wheelFriction override help

cat555 · 09-08-2014 11:32 PM

Hi, i'm overriding

Code:

flt  WheelFriction(C PhysMtrl &ground_material, C PhysMtrl &wheel_material, C ActorInfo &vehicle, WHEEL_TYPE wheel)

... but i get always unreferenced vehicle parameter.

My intention is to use vehicle information to check material under the car, for example:

Code:

flt  WheelFriction(C PhysMtrl &ground_material, C PhysMtrl &wheel_material, C ActorInfo &vehicle, WHEEL_TYPE wheel) {

if (vehicle.obj &&  Game.World.hmMaterial(vehicle.obj.pos().xz())->user_type == GROUND_SAND)

   {

      return someFriction;

   } else {

      return 2.5;

   }

}

bool Init() {

Physics.create(EE_PHYSX_DLL_PATH, CSS_MATERIALS, true).wheelFriction(WheelFriction).timestep(PHYS_TIMESTEP_VARIABLE);

}

Shouldn't Esenthel manage this by himself (passing referenced vehicle parameter), or i'm missing something here?

Thanks!

**Esenthel** · 09-11-2014 04:00 AM

Hi,

You need to first set the:
vehicle.obj(&obj);
EE.Vehicle.obj metod

cat555 · 09-11-2014 03:41 PM

Hi,

I've already tried that before, but can't make it work... i'm using this:

Code:

class Car : Vehicle

{

...

void create(C Vec &pos, C Vec &dir)

{

...

Game.ObjParamsPtr car_obj=UID(1429080598, 2558294431, 1169191620, 3226949371);

Game::Obj *car = Game::World.objCreateNear(*car_obj, Matrix(car_obj->scale(), Vec(0, 1, 0)));

T.obj(car);

}

Thanks!

**Esenthel** · 09-12-2014 03:17 AM

Hi,

Did you check if 'Game.Obj *car' is not null ? wink

Or perhaps you're calling Vehicle.obj before creating the vehicle?

this is the vehicle tutorial with some modifications:

Code:

/******************************************************************************/

const bool EasyReverse=true; // if use simplified reversing (will automatically switch between reverse<->forward gears)

Memc<Actor> actors;

Vehicle     vehicle;

Game.Chr    chr;

/******************************************************************************/

flt WheelFriction(C PhysMtrl &ground_material, C PhysMtrl &wheel_material, C ActorInfo &vehicle, WHEEL_TYPE wheel)

{

   Exit(S+vehicle.obj);

   return 1;

}

void InitPre()

{

   EE_INIT();

   App.flag=APP_RESIZABLE|APP_MINIMIZABLE|APP_MAXIMIZABLE|APP_WORK_IN_BACKGROUND|AP​P_FULL_TOGGLE;

#ifdef DEBUG

   App.flag|=APP_MEM_LEAKS|APP_BREAKPOINT_ON_ERROR;

#endif

   Cam.dist=10;

   Cam.pitch=-0.4;

   D.viewFov(DegToRad(60)).mode(App.desktopW()*0.8, App.desktopH()*0.8);

}

/******************************************************************************/

bool Init()

{

   Physics.create(EE_PHYSX_DLL_PATH).wheelFriction(WheelFriction); // create physics and set custom friction calculation callback

   actors.New().create(Plane(Vec(0, -1, 0), Vec(0, 1, 0))); // create ground

   Vehicle.Params params; // setup vehicle params

   flt x=0.9, y=-0.5, z=1.8;

   params.wheel[WHEEL_LEFT_FRONT ].pos.set(-x, y,  z);

   params.wheel[WHEEL_RIGHT_FRONT].pos.set( x, y,  z);

   params.wheel[WHEEL_LEFT_REAR  ].pos.set(-x, y, -z);

   params.wheel[WHEEL_RIGHT_REAR ].pos.set( x, y, -z);

   PhysBody body; body.parts.New().create(Box(2, 1, 4)); body.setBox(); // create vehicle body

   vehicle.create(body, params, 1); // create vehicle

   vehicle.obj(&chr);

   return true;

}

/******************************************************************************/

void Shut()

{

}

/******************************************************************************/

bool Update()

{

   if(Kb.bp(KB_ESC))return false;

   Physics.startSimulation().stopSimulation(); // update physics

   // set vehicle input

   flt forward=Kb.b(KB_W),

       back   =Kb.b(KB_S),

       angle  =Kb.b(KB_D)-Kb.b(KB_A),

       hand   =Kb.b(KB_SPACE);

   // adjust gears when reversing

   if(EasyReverse)

   {

      if(back   >forward+EPS && vehicle.speed()<=0.5)vehicle.gear(-1); // set reverse gear when 'back   ' exceeds 'forward' and moving very slow

      if(forward>back   +EPS && vehicle.gear ()<=0  )vehicle.gear( 1); // set     1st gear when 'forward' exceeds 'back   ' and gear is reverse or neutral

      if(vehicle.gear()<0)Swap(forward, back);

   }

   vehicle.accel(forward).brake(back).angle(angle).handBrake(hand);

   // manual gear change

   if(Kb.bp(KB_R))vehicle.gearUp  ();

   if(Kb.bp(KB_F))vehicle.gearDown();

   if(Kb.bp(KB_Z))vehicle.matrix(MatrixIdentity).vel(0).angVel(0);

   /* sample code for changing gears depending on engine speed (for this code you should disable 'autoGear')

   if(vehicle.gear()>0)

   {

      flt frac=vehicle.engineFrac();

      if( frac>=0.70f                    )vehicle.gearUp  ();else

      if( frac< 0.50f && vehicle.gear()>1)vehicle.gearDown();

   }*/

   // setup camera

   Cam.at =vehicle.pos();

   Cam.yaw=Angle(vehicle.matrix().z.xz())-PI_2;

   Cam.setSpherical().updateVelocities(CAM_ATTACH_ACTOR).set();

   return true;

}

/******************************************************************************/

void Draw()

{

   D.clear(TURQ);

   Physics.draw();

}

/******************************************************************************/

In the 'WheelFriction' you can see that the obj pointer is not null

cat555 · 09-12-2014 10:44 AM

Hi, well, in fact 'car' was null :\

So, it seems that my need of help in this case is about creating the obj from ObjParams... don't understand why it won't works... pelase take a look at following code and comments (what i'm doing wrong?):

Code:

class Car : Vehicle

{

...

Game::Chr *car;

...

void create(C Vec &pos, C Vec &dir) {

...

Game.ObjParamsPtr car_obj=UID(1429080598, 2558294431, 1169191620, 3226949371); // this is NOT NULL

body =  car_obj->mesh(); // getting body correctly and using it Ok

phys =  car_obj->phys(); // getting body correctly and using it Ok

car = (Game::Chr *) Game::World.objCreateNear(*car_obj, Matrix(car_obj->scale(), Vec(0, 1, 0))); // car is NULL

T.obj(car);

...

}

...

}

Thanks!

cat555 · 09-12-2014 11:57 AM

I've making tests but i can't seem to figure out what's happening... i'm now using your racing game source code.

So, i've got a car running on the track. It's actually added to the world, how can i get vehicle's (Vehicle) object (Game.Obj)? I've searched on vehicle class and i cannot find any reference to it...

Or what it appears to be, this application just manages the physical body parts and renders the mesh of the car... so, really no object car is created in the world. So, shy to have vehicle reference as 'ActorInfo' in wheel friction... it seems that it's not really usefull... maybe it would be very useful to get as param (additionaly), the reference to an object of type 'Vehicle'. In this case, it would be possible to know the position of the car, instead of having to manage a world obj (update accordingly with car body position, etc...), which seems to be totally unnecessary...

Can you give me please some hints... i'm really confused at the moment with this issue grin

Thanks!

cat555 · 09-12-2014 05:35 PM

Hmmm, i'll guess that i should create my own object (and pass it like you referred in last message) and then pass whatever information i need to use in wheelFriction wink

what a confusion for something simple anyway... sorry about making you lose time with this!

Thanks!

**Esenthel** · 09-13-2014 03:36 AM

Hi, 'objCreateNear' can return NULL sometimes, you can read the comment on that method to learn why.

The recommended way to do is make your own Game.Obj class that includes Vehicle as a member:

Code:

class Car : Game.Obj

{

   Vehicle vehicle;

}

and then set vehicle.obj(this);

cat555 · 09-13-2014 11:01 AM

Hi,

It's way better than the solution i've come up with smile

(i was just using a dummy object 'Game.Obj' for passing vehicle information as needed)

Thanks for the suggestion!

wheelFriction override help
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