I am not suggesting the whole radial blur thing on the outside edge, let me add. I'm only talking about atom.opacity and how it blocks light.

If this were added there should be some sort of option for hiding things in half shaded tiles until they're fully revealed.

I support this, if it can be implemented and actually used without murdering performance. Considering how poorly basic alpha transparency performs, though, I don't know what the chances of that are.

I would really like this myself and it's something I've thought about from time to time. Questions that naturally come up are how we would reconcile the lighting with 2D sprites, for instance how they would cast shadows and how the lighting would play off their surface, and this is an even bigger question for isometric modes. I'm very open however to any ideas that would suggest a way to handle these issues, because having built-in lighting would be incredibly awesome and add a lot of wow factor to BYOND. I'm putting this under "Needs Discussion" for now because I'd really like to encourage some brainstorming on how to handle all the technical details.

I'm not sure there can be a meaningful discussion of lighting without considering shadows, though. For instance if you're shining a light and it hits an opaque tile, if it's a standard wall you probably want the whole thing to cast a solid shadow but otherwise you might only want the opaque parts of one icon to cast a shadow. So that's somewhat relevant; it's also not that hard, overall, except that there'd have to be some way to tell one icon's opacity from another so an underlay tile didn't cast any shadows. A very simple 2D lighting scheme could handle all this, and simply attenuate the brightness or color of objects in the lit area, but this would only apply to topdown mode. (Other questions arise like how to handle soft shadows, ambient illumination of an area, etc.) Handling lighting in that manner via isometric would be more difficult, since every icon has the illusion of depth.

The example you brought up is a perfect illustration of the problem though. The walls effectively cast shadows to keep lighting from showing up behind them.

In a case like this, say the edges of the ### are doorways into a room. Most of the # tiles you wouldn't want to light up because the light source is invisible to the mob; there'd be no point. Floor tiles in front of the doorway however you would want to light up. This distinction is fairly easy to make. But as you got near the doorway you'd also want wall tiles near it to be at least partially lit by that source.

Given this map: http://files.byondhome.com/Forumaccount/no-light.png

And a light source positioned similar to my text example: http://files.byondhome.com/Forumaccount/light.png

With shadows it would look something like this: http://files.byondhome.com/Forumaccount/shadow-1.png

The problem is that we have a top-down view. We're not seeing the sides of the wall, we're seeing the top. No matter what we do it won't look nice. Our options are:

this: http://files.byondhome.com/Forumaccount/opacity-1.png

or this: http://files.byondhome.com/Forumaccount/shadow-opacity.png

Whether or not the light passes through the wall is actually the least of our worries.

Falacy wrote:

Just have it work like opacity does;

The problem with opacity is that the current line-of-sight model is not entirely realistic and works on an all-or-nothing basis. Having either all pixels or no pixels within a tile be affected by a light source would look afwul.

When you position the light source such that the edge of its visibility is a 45 degree angle it'll look bad.

Edit: It'll also look bad when wall tiles don't occupy the full 32x32 space.

The simple solution is to not worry about shadows. There are plenty of ways this is useful even if it doesn't support shadows.

An overly complex pixel-based solution still has its problems. This isn't the type of shadow you'd expect from a fence: http://www.byond.com/members/Forumaccount/files/fence.png The problem is that the pixels occupied by the image aren't necessarily representative of the volume of space occupied by the object.