Add optional transparency passthrough for sprite backend with bevy_picking #16388

vandie · 2024-11-14T09:43:42Z

Objective

Allow bevy_sprite_picking backend to pass through transparent sections of the sprite.
Fixes Add support for alpha-testing in sprite picking backend #14929

Solution

After sprite picking detects the cursor is within a sprites rect, check the pixel at that location on the texture and check that it meets an optional transparency cutoff. Change originally created for mod_picking on bevy 0.14 (Ignore transparent sections of sprite using sprite-picking aevyrie/bevy_mod_picking#373)

Testing

Ran Sprite Picking example to check it was working both with transparency enabled and disabled
ModPicking version is currently in use in my own isometric game where this has been an extremely noticeable issue

Showcase

Migration Guide

Sprite picking now ignores transparent regions (with an alpha value less than or equal to 0.1). To configure this, modify the SpriteBackendSettings resource.

github-actions · 2024-11-14T09:43:59Z

Welcome, new contributor!

Please make sure you've read our contributing guide and we look forward to reviewing your pull request shortly ✨

mgi388

I’m excited for this change. I did a quick visual code review but haven’t tested it yet.

mgi388 · 2024-11-14T10:05:28Z

crates/bevy_sprite/src/picking_backend.rs

+    /// Off by default for backwards compatibility. This setting is provided to give you fine-grained
+    /// control over if transparency on sprites is ignored.
+    pub passthrough_transparency: bool,
+    /// How Opaque does part of a sprite need to be in order count as none-transparent (defaults to 10)


Can you elaborate in the docs what the units are? 10 what? What is a valid range I could use, as a user?

Can these two options be combined into a single enum? It doesn't make sense to have an alpha cutoff setting when alpha passthrough is disabled. e.g.

SpritePickingAlphaTest { /// Don't test alpha, only consider the rect of sprites. Ignore, /// Test the pixel alpha when running hit tests. Alpha values below this will not be considered for picking. Threshold(u8) }

Yeah an enum is probably a better idea for those settings. Will rework to include.

crates/bevy_sprite/src/picking_backend.rs

mgi388 · 2024-11-14T10:13:39Z

@vandie also see #14929 I think your PR fixes it.

vandie · 2024-11-14T10:14:16Z

@vandie also see #14929 I think your PR fixes it.

I think it does yeah.

mgi388 · 2024-11-14T10:22:15Z

@vandie also see #14929 I think your PR fixes it.

I think it does yeah.

You can put “Fixes #{id}” in your PR description so merging this PR closes the issue as fixed. 😌

vandie · 2024-11-17T09:15:11Z

Seems everyone agrees that this should be enabled by default so I've updated that and introduced a new SpriteBackendAlphaPassthrough enum so this can be controlled by a single setting rather than multiple.

github-actions · 2024-11-17T13:57:24Z

It looks like your PR is a breaking change, but you didn't provide a migration guide.

Could you add some context on what users should update when this change get released in a new version of Bevy?
It will be used to help writing the migration guide for the version. Putting it after a ## Migration Guide will help it get automatically picked up by our tooling.

alice-i-cecile · 2024-11-17T13:57:41Z

Can you add a small migration guide explaining that this is now on by default? Definitely the better default, but could break existing users.

vandie · 2024-11-17T14:50:15Z

Can you add a small migration guide explaining that this is now on by default? Definitely the better default, but could break existing users.

Added. Hope that's ok and clear?

alice-i-cecile · 2024-11-17T17:24:58Z

The migration guide was clear and effective, but the tone / target audience was a bit weird. The goal is to communicate "why is my stuff broken and how do I fix it", but your initial draft was closer to a change log :) I've quickly edited the PR description incorporating the information you've added. These get automatically scraped / compiled, so it's good to clean them up here.

…e_point`.

andriyDev · 2024-11-23T18:53:05Z

@vandie When you have time, could you take a look at vandie#2 ? I tested it and it looks like it solves a lot of issues! (just wanna make sure it doesn't get lost)

…the sprite.

… in picking_backend. Previously SpriteBackendSettings was private, making it impossible to change the SpritePickingMode. Now we can!

This is already taken care of in `compute_pixel_space_point`.

This matches the `SpritePickingPlugin`.

crates/bevy_sprite/src/picking_backend.rs

…cking (bevyengine#16388) # Objective - Allow bevy_sprite_picking backend to pass through transparent sections of the sprite. - Fixes bevyengine#14929 ## Solution - After sprite picking detects the cursor is within a sprites rect, check the pixel at that location on the texture and check that it meets an optional transparency cutoff. Change originally created for mod_picking on bevy 0.14 (aevyrie/bevy_mod_picking#373) ## Testing - Ran Sprite Picking example to check it was working both with transparency enabled and disabled - ModPicking version is currently in use in my own isometric game where this has been an extremely noticeable issue ## Showcase ![Sprite Picking Text](https://github.com/user-attachments/assets/76568c0d-c359-422b-942d-17c84d3d3009) ## Migration Guide Sprite picking now ignores transparent regions (with an alpha value less than or equal to 0.1). To configure this, modify the `SpriteBackendSettings` resource. --------- Co-authored-by: andriyDev <[email protected]>

alice-i-cecile · 2025-03-25T20:06:33Z

Thank you to everyone involved with the authoring or reviewing of this PR! This work is relatively important and needs release notes! Head over to bevyengine/bevy-website#1961 if you'd like to help out.

alice-i-cecile · 2025-03-25T20:06:53Z

Thank you to everyone involved with the authoring or reviewing of this PR! This work is relatively important and needs release notes! Head over to bevyengine/bevy-website#1966 if you'd like to help out.

# Objective - Docs in sprite picking plugin / example contain outdated information. References: - Sprite picking now always require `Picking` - #17842 - Transparency pass-through added - #16388 ## Solution - Fix the docs.

# Objective - Docs in sprite picking plugin / example contain outdated information. References: - Sprite picking now always require `Picking` - bevyengine#17842 - Transparency pass-through added - bevyengine#16388 ## Solution - Fix the docs.

vandie added 2 commits November 14, 2024 09:38

Add optional transparancy passthrough for sprite backend

c5dd17a

set correct default

bba576b

vandie added 4 commits November 14, 2024 09:44

fix typo

f9088c7

fix too many arguments

d1013cf

fix doc typo

1924e02

clean up final check into match

42c156b

mgi388 reviewed Nov 14, 2024

View reviewed changes

vandie added 2 commits November 14, 2024 10:18

fix docs and naming

3ca1039

change transparency to alpha in variable names

7038101

kristoff3r added S-Needs-Review Needs reviewer attention (from anyone!) to move forward A-Picking Pointing at and selecting objects of all sorts D-Modest A "normal" level of difficulty; suitable for simple features or challenging fixes labels Nov 14, 2024

alice-i-cecile added this to the 0.16 milestone Nov 14, 2024

alice-i-cecile added the M-Needs-Release-Note Work that should be called out in the blog due to impact label Nov 14, 2024

BenjaminBrienen approved these changes Nov 15, 2024

View reviewed changes

vandie added 3 commits November 17, 2024 09:10

Add AlphaPassthrough enum and change default to on

1f48ff2

improve comments

5ee1448

Merge branch 'main' into ignore_transparancy_on_sprite_picking

16f8654

vandie added 2 commits November 17, 2024 09:16

update comments

38eb823

update comments

26f4511

alice-i-cecile added the M-Needs-Migration-Guide A breaking change to Bevy's public API that needs to be noted in a migration guide label Nov 17, 2024

Rewrite the sprite picking backend to use `Sprite::compute_pixel_spac…

6b5a176

…e_point`.

andriyDev and others added 9 commits November 24, 2024 11:35

Add a comment to clarify that we know the cursor is in the bounds of …

23cc626

…the sprite.

Make the sprite_picking system private, but then re-export everything…

f46f67c

… in picking_backend. Previously SpriteBackendSettings was private, making it impossible to change the SpritePickingMode. Now we can!

Remove flipping the y-value of the cursor from the picking backend.

e3d6736

This is already taken care of in `compute_pixel_space_point`.

Rename SpriteBackendSettings to SpritePickingSettings.

f3476e0

This matches the `SpritePickingPlugin`.

Move all the pixel computations to Sprite::compute_pixel_space_point.

8eb09ff

Merge branch 'main' into ignore_transparancy_on_sprite_picking

db392ab

Merge branch 'main' into ignore_transparancy_on_sprite_picking

eca8e10

remove un-needed closure

22e7547

fix comments

64f1cf7

Diddykonga reviewed Nov 29, 2024

View reviewed changes

crates/bevy_sprite/src/picking_backend.rs Show resolved Hide resolved

vandie added 2 commits December 2, 2024 12:44

Merge branch 'main' into ignore_transparancy_on_sprite_picking

7ed99c5

added @andriyDev's comment to code

8bff88a

alice-i-cecile added this pull request to the merge queue Dec 3, 2024

alice-i-cecile added this pull request to the merge queue Dec 5, 2024

Merged via the queue into bevyengine:main with commit 4be7530 Dec 5, 2024
28 checks passed

mgi388 mentioned this pull request Jan 20, 2025

Add optional alpha / transparency passthrough for UI picking backend #17448

Open

akimakinai mentioned this pull request May 5, 2025

Sprite picking docs fix #19016

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Add optional transparency passthrough for sprite backend with bevy_picking #16388

Add optional transparency passthrough for sprite backend with bevy_picking #16388

vandie commented Nov 14, 2024 •

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alice-i-cecile commented Mar 25, 2025

Add optional transparency passthrough for sprite backend with bevy_picking #16388

Add optional transparency passthrough for sprite backend with bevy_picking #16388

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vandie commented Nov 14, 2024 • edited Loading

Objective

Solution

Testing

Showcase

Migration Guide

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