About OpenGL and Vulkan interoperability (XDC 2020)
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The document discusses the interoperability between OpenGL and Vulkan, focusing on the extensions that enable resource allocation and synchronization between the two APIs. It outlines contributions to the Mesa and Piglit testing frameworks, highlighting the implementation of interoperability extensions across different Mesa drivers and detailing various test cases. The conclusion notes that while most tests are passing in certain drivers, there are still limitations in support for depth and stencil buffer exchange.
About OpenGL and Vulkan interoperability (XDC 2020)
- 1. OpenGL and Vulkan Interoperability Eleni Maria Stea <[email protected]> XDC 2020
- 2. Outline 1 OpenGL interoperability extensions 2 Additions to Mesa and Piglit 3 Questions 4 References Eleni Maria Stea <[email protected]> OpenGL and Vulkan Interoperability XDC 2020 2 / 19
- 3. Introduction Outline 1 OpenGL interoperability extensions 2 Additions to Mesa and Piglit 3 Questions 4 References Eleni Maria Stea <[email protected]> OpenGL and Vulkan Interoperability XDC 2020 3 / 19
- 4. Introduction Interoperability Concept INTEROPERABILITY EXT_external_objects(_fd) extensions enable: · Allocation of resources (textures, buffers) from Vulkan and sharing of those resources from both APIs · Synchronization of the access to shared resources between APIs. Example: a VR compositor where the left and right eye images are allocated and displayed by Vulkan but their contents are filled by OpenGL processes. Eleni Maria Stea <[email protected]> OpenGL and Vulkan Interoperability XDC 2020 4 / 19
- 5. Introduction OpenGL extensions for interoperability on Linux OpenGL Extensions (Linux) EXT_external_objects_fd (EXT_memory_object_fd, EXT_semaphore_fd): ▶ enables an OpenGL application to import a memory object or semaphore from POSIX file descriptor external handles EXT_external_objects (EXT_memory_object, EXT_semaphore): ▶ enables an OpenGL application to create OpenGL objects corresponding to Vulkan objects (textures, buffers, semaphores) and synchronize access to shared objects across APIs ▶ extends existing GL calls that set and query properties Eleni Maria Stea <[email protected]> OpenGL and Vulkan Interoperability XDC 2020 5 / 19
- 6. Interoperability on Mesa Outline 1 OpenGL interoperability extensions 2 Additions to Mesa and Piglit 3 Questions 4 References Eleni Maria Stea <[email protected]> OpenGL and Vulkan Interoperability XDC 2020 6 / 19
- 7. Interoperability on Mesa Igalia’s contributions Work on the feature Mesa Igalia contributed to the implementation of the interoperability extensions for different Mesa drivers. Piglit (drivers testing framework) As there were no conformance tests available for the extensions, we’ve written a Vulkan framework for Piglit and Vulkan/GL tests that cover some common EXT_external_objects(_fd) use cases. Eleni Maria Stea <[email protected]> OpenGL and Vulkan Interoperability XDC 2020 7 / 19
- 8. Interoperability on Mesa Additions to Mesa (the details) Contributions to Mesa drivers Driver Igalia’s Contributions Status iris implemented EXT_external_objects, EXT_external_objects_fd under review (MR !4337) freedreno implemented EXT_external_objects, EXT_external_objects_fd upstream radeonsi fixes to the already implemented feature work in progress (WIP MR !6364) i965 helped with the review, patches under review (Draft MR !5594) Contributors, reviewers, people who helped! Driver Patches Reviews, Comments, Advice iris Juan A. Suárez Romero, Eleni Maria Stea, Tapani Pälli, Eduardo Lima Mitev Tapani Pälli, Rohan Garg, Eric Engestrom, Kenneth Graunke, Jason Ekstrand, Oscar Barenys, Daniel Stone, Matt Turner, Tomeu Vizoso freedreno Eduardo Lima Mitev, Hyunjun Ko Rob Clark, Marek Olšák, Jonathan Marek, Rohan Garg radeonsi The feature was implemented by AMD a few years ago and we are mostly working on fixes (WIP). feedback from: Bas Nieuwenhuizen, Marek Olšák i965 Rohan Garg, Juan A. Suárez Romero, Tapani Pälli Tomeu Vizoso, Eleni Maria Stea, Oscar Barenys ▶ The information above was accurate at the beginning of September when I pre-recorded this presentation! Apologies if I’ve not included someone or something! Eleni Maria Stea <[email protected]> OpenGL and Vulkan Interoperability XDC 2020 8 / 19
- 9. Interoperability on Mesa Additions to Piglit (the details) I Contributions to Piglit I Reusing color images: Test name Description Output Status vk-image-overwrite • Vulkan: allocates images of different formats and tiling modes • OpenGL: fills them with green • Expectation: green screen upstream vk-image-display • Vulkan: creates an image and fills it with colored bars • OpenGL: draws the image on screen using semaphores to synchronize access • Expectation: a stripped image on screen upstream vk-image-display-overwrite • Vulkan: creates an image and fills it • OpenGL: overwrites that image with another stripped pattern • Vulkan: reads back the contents of the image • Expectation: the modified contents to be read back upstream Eleni Maria Stea <[email protected]> OpenGL and Vulkan Interoperability XDC 2020 9 / 19
- 10. Interoperability on Mesa Additions to Piglit (the details) II Contributions to Piglit II Reusing the depth and stencil buffer: Test name Description Output Status vk-depth-display • Vulkan: creates a depth buffer pattern • OpenGL: draws a fullscreen quad at a greater depth • Expectation: quad partially obscured under review vk-stencil-display • Vulkan: creates a pattern in the stencil buffer • OpenGL: draws a blue fullscreen quad with stencil testing • Expectation: quad masked by stencil pattern under review Eleni Maria Stea <[email protected]> OpenGL and Vulkan Interoperability XDC 2020 10 / 19
- 11. Interoperability on Mesa Additions to Piglit (the details) III Contributions to Piglit III Reusing a pixel buffer: Test name Description Output Status vk-buf-exchange • Vulkan: creates and fills an image with color bars and copies its content to a buffer • OpenGL: uses the buffer as pixel storage for a texture and displays it • Expectation: colored bars on screen upstream vk-pix-buf-update-errors Same as above and: • OpenGL: attempts to overwrite the buffer • Expectation: error is generated, the buffer remains unchanged work in progress Eleni Maria Stea <[email protected]> OpenGL and Vulkan Interoperability XDC 2020 11 / 19
- 12. Interoperability on Mesa Additions to Piglit (the details) IV Contributions to Piglit IV Reusing a vertex buffer: Test name Description Output Status vk-vert-buf-update-errors • Vulkan: creates a vertex buffer and fills it with only the odd quads of a chess board pattern • OpenGL: clears the screen to red and draws the vertex buffer in blue • OpenGL: attempts to overwrite the VBO • Expectation: a red-blue chess board pattern on screen and an invalid operation error is generated work in progress vk-vert-buf-reuse • Vulkan: same as above • OpenGL: same as above minus the invalid overwrite test • Vulkan: reuses the VBO in a renderpass to draw the chess board • Expectation: chessboard on screen work in progress Eleni Maria Stea <[email protected]> OpenGL and Vulkan Interoperability XDC 2020 12 / 19
- 13. Interoperability on Mesa Additions to Piglit (the details) V Contributions to Piglit V Many people helped us with the work on the tests: Contributors Contributions Eleni Maria Stea tests, Vulkan framework code Juan A. Suárez Romero contributions to the framework, and vk-image-overwrite, testing Tapani Pälli (many thanks!) reviews, testing and patches for the framework Bas Nieuwenhuizen framework patch to support dedicated memory Topi Pohjolainen we’ve used some old patches of him as an example at the very beginning ▶ Also thanks to Eduardo Lima Mitev and to Hyunjun Ko for the reviews and to Germán Poo Caamaño who helped tidying up the initial mess of the Vulkan framework commits. ▶ Again, this information was accurate when I prepared and pre-recorded the slides. Sorry if I am missing someone or something! Eleni Maria Stea <[email protected]> OpenGL and Vulkan Interoperability XDC 2020 13 / 19
- 14. Interoperability on Mesa Piglit Results Conclusions from running the tests: ▶ Most of the new Piglit tests are passing in the mesa drivers mentioned before (iris, freedreno, radeonsi, i965). ▶ Unfortunately Mesa does not yet support the depth and stencil buffer exchange. The only implementation I ’ve found that currently supports this feature is the Nvidia proprietary driver. ▶ radeonsi needs some fixes to better support buffers and optimal tiling (WIP). Eleni Maria Stea <[email protected]> OpenGL and Vulkan Interoperability XDC 2020 14 / 19
- 15. Q & A Outline 1 OpenGL interoperability extensions 2 Additions to Mesa and Piglit 3 Questions 4 References Eleni Maria Stea <[email protected]> OpenGL and Vulkan Interoperability XDC 2020 15 / 19
- 16. Q & A Questions? E-mail: [email protected] IRC/Freenode: hikiko Eleni Maria Stea <[email protected]> OpenGL and Vulkan Interoperability XDC 2020 16 / 19
- 17. References Outline 1 OpenGL interoperability extensions 2 Additions to Mesa and Piglit 3 Questions 4 References Eleni Maria Stea <[email protected]> OpenGL and Vulkan Interoperability XDC 2020 17 / 19
- 18. References Links I OpenGL and Vulkan Interoperability on Linux (Blog posts on the Piglit tests use cases). https://eleni.mutantstargoat.com/hikiko/category/igalia/ graphics_drivers/opengl-and-vulkan-interoperability/. Carsten Rohde, Dave Airlie, James Jones, Jan-Harald Fredriksen, Jeff Juliano, and Michael Worcester. EXT_external_objects (GL_EXT_memory_object, GL_EXT_semaphore), July 18, 2018. https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_ external_objects.txt. Carsten Rhode, James Jones, Jan Harald Fredriksen, and Jeff Juliano. EXT_external_objects_fd (GL_EXT_memory_object_fd, GL_EXT_semaphore_fd), June 2, 2017. https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_ external_objects_fd.txt. Eleni Maria Stea <[email protected]> OpenGL and Vulkan Interoperability XDC 2020 18 / 19
- 19. Thank you!