com.jme3.terrain.geomipmap.picking

Class BresenhamTerrainPicker

java.lang.Object

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.

Author:

Joshua Slack, Brent Owens

Constructor Summary

Constructors

Constructor and Description
BresenhamTerrainPicker(TerrainQuad root)

Method Summary

Methods

Modifier and Type	Method and Description
protected boolean	checkTriangles(float gridX, float gridY, com.jme3.math.Ray pick, com.jme3.math.Vector3f intersection, TerrainPatch patch, com.jme3.math.Triangle store)
protected int	findClosestHeightIndex(com.jme3.math.Vector3f position, TerrainPatch patch) Finds the closest height point to a position.
com.jme3.math.Vector3f	getTerrainIntersection(com.jme3.math.Ray worldPick, com.jme3.collision.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 com.jme3.math.Vector3f getTerrainIntersection(com.jme3.math.Ray worldPick,
                                            com.jme3.collision.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,
                     com.jme3.math.Ray pick,
                     com.jme3.math.Vector3f intersection,
                     TerrainPatch patch,
                     com.jme3.math.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

patch - the TerrainPatch 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(com.jme3.math.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

patch - the patch to get height values from

Returns:

an index to the height position of the given block.