docs: public static void buildMouseOverData(JsonObject json, boolean includeNBTData)
      {
          // We could use Minecraft.getMinecraft().objectMouseOver but it's limited to the block reach distance, and
          // doesn't register floating tile items.
          float partialTicks = 0; // Ideally use Minecraft.timer.renderPartialTicks - but we don't need sub-tick resolution.
          Entity viewer = Minecraft.getMinecraft().player;
          float depth = 50;   // Hard-coded for now - in future will be parameterised via the XML.
          Vec3d eyePos = viewer.getPositionEyes(partialTicks);
          Vec3d lookVec = viewer.getLook(partialTicks);
          Vec3d searchVec = eyePos.addVector(lookVec.xCoord * depth, lookVec.yCoord * depth, lookVec.zCoord * depth);
          RayTraceResult mop = Minecraft.getMinecraft().world.rayTraceBlocks(eyePos, searchVec, false, false, false);
          RayTraceResult mopEnt = findEntity(eyePos, lookVec, depth, mop, true);
          if (mopEnt != null)
              mop = mopEnt;
          if (mop == null)
          {
              return; // Nothing under the mouse.
          }
          // Calculate ranges for player interaction:
          double hitDist = mop.hitVec.distanceTo(eyePos);
          double blockReach = Minecraft.getMinecraft().playerController.getBlockReachDistance();
          double entityReach = Minecraft.getMinecraft().playerController.extendedReach() ? 6.0 : 3.0;
  
          JsonObject jsonMop = new JsonObject();
          if (mop.typeOfHit == RayTraceResult.Type.BLOCK)
          {
              // We're looking at a block - send block data:
              jsonMop.addProperty("hitType", "block");
              jsonMop.addProperty("x", mop.hitVec.xCoord);
              jsonMop.addProperty("y", mop.hitVec.yCoord);
              jsonMop.addProperty("z", mop.hitVec.zCoord);
              IBlockState state = Minecraft.getMinecraft().world.getBlockState(mop.getBlockPos());
              List<IProperty> extraProperties = new ArrayList<IProperty>();
              DrawBlock db = MinecraftTypeHelper.getDrawBlockFromBlockState(state, extraProperties);
              jsonMop.addProperty("type", db.getType().value());
              if (db.getColour() != null)
                  jsonMop.addProperty("colour", db.getColour().value());
              if (db.getVariant() != null)
                  jsonMop.addProperty("variant", db.getVariant().getValue());
              if (db.getFace() != null)
                  jsonMop.addProperty("facing",  db.getFace().value());
              if (extraProperties.size() > 0)
              {
                  // Add the extra properties that aren't covered by colour/variant/facing.
                  for (IProperty prop : extraProperties)
                  {
                      String key = "prop_" + prop.getName();
                      if (prop.getValueClass() == Boolean.class)
                          jsonMop.addProperty(key, Boolean.valueOf(state.getValue(prop).toString()));
                      else if (prop.getValueClass() == Integer.class)
                          jsonMop.addProperty(key, Integer.valueOf(state.getValue(prop).toString()));
                      else
                          jsonMop.addProperty(key, state.getValue(prop).toString());
                  }
              }
              // Add the NBTTagCompound, if this is a tile entity.
              if (includeNBTData)
              {
                  TileEntity tileentity = Minecraft.getMinecraft().world.getTileEntity(mop.getBlockPos());
                  if (tileentity != null)
                  {
                      NBTTagCompound data = tileentity.getUpdateTag();
                      if (data != null)
                      {
                          // Turn data directly into json and add it to what we're already returning.
                          String jsonString = data.toString();
                          try
                          {
                              JsonElement jelement = new JsonParser().parse(jsonString);
                              if (jelement != null)
                                  jsonMop.add("NBTTagCompound", jelement);
                          }
                          catch (JsonSyntaxException e)
                          {
                              // Duff NBTTagCompound - ignore it.
                          }
                      }
                  }
              }
              jsonMop.addProperty("inRange", hitDist <= blockReach);
              jsonMop.addProperty("distance", hitDist);
          }
          else if (mop.typeOfHit == RayTraceResult.Type.ENTITY)
          {
              // Looking at an entity:
              Entity entity = mop.entityHit;
              if (entity != null)
              {
                  jsonMop.addProperty("x", entity.posX);
                  jsonMop.addProperty("y", entity.posY);
                  jsonMop.addProperty("z", entity.posZ);
                  jsonMop.addProperty("yaw",  entity.rotationYaw);
                  jsonMop.addProperty("pitch",  entity.rotationPitch);
                  String name = MinecraftTypeHelper.getUnlocalisedEntityName(entity);
                  String hitType = "entity";
                  if (entity instanceof EntityItem)
                  {
                      ItemStack is = ((EntityItem)entity).getEntityItem();
                      DrawItem di = MinecraftTypeHelper.getDrawItemFromItemStack(is);
                      if (di.getColour() != null)
                          jsonMop.addProperty("colour", di.getColour().value());
                      if (di.getVariant() != null)
                          jsonMop.addProperty("variant", di.getVariant().getValue());
                      jsonMop.addProperty("stackSize", is.getCount());
                      name = di.getType();
                      hitType = "item";
                  }
                  jsonMop.addProperty("type", name);
                  jsonMop.addProperty("hitType", hitType);
              }
              jsonMop.addProperty("inRange", hitDist <= entityReach);
              jsonMop.addProperty("distance", hitDist);
          }
          json.add("LineOfSight", jsonMop);
      }