ROAM and Height mapping

Engines, Libraries and Tools Java 3D
#1

Can anyone please direct me to a pure Java3D ROAM and/or height mapping example?

Many thanks.

#2

IIRC, j3d.org has a ROAM implmentation. For a simpler heightmap, lookup my DRTS-project on sourceforge.

#3

Ok Herkules, I decompiled SimpleHeighmap.class from your DRTS project.(Hope thats ok)

I understand everything until i got to this part


private static Raster getHeightRaster(Image image, int i)
{
        int j = image.getWidth(null);
        int k = image.getHeight(null);
        int l = j / i;
        int i1 = k / i;
        BufferedImage bufferedimage = new BufferedImage(l, i1, 10);
        bufferedimage.createGraphics().drawImage(image, 0, 0, l, i1, null);
        return bufferedimage.getData();
}

I searched around the Java Docs and couldn’t find the method for this


bufferedimage.createGraphics().drawImage(image, 0, 0, l, i1, null);

I know your drawing the image and then retrieving the Raster from the bufferedimage but can you explain the variables that

drawImage(image, 0, 0, l, i1, null);

takes?

Also what is the variable i, and why is j and k, the width and height being divided by it?(See code)


int l = j / i;
int i1 = k / i;

Another question, how would you go about creating a the terrain from the info you get from the Raster? Would you input the height info and stuff into a QuadArray?

Thanks.

#4

You don’t have to decompile since you can download the sourcecode from CVS.

For now, I cannot explain in detail whats going on (and I personally haven’t written that code).

Basically the heigthmap data is split into tiles, and for the tiles geometry is created. IIRC its a TriangleStrip.

In the game, view range and fog are adjusted to the size of the tiles, so that most of them are culled away.

#5

This article covers the basics of height maps and terrains: (JDJ Sept 2004) http://sys-con.com/story/?storyid=46231&DE=1. It does not cover texture mapping or tesselation like ROAM. There is another article that includes creation of terrain from external files including photos with texture mapping here: (JDJ June 2004) http://www.sys-con.com/story/?storyid=45087&DE=1. Both include documented source.

Hope this helps.

Mike

#6

Thanks Mike, Herkules, the info you gave me was really useful. I’ll post any questions when i run into some problems.