Re: [JAVA3D] get position in 3D World from mouse cursor

[Olivier fillon]

oops, I answered directly, maybe other people are interested as well=> this is a very common question -----Original Message----- From: Olivier fillon <[EMAIL PROTECTED]> To: Shinji Tanaka <[EMAIL PROTECTED]> Date: Wednesday, April 05, 2000 7:32 AM Subject: Re: [JAVA3D] get position in 3D World from mouse cursor Hi, a copy of an earlier message I sent which should help you out : >>>>> There are whole set of method to do this: in the following, I use the code to give the x/y position of my mouse pointer in a bird eye view of the scene This should give you some ideas to follow ####################333 >From your mouse event: /**      * Takes the x and y coordinates from the provided mouse event and      * determines the corresponding point in the virtual world.      *      * @param evt  The Mouse Event for which the point is desired      * @return Point3d  a virtual world point corresponding to the Mouse Event's      *                  x and y coordinates on the canvas.      */     public Point3d getCanvasPtToVworldPt(MouseEvent e) {         return getCanvasPtToVworldPt(e.getX(), e.getY());     } with /**      * determines a corresponding virtual world point given a canvas point.      *      * @param Point3d  the point on the canvas      * @return Point3d  a virtual world point corresponding to the canvas point      *                  provided.      */     public Point3d getCanvasPtToVworldPt(int x, int y) {         // convert the canvas point to ImagePlate coords         getPixelLocationInImagePlate(x, y, VworldPt);         // transform the point from an imageplate coordinate to a Vworld         // coordinate         getImagePlateToVworld(imagePlateToVworld);         imagePlateToVworld.transform(VworldPt);         getCenterEyeInImagePlate(centerEyePt);         imagePlateToVworld.transform(centerEyePt);         //Logging.trace(10, "Center eye pt VW " + centerEyePt);         //now compute the z=0 value  in the centereye to VworldPt pt         //centerEyePt_VworldPt = alpha *centerEyePt_planePt with planePt.z=0         double alpha = 0.0;         if ( VworldPt.z != centerEyePt.z ) {             alpha = centerEyePt.z /(VworldPt.z - centerEyePt.z);         }         Point3d planePt =             new Point3d(    centerEyePt.x - alpha *(VworldPt.x - centerEyePt.x),                             centerEyePt.y - alpha *(VworldPt.y - centerEyePt.y),                             0.0);     return planePt;     } ############### Please note that I do not care about the z value here Another way is to pick the point (see FAQ/archive) and so directly get the xyz picked upon Olivier Fillon    Minestar Project [EMAIL PROTECTED]  Mincom Limited Ph.+61-7-3303-3344               61 Wyandra Street Fax+61-7-3303-3232               Teneriffe Qld. 4005. Australia Company home page: http://www.mincom.com/ Personal home page: http://www.powerup.com.au/~fillon --- A word from our sponsor --- This transmission is for the intended addressee only and is confidential information. If you have received this transmission in error, please delete it and notify the sender. The contents of this E-mail are the opinion of the writer only and are not endorsed by Mincom Limited unless expressly stated otherwise.   -- -----Original Message----- From: Shinji Tanaka <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] <[EMAIL PROTECTED]> Date: Wednesday, April 05, 2000 6:57 AM Subject: [JAVA3D] get position in 3D World from mouse cursor I have a 3D environment, and I am looking at it from the top. I need to get the x and z positions of the canvas 3D from the mouse cursor . I don't need the Y position because I am looking at it from the top as I mentioned before. I would rather not use the picking APIs to get these numbers because of the over head. I am still reading the picking API source code, because there must be a way to convert the position of the mouse cursor on the image plate to the corresponding canvas 3D position. Does anyone know anything on this matter that could help me? Thank you very much, Shinji Tanaka