Away3D Forum Placing a cone

dmk, Jr. Member
Posted: 05 June 2014 02:03 PM Total Posts: 32

So let’s say we have a cube that can be rotated in any direction along any axis. (FYI it’s a rectangular cube, which will eventually become a ship.)

Now we want to place a cone on any particular side such that the base of the cone attaches to the face of the cube and points outwards. (FYI this cone will eventually be a fire/booster.)

It must be a separate object, positioned rather than attached, since the same position vector will be used to give an impulse via awayphysics applyImpulse (not applyCentralImpulse)

I’m sure there is some simple method to calculate this for each side using backVector, forwardVector, etc… but I just couldn’t get it. Was starting to do my own calculations with trig functions but that’s a bit of a hassle and potentially wasteful if the data’s already there somewhere… Would post code but nothing I have really works

Thanks in advance!

Mr Margaret Scratcher, Sr. Member
Posted: 07 June 2014 11:22 AM Total Posts: 344 [ # 1 ]

I’m about to do someing similar to apply decals to an object - check out the mouse interaction example, where you can draw on the head as a marker is drawn which sticks out perpendicular to the face your mouse is over..

dmk, Jr. Member
Posted: 08 June 2014 07:43 AM Total Posts: 32 [ # 2 ]

Thanks for the reply. Seems like the example at https://github.com/away3d/away3d-tutorials-fp11/blob/master/tutorials/picking/overview/src/PickingTutorialListing05.as (live example: http://away3d.com/wikicontent/tutorials/picking/overview/bin/listing_05/Launcher.html) is pretty much along those lines (pun intended)

So this is really two problems:

1) Getting the location on the surface (location is mid-point on any particular face)
2) Getting the perpendicular vector out from that location

For problem #1, I’m still a bit stuck… with the mouse interaction examples, it seems like it’s just using MouseEvent3D (or in other examples, a ray cast from the camera I think?), so it doesn’t really do any calculation- it’s just wherever the user’s mouse is vs. camera

For problem #2 it seems like the answer is “get the normal” (i.e. in the example above, it’s a MouseEvent3D.sceneNormal, that does help.

Will continue to experiment unless someone has more guidance in the meantime… thanks

dmk, Jr. Member
Posted: 08 June 2014 09:14 AM Total Posts: 32 [ # 3 ]

OK- I think I figured it out

Now to make the fire look good and tweak the values…

Though now I realize that having boosters on the side makes it kindof pointless to have tilting, or vice-versa…

package
{
 
 import flash.geom.Vector3D;
 
 import away3d.containers.ObjectContainer3D;
 import away3d.containers.Scene3D;
 import away3d.entities.Mesh;
 import away3d.materials.ColorMaterial;
 import away3d.materials.lightpickers.StaticLightPicker;
 import away3d.primitives.ConeGeometry;
 import away3d.primitives.CubeGeometry;
 
 import awayphysics.collision.shapes.AWPBoxShape;
 import awayphysics.dynamics.AWPDynamicsWorld;
 import awayphysics.dynamics.AWPRigidBody;

 public class Ship extends AWPRigidBody
 {
  
  public static const FORWARD:String = 'forward';
  public static const LEFT:String = 'left';
  public static const RIGHT:String = 'right';
  public static const BACK:String = 'back';
  public static const UP:String = 'up';
  public static const DOWN:String = 'down';
  
  
  
  private var scene:Scene3D;
  private var physicsWorld: AWPDynamicsWorld;
  private var lightPicker:StaticLightPicker;
  
  private var shipMesh:Mesh;
  private var shipBody:AWPBoxShape;
  private var shipGeometry:CubeGeometry;
  
  private var fireContainer:ObjectContainer3D;
  private var fireGeometry:ConeGeometry;
  
  private var fireMeshPosition:Vector3D;
  private var fireForce:Vector3D;
  
  private var jetStrength:Number = 100;
  private var tiltStrength:Number = 2;
  
  private var fireMesh:Mesh;
  private var jetDirection:String = BACK;
  
  public function Ship(_scene:Scene3D, _lightPicker:StaticLightPicker, _physicsWorld:AWPDynamicsWorld)
  {
   
   scene = _scene;
   lightPicker = _lightPicker;
   physicsWorld = _physicsWorld;
   
   
   createShip();
   scene.addChild(shipMesh);
   
   
   
   super(shipBody, shipMesh, 10);
   physicsWorld.addRigidBody(this);
   
   this.gravity = new Vector3D();
   
   createFire();
  }
  
  private function createShip() {
   
   var mat:ColorMaterial = new ColorMaterial(0x00FF00);
  
   shipGeometry = new CubeGeometry(50,50,200);
   mat.lightPicker = lightPicker;
   shipMesh = new Mesh(shipGeometry, mat);
   shipBody = new AWPBoxShape(shipGeometry.width, shipGeometry.height, shipGeometry.depth);
   
   
  }
  
  private function createFire() {
   
   var mat:ColorMaterial = new ColorMaterial(0xFF0000);
   mat.lightPicker = lightPicker;
   
   fireGeometry = new ConeGeometry(25);
   fireMesh = new Mesh(fireGeometry, mat);
   
   fireMesh.rotationX = -90;
   fireMesh.z = -fireGeometry.height/2;
   
   fireContainer = new ObjectContainer3D();
   fireContainer.addChild(fireMesh);
   
   scene.addChild(fireContainer);
   
   fireMeshPosition = new Vector3D();
   fireForce = new Vector3D();
   fireMesh.visible = false;
   
  }
  
  //Triggered via Starling container
  public function everyFrame(passedTime:Number) {
   
   if(fireMesh.visible) {
    updateJetPosition();
   }
   
  }
  
  private function updateJetPosition() {
   var halfShipDepth:Number = shipGeometry.depth/2;
   var halfShipWidth:Number = shipGeometry.width/2;
   
   
   switch(jetDirection) {
    case FORWARD:   fireMeshPosition.copyFrom(shipMesh.backVector);
     fireMeshPosition.scaleBy(halfShipDepth);
     break;
    
    case LEFT:   fireMeshPosition.copyFrom(shipMesh.leftVector);
     fireMeshPosition.scaleBy(halfShipWidth);
     break;
    
    case RIGHT:  fireMeshPosition.copyFrom(shipMesh.rightVector);
     fireMeshPosition.scaleBy(halfShipWidth);
     break;
    
    case BACK:   fireMeshPosition.copyFrom(shipMesh.forwardVector);
     fireMeshPosition.scaleBy(halfShipDepth);
     break;
    default:  break;
   }
   
   fireMeshPosition.incrementBy(shipMesh.position);
   fireContainer.position = fireMeshPosition;
   
   fireContainer.lookAt(shipMesh.position);
  }
  
  public function jetsTo(dir:String) {
   jetDirection = dir;
   fireMesh.visible = true;
   updateJetPosition();
   
   switch(jetDirection) {
    case FORWARD:   fireForce.copyFrom(shipMesh.forwardVector);
         break;
    
    case LEFT:    fireForce.copyFrom(shipMesh.rightVector);
         break;
    
    case RIGHT:   fireForce.copyFrom(shipMesh.leftVector);
         break;
    
    case BACK:    fireForce.copyFrom(shipMesh.backVector);
         break;
    
    default:   break;
   }
   
   fireForce.scaleBy(jetStrength);
   this.applyCentralForce(fireForce);
   
   
  }
  
  public function jetsOff(dir:String) {
   fireMesh.visible = false;
  }
  
//triggered external controller that listens for keypresses, etc.
  public function tiltTo(dir:String) {
   //Note- need to make this smoother, based on timestep in everyFrame, etc. 
   switch(dir) {
    case UP:  this.rotationX -= tiltStrength; break;
    case DOWN:  this.rotationX += tiltStrength; break;
    case LEFT:  this.rotationY -= tiltStrength; break;
    case RIGHT:  this.rotationY += tiltStrength; break;
    
   }
   
  }
  
 }
} 

Placing a cone Software: Away3D 4.x

dmk, Jr. Member Posted: 05 June 2014 02:03 PM Total Posts: 32 So let’s say we have a cube that can be rotated in any direction along any axis. (FYI it’s a rectangular cube, which will eventually become a ship.) Now we want to place a cone on any particular side such that the base of the cone attaches to the face of the cube and points outwards. (FYI this cone will eventually be a fire/booster.) It must be a separate object, positioned rather than attached, since the same position vector will be used to give an impulse via awayphysics applyImpulse (not applyCentralImpulse) I’m sure there is some simple method to calculate this for each side using backVector, forwardVector, etc… but I just couldn’t get it. Was starting to do my own calculations with trig functions but that’s a bit of a hassle and potentially wasteful if the data’s already there somewhere… Would post code but nothing I have really works Thanks in advance!
Mr Margaret Scratcher, Sr. Member Posted: 07 June 2014 11:22 AM Total Posts: 344 [ # 1 ] I’m about to do someing similar to apply decals to an object - check out the mouse interaction example, where you can draw on the head as a marker is drawn which sticks out perpendicular to the face your mouse is over..
dmk, Jr. Member Posted: 08 June 2014 07:43 AM Total Posts: 32 [ # 2 ] Thanks for the reply. Seems like the example at https://github.com/away3d/away3d-tutorials-fp11/blob/master/tutorials/picking/overview/src/PickingTutorialListing05.as (live example: http://away3d.com/wikicontent/tutorials/picking/overview/bin/listing_05/Launcher.html) is pretty much along those lines (pun intended) So this is really two problems: 1) Getting the location on the surface (location is mid-point on any particular face) 2) Getting the perpendicular vector out from that location For problem #1, I’m still a bit stuck… with the mouse interaction examples, it seems like it’s just using MouseEvent3D (or in other examples, a ray cast from the camera I think?), so it doesn’t really do any calculation- it’s just wherever the user’s mouse is vs. camera For problem #2 it seems like the answer is “get the normal” (i.e. in the example above, it’s a MouseEvent3D.sceneNormal, that does help. Will continue to experiment unless someone has more guidance in the meantime… thanks
dmk, Jr. Member Posted: 08 June 2014 09:14 AM Total Posts: 32 [ # 3 ] OK- I think I figured it out Now to make the fire look good and tweak the values… Though now I realize that having boosters on the side makes it kindof pointless to have tilting, or vice-versa… package { import flash.geom.Vector3D; import away3d.containers.ObjectContainer3D; import away3d.containers.Scene3D; import away3d.entities.Mesh; import away3d.materials.ColorMaterial; import away3d.materials.lightpickers.StaticLightPicker; import away3d.primitives.ConeGeometry; import away3d.primitives.CubeGeometry; import awayphysics.collision.shapes.AWPBoxShape; import awayphysics.dynamics.AWPDynamicsWorld; import awayphysics.dynamics.AWPRigidBody; public class Ship extends AWPRigidBody { public static const FORWARD:String = 'forward'; public static const LEFT:String = 'left'; public static const RIGHT:String = 'right'; public static const BACK:String = 'back'; public static const UP:String = 'up'; public static const DOWN:String = 'down'; private var scene:Scene3D; private var physicsWorld: AWPDynamicsWorld; private var lightPicker:StaticLightPicker; private var shipMesh:Mesh; private var shipBody:AWPBoxShape; private var shipGeometry:CubeGeometry; private var fireContainer:ObjectContainer3D; private var fireGeometry:ConeGeometry; private var fireMeshPosition:Vector3D; private var fireForce:Vector3D; private var jetStrength:Number = 100; private var tiltStrength:Number = 2; private var fireMesh:Mesh; private var jetDirection:String = BACK; public function Ship(_scene:Scene3D, _lightPicker:StaticLightPicker, _physicsWorld:AWPDynamicsWorld) { scene = _scene; lightPicker = _lightPicker; physicsWorld = _physicsWorld; createShip(); scene.addChild(shipMesh); super(shipBody, shipMesh, 10); physicsWorld.addRigidBody(this); this.gravity = new Vector3D(); createFire(); } private function createShip() { var mat:ColorMaterial = new ColorMaterial(0x00FF00); shipGeometry = new CubeGeometry(50,50,200); mat.lightPicker = lightPicker; shipMesh = new Mesh(shipGeometry, mat); shipBody = new AWPBoxShape(shipGeometry.width, shipGeometry.height, shipGeometry.depth); } private function createFire() { var mat:ColorMaterial = new ColorMaterial(0xFF0000); mat.lightPicker = lightPicker; fireGeometry = new ConeGeometry(25); fireMesh = new Mesh(fireGeometry, mat); fireMesh.rotationX = -90; fireMesh.z = -fireGeometry.height/2; fireContainer = new ObjectContainer3D(); fireContainer.addChild(fireMesh); scene.addChild(fireContainer); fireMeshPosition = new Vector3D(); fireForce = new Vector3D(); fireMesh.visible = false; } //Triggered via Starling container public function everyFrame(passedTime:Number) { if(fireMesh.visible) { updateJetPosition(); } } private function updateJetPosition() { var halfShipDepth:Number = shipGeometry.depth/2; var halfShipWidth:Number = shipGeometry.width/2; switch(jetDirection) { case FORWARD: fireMeshPosition.copyFrom(shipMesh.backVector); fireMeshPosition.scaleBy(halfShipDepth); break; case LEFT: fireMeshPosition.copyFrom(shipMesh.leftVector); fireMeshPosition.scaleBy(halfShipWidth); break; case RIGHT: fireMeshPosition.copyFrom(shipMesh.rightVector); fireMeshPosition.scaleBy(halfShipWidth); break; case BACK: fireMeshPosition.copyFrom(shipMesh.forwardVector); fireMeshPosition.scaleBy(halfShipDepth); break; default: break; } fireMeshPosition.incrementBy(shipMesh.position); fireContainer.position = fireMeshPosition; fireContainer.lookAt(shipMesh.position); } public function jetsTo(dir:String) { jetDirection = dir; fireMesh.visible = true; updateJetPosition(); switch(jetDirection) { case FORWARD: fireForce.copyFrom(shipMesh.forwardVector); break; case LEFT: fireForce.copyFrom(shipMesh.rightVector); break; case RIGHT: fireForce.copyFrom(shipMesh.leftVector); break; case BACK: fireForce.copyFrom(shipMesh.backVector); break; default: break; } fireForce.scaleBy(jetStrength); this.applyCentralForce(fireForce); } public function jetsOff(dir:String) { fireMesh.visible = false; } //triggered external controller that listens for keypresses, etc. public function tiltTo(dir:String) { //Note- need to make this smoother, based on timestep in everyFrame, etc. switch(dir) { case UP: this.rotationX -= tiltStrength; break; case DOWN: this.rotationX += tiltStrength; break; case LEFT: this.rotationY -= tiltStrength; break; case RIGHT: this.rotationY += tiltStrength; break; } } } }

Placing a cone

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