More idiomatic texture atlas builder

[s-puig]

Objective

• TextureAtlasBuilder has some non-idiomatic methods.

Solution

• Refactor non-idiomatic methods

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Changelog

• Renamed TextureAtlasBuilder::finish() to TextureAtlasBuilder::build()
• Builder methods return &mut Self instead of Self

Migration Guide

- let mut texture_atlas_builder = TextureAtlasBuilder::default().padding(UVec2::default()).format(..);
+ let mut texture_atlas_builder = TextureAtlasBuilder::default();
+ texture_atlas_builder.padding(UVec2::default()).format(..);

- let (texture_atlas_layout, texture) = texture_atlas_builder.finish().unwrap();
+ let (texture_atlas_layout, texture) = texture_atlas_builder.build().unwrap();

[jgayfer]

I think we can remove this assignment now and chain it together?

[s-puig]

let mut texture_atlas_builder = TextureAtlasBuilder::default().padding(padding.unwrap_or_default());
[..]
texture_atlas_builder.add_texture();
let texture_atlas = texture_atlas_builder.build();

Doesn't compile because padding() returns a borrow, thus dropping TextureAtlasBuilder.

[jgayfer]

Mm, gotcha.

This does feel like a step backwards in the API. Would be a bit of an unfortunate migration for users to need to split up chained calls into separate statements.