:setVisible() not functioning

[mannjustinj]

copied from the love forums:

I have been using light_world for a while now, though to date I've been using it with statically-placed lights that do not move. Lately I am discovering a really odd behavior when I want to selectively decide if a light is visible or not.

The logic is rather simple:

1. in love.draw, set all lights to not visible ( setVisible(false) )
2. for each tile to render, see if that tile contains a light. if it does, update its relative position and make it visible

This does not work at all. As soon as the light has been made invisible, it will never appear again. Dumping the contents of the object, you can clearly see the light SHOULD be appearing. It'll look something like this:

[code]        (*)     l       |
        z       =>      1
        visible =>      true
        red     =>      1
        green   =>      1
        blue    =>      1
        glowStrength    =>      0
        glowSize        =>      0.1
        x       =>      1013
        y       =>      631
        angle   =>      6.2831853071796
        direction       =>      0
        range   =>      110
        smooth  =>      1
        is_on_screen    =>      true[/code]

I can immediately invoke update() on the light world or not, it doesn't make a difference. What DOES work is if I completely destroy the light object and then immediately re-create but, but this is so slow as to be totally unusable. I have no idea why the library is behaving in this way, and it seems to have not been updated in a long time, so I guess this is a long shot, but I'm hoping someone here might be able to help.

Here's a bit of code that determines if a light is going to be drawn or not:

[code]          if (maps[room][layer][roomx][roomy].fn) then -- tile has a light
            if (global.state.screen.light) then
              local lsdx = rangeXmax - mx + 1 -- tracking which portion of the map is going to be drawn
              local lsdy = rangeYmax - my + 1
              if not(lights) then lights = { } end
              local id = room .. maps[room][layer][roomx][roomy].uid --creating a unique identifier for the light
              if not(lights[id]) then -- need to re-create this light
                print("creating light in room " .. room .. " at position " .. lsdx .. " " .. lsdy .. " " .. ((spreadX*64)+offsetX-64) .. " " .. ((spreadY*64)+offsetY-64))
                local ld = f_ed_get_light(lightsdata[maps[room][layer][roomx][roomy].fn].fn) -- describe the light
                local offset_x, offset_y = 0, 0
                if ld[7] then offset_x = offset_x + ld[7] end
                if ld[8] then offset_y = offset_y + ld[8] end 
                lights[id] = light:newLight(((spreadX*64)+offsetX-64) + offset_x, ((spreadY*64)+offsetY-64) + offset_y, ld[1], ld[2], ld[3], ld[4])
                if ld[5] then lights[id]:setAngle(ld[5]) end
                if ld[6] then lights[id]:setDirection(ld[6]) end
              else -- light was already made, update position
                --print("updating light " .. id .. " in room " .. room .. " at position " .. lsdx .. " " .. lsdy)
                local ld = f_ed_get_light(lightsdata[maps[room][layer][roomx][roomy].fn].fn)
                local offset_x, offset_y = 0, 0
                if ld[7] then offset_x = offset_x + ld[7] end
                if ld[8] then offset_y = offset_y + ld[8] end
                lights[id]:setVisible(true)
                lights[id]:setPosition(((spreadX*64)+offsetX-64) + offset_x, ((spreadY*64)+offsetY-64) + offset_y)
              end[/code]

If I simply run that code as-is, the lights work, but as soon as you move, many other lights will start to be be created and will never get cleaned up. I tried many, many, many methods to clean them up, and none short of destroying the light worked. Using this method below causes all the lights to go invisible and never return, no matter how many times you make them visible again afterward:

[code]
        if (global.state.screen.light) then
          for k,v in pairs(lights) do
            if (lights[k]) then
              lights[k]:setVisible(false)
            end
          end
        end[/code]