/// Picks a point on the surface of the terrain volume.
/**
* Note that the result may be slightly inaccurate due to the fixed step size.
*/
public static bool PickSurface(TerrainVolume volume, Vector3 origin, Vector3 direction, float distance, out PickSurfaceResult pickResult)
{
validateDistance(distance);
// This 'out' value needs to be initialised even if we don't hit
// anything (in which case it will be left at it's default value).
pickResult = new PickSurfaceResult();
// Can't hit it the volume if there's no data.
if ((volume.data == null) || (volume.data.volumeHandle == null))
{
return(false);
}
// Cubiquity's picking code works in volume space whereas we expose an interface that works in world
// space (for consistancy with other Unity functions). Therefore we apply the inverse of the volume's
// volume-to-world transform to the ray, to bring it from world space into volume space.
//
// Note that we do this by transforming the start and end points of the ray (rather than the direction
// of the ray) as Unity's Transform.InverseTransformDirection method does not handle scaling.
Vector3 target = origin + direction * distance;
origin = volume.transform.InverseTransformPoint(origin);
target = volume.transform.InverseTransformPoint(target);
direction = target - origin;
// Now call through to the Cubiquity dll to do the actual picking.
uint hit = CubiquityDLL.PickTerrainSurface((uint)volume.data.volumeHandle,
origin.x, origin.y, origin.z,
direction.x, direction.y, direction.z,
out pickResult.volumeSpacePos.x, out pickResult.volumeSpacePos.y, out pickResult.volumeSpacePos.z);
// The result is in volume space, but again it is more convienient for Unity users to have the result
// in world space. Therefore we apply the volume's volume-to-world transform to the volume space position.
pickResult.worldSpacePos = volume.transform.TransformPoint(pickResult.volumeSpacePos);
// Return true if we hit a surface.
return(hit == 1);
}