com.jme3.terrain.geomipmap.picking
Class BresenhamTerrainPicker

java.lang.Object
  extended by com.jme3.terrain.geomipmap.picking.BresenhamTerrainPicker
All Implemented Interfaces:
TerrainPicker

public class BresenhamTerrainPicker
extends java.lang.Object
implements TerrainPicker

It basically works by casting a pick ray against the bounding volumes of the TerrainQuad and its children, gathering all of the TerrainPatches hit (in distance order.) The triangles of each patch are then tested using the BresenhamYUpGridTracer to determine which triangles to test and in what order. When a hit is found, it is guaranteed to be the first such hit and can immediately be returned.


Constructor Summary
BresenhamTerrainPicker(TerrainQuad root)
           
 
Method Summary
protected  boolean checkTriangles(float gridX, float gridY, Ray pick, Vector3f intersection, TerrainPatch patch, Triangle store)
           
protected  int findClosestHeightIndex(Vector3f position, TerrainPatch patch)
          Finds the closest height point to a position.
 Vector3f getTerrainIntersection(Ray worldPick, CollisionResults results)
          Ask for the point of intersection between the given ray and the terrain.
protected  boolean getTriangles(float gridX, float gridY, TerrainPatch patch)
          Request the triangles (in world coord space) of a TerrainBlock that correspond to the given grid location.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

BresenhamTerrainPicker

public BresenhamTerrainPicker(TerrainQuad root)
Method Detail

getTerrainIntersection

public Vector3f getTerrainIntersection(Ray worldPick,
                                       CollisionResults results)
Description copied from interface: TerrainPicker
Ask for the point of intersection between the given ray and the terrain.

Specified by:
getTerrainIntersection in interface TerrainPicker
Parameters:
worldPick - our pick ray, in world space.
Returns:
null if no pick is found. Otherwise it returns a Vector3f populated with the pick coordinates.

checkTriangles

protected boolean checkTriangles(float gridX,
                                 float gridY,
                                 Ray pick,
                                 Vector3f intersection,
                                 TerrainPatch patch,
                                 Triangle store)

getTriangles

protected boolean getTriangles(float gridX,
                               float gridY,
                               TerrainPatch patch)
Request the triangles (in world coord space) of a TerrainBlock that correspond to the given grid location. The triangles are stored in the class fields _gridTriA and _gridTriB.

Parameters:
gridX - grid row
gridY - grid column
block - the TerrainBlock we are working with
Returns:
true if the grid point is valid for the given block, false if it is off the block.

findClosestHeightIndex

protected int findClosestHeightIndex(Vector3f position,
                                     TerrainPatch patch)
Finds the closest height point to a position. Will always be left/above that position.

Parameters:
position - the position to check at
block - the block to get height values from
Returns:
an index to the height position of the given block.