreOfMass: origin;          
      linearDamping:0.0 .
     
self bodyCollision release.

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VehicleWheel>>setupIn: aPosition  

       "Setup the receiver with default values"  

      |position rotation  matrix|
                             
position:=D3DXMATRIX  identity translation: aPosition. 
rotation:= D3DXMATRIX identity rotationY:89.55.  
                               
matrix:= rotation multiply: position .    
                               
                            
id:=WINAPI NewtonVehicleAddTire: self vehicleJoint 
                       with: matrix  basicAddress 
                       with: (GeVec3D x:0.0 y:0.0 z:1.0) basicAddress
                       with: self mass
                       with: self width
                       with: self radius
                       with: self suspensionShock
                       with: self suspensionSpring
                       with: self suspensionLength
                       with: self basicAddress
                       with: 0x100 .

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VehicleDemo(Class)>>controlCallback: pVehicleJoint

     |vehicle|
     
vehicle:= NewtonVehicleJoint userDataFrom: pVehicleJoint.

vehicle control.

^NULL

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VehicleDemo>>control

            |omega count|

omega := 0.0.
count := 0            .
self tires do:[:each | omega:= omega + each omeg]            .

omega:= (omega / 4.0) abs.

self manualTransmission ifFalse:[

"& (omegaIsPositive)"
((self currentGear = 1)&  (omega <= 1.0)  & (self brakesOn))
	                     ifTrue:[ self currentGear: 0].
	

(self currentGear = 0)	ifTrue:[	
	(self throttle = 0.0)not ifTrue:[ self currentGear: 1]
				            ifFalse:[ (self brakeOn) ifTrue:[ self mThrottle:1.0;
				                                            	brakesOn: false]
 			                        ]. 
 			                        
 			                    ]    
		                        ]

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VehicleDemo(Class)>>tirePhysicsUpdate: pVehicleJoint          
            
       " Update tire physics of the receiver"  
          
        |vehicle|       
                   
vehicle:= NewtonVehicleJoint userDataFrom: pVehicleJoint .           
            
vehicle tirePhysics.         
                                                       

^NULL

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VehicleDemo>>tirePhysics
     
     "Apply tire physics"
                   
self tires do:[:each | each tirePhysics]. 

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VehicleRearWheel>>tirePhysics
              
                 |speed  brakeAcceleration |
                     

	
                          
                                               
(brakes > 0.0) ifTrue:[
		 
		brakeAcceleration := self vehicleJoint calculateMaxBrakeAccelerationFor: self id.
		
		

" tell Newton you want this tire stooped but only if the torque need it is less than 
 the brakes pad can withstand (assume max brake pad torque is 500 newton * meter)"

		self vehicleJoint brakeAccelerationFor:  self id 
		                          acceleration: brakeAcceleration
		                          maxFrictionTorque:1500.0 .
		

 " set some side slip as function of the linear speed "
		
		speed := self vehicleJoint longitudinalSpeedFor: self id  .
		self vehicleJoint maxSideSleepSpeedFor: self id with: speed *1000  ]
		
		
ifFalse:[brakes = 0.0].          

                      
 super tirePhysics.
                                  
   WINAPI NewtonVehicleSetTireTorque: self vehicleJoint
	                             with: self id
	                             with: self torque .

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VehicleFrontWheel>>tirePhysics

        | speed load delta | 


                    

WINAPI	NewtonVehicleSetTireSteerAngle: vehicleJoint
                                  with: self id
                                  with:  steerAngle.                    
super tirePhysics   . 

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VehicleWheel>>tirePhysics
                
                  |speed load  |
                                   
                  
 speed := (self omega "* radius* 3.6") abs.
load  := self normalLoad.
		
                      
self maxSideSleepSpeed:  (speed * 0.1) ;
     sideSleepCoefficient: (speed * load * load *0.8)  .
                 
speed := self longitudinalSpeed.
                    
self maxLongitudinalSlideSpeed: (speed *0.1 );
	longitudinalSlideCoefficient: ( speed * load *load* 0.8 ) .

In all ways it can be he very useful to look at Newton example and StundPlayGround.

I have problems to control the you skid


I hope you understand.

Have present that can have code to improve.

kiko