When a texel from the Vulkan format VK_FORMAT_B8G8R8A8_SRGB is read,
the sRGB to linear conversion is applied independently to the R, G,
and B channels; the A channel has no influence on this. However,
DRM_FORMAT_ARGB8888 buffers are, per Wayland protocol, not encoded
in this fashion; one must first unpremultiply the color channels
before doing sRGB to linear conversion. This commit switches to
handling ARGB8888 and ABGR8888 formats using the general fragment
shader conversion from electrical to optical values.
Avoids repeating the common bits between dma_tex_features and
dma_tex_ycbcr_features, and we will need just the YCbCr-related
flags for shm YCbCr support soon.
These features are required for shm only: the TRANSFER stuff is
for texture upload. We don't need these for DMA-BUFs. Make this
clearer by changing the name.
Also re-order the definitions to group all texture-related features
together.
The Vulkan spec states:
> For the purposes of range expansion and Y′CBCR model conversion,
> the R and B components contain color difference (chroma) values
> and the G component contains luma.
The equations below that sentence also help understand the mapping.
This is implemented by a two-subpass rendering scheme; the first
subpass draws (and blends) onto a linear R16G16B16A16_SFLOAT buffer,
while the second subpass performs linear->srgb conversion, writing
onto the actual output buffer.
struct wlr_vk_format_props contains a mix of properties for shm
and dmabuf, and it's not immediately clear which fields are for
which kind of buffer. Use a nested struct to group the fields.
We were checking whether any of the features was supported. We need
to check if all of them are.
This makes the check consistent with query_modifier_support() above.
`vulkan_format_props_query` calls `query_modifier_support` which
initializes fields of `props` with allocated memory. this memory is
leaked if `query_modifier_support` does not find a supported format
and shmtex is not supported, as in this case `add_fmt_props` ends
up being false and the allocated fields of `props` are never freed.
This new renderer is implemented with the existing wlr_renderer API
(which is known to be sub-optimal for some operations). It's not
used by default, but users can opt-in by setting WLR_RENDERER=vulkan.
The renderer depends on VK_EXT_image_drm_format_modifier and
VK_EXT_physical_device_drm.
Co-authored-by: Simon Ser <contact@emersion.fr>
Co-authored-by: Jan Beich <jbeich@FreeBSD.org>
