| // Copyright (c) 2014-2018 Khronos Group. This work is licensed under a |
| // Creative Commons Attribution 4.0 International License; see |
| // http://creativecommons.org/licenses/by/4.0/ |
| |
| include::meta/VK_KHR_incremental_present.txt[] |
| |
| *Last Modified Date*:: |
| 2016-11-02 |
| *IP Status*:: |
| No known IP claims. |
| *Contributors*:: |
| - Ian Elliott, Google |
| - Jesse Hall, Google |
| - Alon Or-bach, Samsung |
| - James Jones, NVIDIA |
| - Daniel Rakos, AMD |
| - Ray Smith, ARM |
| - Mika Isojarvi, Google |
| - Jeff Juliano, NVIDIA |
| - Jeff Bolz, NVIDIA |
| |
| This device extension extends slink:vkQueuePresentKHR, from the |
| `<<VK_KHR_swapchain>>` extension, allowing an application to specify a list |
| of rectangular, modified regions of each image to present. |
| This should be used in situations where an application is only changing a |
| small portion of the presentable images within a swapchain, since it enables |
| the presentation engine to avoid wasting time presenting parts of the |
| surface that haven't changed. |
| |
| This extension is leveraged from the +EGL_KHR_swap_buffers_with_damage+ |
| extension. |
| |
| === New Object Types |
| |
| None. |
| |
| === New Enum Constants |
| |
| * Extending elink:VkStructureType: |
| ** ename:VK_STRUCTURE_TYPE_PRESENT_REGIONS_KHR |
| |
| === New Enums |
| |
| None. |
| |
| === New Structures |
| |
| * slink:VkRectLayerKHR |
| * slink:VkPresentRegionKHR |
| * slink:VkPresentRegionsKHR |
| |
| === New Functions |
| |
| None. |
| |
| === Examples |
| |
| None. |
| |
| === Issues |
| |
| 1) How should we handle steroescopic-3D swapchains? We need to add a layer |
| for each rectangle. |
| One approach is to create another struct that contains the slink:VkRect2D |
| plus layer, and have slink:VkPresentRegionsKHR point to an array of that |
| struct. |
| Another approach is to have two parallel arrays, ptext:pRectangles and |
| ptext:pLayers, where ptext:pRectangles[i] and ptext:pLayers[i] must be used |
| together. |
| Which approach should we use, and if the array of a new structure, what |
| should that be called? |
| |
| *RESOLVED*: Create a new structure, which is a slink:VkRect2D plus a layer, |
| and will be called slink:VkRectLayerKHR. |
| |
| 2) Where is the origin of the slink:VkRectLayerKHR? |
| |
| *RESOLVED*: The upper left corner of the presentable image(s) of the |
| swapchain, per the definition of framebuffer coordinates. |
| |
| 3) Does the rectangular region, slink:VkRectLayerKHR, specify pixels of the |
| swapchain's image(s), or of the surface? |
| |
| *RESOLVED*: Of the image(s). |
| Some presentation engines may scale the pixels of a swapchain's image(s) to |
| the size of the surface. |
| The size of the swapchain's image(s) will be consistent, where the size of |
| the surface may vary over time. |
| |
| 4) What if all of the rectangles for a given swapchain contain a width |
| and/or height of zero? |
| |
| *RESOLVED*: The application is indicating that no pixels changed since the |
| last present. |
| The presentation engine may use such a hint and not update any pixels for |
| the swapchain. |
| However, all other semantics of flink:vkQueuePresentKHR must still be |
| honored, including waiting for semaphores to signal. |
| |
| === Version History |
| |
| * Revision 1, 2016-11-02 (Ian Elliott) |
| - Internal revisions |