Object visibility is not respected

[Amadman]

Creating an object layer in tiled, then adding an object with "Visible: False" property should make the object invisible when loaded in. Currently this variable seems to be ignored.

[karai17]

The issue with that is how sprite batches work. STI batches all the tiles in a layer into single draw calls, so toggling the visibility of individual objects would require manually modifying the batch upon toggle.

I could probably add a function to each object that you could use to toggle the object's visibility which would adjust the sprite batch.

[Amadman]

My (admittedly uninformed) fix is:

	for _, object in ipairs(layer.objects) do
		if object.visible == true then
			if object.shape == "rectangle" and not object.gid then
				drawShape(object.rectangle, "rectangle")
			elseif object.shape == "ellipse" then
				drawShape(object.ellipse, "ellipse")
			elseif object.shape == "polygon" then
				drawShape(object.polygon, "polygon")
			elseif object.shape == "polyline" then
				drawShape(object.polyline, "polyline")
			end
		end
	end

I'm not too well informed about sprite batches so this "fix" probably doesn't fully work for the problem but it has worked in my simple case.

https://github.com/karai17/Simple-Tiled-Implementation/blob/master/sti/init.lua#L820

[karai17]

That would work for Tiled's geometry objects, but not so well for tile objects that draw sprites, those get batched into a single draw call.

[ikhaliq15]

Okay, so I ran into this same problem and my solution was to add a function that would recreate the batch for the layer and then in the Map:setObjectSpriteBatches function, I just added a condition of the object being visible.

--- Recreates the batch for a layer.
-- @param index Draw order within Layer stack
function Map:updateLayerBatches(index)
	local layer = assert(self.layers[index], "Layer not found: " .. index)
	self:setObjectSpriteBatches(layer)
end

--- Batch Tiles in Object Layer for improved draw speed
-- @param layer The Object Layer
function Map:setObjectSpriteBatches(layer)
	local newBatch = lg.newSpriteBatch
	local batches  = {}

	if layer.draworder == "topdown" then
		table.sort(layer.objects, function(a, b)
			return a.y + a.height < b.y + b.height
		end)
	end

	for _, object in ipairs(layer.objects) do
		if object.gid and object.visible then
			local tile    = self.tiles[object.gid] or self:setFlippedGID(object.gid)
			local tileset = tile.tileset
			local image   = self.tilesets[tileset].image

			batches[tileset] = batches[tileset] or newBatch(image)

			local sx = object.width  / tile.width
			local sy = object.height / tile.height

			-- Tiled rotates around bottom left corner, where love2D rotates around top left corner
			local ox = 0
			local oy = tile.height

			local batch = batches[tileset]
			local tileX = object.x + tile.offset.x
			local tileY = object.y + tile.offset.y
			local tileR = math.rad(object.rotation)

			-- Compensation for scale/rotation shift
			if tile.sx == -1 then
				tileX = tileX + object.width

				if tileR ~= 0 then
					tileX = tileX - object.width
					ox = ox + tile.width
				end
			end

			if tile.sy == -1 then
				tileY = tileY - object.height

				if tileR ~= 0 then
					tileY = tileY + object.width
					oy = oy - tile.width
				end
			end

			local instance = {
				id    = batch:add(tile.quad, tileX, tileY, tileR, tile.sx * sx, tile.sy * sy, ox, oy),
				batch = batch,
				layer = layer,
				gid   = tile.gid,
				x     = tileX,
				y     = tileY,
				r     = tileR,
				oy    = oy
			}

			self.tileInstances[tile.gid] = self.tileInstances[tile.gid] or {}
			table.insert(self.tileInstances[tile.gid], instance)
		end
	end

	layer.batches = batches
end

So whenever I changed the visibility of an object, I called the updateLayerBatches and it worked great. I don't know if this is at all efficient or anything so let me know if this is totally stupid.

[karai17]

The issue with the above code is that you're creating a whole new batch and rebuilding all of the objects instead of just updating the current batch and the one object. You're also not clearing any of the old data so your tileInstances table becomes dirty and unreliable, not to mention introducing a memory leak.