Fix "Light Only" mode of CanvasItemMaterial
#75181
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| @@ -611,6 +611,9 @@ void main() { | |||
| } | |||
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| light_blend_compute(light_base, light_color, color.rgb); | |||
| #ifdef MODE_LIGHT_ONLY | |||
| ligth_only_alpha += light_color.a; | |||
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I'm not sure what should be used here, sum, average or something else. And is clamp needed here?
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By the way, I noticed 2 more bugs:
EDIT: This applies to the Light Only mode, so we can consider this as the same bug. 2. In 4.0, the alpha channel of the EDIT: In 4.0 the alpha channel is used for energy. I tried to fix it, but in 3.x alpha and energy give slightly different results (perhaps they just have different weights). Another possible solution is to add |
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Note it also needs to be fixed for GLES3: https://github.com/godotengine/godot/blob/0067578b5ba48be812b9c74421867ceba1bbc330/drivers/gles3/shaders/canvas.glsl. |
dalexeev
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Test projects for comparison with 3.x: light-only-3.x.zip Note that background and canvas modulate affect the result. The difficulty is that the Light Only mode must take into account the background color. |
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This is on the right track, but it is still drawing the original sprite. The "Light Only" mode in 3.x only drew the contribution from the Light2D 3.x: notice how the original sprite looks very faint? This PR: notice how the Light2D is essentially only acting as a mask This PR is a step in the right direction. But the trouble is that the final color is ultimately mixed with the background using the blend mode of the Sprite rather than the blend mode of the light (which is kind of necessary with how "Light Only" worked. It would be interesting to hear from people like @KoBeWi to see if this PR would be enough for their use case as I think matching the 3.x behaviour exactly may be too difficult Edit: I guess the difference is only really noticeable with the Add blend mode: 3.x: left is with normal mode, right is with "light only" lights are using mix, sub, and add edit: edit: Looks like you can get the 3.x behaviour with this PR by setting the Sprite's blend mode to Add and the light's blend mode to Mix |
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Well, my use-case is using lights to reveal hidden things (objects, outlines). The lights and hidden objects are using exclusive godot.windows.editor.dev.x86_64_WlmFQy7ISB.mp4 |
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I marked this PR as draft for two reasons:
So I undraft this PR. If someone has the desire and confidence to fix it properly, then I don't mind. Let us know about it and feel free to use it as a basis. Or we can merge this PR as is, for the reason "it's better to have a feature that doesn't work well with advanced scenarios than a feature that doesn't work at all" and fix it properly in future PRs. |
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Would you be willing to share your compiled exe file with these fixes? Light only mode is pretty integral for my project, and i cannot continue development without it working properly. Ive tried compiling the code myself, but i must be doing something horribly wrong, as i cannot seem to get it working. It would be a huge help as the only other alternative i have is manualy porting the project back to godot 3, which would be a major headache. |
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I rebased and force-pushed the branch. When the build is over you will be able to download the artifacts.
@Janonas https://github.com/godotengine/godot/actions/runs/4965461719?pr=75181#artifacts |
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Thank you, it works flawlessly for my purposes. |
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Let's go ahead with this. The users who are missing a "light only" mode seem to all be happy with this approach. I'm not sure that fully replicating the 3.x behaviour is possible/desirable and this approach makes a lot of sense given how 2D light rendering works in Godot 4
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Sounds good. Thanks! |
Closes #44559.