Make the generator generate calls for the correct glBindAttribLocation()
calls.
Usually this was done correctly, but we can't rely on it. So do it
explicitly.
Unless GSK_GPU_SKIP=gradients is given, we sample every point 4x instead
of 1x. That makes the shader run slower (by roughly a factor of 2.5x)
but it improves quality quite a bit.
I'm a bit unsure about using the zero rect in the fallback situtation
where one image doesn't exist, but it seems to work.
This removes the last pattern-only rendernode and with that the last
fallback usage with disabled ubershader.
This way we can toggle opacity handling on/off.
THe shader slowly turns into a fancy texture op - but I don't want to
rename it to "fancytexture" just yet.
A variation is a #define/specialization constant that every shader can
use to specialize itself as it sees fit.
This commit adds the infrastrcture, future commits will add
implementations.
There are various places where the alpha is implicitly assumed to be
handled, so just handle it.
As a bonus, this simplifies a bunch of code and makes the texture node
rendering work with alpha.
If there are more than 7 color stops, we can split the gradient into
multiple gradients with color stops like so:
0, 1, 2, 3, 4, 5, transparent
transparent, 6, 7, 8, 9, 10, transparent
...
transparent, n-2, n-1, n
and use the new BLEND_ADD to draw them on top of each other.
Adapt the testcae that tests this to use colors that work with the fancy
algorithm we use now, so that BLEND_ADD and transitions to transparent
do not cause issues.
Instead of scaled coordinates, use the unscaled ones.
This ensure that gradients get computed correctly as they are not safe
against nonorthogonal transforms - like scales with different scale
factors.
The shader can only deal with up to 7 color stops - but that's good
enough for the real world.
Plus, we have the uber shader.
And if that fails, we can still fall back to Cairo.
The code also doesn't handle repeating linear gradients yet.
This shader can take over from the ubershader. And it can be used
instead of launching the ubershader when no offscreens are necessary.
Also includes an optimization that uses the colorize shader when
appropriate.
This makes the (currently single) storage buffer handled by
GskGpuDescriptors.
A side effect is that we now have support for multiple buffers in place.
We just have to use it.
Mixed into this commit is a complete rework of the pattern writer.
Instead of writing straight into the buffer (complete with repeatedly
backtracking when we have to do offscreens), write into a temporary
buffer and copy into the storage buffer on committing.
Shader compilers struggle with compiling code that indexes texture
arrays by indexes, so keep the fallback shaders simple and don't do that
there.
There's not much of a performance difference anyway between those two
methods.
We compile custom shaders for Vulkan 1.0 that don't require the
extension.
We also ensure that our accesses are uniform by only executing one
shader at a time.
This is relevant went encountering repeat nodes, where the repeat cutoff
will make the fwidth of the position go wild otherwise.
Gradients require more work now, because we need to compute offsets
twice - once for the pixel, once for the offst.
Carry an n_external_textures variable around when selecting programs and
compile different programs for different amounts of external textures.
For now, this code is unused, but dmabufs will need it.
Add a GSK_GPU_IMAGE_STRAIGHT_ALPHA and use it for images that have
straight alpha.
Make sure those images get passed through a premultiplying pass with
the new straight alpha shader.
Also remove the old Postprocess flags from the Vulkan image that were a
leftover from copying that code from the old Vulkan renderer.
There's a well hidden line in the spec that says in
https://registry.khronos.org/vulkan/specs/1.3/html/chap15.html#interfaces-resources-descset
If the combined image sampler enables sampler Y′CBCR conversion,
it **must** be indexed only by constant integral expressions when
aggregated into arrays in shader code, irrespective of the
shaderSampledImageArrayDynamicIndexing feature.
So we'll use the same trick that we use for old GL here and do an
if dance that gives us dynamically uniform expressions.
Define an array with a compile-time-constant variable size for the
immutable samplers.
A bunch of work is necessary to ensure that at least one element is in
the sampler array, because the GLSL code
sampler2D immutable_textures[0];
is invalid.
This allows having different layouts sothat we can support immutable
samplers, whcih are required for multiplane and YUV formats.
We don't use them yet.
There's multiple uses I want it for:
1. Generating the box-shadow area for blurring
2. Generating masks for rounded-rect masking
3. Optimizing the common use case of rounded-clip + color
Only the last one is implemented in this commit.
The code generated by glslc -O is optimized worse by Mesa than
code generated unoptimized.
So generate unoptimized code until somebody figures out what's going
wrong here.
They're done using the pattern shader.
The pattern shader now gained a stack where vec4's can be pushed and
popped back later, which allows storing the position before computing
the new position inside the repeat node's child.
Due to GLES and old GL not allowing non-constant texture array
lookups,we need to turn the array lookup into a big switch statementin
those versions, and that requires putting the texture() call into that
switch.
But with that trick, we can use texture IDs in GLSL.
... and use it for glyphs.
The name is a slight variation of the "coloring" name from the GL
renderer.
The functionality is exactly what the "glyph" shader from the Vulkan
renderer does.
1. Compute the fwidth() twice with offset offsets
That way, we avoid glitches at the boundary between 0.0 and 1.0,
because by offsetting it by 0.5, that boundary goes away.
Then we take the min() of both which gives us the one we care about.
2. Set the gradient to repeating
By doing that, we don't get values at the 0.0/1.0 boundary clamped,
but things smoothly transition.
This smoothes the line at that boundary and makes it look just like
every other line.
Pretty much a copy of the Vulkan border shader.
A notable change is that the input arguments are changed, because GL
gets confused if you put a mat4 at the end.
