Improve mipmap LOD calculation precision.

Our approximation for log2() linearly interpolates between powers of
two. This is not accurate enough for some use cases. Squaring the input
effectively doubles the number of piecewise linear segments.

Bug swiftshader:71

Change-Id: Ie7a1da6b93cb5fbed018b61cf8510393964b5aa4
Reviewed-on: https://swiftshader-review.googlesource.com/10450
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
2 files changed
tree: d7ace95952d47dc5c3840b835d3d016c2b79d5a6
  1. .vscode/
  2. docs/
  3. extensions/
  4. include/
  5. src/
  6. tests/
  7. third_party/
  8. .dir-locals.el
  9. .gitignore
  10. .gitmodules
  11. .travis.yml
  12. Android.mk
  13. AUTHORS.txt
  14. BUILD.gn
  15. CMakeLists.txt
  16. CONTRIBUTING.txt
  17. CONTRIBUTORS.txt
  18. DEPS
  19. LICENSE.txt
  20. OWNERS
  21. README.google
  22. README.md
  23. README.version
  24. SwiftShader.sln
README.md

SwiftShader Build Status Build status


Introduction

SwiftShader is a high-performance CPU-based implementation of the OpenGL ES and Direct3D 9 graphics APIs12. Its goal is to provide hardware independence for advanced 3D graphics.

Usage

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.

Prebuilt binaries can be found at: https://goo.gl/5MOcdb

Contributing

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 performing:

git push origin HEAD:refs/for/master

Third-Party Dependencies

The third_party directory contains projects which originated outside of SwiftShader:

LLVM contains an outdated and diverged copy of the LLVM compiler framework. Until further notice, maintenance fixes can be made directly in the SwiftShader repository.

subzero contains a fork of the Subzero project. It is part of Google Chrome‘s (Portable) Native Client project. Its authoritative source is at https://chromium.googlesource.com/native_client/pnacl-subzero/. The fork was made using git-subtree to include all of Subzero’s history, and until further notice it should not diverge from the upstream project. Contributions must be tested using the README instructions, reviewed at https://chromium-review.googlesource.com, and then pulled into the SwiftShader repository.

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.

Documentation

See docs/Index.md.

Contact

Public mailing list: swiftshader@googlegroups.com

Bug tracker: https://bugs.chromium.org/p/swiftshader

License

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.

Authors and Contributors

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.

Disclaimer

  1. Trademarks are the property of their respective owners.
  2. We do not claim official conformance with any graphics APIs at this moment.
  3. This is not an official Google product.