This adds a new dependency on peniko, reintroduces kurbo for geometry (!), removes the now defunct types from piet-scene and updates all the test scenes to use the new types.
* Fix call to removed encoded_scene method in pgpu-render
* Add new ImageFormat::Surface variant to select a pixel format that matches the platform specific surface format. This makes gradients consistent across platforms.
Removes the dependency on the piet crate and replaces all uses with the scene crate. Also does some cleanup of the scene API, renaming some types and moving them all to the crate root for better ergonomics.
* capi: Add PathIter type and support for encoding fills
* capi: Minimal support for brushes (solid color only)
* Add flush method to command buffers
* Better initial heuristic for memory buffer size based on target dimensions
This removes the GPU transform stage, changes shaders to reference transforms directly from the scene, and modifies the render context to maintain a transform stack.
This is the core logic for robust dynamic memory. There are changes to both shaders and the driver logic.
On the shader side, failure information is more useful and fine grained. In particular, it now reports which stage failed and how much memory would have been required to make that stage succeed.
On the driver side, there is a new RenderDriver abstraction which owns command buffers (and associated query pools) and runs the logic to retry and reallocate buffers when necessary. There's also a fairly significant rework of the logic to produce the config block, as that overlaps the robust memory.
The RenderDriver abstraction may not stay. It was done this way to minimize code disruption, but arguably it should just be combined with Renderer.
Another change: the GLSL length() method on a buffer requires additional infrastructure (at least on Metal, where it needs a binding of its own), so we now pass that in as a field in the config.
This also moves blend memory to its own buffer. This worked out well because coarse rasterization can simply report the size of the blend buffer and it can be reallocated without needing to rerun the pipeline. In the previous state, blend allocations and ptcl writes were interleaved in coarse rasterization, so a failure of the former would require rerunning coarse. This should fix#83 (finally!)
There are a few loose ends. The binaries haven't (yet) been updated (I've been testing using a hand-written test program). Gradients weren't touched so still have a fixed size allocation. And the logic to calculate the new buffer size on allocation failure could be smarter.
Closes#175
Adds a test to visualize the blend modes. Fixes a dumb bug in blend.h and also a more subtle issue where default blending is not the same as clipping, as the former needs to always push a blend group (to cause isolation) and the latter does not. This might be something we need to get back to.
This should fix the rendering, so it fairly closely resembles the Mozilla reference image. There's also a compile-time switch to disable sRGB conversion, which is (sadly) needed for compatible rendering.
Split the blend stack into register and memory segments. Do blending in registers up to that size, then spill to memory if needed.
This version may regress performance on Pixel 4, as it uses common memory for the blend stack, rather than keeping that memory read-only in fine rasterization, and using a separate buffer for blend stack. This needs investigation. It's possible we'll want to have single common memory as a config option, as it pools allocations and decreases the probability of failure.
Also a flaw in this version: there is no checking of memory overflow.
For understanding code history: this commit largely reverts #77, but there were some intervening changes to blending, and this commit also implements the split so some of the stack is in registers.
Closes#156
The blending math had two errors: first, colors were not separated for the purpose of blending (blending was wrongly applied to premultiplied values), and second, alpha was applied over-aggressively to the alpha channel.
This PR does *not* address the issue of gamma correctness. That is a complex issue and should probably be handled in the short term by disabling sRGB conversions and doing the internal math in sRGB color space rather than linear. This will degrade the quality of antialiasing but on the other hand give spec-compliant results for compositing.
We remove the plus-darker mode as its specification does not appear to be valid. The plus-lighter mode remains as it is quite useful for cross-fading effects.
Also the generated shaders were compiled on mac so the DXIL is unsigned. Those should be compiled on Windows before this PR is merged. (and we should figure out a better strategy for all that)
