Transparency Sorting Mode (Custom Axis)

[AxZelAnims]

So I've been reworking my Unity Project into Godot for over a year now and while Godot has convinced me right away to jump in and do this project, I did not bother to see if it has Transparency Sorting Issue (as Unity didn't give me a hard time with this issue) until I was deep in the development and started working on my Sprite Assets.

So Unity and Godot has a very similar issue of drawing Transparent Sprites properly but Unity has a Transparency Sorting Mode that fixes this.

Editor Preview
https://youtu.be/HW9f1UgtFho?feature=shared

Play Preview
https://youtu.be/XFnq9mzor9U?feature=shared

By any chance are we going to have a very similar feature? Because this is making my progress slow.

[theraot]

As long as you don't need semi transparency, you can use a material with alpha scissor (i.e. alpha_cut set to discard on 3d sprites), and that will resolve the problem. Other than that, I think the only real solution is to script render_priority.

[AxZelAnims]

Discard does do the trick but it makes my Sprites have jagged edges.

I could work with render_priority but I'm not sure how I would be able to properly sort each objects properly based on their pivot point (and I know 256 is alot, but I might still consume them in the long run)

By any chance Transparency Sorting with custom axis will be implemented in the future? This seems like a very good solution to make a 2.5D Game without having to reinvent collisions and faking z-axis in 2D.

[theraot]

@AxZelAnims It seems this fell through the cracks in the effort to bring Godot 4.0 to stable:

• 3D transparency sorting features for 2.5D games godot#59404

I do not know what are the plans for it, but hopefully this discussion can be a reminder to look into it.

[AxZelAnims]

I might have seen this before. And although I agree it does sounds like trying to copying what Unity is doing, I thought this is a common idea for this scenario?

Should I open up an issue or should I just wait for them?

[theraot]

In general, the process for a new features is like this: Somebody makes a proposal, somebody makes a pull request, then others review the pull request (usually this won't happen if the pull request is a draft), from the reviews the author of the pull request will make changes, eventually the pull request is approved and merged.

See Contribution workflow for more details.

Now, given the large amount of issues, proposals and pull requests, the Godot team triages what to merge and what to work on. While flawed, one of the factors is the emoji reaction (this is flawed because issues that get shared in social media tend to have the number of reaction inflated, but in lieu of a better way to measure interest, it works).

Also know that Leaving a comment to bump an issue is frown upon.

Note: Legitimate reasons to comment include but are not limited to: pointing out pitfalls, sharing use cases that might not have been considered, suggesting alterative solutions, or sharing workarounds.

With that in mind, to move this feature along, here are some things you can do:

• If you have a better idea: You can open your own proposal (an issue on this repository), saying it supersedes the existing proposal. If you also want to implement your own idea, you can make a pull request, saying it implements your proposal, and supersedes the existing pull request. If your implementation is based on the existing pull request, add its authors as co-author.
• If you want to implement the existing proposal: You can open a pull request, saying it implement the existing proposal, and supersedes the existing pull request. If your implementation is based on the existing pull request, add its authors as co-author.
• If you want to signal signal interest in the existing pull request: leave an emoji reaction on the existing pull request.
• If you want to signal signal interest in the existing proposal (regardless of it is implemented by the current pull request or not): leave an emoji reaction on the existing proposal.
• If you have something to say about the existing pull request, other than signaling interest: leave a comment on the existing pull request.
• If you have something to say about the existing proposal, other than signaling interest: leave a comment on the existing proposal.
• Other discussion: It can happen here. People will check from time to time, including Godot staff (at least moderators do), and perhaps the author of the author of the existing pull request, or not... I do not know what they are up to, nor if they are interested in resuming work on the pull request.

[AxZelAnims]

• 3D transparency sorting features for 2.5D games godot#59404

Also know that Leaving a comment to bump an issue is frown upon.

My bad, I commented before seeing your response. I'm still relatively confused about how all of this works. Thank you.

[jitspoe]

Godot 3 used to sort on the axis of the camera, but that was changed to be purely distance sorting. I hacked the old behavior back in for my 2.5D platformer project since the camera angle is fixed and the sorting looked better with that. If you want to modify the engine yourself to do that, you can go to render_forward_clustered.cpp and edit this block of code:

		if (p_render_data->scene_data->cam_orthogonal) {
			if (inst->use_aabb_center) {
				center = inst->transformed_aabb.get_support(-near_plane.normal);
			}
			inst->depth = near_plane.distance_to(center) - inst->sorting_offset;
		} else {
			if (inst->use_aabb_center) {
				center = inst->transformed_aabb.position + (inst->transformed_aabb.size * 0.5);
			}
			inst->depth = p_render_data->scene_data->cam_transform.origin.distance_to(center) - inst->sorting_offset;
		}

Change the p_render_data->scene_data->cam_orthogonal check to just be if (true). You could also modify it to use a specific axis instead of the plane normal. Note that there are multiple renderers, so if you're using gles3, you'd have to make that change in rasterizer_scene_gles3.cpp as well. There's another if statement above, where the near_plane is set that needs to be changed to true as well.