• sinu
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  • Registered: 2007-03-22
  • Posts: 6

Topic: deltayaw/roll/pitch?

Is their any chance these commands will get added to irrB3d, i used them alot in my b3d project and pretty much need them in this.

2 Reply by H&K (edited by H&K 2007-03-22 19:55:11)

  • H&K
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  • Registered: 2006-04-29
  • Posts: 41

Re: deltayaw/roll/pitch?

Import irrlicht.b3d

Function ib3d_DeltaYaw:Float(Entity1:ib3d_Entity,Entity2:ib3d_Entity)

    Local TempRotation:Vector3df = entity1._node.GetRotation()
    
    entity1.Point (Entity2)
    
    Local DeltaYaw:Int = Entity1._node.GetRotation().getY() -TempRotation.getY()
    
    Entity1._node.SetRotation(TempRotation)    
    
    Return DeltaYaw
    
End Function

Function ib3d_DeltaPitch:Float(Entity1:ib3d_Entity,Entity2:ib3d_Entity)

    Local TempRotation:Vector3df = entity1._node.GetRotation()
    
    entity1.Point (Entity2)
    
    Local DeltaPitch:Int = Entity1._node.GetRotation().getX()-TempRotation.getX()
    
    Entity1._node.SetRotation(TempRotation)    
    
    Return DeltaPitch
    
End Function

Dont know if this works, cos to be honest Ive never used DeltaYaw or DeltaPitch. And I dont think there is a Delta Roll.

But anyway you should be able to see what I have tried to do, and fix it so that it works.

@Gman
Obviously they should be Methods of entity and then wrapper functions , but I didnt want to confuse the issue. Also there is probably some realy easy way deep in irrlicht. But haha, it killed ten minutes wink

  • gman
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  • Registered: 2006-01-04
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Re: deltayaw/roll/pitch?

thx H&K smile  have no idea if it works or not.  here is some code i found on the Irrlicht forums that i was going to use as a basis for the ib3d functions.  it will be interesting to compare the two.

// by Xaron: http://irrlicht.sourceforge.net/phpBB2/viewtopic.php?t=11333
/** 
 * @brief guided missile steering helper function 
 * 
 * @param missilePosition - current absolute position of the missile 
 * @param missileRotation - current absolute rotation of the missile 
 * @param targetPosition  - current absolute target position 
 * @param oversteer       - oversteer factor in degrees 
 * 
 * @return targetPitchRoll - delta pitch (x) and delta roll (z) values to the target 
 * 
 *******************************************************************************************************/core::vector3df getToTargetPitchRoll( core::vector3df& missilePosition, core::vector3df& missileRotation, core::vector3df& targetPosition, float oversteer = 0.0f ) 
{ 
  core::matrix4 rotMatrix, invRotMatrix; 
  rotMatrix.setRotationDegrees( missileRotation ); 
  core::vector3df targetPitchRoll( 0.0f, 0.0f, 0.0f ); 
  // get the current missile direction 
  core::vector3df currentMissileTargetVec( 0.0f, 0.0f, 1.0f ); 

  // get the vector to the target (from the missile position) 
  core::vector3df missileTargetVec = ( targetPosition - missilePosition ).normalize(); 
  // invert the rotation matrix to transform the target vector into the missile's local space 
  rotMatrix.getInverse( invRotMatrix ); 
  // transform the target vector into missile's local space 
  invRotMatrix.rotateVect( missileTargetVec ); 
  // compute the roll angle to the target 
  float deltaRoll = atan2f( missileTargetVec.Y, missileTargetVec.X ) * core::RADTODEG - 90.0f; 
  if( deltaRoll < 0.0f ) 
    deltaRoll += 360.0f; 
  if( deltaRoll >= 360.0f ) 
    deltaRoll -= 360.0f; 

  if( deltaRoll > 180.0f ) 
    deltaRoll -= 360.0f; 

  // compute the pitch angle to the target 
  float deltaPitch = acosf( currentMissileTargetVec.dotProduct( missileTargetVec ) ) 
    * core::RADTODEG + oversteer; 

  targetPitchRoll.X = -deltaPitch; 
  targetPitchRoll.Z = deltaRoll; 

  return targetPitchRoll; 
}