Tilemap - per area lighting - Godot Community Forums

Tilemap - per area lighting

Tom

Hi - how do/would you guys graphically implement a lighting level on a tilemap - given that I have the level of light in a given area (calculated by sun light outdoors, and the presence/absence of articifial light indoors or windows). I was going the route of putting polygons on top of the areas and modulate them with a certain opacity. It works. But I am stuck on the outdoor area which is a big polygon with holes cut out where the indoor areas are. It worked for one hole, using the "invert" option on a polgon. And looking around on forums, godot isnt able to handle multiple holes in a polygon2d? So I am a bit stuck...

zoedoz

What kind of a game are you making? Do you have an image of what you've managed so far?

Tom

Sorry, I probably forgot to mention. It is a topdown game, like rimworld (I am using rimworld and prison architect assets as placeholders)

In the screenshot you see a building that is 100% lit while the outdoor area is dark and tinted a bit blue-ish.

zoedoz

Cut the polygon for the outdoor area up into several pieces instead?

Tom

Hi zoedoz, thanks for your suggestion. It has crossed my mind as well, but I quickly got overwhelmed with how the implementation would look like. As an example I took an U-shaped building with a unconnected small building in the middle of that. I would have to think about how to cut the polygon manually in such a case, let alone write it in software to cover all kind of cases dynamically. (note that the buildings are not manually drawn, they are randomly generated)

Let me share an option I am currently investigating: I have a big sprite overlaying the whole map, and drawing squares on it, one for every cell, filled with the correct rgba value. I'm guessing this must be fast enough - opposed to having a polygon for every cell. (that would be about 10000 polygon2d nodes).

zoedoz

Tom

Let me conclude how I have done it now (in case anybody wants to do the same). I created a new class that inherits from Node2D. In the constructor I pass the map data. I overwrite the draw call and in there I go over the map data, and for every outdoor cell I do DrawColoredPolygon (64x64 square in a grey color on the cell's coordinates). For 65536 cells (which is the biggest map in my game) it actually goes very fast. Then in the game tick I change the modulate color of that node2d depending on the time of day. (no need to call update and redraw things when changing modulate color) Only when buildings on the map change I need to do an update call of that node2d.