I am having issues after i change the player's hitbox. Once i set the hitbox using EntityPlayer setEntityBoundingBox() the hitbox is set correctly and is shown correctly using f3 + b, But when i try going under a block if pushes me out like i was 2 blocks tall. If i sprint under i can manage to get though the issue, But if i get near the edge of the 1 block high area i get sucked out as though i was 2 blocks tall. Note i can move fine not near the edge of the 1 block high area. For those wondering i have also tried reflection to use the setSize Method but it doesn't even change the player's hitbox (I may be doing it incorrectly).

 

Anyone have any Fixes or Suggestions?

 

   
@SubscribeEvent
public void onPlayerTick(TickEvent.PlayerTickEvent e) {

        EntityPlayer player = e.player;

        float height = 0.9f;
        float width = 0.3f;

        player.height = height;
        player.width = width;
        player.eyeHeight = 0.8f;

        player.setEntityBoundingBox(new AxisAlignedBB(player.getEntityBoundingBox().minX, player.getEntityBoundingBox().minY, player.getEntityBoundingBox().minZ, player.getEntityBoundingBox().minX + width, player.getEntityBoundingBox().minY + height, player.getEntityBoundingBox().minZ + width));

        if (getBlockAbove(player) != null && !(getBlockAbove(player) instanceof BlockAir && RaceManager.getPlayerRace(player).Height() <= 0.9f)) {
            // Player is 1 block high and a block is above
        }
    }

    private static Block getBlockAbove(Entity entity) {

    	World world = entity.worldObj;

    	return world.getBlockState(new BlockPos(entity.posX, entity.posY+1,entity.posZ)).getBlock();

    }

    private static final String setSizeObf = "func_177725_a";
    private static final String setSizeDeobf = "setSize";

    public static Method setSizeMethod;

  public static void setSize(Entity entity, float width, float height) {

            try {

                Method m = EntityLivingBase.class.getDeclaredMethod(isObfuscation() ? setSizeObf : setSizeDeobf, float.class, float.class);
                setSizeMethod = m;

            }
            catch(NoSuchMethodException e)  {

                entity.width = width;
                entity.height = height;

            }
            catch(Exception e) {

                e.printStackTrace();

            }

        if(setSizeMethod != null) {

            try {

                setSizeMethod.setAccessible(true);
                setSizeMethod.invoke(entity, width, height);

            } catch(Exception e) {

                e.printStackTrace();

            }
        }
    }

    public static boolean isObfuscation()   {

        boolean obfuscation = true;

        try {

            Field[] fields = Class.forName("net.minecraft.world.World").getDeclaredFields();

            for(Field f : fields)  {

                f.setAccessible(true);

                if(f.getName().equalsIgnoreCase("loadedEntityList"))  {

                    obfuscation = false;

                }
            }
        }
        catch (Exception e) {}

        return obfuscation;

    }

I have the same problem and I've asked on MinecraftForum...the issue is probably in pushOutOfBlocks in EntityPlayerSP, I'll let you know when I get it to work ^^

I had my fun with hitboxes and EVERYTHING worked.

 

Since right now I have no clue what might be wrong (unless your event is somehow not called on server), I can only note few things:

 

1. ObfuscationReflectionHelper - it does whole reflection part for you.

2. When using reflection - get field/method once. Point of interest: Java 7 - MethodHandle (and yes, don't bother with java 6 compatibility, users should update their shit, seriously).

3. TickEvents have 2 phases, pick one (code will be ran twice otherwise) - if (event.phase == Phase.START).

4. It is entirely possible (and should be done that way) to setSize once, not every tick, but I understand this is a test code.

5. Finally - look for solution in PlayerAPI, more exact - SmartMoving mod. It allows players to crawl, so basically what you want.

I tried it with PlayerAPI and the way SmartMoving does it and I can go under one block, but I still can't get in the near of a wall...