Why is there no Area light in Godot

modulecode · June 3, 2024, 5:31pm

Godot Version

v4.3.beta1.official [a4f2ea91a]

Question

Why is there no surface light in Godot.For example, there is area light in Blender

smix8 · June 4, 2024, 8:02am

Blender is a digital content creation tool with a ray-traced non-realtime renderer for production rendering where a single frame can take hours as time is not a real concern.

Real surface lights are absurdly costly to calculate compared to other light options. That is why they are commonly not supported in realtime game engines that need to render 60+ frames a second.

With partly ray-traced rendering getting more and more common that tests against the surfaces things get a little better in game engines but it is still a far cry from what is done in Blender.

The main problem with surface lights is that their shapes are arbitrary compared to all other common light options like directional, spot and omnilights. That makes them very costly to calculate and update. Considering that the light pass is already one of the most costly features in a rendering pipeline it is just a bad fit to use “real” surface lights in a realtime renderer.

modulecode · June 4, 2024, 7:16pm

But why is there regional light in Unity

gertkeno · June 4, 2024, 9:17pm

Because Unity chose to support it, Godot is open source and a lot of features come down to if somebody wants a feature enough to program it; so far it hasn’t been worth it, and as stated by smix8 it’s runtime cost is inheritly high too.

athousandships · June 4, 2024, 9:31pm

github.com/godotengine/godot-proposals

Add support for specifying light sizes and shapes for specular reflections / area lights

opened 08:08AM - 29 Jul 20 UTC

mindinsomnia

topic:rendering topic:3d

**Describe the project you are working on:** Third person shooter **Descri…be the problem or limitation you are having in your project:** I would like to achieve more accurate / realistic lighting across surfaces and have more control over the shape and size of specular highlights. **Describe the feature / enhancement and how it helps to overcome the problem or limitation:** Some real time engines provide the ability to define the shape of a light source to control the shape of the specular highlights. This produces much greater realism and more interesting visuals, and allows for approximating the shape of some light emitting scene objects with a shaped light. When combined with surfaces that have interesting properties, such as varying roughness and normal mapss, the results can be quite beautiful. The reflections are also real time, have no issues with sampling or noise, work even with the source of the reflection is outside of the camera frame (unlike screenspace reflections) and don't require any baking, lightmaps or lightprobes. Example of this feature as it was implemented in Eevee, runs butter smooth in real time: ![tFc6nphSNv](https://user-images.githubusercontent.com/15921126/88771528-b80de380-d1c2-11ea-9361-0ea2671e842d.gif) ![OUBwdEmC2L](https://user-images.githubusercontent.com/15921126/88773817-fbb61c80-d1c5-11ea-82e3-dbc94ee273a2.gif) **Describe how your proposal will work, with code, pseudocode, mockups, and/or diagrams:** I am not familiar enough with Godot's internal code to know how compatible a change like this would be, or if it would be acceptable to make a change like this that would alter how existing specular highlights look for existing projects using OmniLights. I also understand that it's possible this kind of feature could introduce higher performance requirements. If breaking compatibility is acceptable, and the performance impact for each light is negligible, I would like there to be simply be an option added to existing OmniLights and Spotlights to control their radius and shape (circle, sphere, rectangle as a minimum would be nice). If breaking compatibility is not an option, or if this kind of light requires substantially more computation than a regular light, perhaps a different set of light nodes could be implemented, such as 'SphereLight', 'RectLight', 'CircleLight', etc. Or simply one 'catch all' light called 'ShapedLight' etc. **If this enhancement will not be used often, can it be worked around with a few lines of script?:** I do not believe it would be possible to implement this with just a few lines of scripting. For 3D artist chasing realism in their 3D environments, I would expect they would use this feature on virtually every light in their scene. **Is there a reason why this should be core and not an add-on in the asset library?:** This feature would greatly increase the potential head room for realistic 3D imagery in Godot, something which would be useful to a broad range of users, and even for cartoony art styles, having more artistic control over lighting would allow for producing much more interesting and visually beautiful imagery. I am not capable of making an assessment on whether or not it would be possible to implement a change like this as an addon but I imagine such lighting calculations are fairly 'core' to how Godot works and could not be easily changed by an addon, and such an addon would be tedious to maintain and equally tedious for users to repeatedly install.