Picking objects *near* the mouse

[jwheeler]

Hi,

For our application we need to extend the picking behaviour as follows:

1. Pick all objects in the pick location not just the top one
2. Find all objects in an area not just under the mouse pointer

We have made some progress (below), but if anyone else has looked at either of these, maybe we could discuss. The code below works for ordinary renderables but not for surface objects in a SurfaceShapeLayer as the rendering technique is rather different.

Thanks

This new PickSupport method is called after rendering EVERY object:

    public void resolvePickArea(final DrawContext dc, java.awt.Point centrePoint, int w, int h)
    {
        if (this.getPickableObjects().isEmpty())
            return;
        
        final GL gl = dc.getGL();
        
        // GL has (0,0) in the bottom left, the point has (0,0) in the top left so we need to convert the y axis 
        final int x = centrePoint.x - (w / 2);
        final int y = dc.getView().getViewport().height - (centrePoint.y + (h / 2)) - 1;
        // read the pixels in bulk
        gl.glReadPixels(x, y, w, h, javax.media.opengl.GL.GL_RGB, GL.GL_UNSIGNED_BYTE, PickSupport.pixels);
        
        java.awt.Color tCol = null;
        final int clearPixel = dc.getClearColor().getRGB();
        final List<Integer> prevCols = new ArrayList<Integer> (0);
        int c;
        Integer cVal;
        PickedObject obj;
        
        for (int n = 0; n < (w * h) * 3; n += 3)
        {
            tCol = new java.awt.Color(PickSupport.pixels.get(n) & 0xff, PickSupport.pixels.get(n + 1) & 0xff, 
                    PickSupport.pixels.get(n + 2) & 0xff, 0);
            c = tCol.getRGB();
            cVal = Integer.valueOf(c);
            if (c != clearPixel && !prevCols.contains(cVal))
            {
                obj = getPickableObjects().get(cVal);
                if (obj != null && !dc.getPickedObjects().contains(obj))
                {
                    dc.addPickedObject(obj);
                    prevCols.add(cVal);
                }
            }
        }
        this.clearPickList();
    }

Please, can you post all the code that you have used.
I'm with the problem that I have points very near or in the same position. When they are in the same position only the last is picked.

[ens121]

> For typical picking, the selection is resolved by color. If your point
> is completely hidden by another point, it won't be picked. There
> may be a way around this using picking supplied by WorldWind
> but I haven't been able to discover one.
Use deep picking ->
http://forum.worldwindcentral.com/sh...ad.php?t=33046
http://forum.worldwindcentral.com/sh...ad.php?t=33108

Originally Posted by ens121

> For typical picking, the selection is resolved by color. If your point
> is completely hidden by another point, it won't be picked. There
> may be a way around this using picking supplied by WorldWind
> but I haven't been able to discover one.
Use deep picking ->
http://forum.worldwindcentral.com/sh...ad.php?t=33046
http://forum.worldwindcentral.com/sh...ad.php?t=33108

I'm enable the deep picking and all the points in the same position are picked, exactly how I need.
In the post http://forum.worldwindcentral.com/sh...ad.php?t=32709 has the solution to use the deep picking in the renderable layer.
Thanks.

Perfect!! I enable the deep picking and all the points is picked, even the points with same coordinates.
I follow the post http://forum.worldwindcentral.com/sh...ad.php?t=32709 to enable the deep picking on the renderable layer.
Thanks.