* engine: common: imagelib: add KTX2 support
Adds basic KTX2 support for a few compressed formats. KTX2 essentially
is a Vulkan-centric texture format that supports literally hundreds of
pixel formats.
For now only support for these is added:
- `VK_FORMAT_BC4_UNORM_BLOCK`
- `VK_FORMAT_BC4_SNORM_BLOCK`
- `VK_FORMAT_BC5_UNORM_BLOCK`
- `VK_FORMAT_BC5_SNORM_BLOCK`
- `VK_FORMAT_BC6H_UFLOAT_BLOCK`
- `VK_FORMAT_BC6H_SFLOAT_BLOCK`
- `VK_FORMAT_BC7_UNORM_BLOCK`
- `VK_FORMAT_BC7_SRGB_BLOCK`
Adding more formats is relatively straightforward:
- Copy format definition from `VkFormat` enum in `vulkan_core.h`
- Add a new definition into `pixformat_t` enum.
- Add format size calculation into `Image_ComputeSize()`
While we're at it, also adds a few new formats to DDS:
- BC4_UNORM -- PF_BC4_UNSIGNED
- BC4_SNORM -- PF_BC4_SIGNED
- BC5_UNORM -- PF_BC5_UNSIGNED
- BC5_SNORM -- PF_BC5_SIGNED
- BC7 is expanded into BC7_UNORM and BC7_SRGB
ref_gl and ref_soft code is updated where it made sense. But not tested
really. Support for these formats has been tested with ref_vk.
* address spaces-vs-parentheses formatting where noticed
* parenthesize sizeofs
* move ktx2.h to imagelib as img_ktx2.h; massage it a bit
* use SetBits() instead of |=
* remove stale TODO comments
The `.editorconfig` file in this repo is configured to trim all trailing
whitespace regardless of whether the line is modified.
Trims all trailing whitespace in the repository to make the codebase easier
to work with in editors that respect `.editorconfig`.
`git blame` becomes less useful on these lines but it already isn't very useful.
Commands:
```
find . -type f -name '*.h' -exec sed --in-place 's/[[:space:]]\+$//' {} \+
find . -type f -name '*.c' -exec sed --in-place 's/[[:space:]]\+$//' {} \+
```
