| commit | eeb81843c74adbbb81d9b282a8233a5907e7955c | [log] [tgz] |
|---|---|---|
| author | Nicolas Capens <capn@google.com> | Tue Jan 12 17:44:40 2021 -0500 |
| committer | Nicolas Capens <nicolascapens@google.com> | Wed Jan 13 18:09:24 2021 +0000 |
| tree | 1a338ed7c85f29df419eb647b366fd288c7820a4 | |
| parent | 3549479dc4ccd92ef3b9e179080dcec1a430b01d [diff] |
Fix back-face culling for vertices near w=0 When the homogeneous w coordinate is near 0, the projected x or y coordinates (after viewport and subpixel scaling) may be larger than what's representable by 32-bit signed integers. On x86 this produces the "indefinite" integer value 0x80000000. This negative value is returned even for positive inputs. This causes the back-face culling calculations to reject triangles which are in fact visible. This change addresses that by introducing the rr::RoundIntClamped() function, which guarantees that very large positive floating-point values are converted to a positive integer value near INT_MAX. Note that the Vulkan spec states that "[the determination whether the triangle is back-facing or front-facing] is made based on the sign of the (clipped or unclipped) polygon’s area computed in framebuffer coordinates." Thus the alternative of performing culling using the unprojected coordinates would have to take negative viewport dimensions into account, and may not produce the same results as sub-pixel snapped coordinates. Adjust back-face culling of wireframe triangles to use the same calculations as solid triangles. Bug: b/177382194 Change-Id: Ice8493d4cfd164638f091bf5a39b5396d65458e2 Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/51648 Tested-by: Nicolas Capens <nicolascapens@google.com> Reviewed-by: Alexis Hétu <sugoi@google.com>
SwiftShader is a high-performance CPU-based implementation of the Vulkan graphics API12. Its goal is to provide hardware independence for advanced 3D graphics.
NOTE: SwiftShader's OpenGL ES frontend is no longer supported, and will eventually be removed. Read more about our recommendation to use ANGLE on top of SwiftShader Vulkan here.
SwiftShader libraries can be built for Windows, Linux, and macOS.
Android and Chrome (OS) build environments are also supported.
CMake
Install CMake for Linux, macOS, or Windows and use either the GUI or run the following terminal commands:
cd build cmake .. cmake --build . --parallel ./vk-unittests
Tip: Set the CMAKE_BUILD_PARALLEL_LEVEL environment variable to control the level of parallelism.
Visual Studio
To build the Vulkan ICD library, use Visual Studio 2019 to open the project folder and wait for it to run CMake. Open the CMake Targets View in the Solution Explorer and select the vk_swiftshader project to build it.
The SwiftShader libraries act as drop-in replacements for graphics drivers.
On Windows, most applications can be made to use SwiftShader's DLLs by placing them in the same folder as the executable. On Linux, the LD_LIBRARY_PATH environment variable or -rpath linker option can be used to direct applications to search for shared libraries in the indicated directory first.
In general, Vulkan applications look for a shared library named vulkan-1.dll on Windows (vulkan-1.so on Linux). This ‘loader’ library then redirects API calls to the actual Installable Client Driver (ICD). SwiftShader's ICD is named libvk_swiftshader.dll, but it can be renamed to vulkan-1.dll to be loaded directly by the application. Alternatively, you can set the VK_ICD_FILENAMES environment variable to the path to vk_swiftshader_icd.json file that is generated under the build directory (e.g. .\SwiftShader\build\Windows\vk_swiftshader_icd.json). To learn more about how Vulkan loading works, read the official documentation here.
See CONTRIBUTING.txt for important contributing requirements.
The canonical repository for SwiftShader is hosted at: https://swiftshader.googlesource.com/SwiftShader
All changes must be reviewed and approved in the Gerrit review tool at: https://swiftshader-review.googlesource.com
Authenticate your account here: https://swiftshader-review.googlesource.com/new-password
All changes require a Change-ID tag in the commit message. A commit hook may be used to add this tag automatically, and can be found at: https://gerrit-review.googlesource.com/tools/hooks/commit-msg. To clone the repository and install the commit hook in one go:
git clone https://swiftshader.googlesource.com/SwiftShader && (cd SwiftShader && curl -Lo `git rev-parse --git-dir`/hooks/commit-msg https://gerrit-review.googlesource.com/tools/hooks/commit-msg ; chmod +x `git rev-parse --git-dir`/hooks/commit-msg)
Changes are uploaded to Gerrit by executing:
git push origin HEAD:refs/for/master
When ready, add a project owner as a reviewer on your change.
Some tests will automatically be run against the change. Notably, presubmit.sh verifies the change has been formatted using clang-format 10.0. Most IDEs come with clang-format support, but may require downgrading to clang-format version 10.0.
SwiftShader's OpenGL ES implementation can be tested using the dEQP test suite.
See docs/dEQP.md for details.
The third_party directory contains projects which originated outside of SwiftShader:
subzero contains a fork of the Subzero project. It originates from Google Chrome‘s (Portable) Native Client project. The fork was made using git-subtree to include all of Subzero’s history.
llvm-subzero contains a minimized set of LLVM dependencies of the Subzero project.
PowerVR_SDK contains a subset of the PowerVR Graphics Native SDK for running several sample applications.
googletest contains the Google Test project, as a Git submodule. It is used for running unit tests for Chromium, and Reactor unit tests. Run git submodule update --init to obtain/update the code. Any contributions should be made upstream.
See docs/Index.md.
Public mailing list: swiftshader@googlegroups.com
General bug tracker: https://g.co/swiftshaderbugs
Chrome specific bugs: https://bugs.chromium.org/p/swiftshader
The SwiftShader project is licensed under the Apache License Version 2.0. You can find a copy of it in LICENSE.txt.
Files in the third_party folder are subject to their respective license.
The legal authors for copyright purposes are listed in AUTHORS.txt.
CONTRIBUTORS.txt contains a list of names of individuals who have contributed to SwiftShader. If you‘re not on the list, but you’ve signed the Google CLA and have contributed more than a formatting change, feel free to request to be added.