# Objective
- Add Vertex Color support to 2D meshes and ColorMaterial. This extends the work from #4528 (which in turn builds on the excellent tangent handling).
## Solution
- Added `#ifdef` wrapped support for vertex colors in the 2D mesh shader and `ColorMaterial` shader.
- Added an example, `mesh2d_vertex_color_texture` to demonstrate it in action.
---
## Changelog
- Added optional (ifdef wrapped) vertex color support to the 2dmesh and color material systems.
# Objective
- Fixes#4456
## Solution
- Removed the `near` and `far` fields from the camera and the views.
---
## Changelog
- Removed the `near` and `far` fields from the camera and the views.
- Removed the `ClusterFarZMode::CameraFarPlane` far z mode.
## Migration Guide
- Cameras no longer accept near and far values during initialization
- `ClusterFarZMode::Constant` should be used with the far value instead of `ClusterFarZMode::CameraFarPlane`
# Objective
Add support for vertex colors
## Solution
This change is modeled after how vertex tangents are handled, so the shader is conditionally compiled with vertex color support if the mesh has the corresponding attribute set.
Vertex colors are multiplied by the base color. I'm not sure if this is the best for all cases, but may be useful for modifying vertex colors without creating a new mesh.
I chose `VertexFormat::Float32x4`, but I'd prefer 16-bit floats if/when support is added.
## Changelog
### Added
- Vertex colors can be specified using the `Mesh::ATTRIBUTE_COLOR` mesh attribute.
# Objective
- While optimising many_cubes, I noticed that all material handles are extracted regardless of whether the entity to which the handle belongs is visible or not. As such >100k handles are extracted when only <20k are visible.
## Solution
- Only extract material handles of visible entities.
- This improves `many_cubes -- sphere` from ~42fps to ~48fps. It reduces not only the extraction time but also system commands time. `Handle<StandardMaterial>` extraction and its system commands went from 0.522ms + 3.710ms respectively, to 0.267ms + 0.227ms an 88% reduction for this system for this case. It's very view dependent but...
# Objective
Reduce the catch-all grab-bag of functionality in bevy_core by moving FloatOrd to bevy_utils.
A step in addressing #2931 and splitting bevy_core into more specific locations.
## Solution
Move FloatOrd into bevy_utils. Fix the compile errors.
As a result, bevy_core_pipeline, bevy_pbr, bevy_sprite, bevy_text, and bevy_ui no longer depend on bevy_core (they were only using it for `FloatOrd` previously).
# Objective
- Related #4276.
- Part of the splitting process of #3503.
## Solution
- Move `Size` to `bevy_ui`.
## Reasons
- `Size` is only needed in `bevy_ui` (because it needs to use `Val` instead of `f32`), but it's also used as a worse `Vec2` replacement in other areas.
- `Vec2` is more powerful than `Size` so it should be used whenever possible.
- Discussion in #3503.
## Changelog
### Changed
- The `Size` type got moved from `bevy_math` to `bevy_ui`.
## Migration Guide
- The `Size` type got moved from `bevy::math` to `bevy::ui`. To migrate you just have to import `bevy::ui::Size` instead of `bevy::math::Math` or use the `bevy::prelude` instead.
Co-authored-by: KDecay <KDecayMusic@protonmail.com>
# Objective
- Make use of storage buffers, where they are available, for clustered forward bindings to support far more point lights in a scene
- Fixes#3605
- Based on top of #4079
This branch on an M1 Max can keep 60fps with about 2150 point lights of radius 1m in the Sponza scene where I've been testing. The bottleneck is mostly assigning lights to clusters which grows faster than linearly (I think 1000 lights was about 1.5ms and 5000 was 7.5ms). I have seen papers and presentations leveraging compute shaders that can get this up to over 1 million. That said, I think any further optimisations should probably be done in a separate PR.
## Solution
- Add `RenderDevice` to the `Material` and `SpecializedMaterial` trait `::key()` functions to allow setting flags on the keys depending on feature/limit availability
- Make `GpuPointLights` and `ViewClusterBuffers` into enums containing `UniformVec` and `StorageBuffer` variants. Implement the necessary API on them to make usage the same for both cases, and the only difference is at initialisation time.
- Appropriate shader defs in the shader code to handle the two cases
## Context on some decisions / open questions
- I'm using `max_storage_buffers_per_shader_stage >= 3` as a check to see if storage buffers are supported. I was thinking about diving into 'binding resource management' but it feels like we don't have enough use cases to understand the problem yet, and it is mostly a separate concern to this PR, so I think it should be handled separately.
- Should `ViewClusterBuffers` and `ViewClusterBindings` be merged, duplicating the count variables into the enum variants?
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- Fixes#1616, fixes#2225
- Let user specify an anchor for a sprite
## Solution
- Add an enum for an anchor point for most common values, with a variant for a custom point
- Defaults to Center to not change current behaviour
Co-authored-by: François <8672791+mockersf@users.noreply.github.com>
# Objective
An entity spawned with `MaterialMesh2dBundle<M>` cannot be saved and spawned using `DynamicScene` because the `Mesh2dHandle` component does not `impl Reflect`.
## Solution
Add `#[derive(Reflect)]` and `#[reflect(Component)]` to `Mesh2dHandle`, and call `register_type` in `SpritePlugin`. Also add `#[derive(Debug)]` since I'm touching the `derive`s anyway.
# Objective
Cleans up some duplicated color -> u32 conversion code in `bevy_sprite` and `bevy_ui`
## Solution
Use `as_linear_rgba_u32` which was added recently by #4088
# Objective
- Fixes#3970
- To support Bevy's shader abstraction(shader defs, shader imports and hot shader reloading) for compute shaders, I have followed carts advice and change the `PipelinenCache` to accommodate both compute and render pipelines.
## Solution
- renamed `RenderPipelineCache` to `PipelineCache`
- Cached Pipelines are now represented by an enum (render, compute)
- split the `SpecializedPipelines` into `SpecializedRenderPipelines` and `SpecializedComputePipelines`
- updated the game of life example
## Open Questions
- should `SpecializedRenderPipelines` and `SpecializedComputePipelines` be merged and how would we do that?
- should the `get_render_pipeline` and `get_compute_pipeline` methods be merged?
- is pipeline specialization for different entry points a good pattern
Co-authored-by: Kurt Kühnert <51823519+Ku95@users.noreply.github.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- Support compressed textures including 'universal' formats (ETC1S, UASTC) and transcoding of them to
- Support `.dds`, `.ktx2`, and `.basis` files
## Solution
- Fixes https://github.com/bevyengine/bevy/issues/3608 Look there for more details.
- Note that the functionality is all enabled through non-default features. If it is desirable to enable some by default, I can do that.
- The `basis-universal` crate, used for `.basis` file support and for transcoding, is built on bindings against a C++ library. It's not feasible to rewrite in Rust in a short amount of time. There are no Rust alternatives of which I am aware and it's specialised code. In its current state it doesn't support the wasm target, but I don't know for sure. However, it is possible to build the upstream C++ library with emscripten, so there is perhaps a way to add support for web too with some shenanigans.
- There's no support for transcoding from BasisLZ/ETC1S in KTX2 files as it was quite non-trivial to implement and didn't feel important given people could use `.basis` files for ETC1S.
# Objective
- In the large majority of cases, users were calling `.unwrap()` immediately after `.get_resource`.
- Attempting to add more helpful error messages here resulted in endless manual boilerplate (see #3899 and the linked PRs).
## Solution
- Add an infallible variant named `.resource` and so on.
- Use these infallible variants over `.get_resource().unwrap()` across the code base.
## Notes
I did not provide equivalent methods on `WorldCell`, in favor of removing it entirely in #3939.
## Migration Guide
Infallible variants of `.get_resource` have been added that implicitly panic, rather than needing to be unwrapped.
Replace `world.get_resource::<Foo>().unwrap()` with `world.resource::<Foo>()`.
## Impact
- `.unwrap` search results before: 1084
- `.unwrap` search results after: 942
- internal `unwrap_or_else` calls added: 4
- trivial unwrap calls removed from tests and code: 146
- uses of the new `try_get_resource` API: 11
- percentage of the time the unwrapping API was used internally: 93%
This PR makes a number of changes to how meshes and vertex attributes are handled, which the goal of enabling easy and flexible custom vertex attributes:
* Reworks the `Mesh` type to use the newly added `VertexAttribute` internally
* `VertexAttribute` defines the name, a unique `VertexAttributeId`, and a `VertexFormat`
* `VertexAttributeId` is used to produce consistent sort orders for vertex buffer generation, replacing the more expensive and often surprising "name based sorting"
* Meshes can be used to generate a `MeshVertexBufferLayout`, which defines the layout of the gpu buffer produced by the mesh. `MeshVertexBufferLayouts` can then be used to generate actual `VertexBufferLayouts` according to the requirements of a specific pipeline. This decoupling of "mesh layout" vs "pipeline vertex buffer layout" is what enables custom attributes. We don't need to standardize _mesh layouts_ or contort meshes to meet the needs of a specific pipeline. As long as the mesh has what the pipeline needs, it will work transparently.
* Mesh-based pipelines now specialize on `&MeshVertexBufferLayout` via the new `SpecializedMeshPipeline` trait (which behaves like `SpecializedPipeline`, but adds `&MeshVertexBufferLayout`). The integrity of the pipeline cache is maintained because the `MeshVertexBufferLayout` is treated as part of the key (which is fully abstracted from implementers of the trait ... no need to add any additional info to the specialization key).
* Hashing `MeshVertexBufferLayout` is too expensive to do for every entity, every frame. To make this scalable, I added a generalized "pre-hashing" solution to `bevy_utils`: `Hashed<T>` keys and `PreHashMap<K, V>` (which uses `Hashed<T>` internally) . Why didn't I just do the quick and dirty in-place "pre-compute hash and use that u64 as a key in a hashmap" that we've done in the past? Because its wrong! Hashes by themselves aren't enough because two different values can produce the same hash. Re-hashing a hash is even worse! I decided to build a generalized solution because this pattern has come up in the past and we've chosen to do the wrong thing. Now we can do the right thing! This did unfortunately require pulling in `hashbrown` and using that in `bevy_utils`, because avoiding re-hashes requires the `raw_entry_mut` api, which isn't stabilized yet (and may never be ... `entry_ref` has favor now, but also isn't available yet). If std's HashMap ever provides the tools we need, we can move back to that. Note that adding `hashbrown` doesn't increase our dependency count because it was already in our tree. I will probably break these changes out into their own PR.
* Specializing on `MeshVertexBufferLayout` has one non-obvious behavior: it can produce identical pipelines for two different MeshVertexBufferLayouts. To optimize the number of active pipelines / reduce re-binds while drawing, I de-duplicate pipelines post-specialization using the final `VertexBufferLayout` as the key. For example, consider a pipeline that needs the layout `(position, normal)` and is specialized using two meshes: `(position, normal, uv)` and `(position, normal, other_vec2)`. If both of these meshes result in `(position, normal)` specializations, we can use the same pipeline! Now we do. Cool!
To briefly illustrate, this is what the relevant section of `MeshPipeline`'s specialization code looks like now:
```rust
impl SpecializedMeshPipeline for MeshPipeline {
type Key = MeshPipelineKey;
fn specialize(
&self,
key: Self::Key,
layout: &MeshVertexBufferLayout,
) -> RenderPipelineDescriptor {
let mut vertex_attributes = vec![
Mesh::ATTRIBUTE_POSITION.at_shader_location(0),
Mesh::ATTRIBUTE_NORMAL.at_shader_location(1),
Mesh::ATTRIBUTE_UV_0.at_shader_location(2),
];
let mut shader_defs = Vec::new();
if layout.contains(Mesh::ATTRIBUTE_TANGENT) {
shader_defs.push(String::from("VERTEX_TANGENTS"));
vertex_attributes.push(Mesh::ATTRIBUTE_TANGENT.at_shader_location(3));
}
let vertex_buffer_layout = layout
.get_layout(&vertex_attributes)
.expect("Mesh is missing a vertex attribute");
```
Notice that this is _much_ simpler than it was before. And now any mesh with any layout can be used with this pipeline, provided it has vertex postions, normals, and uvs. We even got to remove `HAS_TANGENTS` from MeshPipelineKey and `has_tangents` from `GpuMesh`, because that information is redundant with `MeshVertexBufferLayout`.
This is still a draft because I still need to:
* Add more docs
* Experiment with adding error handling to mesh pipeline specialization (which would print errors at runtime when a mesh is missing a vertex attribute required by a pipeline). If it doesn't tank perf, we'll keep it.
* Consider breaking out the PreHash / hashbrown changes into a separate PR.
* Add an example illustrating this change
* Verify that the "mesh-specialized pipeline de-duplication code" works properly
Please dont yell at me for not doing these things yet :) Just trying to get this in peoples' hands asap.
Alternative to #3120Fixes#3030
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Context
I wanted to add a `texture` to my `ColorMaterial` without explicitly adding a `color`. To do this I used `..Default::default()` which in turn gave me unexpected results. I was expecting that my texture would render without any color modifications, but to my surprise it got rendered in a purple tint (`Color::rgb(1.0, 0.0, 1.0)`). To fix this I had to explicitly define the `color` using `color: Color::WHITE`.
## What I wanted to use
```rust
commands
.spawn_bundle(MaterialMesh2dBundle {
mesh: mesh_handle.clone().into(),
transform: Transform::default().with_scale(Vec3::splat(8.)),
material: materials.add(ColorMaterial {
texture: Some(texture_handle.clone()),
..Default::default() // here
}),
..Default::default()
})
```
## What I had to use instead
```rust
commands
.spawn_bundle(MaterialMesh2dBundle {
mesh: mesh_handle.clone().into(),
transform: Transform::default().with_scale(Vec3::splat(8.)),
material: materials.add(ColorMaterial {
texture: Some(texture_handle.clone()),
color: Color::WHITE, // here
}),
..Default::default()
})
```
Adds "hot reloading" of internal assets, which is normally not possible because they are loaded using `include_str` / direct Asset collection access.
This is accomplished via the following:
* Add a new `debug_asset_server` feature flag
* When that feature flag is enabled, create a second App with a second AssetServer that points to a configured location (by default the `crates` folder). Plugins that want to add hot reloading support for their assets can call the new `app.add_debug_asset::<T>()` and `app.init_debug_asset_loader::<T>()` functions.
* Load "internal" assets using the new `load_internal_asset` macro. By default this is identical to the current "include_str + register in asset collection" approach. But if the `debug_asset_server` feature flag is enabled, it will also load the asset dynamically in the debug asset server using the file path. It will then set up a correlation between the "debug asset" and the "actual asset" by listening for asset change events.
This is an alternative to #3673. The goal was to keep the boilerplate and features flags to a minimum for bevy plugin authors, and allow them to home their shaders near relevant code.
This is a draft because I haven't done _any_ quality control on this yet. I'll probably rename things and remove a bunch of unwraps. I just got it working and wanted to use it to start a conversation.
Fixes#3660
This enables shaders to (optionally) define their import path inside their source. This has a number of benefits:
1. enables users to define their own custom paths directly in their assets
2. moves the import path "close" to the asset instead of centralized in the plugin definition, which seems "better" to me.
3. makes "internal hot shader reloading" way more reasonable (see #3966)
4. logically opens the door to importing "parts" of a shader by defining "import_path blocks".
```rust
#define_import_path bevy_pbr::mesh_struct
struct Mesh {
model: mat4x4<f32>;
inverse_transpose_model: mat4x4<f32>;
// 'flags' is a bit field indicating various options. u32 is 32 bits so we have up to 32 options.
flags: u32;
};
let MESH_FLAGS_SHADOW_RECEIVER_BIT: u32 = 1u;
```
What is says on the tin.
This has got more to do with making `clippy` slightly more *quiet* than it does with changing anything that might greatly impact readability or performance.
that said, deriving `Default` for a couple of structs is a nice easy win
# Objective
Fix `SetSpriteTextureBindGroup` to use index instead of hard coded 1.
Fixes#3895
## Solution
1 -> I
Co-authored-by: devjobe <git@devjobe.com>
(cherry picked from commit de943381bd2a8b242c94db99e6c7bbd70006d7c3)
# Objective
The view uniform lacks view transform information. The inverse transform is currently provided but this is not sufficient if you do not have access to an `inverse` function (such as in WGSL).
## Solution
Grab the view transform, put it in the view uniform, use the same matrix to compute the inverse as well.
# Objective
I think the 'collide' function inside the 'bevy/crates/bevy_sprite/src/collide_aabb.rs' file should return 'Some' if the two rectangles are fully overlapping or one is inside the other. This can happen on low-end machines when a lot of time passes between two frames because of a stutter, so a bullet for example gets inside its target. I can also think of situations where this is a valid use case even without stutters.
## Solution
I added an 'Inside' version to the Collision enum declared in the file. And I use it, when the two rectangles are overlapping, but we can't say from which direction it happened. I gave a 'penetration depth' of minus Infinity to these cases, so that this variant only appears, when the two rectangles overlap from each side fully. I am not sure if this is the right thing to do.
Fixes#1980
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
In this PR I added the ability to opt-out graphical backends. Closes#3155.
## Solution
I turned backends into `Option` ~~and removed panicking sub app API to force users handle the error (was suggested by `@cart`)~~.
# Objective
The current 2d rendering is specialized to render sprites, we need a generic way to render 2d items, using meshes and materials like we have for 3d.
## Solution
I cloned a good part of `bevy_pbr` into `bevy_sprite/src/mesh2d`, removed lighting and pbr itself, adapted it to 2d rendering, added a `ColorMaterial`, and modified the sprite rendering to break batches around 2d meshes.
~~The PR is a bit crude; I tried to change as little as I could in both the parts copied from 3d and the current sprite rendering to make reviewing easier. In the future, I expect we could make the sprite rendering a normal 2d material, cleanly integrated with the rest.~~ _edit: see <https://github.com/bevyengine/bevy/pull/3460#issuecomment-1003605194>_
## Remaining work
- ~~don't require mesh normals~~ _out of scope_
- ~~add an example~~ _done_
- support 2d meshes & materials in the UI?
- bikeshed names (I didn't think hard about naming, please check if it's fine)
## Remaining questions
- ~~should we add a depth buffer to 2d now that there are 2d meshes?~~ _let's revisit that when we have an opaque render phase_
- ~~should we add MSAA support to the sprites, or remove it from the 2d meshes?~~ _I added MSAA to sprites since it's really needed for 2d meshes_
- ~~how to customize vertex attributes?~~ _#3120_
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
#3457 adds the `doc_markdown` clippy lint, which checks doc comments to make sure code identifiers are escaped with backticks. This causes a lot of lint errors, so this is one of a number of PR's that will fix those lint errors one crate at a time.
This PR fixes lints in the `bevy_sprite` crate.
# Objective
- While reading code, found some queries that are `mut` and not used as such
## Solution
- Remove `mut` when possible
Co-authored-by: François <8672791+mockersf@users.noreply.github.com>
# Objective
- Our crevice is still called "crevice", which we can't use for a release
- Users would need to use our "crevice" directly to be able to use the derive macro
## Solution
- Rename crevice to bevy_crevice, and crevice-derive to bevy-crevice-derive
- Re-export it from bevy_render, and use it from bevy_render everywhere
- Fix derive macro to work either from bevy_render, from bevy_crevice, or from bevy
## Remaining
- It is currently re-exported as `bevy::render::bevy_crevice`, is it the path we want?
- After a brief suggestion to Cart, I changed the version to follow Bevy version instead of crevice, do we want that?
- Crevice README.md need to be updated
- in the `Cargo.toml`, there are a few things to change. How do we want to change them? How do we keep attributions to original Crevice?
```
authors = ["Lucien Greathouse <me@lpghatguy.com>"]
documentation = "https://docs.rs/crevice"
homepage = "https://github.com/LPGhatguy/crevice"
repository = "https://github.com/LPGhatguy/crevice"
```
Co-authored-by: François <8672791+mockersf@users.noreply.github.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- Only bevy_render should depend directly on wgpu
- This helps to make sure bevy_render re-exports everything needed from wgpu
## Solution
- Remove bevy_pbr, bevy_sprite and bevy_ui dependency on wgpu
Co-authored-by: François <8672791+mockersf@users.noreply.github.com>
# Objective
This PR implements the `overflow` style property in `bevy_ui`. When set to `Overflow::Hidden`, the children of that node are clipped so that overflowing parts are not rendered. This is an important building block for UI widgets.
## Solution
Clipping is done on the CPU so that it does not break batching.
The clip regions update was implemented as a separate system for clarity, but it could be merged with the other UI systems to avoid doing an additional tree traversal. (I don't think it's important until we fix the layout performance issues though).
A scrolling list was added to the `ui_pipelined` example to showcase `Overflow::Hidden`. For the sake of simplicity, it can only be scrolled with a mouse.
# Objective
Fixes#3352Fixes#3208
## Solution
- Update wgpu to 0.12
- Update naga to 0.8
- Resolve compilation errors
- Remove [[block]] from WGSL shaders (because it is depracated and now wgpu cant parse it)
- Replace `elseif` with `else if` in pbr.wgsl
This makes the [New Bevy Renderer](#2535) the default (and only) renderer. The new renderer isn't _quite_ ready for the final release yet, but I want as many people as possible to start testing it so we can identify bugs and address feedback prior to release.
The examples are all ported over and operational with a few exceptions:
* I removed a good portion of the examples in the `shader` folder. We still have some work to do in order to make these examples possible / ergonomic / worthwhile: #3120 and "high level shader material plugins" are the big ones. This is a temporary measure.
* Temporarily removed the multiple_windows example: doing this properly in the new renderer will require the upcoming "render targets" changes. Same goes for the render_to_texture example.
* Removed z_sort_debug: entity visibility sort info is no longer available in app logic. we could do this on the "render app" side, but i dont consider it a priority.
# Objective
- New clippy lints with rust 1.57 are failing
## Solution
- Fixed clippy lints following suggestions
- I ignored clippy in old renderer because there was many and it will be removed soon
# Objective
- Fixes#2919
- Initial pixel was hard coded and not dependent on texture format
- Replace #2920 as I noticed this needed to be done also on pipeline rendering branch
## Solution
- Replace the hard coded pixel with one using the texture pixel size
Objective
During work on #3009 I've found that not all jobs use actions-rs, and therefore, an previous version of Rust is used for them. So while compilation and other stuff can pass, checking markup and Android build may fail with compilation errors.
Solution
This PR adds `action-rs` for any job running cargo, and updates the edition to 2021.
Upgrades both the old and new renderer to wgpu 0.11 (and naga 0.7). This builds on @zicklag's work here #2556.
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
This implements the most minimal variant of #1843 - a derive for marker trait. This is a prerequisite to more complicated features like statically defined storage type or opt-out component reflection.
In order to make component struct's purpose explicit and avoid misuse, it must be annotated with `#[derive(Component)]` (manual impl is discouraged for compatibility). Right now this is just a marker trait, but in the future it might be expanded. Making this change early allows us to make further changes later without breaking backward compatibility for derive macro users.
This already prevents a lot of issues, like using bundles in `insert` calls. Primitive types are no longer valid components as well. This can be easily worked around by adding newtype wrappers and deriving `Component` for them.
One funny example of prevented bad code (from our own tests) is when an newtype struct or enum variant is used. Previously, it was possible to write `insert(Newtype)` instead of `insert(Newtype(value))`. That code compiled, because function pointers (in this case newtype struct constructor) implement `Send + Sync + 'static`, so we allowed them to be used as components. This is no longer the case and such invalid code will trigger a compile error.
Co-authored-by: = <=>
Co-authored-by: TheRawMeatball <therawmeatball@gmail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
If you need to build a texture atlas from an already created texture that is not match a grid, you need to use new_empty and add_texture to create it. However it is not straight forward to get the index to be used with TextureAtlasSprite. add_texture should be changed to return the index to the texture.
Currently you can do something like this:
```rs
let texture = asset_server.load::<Texture>::("texture.png");
let texture_atlas = TextureAtlas::new_empty(texture, Vec2::new(40.0, 40.0));
texture_atlas.add_texture(Rect {
min: Vec2::new(20.0, 20.0),
max: Vec2::new(40.0, 40.0),
});
let index = (texture_atlas.len() - 1) as u32;
let texture_atlas_sprite = TextureAtlasSprite {
index,
Default::default()
};
```
But this is more clear
```rs
let index = texture_atlas.add_texture(Rect {
min: Vec2::new(20.0, 20.0),
max: Vec2::new(40.0, 40.0),
});
```
