Allow ImageNode with a texture atlas to be construct in BSN, fixes #24889

[bitblocks-dev]

Objective

Allow ImageNode with a texture atlas to be construct in BSN, fixes #24889

Solution

Replaces

pub struct ImageNode {
  #[template(built_in)]
  pub texture_atlas: Option<TextureAtlas>,
  // -- snip --
}

with

pub struct ImageNode {
  #[template(OptionTemplate<TextureAtlasTemplate>)]
  pub texture_atlas: Option<TextureAtlas>,
  // -- snip --
}

which makes it possible to construct ImageNode with a texture atlas, though the ergonomics could use some work.

Testing

Tested using the following code, adapted from the UI Texture Atlas Slice example.

Click to view

use bevy::{
    color::palettes::css::{GOLD, ORANGE},
    image::TextureAtlasTemplate,
    prelude::*,
    ui::widget::NodeImageMode,
};

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_systems(Startup, setup)
        .add_systems(Update, button_system)
        .run();
}

fn button_system(
    mut interaction_query: Query<
        (&Interaction, &Children, &mut ImageNode),
        (Changed<Interaction>, With<Button>),
    >,
    mut text_query: Query<&mut Text>,
) {
    for (interaction, children, mut image) in &mut interaction_query {
        let mut text = text_query.get_mut(children[0]).unwrap();
        match *interaction {
            Interaction::Pressed => {
                **text = "Press".to_string();
                if let Some(atlas) = &mut image.texture_atlas {
                    atlas.index = (atlas.index + 1) % 30;
                }
                image.color = GOLD.into();
            }
            Interaction::Hovered => {
                **text = "Hover".to_string();
                image.color = ORANGE.into();
            }
            Interaction::None => {
                **text = "Button".to_string();
                image.color = Color::WHITE;
            }
        }
    }
}

fn setup(mut commands: Commands) {
    // ui camera
    commands.spawn(Camera2d);

    commands.spawn_scene(bsn! {
       Node {
            width: percent(100),
            height: percent(100),
            align_items: AlignItems::Center,
            justify_content: JustifyContent::Center,
        }
        Children [
            Button
            ImageNode {
                image: "textures/fantasy_ui_borders/border_sheet.png",
                texture_atlas: Option::<TextureAtlasTemplate>::Some(TextureAtlasTemplate { layout: asset_value(TextureAtlasLayout::from_grid(UVec2::new(50,50), 6, 6, Some(UVec2::splat(2)), None)), index: 0 })
                image_mode: NodeImageMode::Sliced(
                TextureSlicer {
                    border: BorderRect::all(24.0),
                    center_scale_mode: SliceScaleMode::Stretch,
                    sides_scale_mode: SliceScaleMode::Stretch,
                    max_corner_scale: 1.0,
                }),
            }
            Node {
                width: px(300.0),
                height: px(150.0),
                // horizontally center child text
                justify_content: JustifyContent::Center,
                // vertically center child text
                align_items: AlignItems::Center,
                margin: UiRect::all(px(20.0)),
            }
            Children [
                Text::new("Button"),
                TextColor(Color::srgb(0.9, 0.9, 0.9)),
            ]
        ]
    });
}

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[kfc35]

Hmm, does this mean something is wrong with built_in? As far as I know from the original PR https://github.com/bevyengine/bevy/pull/23699/changes#diff-227e59a8188aa92faa1fb6bd502828d6aad148bebff25ee72528b408d6c5078dL26, this was meant to replace the verbosity of OptionTemplate<TextureAtlasTemplate>

[bitblocks-dev]

Maybe? I'm not super familiar with how built_in functions... I just tried replacing it and that worked. Definitely worth looking into

[alice-i-cecile]

FYI @cart

[cart]

Strange yeah built_in exists to avoid needing to manually specify final template in these cases. I'll need to look into it.

Its worth noting that my WIP Assets as Entities branch removes built_in completely and generally reduces the weirdness factor for these types by removing the need for a separate OptionTemplate.