# Objective
- Fixes (partially) #15701.
## Solution
- Use little-endian bytes over native-endian bytes where applicable.
## Testing
- Ran CI.
## Open Questions
- Should we config-gate these for big-endian targets? It looks like
there are [very few
targets](https://doc.rust-lang.org/nightly/rustc/platform-support.html)
that use big-endian.
# Objective
Bevy supports feature gates for each format it supports, but several
formats that it loads via the `image` crate do not have feature gates.
Additionally, the QOI format is supported by the `image` crate and
wasn't available at all. This fixes that.
## Solution
The following feature gates are added:
* `avif`
* `ff` (Farbfeld)
* `gif`
* `ico`
* `qoi`
* `tiff`
None of these formats are enabled by default, despite the fact that all
these formats appeared to be enabled by default before. Since
`default-features` was disabled for the `image` crate, it's likely that
using any of these formats would have errored by default before this
change, although this probably needs additional testing.
## Testing
The changes seemed minimal enough that a compile test would be
sufficient.
## Migration guide
Image formats that previously weren't feature-gated are now
feature-gated, meaning they will have to be enabled if you use them:
* `avif`
* `ff` (Farbfeld)
* `gif`
* `ico`
* `tiff`
Additionally, the `qoi` feature has been added to support loading QOI
format images.
Previously, these formats appeared in the enum by default, but weren't
actually enabled via the `image` crate, potentially resulting in weird
bugs. Now, you should be able to add these features to your projects to
support them properly.
# Objective
If you want to draw / generate images from the CPU, such as:
- to create procedurally-generated assets
- for games whose artstyle is best implemented by poking pixels directly
from the CPU, instead of using shaders
It is currently very unergonomic to do in Bevy, because you have to deal
with the raw bytes inside `image.data`, take care of the pixel format,
etc.
## Solution
This PR adds some helper methods to `Image` for pixel manipulation.
These methods allow you to use Bevy's user-friendly `Color` struct to
read and write the colors of pixels, at arbitrary coordinates (specified
as `UVec3` to support any texture dimension). They handle
encoding/decoding to the `Image`s `TextureFormat`, incl. any sRGB
conversion.
While we are at it, also add methods to help with direct access to the
raw bytes. It is now easy to compute the offset where the bytes of a
specific pixel coordinate are found, or to just get a Rust slice to
access them.
Caveat: `Color` roundtrips are obviously going to be lossy for non-float
`TextureFormat`s. Using `set_color_at` followed by `get_color_at` will
return a different value, due to the data conversions involved (such as
`f32` -> `u8` -> `f32` for the common `Rgba8UnormSrgb` texture format).
Be careful when comparing colors (such as checking for a color you wrote
before)!
Also adding a new example: `cpu_draw` (under `2d`), to showcase these
new APIs.
---
## Changelog
### Added
- `Image` APIs for easy access to the colors of specific pixels.
---------
Co-authored-by: Pascal Hertleif <killercup@gmail.com>
Co-authored-by: François <mockersf@gmail.com>
Co-authored-by: ltdk <usr@ltdk.xyz>
