Can I create a not-FPS camera?

Peppe · Post by **Peppe** » Wed Aug 15, 2007 7:16 pm

Hi to all!

I want to create a camera not-fps, but I don't know the procedures. Can you explain to me the procedures?

thank you very much!

PS: excuse me if I committed several mistakes, but I'm Italian and I know only little bit of English.

randomMesh · Post by **randomMesh** » Wed Aug 15, 2007 8:19 pm

Have a looke here.

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irr::scene::ICameraSceneNode* camera = smgr->addCameraSceneNode();

And then you are able to set the parent, position, target to look at, etc. like this:

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camera->setParent(parentNode);
camera->setPosition(irr::core::vector3df(0.0f, 0.0f, 0.0f));
camera->setTarget(irr::core::vector3df(0.0f, 0.0f, 0.0f));

The API dokumentation is your friend.

Peppe · Post by **Peppe** » Thu Aug 16, 2007 9:25 am

Thank you, randomMesh, but my real problem is the input..

I partially solved the problem, for the camera movement foward/Backward, Left/Right:

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class MyEventReceiver : public IEventReceiver
{
 
	 
 

	virtual bool OnEvent(SEvent event)
	{
		 
		if (event.EventType == irr::EET_KEY_INPUT_EVENT&& event.KeyInput.PressedDown)
		{
			 if(event.KeyInput.Key== KEY_ESCAPE)
              {
              
 device->closeDevice(); 
 return true;
    }
       if(event.KeyInput.Key== KEY_UP )
              {  
                    Spostamento_CameraX=Spostamento_CameraX+5;           
                                return true;
    }
      
             if(event.KeyInput.Key== KEY_DOWN )
              {  
                    Spostamento_CameraX=Spostamento_CameraX-5;           
                                return true;
    }
      
       if(event.KeyInput.Key== KEY_RIGHT )
              {  
                    Spostamento_CameraZ=Spostamento_CameraZ-5;           
                                return true;
    }	
        if(event.KeyInput.Key== KEY_LEFT )
              {  
                    Spostamento_CameraZ=Spostamento_CameraZ+5;           
                                return true;
    }	

//next ->

But now i have a problem whit mouse control fot the target movement:

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//<-previus
if (event.EventType==irr::EET_MOUSE_INPUT_EVENT){
    if(event.MouseInput.Event==EMIE_MOUSE_MOVED&&event.MouseInput.Event==EMIE_RMOUSE_PRESSED_DOWN)                                           
  {
  if(device->getCursorControl()->getPosition().X>512){                                            
    CameraTarX=CameraTarX-3;
    return true;
    }                                           
    }                                           
   }                                            
  }                                             
  }
	private:
	scene::ISceneNode* Terrain;	
	};

I pressed the Right Mouse Button, but I can't move the target

can you help me?

Peppe · Post by **Peppe** » Fri Aug 17, 2007 12:13 pm

can you help me?

hybrid · Post by **hybrid** » Fri Aug 17, 2007 12:37 pm

One event cannot be of two types. You have to remember the state of the mouse buttons and reset it when the button_up event arrives.

Peppe · Post by **Peppe** » Mon Aug 20, 2007 1:04 pm

Ok, I solved...but I have another problem:

I move the target, but the target stop at 90 degrees and at -90 degrees.

.

the maximum rotation of the target, in my program is 180 degrees

... I post my code:

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camera->setPosition(core::vector3df( Spostamento_CameraX*2,255*2,Spostamento_CameraZ*2));
  if (sganctarg==true){
  
  rotazione_iniziale = camera->getTarget() ;
   point = device->getCursorControl()->getPosition(); 
   if (point.X  >= 645){ 
  
    rotazione_iniziale.X=rotazione_iniziale.X-50;
 
   }
   if (point.X <= 635){ 
   
    rotazione_iniziale.X=rotazione_iniziale.X+50;
   }
      if (point.Y  >= 390){ 
   rotazione_iniziale.Y=rotazione_iniziale.Y-50;
   
   }
   if (point.Y <= 410){ 
   rotazione_iniziale.Y=rotazione_iniziale.Y+50;
   }
   camera->setTarget(rotazione_iniziale);

I want my camera rotation is = 360 degrees and not 180 degrees.

Can you help me?

Acki · Post by **Acki** » Mon Aug 20, 2007 1:28 pm

No, you don't have 180°, its lesser !!!

The problem is you're looking just at one axis, you'll have to look in a circle around you...
look at this pic, it should show you what's wrong with your code:

(same for the Y-axis)

Peppe · Post by **Peppe** » Mon Aug 20, 2007 7:25 pm

Uhm...I understand...

I calculate the Z position by the Pythagoras' theorem :

the radius of circle is the hypotenuse and the x value is a triangle's leg.

the z value is another triangle's leg.

Value.Z = sqrt(radius*radius - Value.X*Value.X) .

but how I have the radius value??

thank you very much.

Acki · Post by **Acki** » Mon Aug 20, 2007 8:41 pm

Well, Pythagoras is the wrong guy for this

you should use an view angle and then triangulate X and Z...
you should do something like this:

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   if (point.X  >= 645){
     rotAngle -= 1; // rotate 1° anti clockwise, but should it not be clockwise?
     if(rotAngle < 0) rotAngle += 360;
   }
   if (point.X <= 635){
     rotAngle += 1; // rotate 1° clockwise, but should it not be anti clockwise?
     if(rotAngle >= 360) rotAngle -= 360;
   }

then you should define a view distance that always is the same, this can be any value so we simply can take 1

now you can easily calculate X and Z:
sin(alpha) = X / 1 >>> X = sin(alpha) * 1 >>> X = sin(rotAngle)
cos(alpha) = Z / 1 >>> Z = cos(alpha) * 1 >>> Z = cos(rotAngle)

well, I hope I made no mistakes as I wrote this out of the top of my head and I'm tired...

Peppe · Post by **Peppe** » Mon Aug 20, 2007 9:09 pm

ok, the debug values reading the movement, but the camera don't move

Peppe · Post by **Peppe** » Mon Aug 20, 2007 9:21 pm

If I moltiplicate the cosinus and the sinus for a high value (eg: 880) I generate a "earthquake"

hum...like a two forces stop the camera:

Anti-camera movement <----MyCamera----> camera movement

Acki · Post by **Acki** » Mon Aug 20, 2007 9:31 pm

Well, I don't know what you're exactly doing there...

but you don't need to multiply cos and sin with any other value than 1, but you have to add your camera position...
for the earthquake it could be that you'll have to update the absolute camera position afterwards:

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vector3df target = cam->getPosition();
target.X += sin(rotAngle);
target.Z += cos(rotAngle);
camera->setTarget(target);
camera->updateAbsolutePosition();

this should work for left/right view, for up/down it's similar...
Maybe sin and cos needs radians instead of degrees (the code I wrote is more a pseudo code)...

Peppe · Post by **Peppe** » Mon Aug 20, 2007 9:38 pm

Dont work

this is my loop:

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camera->setPosition(core::vector3df( Spostamento_CameraX*2,255*2,Spostamento_CameraZ*2));
  
  if (sganctarg==true){
  //I use the boolean SgancTarg for the right mouse button is pressed.

  
   point = device->getCursorControl()->getPosition(); 
   if (point.X  >= 645){ 
   Rotangle  = Rotangle - 1;
   if(Rotangle < 0) Rotangle  =Rotangle + 360;
   
    }
   if (point.X <= 635){ 
   
      Rotangle  = Rotangle +1;
   if(Rotangle >= 0) Rotangle  = Rotangle -360;
    
 
   }
      if (point.Y  >= 390){ 
   rotazione_iniziale.Y=rotazione_iniziale.Y-50; 
   
   }
   if (point.Y <= 410){ 
   rotazione_iniziale.Y=rotazione_iniziale.Y+50;
   }

//"rotazione_iniziale" is the target movement.
   rotazione_iniziale.X =Spostamento_CameraX + sin(Rotangle)  ;
   rotazione_iniziale.Z =Spostamento_CameraZ + cos(Rotangle)   ;
  
   camera->setTarget(rotazione_iniziale);
  camera->updateAbsolutePosition();
    
}
   
 
   
			
        driver->endScene();
		       


		// display frames per second in window title
		int fps = driver->getFPS();
		if (lastFPS != fps)
		{
			core::stringw str = L"Terrain Renderer - Irrlicht Engine [";
			str += driver->getName();
			str += "] FPS:";
			str += fps;
			// Also print terrain height of current camera position
			// We can use camera position because terrain is located at coordinate origin
			str += " rot: ";
			 
            str += Rotangle;
       
			device->setWindowCaption(str.c_str());
			lastFPS = fps;
		}
		
	}

Acki · Post by **Acki** » Mon Aug 20, 2007 9:47 pm

ohh, your fast (or I'm to tired) !!!

well, one error in the code:

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 if (point.X <= 635){
      Rotangle  = Rotangle +1;
   if(Rotangle >= 0) Rotangle  = Rotangle -360;
   }

must be:

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 if (point.X <= 635){
      Rotangle  = Rotangle +1;
   if(Rotangle >= 360) Rotangle  = Rotangle -360;
   }

and if I rember right you'll have to use radians, so you'll have to multibly the angle with pi/180:

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rotazione_iniziale.X =Spostamento_CameraX + sin(Rotangle * 3.14156 / 180.0);
   rotazione_iniziale.Z =Spostamento_CameraZ + cos(Rotangle * 3.14156 / 180.0);

and don't forget to use a float type for the Rotangle var...

as I mentioned, all this I'm doing just out of my head...

Peppe · Post by **Peppe** » Mon Aug 20, 2007 9:54 pm

uhm..I have a strange effect:

If I click right mouse button, My target is (0,0,0), but if I move the camera with directional keys , I rotate the camera

.

Hem...can I rotate the camera whit the mouse?