Get the side a player is looking on the block | bukkit - bukkit

Question

It is possible to get the Block the Player actually is looking at.
p.getTargetBlock()
But is there a way to get the side of the block that the player is looking at?
(top, down, north, south, east, west side of the block)
I haven't found a function that will do that. Does it give me something, that I can use to find this side?

Answer 1

I have implemented a Utility method for achieving this given the AxisAlignedBB (NMS) of the Block the player is targeting. This block can be obtained by Player#getTargetBlock() as mentioned in the question or with a custom raycast algorithm.
public static BlockFace blockFaceCollide(Vector startLocation, Vector direction, AxisAlignedBB objectBoundry){
double constant = Double.MAX_VALUE;
BlockFace blockFace = null;
double directionX = direction.getX();
double directionY = direction.getY();
double directionZ = direction.getZ();
if(directionY > 0){
double b = objectBoundry.b - startLocation.getY();
double tempConstant = b / directionY;
if(tempConstant > 0 && tempConstant < constant){
double xAtCollide = tempConstant * directionX + startLocation.getX();
double zAtCollide = tempConstant * directionZ + startLocation.getZ();
if (between(xAtCollide, objectBoundry.a, objectBoundry.d, 0)
&& between(zAtCollide, objectBoundry.c, objectBoundry.f, 0)) {
constant = tempConstant;
blockFace = BlockFace.DOWN;
}
}
}
else {
double e = objectBoundry.e - startLocation.getY();
double tempConstant = e / directionY;
if (tempConstant > 0 && tempConstant < constant) {
double xAtCollide = tempConstant * directionX + startLocation.getX();
double zAtCollide = tempConstant * directionZ + startLocation.getZ();
if (between(xAtCollide, objectBoundry.a, objectBoundry.d, 0)
&& between(zAtCollide, objectBoundry.c, objectBoundry.f, 0)) {
constant = tempConstant;
blockFace = BlockFace.UP;
}
}
}
if(directionX < 0) {
double d = objectBoundry.d - startLocation.getX();
double tempConstant = d / directionX;
if (tempConstant > 0 && tempConstant < constant) {
double yAtCollide = tempConstant * directionY + startLocation.getY();
double zAtCollide = tempConstant * directionZ + startLocation.getZ();
if (between(yAtCollide, objectBoundry.b, objectBoundry.e, 0)
&& between(zAtCollide, objectBoundry.c, objectBoundry.f, 0)) {
constant = tempConstant;
blockFace = BlockFace.EAST;
}
}
}
else {
double a = objectBoundry.a - startLocation.getX();
double tempConstant = a / directionX;
if (tempConstant > 0 && tempConstant < constant) {
double yAtCollide = tempConstant * directionY + startLocation.getY();
double zAtCollide = tempConstant * directionZ + startLocation.getZ();
if (between(yAtCollide, objectBoundry.b, objectBoundry.e, 0)
&& between(zAtCollide, objectBoundry.c, objectBoundry.f, 0)) {
constant = tempConstant;
blockFace = BlockFace.WEST;
}
}
}
if(directionZ > 0) {
double c = objectBoundry.c - startLocation.getZ();
double tempConstant = c / directionZ;
if(tempConstant > 0 && tempConstant < constant) {
double yAtCollide = tempConstant * directionY + startLocation.getY();
double xAtCollide = tempConstant * directionX + startLocation.getX();
if (between(yAtCollide, objectBoundry.b, objectBoundry.e, 0)
&& between(xAtCollide, objectBoundry.a, objectBoundry.d, 0)) {
blockFace = BlockFace.NORTH;
}
}
}
else {
double f = objectBoundry.f - startLocation.getZ();
double tempConstant = f / directionZ;
if(tempConstant < constant) {
double yAtCollide = tempConstant * directionY + startLocation.getY();
double xAtCollide = tempConstant * directionX + startLocation.getX();
if (between(yAtCollide, objectBoundry.b, objectBoundry.e, 0)
&& between(xAtCollide, objectBoundry.a, objectBoundry.d, 0)) {
blockFace = BlockFace.SOUTH;
}
}
}
return blockFace;
}
public static boolean between(double num, double a, double b, double EOF) {
if (a <= b)
return num + EOF >= a && num - EOF <= b;
return num + EOF >= b && num - EOF <= a;
}

Answer 2

I don't think there is way to get the block they are looking at, however you can get the block face that they click by using PlayerInteractEvent and its getBlockFace() method.
EDIT: Check out this thread on the bukkit forums.
EDIT 2: Or as mentioned in this thread, you can try putting this in a PlayerMoveEvent:
List<Block> blocks = event.getPlayer().getLastTwoTargetBlocks(null, 10);
if (blocks.size() > 1)
face = blocks.get(1).getFace(blocks.get(0));