Instead of emitting the render commands once per rectangle of the clip
region, just emit them once with the region's extents.
This is generally faster because it emits fewer commands to the GPU,
even though it may touch significantly more pixels.
For a proper method, we'd need to record the commands per clip rectangle
instead of emitting all of them all the time.
The border and color shaders - the ones that do AA - now multiply their
coordinates by the scale factor, which gives them better rounding
capabilities.
This in particular improves the case where they are used in fractional
scaling situations, where the scale is defined at the root element.
Previously, we just used the defaultscale factor, but now that we're
having it available in push constants, we can read it back for creating
offscreens and rendering fallbacks.
So do that.
It's a 1:1 replacement for GskVulkanPushConstants, just without the
indirection through a different file.
GskVulkanPushConstants as a struct is gone now.
The file still exists to handle the push_constants operation.
1. Use a graphene_vec2_t
2. Ensure it's always positive
3. Don't break with fallback
The scale value is nothing more than an indication of how many pixels to
assume per unit of a node.
We don't want to render the offscreen trnsformed, we want to render it
as-is.
We lose the correct scale factor, but that requires some separate work,
so for now it gets a bit blurry on hidpi.
This introduces the rect object and adds a rect_distance() and
rect_coverage() function.
_distance() returns the signed distance tp the rectangle.
_coverage() returns the coverage of a pixel centered at that position.
Note that the pixel size is computed using dFdx/dFdy.
When the node bounds were a non-integer size, the texture would get
ceil()ed pixels, but various viewport or scissor computations might
floor() instead, leaving the right/bottom row of pixels untouched.
Make sure those functions ceil(), too.
Vulkan has a different initial coordinate system to GL.
GL:
(-1, 1, -1) +------+.
|`. | `.
| `·--|---·
| : | :
+------+. :
`. : `.:
`·------· (1, -1, 1)
Vulkan:
(-1, -1, 0) +------+.
|`. | `.
| `·--|---·
| : | :
+------+. :
`. : `.:
`·------· (1, 1, 1)
so adjust the near and far plane we pass to
graphene_matrix_init_ortho() to make it end up with the same
projection as the GL renderer.
Most of the time we want to compute them based on the child node we
render to the offscreen, but not always.
For blend and cross-fade nodes, they need to be computed based on the
node's bounds.
Fixes widget-factory page fade animation weirdly resizing the fading
pages.
gsk_vulkan_render_download_target() currently resets the uploader
objects before downloading the image that it produces. This is
problematic because there might be unreleased buffers and images
in the command queue.
In particular, this can make validation layers complain about the
glyph atlas - of all things! - upload buffer being released while
still being used by the command queue.
Fix that by resetting the uploader after downloading the image.
The current implementation of the glyph cache deals with atlases by
padding them with 1 pixel at the beginning, at the end, and between
each glyph.
That's cool and all, however, there's a very subtle problem with
this approach: the contents of the atlas are garbage, so this padding
is filled with garbage memory!
Rework the Vulkan glyph cache to draw each and every glyph in a
surface that has 1 pixel border of padding around it. Ensure the
surface is completely black by drawing a rectangle before handing
it to Pango to draw the glyph. Update tx and ty to pick the texture
position adjusted to the 1 pixel padding. The atlas now starts at
position (0, 0), since each glyph individually contains its own padding.
To improve legibility, add a PADDING define and use it everywhere.
Vulkan renders text using VK_BLEND_FACTOR_ONE_MINUS_SRC_ALPHA and
VK_BLEND_FACTOR_SRC_ALPHA, but that implies per-channel alpha
blending, which currently produces the wrong results when blending
glyphs with the images beneath them.
Use the default pipeline constructors, which implies using the
ONE and ONE_MINUS_SRC_ALPHA.
