/**
* 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.
*
* @param gridX grid row
* @param gridY grid column
* @param block the TerrainBlock we are working with
* @return true if the grid point is valid for the given block, false if it is off the block.
*/
protected boolean getTriangles(float gridX, float gridY, TerrainBlock block) {
_calcVec1.set(gridX, 0, gridY);
int index = findClosestHeightIndex(_calcVec1, block);
if (index == -1) return false;
float h3 = block.getHeightMap()[index + block.getSize()];
float h4 = block.getHeightMap()[index + block.getSize() + 1];
float h1 = block.getHeightMap()[index];
float h2 = block.getHeightMap()[index + 1];
final Vector3f scaleVec =
_calcVec1.set(_tracer.getGridSpacing()).multLocal(block.getWorldScale());
_gridTriA.get(0).x = (gridX);
_gridTriA.get(0).y = (h1);
_gridTriA.get(0).z = (gridY);
_gridTriA.get(0).multLocal(scaleVec).addLocal(_tracer.getGridOrigin());
_gridTriA.get(1).x = (gridX);
_gridTriA.get(1).y = (h3);
_gridTriA.get(1).z = (gridY + 1);
_gridTriA.get(1).multLocal(scaleVec).addLocal(_tracer.getGridOrigin());
_gridTriA.get(2).x = (gridX + 1);
_gridTriA.get(2).y = (h2);
_gridTriA.get(2).z = (gridY);
_gridTriA.get(2).multLocal(scaleVec).addLocal(_tracer.getGridOrigin());
_gridTriB.get(0).x = (gridX + 1);
_gridTriB.get(0).y = (h2);
_gridTriB.get(0).z = (gridY);
_gridTriB.get(0).multLocal(scaleVec).addLocal(_tracer.getGridOrigin());
_gridTriB.get(1).x = (gridX);
_gridTriB.get(1).y = (h3);
_gridTriB.get(1).z = (gridY + 1);
_gridTriB.get(1).multLocal(scaleVec).addLocal(_tracer.getGridOrigin());
_gridTriB.get(2).x = (gridX + 1);
_gridTriB.get(2).y = (h4);
_gridTriB.get(2).z = (gridY + 1);
_gridTriB.get(2).multLocal(scaleVec).addLocal(_tracer.getGridOrigin());
return true;
}
