Terrain Ray Casting

Terrain Ray Casting

maluoi 21 Mar 2009 09:58

I was attempting to use the SegmentIntersect method of the Heightmap object in order to find a collision between the ray of my mouse and the terrain (for world editing purposes). However, it comes up with some pretty funky results. I did notice a bug report about this in the bug forum, and I was wondering if there was a fix for it, or if I'm going about it the wrong way? Thanks.

public Vector3 IntersectTerrain(Ray aRay)
{
    Vector3 oPos,oNorm;
    float oDist;
    if (!skin.SegmentIntersect(out oDist, out oPos, out oNorm, new Segment(aRay.Position, aRay.Direction * mapsize * scale)))
        oPos = Vector3.Zero;
    return oPos;
}

Re: Terrain Ray Casting

maluoi 21 Mar 2009 10:11

In the meantime, I wrote a temporary piece that works ~well enough, based on the information provided in the bug forum. It still fails when the ray is pointing up however.

This is based on the fact that the collision should work in a space smaller than one triangle.

public Vector3 IntersectTerrain(Ray aRay)
{
    Vector3 oPos,oNorm;
    float oDist;
    for (int i = 0; i < mapsize; i++)
    {
        if (skin.SegmentIntersect(out oDist, out oPos, out oNorm, new Segment(aRay.Position, aRay.Direction * scale)))
            return oPos;

        aRay.Position += aRay.Direction * scale;
    }
    return Vector3.Zero;
}