[Papervision3D] Partial cylinder mapping

Dan Carter dan at monobyte.co.uk
Mon Sep 1 07:10:23 PDT 2008


Hey Olee,

No, and I am guessing it would slow it down drastically, especially as my texture is already 1000x3000px

I would ideally like to be able to map several images around the cylinder.

I actually found a workaround which involves creating a partial cylinder instead of a full cylinder, it works for what I need it for.

Here's the modified Cylinder.as class which now accepts an angle between 0 and 1 to create a cylinder segment:

package org.papervision3d.objects.primitives {
 import org.papervision3d.Papervision3D;
 import org.papervision3d.core.geom.*;
 import org.papervision3d.core.geom.renderables.Triangle3D;
 import org.papervision3d.core.geom.renderables.Vertex3D;
 import org.papervision3d.core.math.NumberUV;
 import org.papervision3d.core.proto.*; 

 /**
 * The Cylinder class lets you create and display Cylinders.
 * <p/>
 * The Cylinder is divided in vertical and horizontal segment, the smallest combination is two vertical and three horizontal segments.
 */
 public class Cylinder extends TriangleMesh3D
 {
  /**
  * Number of segments horizontally. Defaults to 8.
  */
  public var segmentsW :Number;
 
  /**
  * Number of segments vertically. Defaults to 6.
  */
  public var segmentsH :Number;
 
  /**
  * Default radius of Cylinder if not defined.
  */
  static public const DEFAULT_RADIUS :Number = 100;
 
  /**
  * Default height if not defined.
  */
  static public const DEFAULT_HEIGHT :Number = 100;
 
  /**
  * Default scale of Cylinder texture if not defined.
  */
  static public const DEFAULT_SCALE :Number = 1;
 
  /**
  * Default value of gridX if not defined.
  */
  static public const DEFAULT_SEGMENTSW :Number = 8;
 
  /**
  * Default value of gridY if not defined.
  */
  static public const DEFAULT_SEGMENTSH :Number = 6;
 
  /**
  * Minimum value of gridX.
  */
  static public const MIN_SEGMENTSW :Number = 3;
 
  /**
  * Minimum value of gridY.
  */
  static public const MIN_SEGMENTSH :Number = 1;
 
 
  // ___________________________________________________________________________________________________
  //                                                                                               N E W
  // NN  NN EEEEEE WW    WW
  // NNN NN EE     WW WW WW
  // NNNNNN EEEE   WWWWWWWW
  // NN NNN EE     WWW  WWW
  // NN  NN EEEEEE WW    WW
 
  /**
  * Create a new Cylinder object.
  * <p/>
  * @param material A MaterialObject3D object that contains the material properties of the object.
  * <p/>
  * @param radius  [optional] - Desired radius.
  * <p/>
  * @param segmentsW [optional] - Number of segments horizontally. Defaults to 8.
  * <p/>
  * @param segmentsH [optional] - Number of segments vertically. Defaults to 6.
  * <p/>
  * @param topRadius [optional] - An optional parameter for con- or diverging cylinders.
  * <p/>
  * @param topFace  [optional] - An optional parameter specifying if the top face of the cylinder should be drawn.
  * <p/>
  * @param bottomFace [optional] - An optional parameter specifying if the bottom face of the cylinder should be drawn.
  * <p/>
  */
  public function Cylinder( material:MaterialObject3D=null, angle : Number = 0.25, radius:Number=100, height:Number=100, segmentsW:int=8, segmentsH:int=6, topRadius:Number=-1, topFace:Boolean=true, bottomFace:Boolean=true )
  {
   super( material, new Array(), new Array(), null );
 
   this.segmentsW = Math.max( MIN_SEGMENTSW, segmentsW || DEFAULT_SEGMENTSW); // Defaults to 8
   this.segmentsH = Math.max( MIN_SEGMENTSH, segmentsH || DEFAULT_SEGMENTSH); // Defaults to 6
   if (radius==0) radius = DEFAULT_RADIUS; // Defaults to 100
   if (height==0) height = DEFAULT_HEIGHT; // Defaults to 100
   if (topRadius==-1) topRadius = radius;
 
   var scale :Number = DEFAULT_SCALE;
   
   angle = angle > 1 ? 1 : angle < 0 ? 0 : angle;
 
   buildCylinder(angle, radius, height, topRadius, topFace, bottomFace );
  }
 
  private function buildCylinder( fAngle : Number, fRadius:Number, fHeight:Number, fTopRadius:Number, fTopFace:Boolean, fBottomFace:Boolean ):void
  {
   var matInstance:MaterialObject3D = material;
   
   var i:Number, j:Number, k:Number;
 
   var iHor:Number = Math.max(MIN_SEGMENTSW, this.segmentsW);
   var iVer:Number = Math.max(MIN_SEGMENTSH, this.segmentsH);
   var aVertice:Array = this.geometry.vertices;
   var aFace:Array = this.geometry.faces;
   var aVtc:Array = new Array();
   for (j=0;j<(iVer+1);j++) { // vertical
    var fRad1:Number = Number(j/iVer);
    var fZ:Number = fHeight*(j/(iVer+0))-fHeight/2;//-fRadius*Math.cos(fRad1*Math.PI);
    var fRds:Number = fTopRadius+(fRadius-fTopRadius)*(1-j/(iVer));//*Math.sin(fRad1*Math.PI);
    var aRow:Array = new Array();
    var oVtx:Vertex3D;
    for (i=0;i<iHor;i++) { // horizontal
     var fRad2:Number = Number(2*i/iHor);
     var fX:Number = fRds*Math.sin(fRad2*Math.PI * fAngle);
     var fY:Number = fRds*Math.cos(fRad2*Math.PI * fAngle);
     //if (!((j==0||j==iVer)&&i>0)) { // top||bottom = 1 vertex
     oVtx = new Vertex3D(fY,fZ,fX);
     aVertice.push(oVtx);
     //}
     aRow.push(oVtx);
    }
    oVtx = new Vertex3D(0, fZ, 0);
    aVertice.push(oVtx);
    aRow.push(oVtx);
    
    aVtc.push(aRow);
   }
   var iVerNum:int = aVtc.length;
 
   var aP4uv:NumberUV, aP1uv:NumberUV, aP2uv:NumberUV, aP3uv:NumberUV;
   var aP1:Vertex3D, aP2:Vertex3D, aP3:Vertex3D, aP4:Vertex3D;
 
   for (j=0;j<iVerNum;j++) {
    var iHorNum:int = aVtc[j].length;
    for (i=0;i<iHorNum;i++) {
     if (j>0&&i>=0) {
      // select vertices
      var bEnd:Boolean = i==(iHorNum-0);
      aP1 = aVtc[j][bEnd?0:i];
      aP2 = aVtc[j][(i==0?iHorNum:i)-1];
      aP3 = aVtc[j-1][(i==0?iHorNum:i)-1];
      aP4 = aVtc[j-1][bEnd?0:i];
      // uv
      var fJ0:Number = j  / iVerNum;
      var fJ1:Number = (j-1) / iVerNum;
      var fI0:Number = (i+1) / iHorNum;
      var fI1:Number = i  / iHorNum;
      aP4uv = new NumberUV(fI0,fJ1);
      aP1uv = new NumberUV(fI0,fJ0);
      aP2uv = new NumberUV(fI1,fJ0);
      aP3uv = new NumberUV(fI1,fJ1);
      // 2 faces
      aFace.push( new Triangle3D(this, [aP1,aP2,aP3], matInstance, [aP1uv,aP2uv,aP3uv]) );
      aFace.push( new Triangle3D(this, [aP1,aP3,aP4], matInstance, [aP1uv,aP3uv,aP4uv]) );
     }
    }
    if (j==0||j==(iVerNum-1)) {
     for (i=0;i<(iHorNum-2);i++) {
      // uv
      var iI:int = Math.floor(i/2);
      aP1 = aVtc[j][iI];
      aP2 = (i%2==0)? (aVtc[j][iHorNum-2-iI]) : (aVtc[j][iI+1]);
      aP3 = (i%2==0)? (aVtc[j][iHorNum-1-iI]) : (aVtc[j][iHorNum-2-iI]);
 
      var bTop:Boolean = j==0;
      aP1uv = new NumberUV( (bTop?1:0)+(bTop?-1:1)*(aP1.x/fRadius/2+.5), aP1.z/fRadius/2+.5 );
      aP2uv = new NumberUV( (bTop?1:0)+(bTop?-1:1)*(aP2.x/fRadius/2+.5), aP2.z/fRadius/2+.5 );
      aP3uv = new NumberUV( (bTop?1:0)+(bTop?-1:1)*(aP3.x/fRadius/2+.5), aP3.z/fRadius/2+.5 );
 
      // face
      if (j == 0) {
       if (fBottomFace) aFace.push( new Triangle3D(this, [aP1, aP3, aP2], matInstance, [aP1uv, aP3uv, aP2uv]) );
      }
      else {
       if (fTopFace) aFace.push( new Triangle3D(this, [aP1, aP2, aP3], matInstance, [aP1uv, aP2uv, aP3uv]) );
      }
     }
    }
   }
   this.geometry.ready = true;
   
   if(Papervision3D.useRIGHTHANDED)
    this.geometry.flipFaces();
  }
 }
}


Regards,

Dan Carter

MonoByte Web Development
------------------------------
t:  07792 635287
e: dan at monobyte.co.uk
  ----- Original Message ----- 
  From: o renken 
  To: papervision3d at osflash.org 
  Sent: Monday, September 01, 2008 2:52 PM
  Subject: Re: [Papervision3D] Partial cylinder mapping


  Hey Dan,

  did you try to work with a transparent PNG? 

  olee


  2008/9/1 Dan Carter <dan at monobyte.co.uk>

    Hi all,

    Can anyone help me, I am a bit stuck on this one.
    I have a panoramic image that I am trying to map to part a Cylinder primitive, but I can only work out how to have it wrap around the whole cylinder.
    Does anyone know how to make the image mapping go from say 30% to say 70% of the cylinder?

    Any help very greatly appreciated!!


    Regards,

    Dan Carter

    MonoByte Web Development
    ------------------------------
    t:  07792 635287
    e: dan at monobyte.co.uk

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