/* Copyright (C) 2010-2016 The RetroArch team * * --------------------------------------------------------------------------------------------- * The following license statement only applies to this libretro API header (libretro_vulkan.h) * --------------------------------------------------------------------------------------------- * * Permission is hereby granted, free of charge, * to any person obtaining a copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation the rights to * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, * and to permit persons to whom the Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #ifndef LIBRETRO_VULKAN_H__ #define LIBRETRO_VULKAN_H__ #include "libretro.h" #include #define RETRO_HW_RENDER_INTERFACE_VULKAN_VERSION 1 struct retro_vulkan_image { VkImageView image_view; VkImageLayout image_layout; VkImageViewCreateInfo create_info; }; typedef void (*retro_vulkan_set_image_t)(void *handle, const struct retro_vulkan_image *image, uint32_t num_semaphores, const VkSemaphore *semaphores); typedef uint32_t (*retro_vulkan_get_sync_index_t)(void *handle); typedef uint32_t (*retro_vulkan_get_sync_index_mask_t)(void *handle); typedef void (*retro_vulkan_set_command_buffers_t)(void *handle, uint32_t num_cmd, const VkCommandBuffer *cmd); typedef void (*retro_vulkan_wait_sync_index_t)(void *handle); typedef void (*retro_vulkan_lock_queue_t)(void *handle); typedef void (*retro_vulkan_unlock_queue_t)(void *handle); /* Note on thread safety: * The Vulkan API is heavily designed around multi-threading, and * the libretro interface for it should also be threading friendly. * A core should be able to build command buffers and submit command buffers to the GPU from * any thread. */ struct retro_hw_render_interface_vulkan { /* Must be set to RETRO_HW_RENDER_INTERFACE_VULKAN. */ enum retro_hw_render_interface_type interface_type; /* Must be set to RETRO_HW_RENDER_INTERFACE_VULKAN_VERSION. */ unsigned interface_version; /* Opaque handle to the Vulkan backend in the frontend * which must be passed along to all function pointers * in this interface. * * The rationale for including a handle here (which libretro v1 doesn't current do in general) is: * * - Vulkan cores should be able to be freely threaded without lots of fuzz. * This would break frontends which currently rely on TLS * to deal with multiple cores loaded at the same time. * - Fixing this in general is TODO for an eventual libretro v2. */ void *handle; /* The Vulkan instance the context is using. */ VkInstance instance; /* The physical device used. */ VkPhysicalDevice gpu; /* The logical device used. */ VkDevice device; /* The queue the core must use to submit data. * This queue and index must remain constant throughout the lifetime * of the context. * * This queue will be the queue that supports graphics and compute * if the device supports compute. */ VkQueue queue; unsigned queue_index; /* Before calling retro_video_refresh_t with RETRO_HW_FRAME_BUFFER_VALID, * set which image to use for this frame. * * If num_semaphores is non-zero, the frontend will wait for the semaphores provided to be signaled * before using the results further in the pipeline. * Using semaphores is optional for synchronization purposes, but if not using * semaphores, an image memory barrier in vkCmdPipelineBarrier should be used in the graphics_queue. * Example: * * vkCmdPipelineBarrier(cmd, * srcStageMask = VK_PIPELINE_STAGE_ALL_GRAPHICS_BIT, * dstStageMask = VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT, * image_memory_barrier = { * srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT, * dstAccessMask = VK_ACCESS_SHADER_READ_BIT, * }); * * The use of pipeline barriers instead of semaphores is encouraged as it is simpler * and more fine-grained. A layout transition must generally happen anyways which requires a * pipeline barrier. * * The image passed to set_image must have imageUsage flags set to at least * VK_IMAGE_USAGE_TRANSFER_SRC_BIT and VK_IMAGE_USAGE_SAMPLED_BIT. * The core will naturally want to use flags such as * VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT and/or VK_IMAGE_USAGE_TRANSFER_DST_BIT depending * on how the final image is created. * * The image must also have been created with MUTABLE_FORMAT bit set if 8-bit formatt are used, so that the frontend can * reinterpret sRGB formats as it sees fit. * * Images passed to set_image should be created with TILING_OPTIMAL. * The image layout should be transitioned to either VK_IMAGE_LAYOUT_GENERIC or VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL. * The actual image layout used must be set in image_layout. * * The image must be a 2D texture which may or not be layered and/or mipmapped. * The image must be suitable for linear sampling. * While the image_view is typically the only field used, * the frontend may want to reinterpret the texture as sRGB vs. no-sRGB for example * so the VkImageViewCreateInfo used to create the image view must also be passed in. * The data in the pointer to the image struct will not be copied * as the pNext field in create_info cannot be reliably deep-copied. * The image pointer passed to set_image must be valid until retro_video_refresh_t has returned. * * If frame duping is used when passing NULL to retro_video_refresh_t, * the frontend is free to either use the latest image passed to set_image or reuse the older pointer * passed to set_image the frame RETRO_HW_FRAME_BUFFER_VALID was last used. * Essentially, the lifetime of the pointer passed to retro_video_refresh_t should be extended * if frame duping is used so that the frontend can reuse the older pointer. * * If frame duping is used, the frontend will not wait for any semaphores. */ retro_vulkan_set_image_t set_image; /* Get the current sync index for this frame which is obtained in frontend by calling * e.g. vkAcquireNextImageKHR before calling retro_run(). * This index will correspond to which swapchain buffer is currently the active one. * Knowing this index is very useful for maintaining safe async CPU and GPU operation without stalling. * * The common pattern for synchronization is to receive fences when submitting command buffers * to Vulkan (vkQueueSubmit) and add this fence to a list of fences for frame number get_sync_index(). * Next time we receive the same get_sync_index(), we can wait for the fences from before, * which will usually return immediately as the frontend will generally also avoid letting the GPU run ahead too much. * After the fence has signaled, we know that the GPU has completed all GPU work related to work submitted in the frame * we last saw get_sync_index(). This means we can safely reuse or free resources allocated in this frame. * * In theory, even if we wait for the fences correctly, it is not technically safe to write to the image * we earlier passed to the frontend since we're not waiting for the frontend GPU jobs to complete. * The frontend will guarantee that the appropriate pipeline barrier * in graphics_queue has been used such that VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT cannot * start until the frontend is done with the image. */ retro_vulkan_get_sync_index_t get_sync_index; /* Returns a bitmask of how many swapchain images we currently have in the frontend. * If bit #N is set in the return value, get_sync_index can return N. * Knowing this value is useful for preallocating per-frame management structures ahead of time. * * While this value will typically remain constant throughout the applications lifecycle, * it may for example change if the frontend suddently changes fullscreen state and/or latency. * If this value ever changes, it is safe to assume that the device is completely idle and all synchronization * objects can be deleted right away as desired. */ retro_vulkan_get_sync_index_mask_t get_sync_index_mask; /* Instead of submitting the command buffer to the queue first, the core can pass along * its command buffer to the frontend, and the frontend will submit the command buffer together * with the frontends command buffers. This has the advantage that the overhead of vkQueueSubmit * can be amortized into a single call. For this mode, semaphores in set_image will be ignored, so * vkCmdPipelineBarrier must be used to synchronize the core and frontend. * The command buffers in set_command_buffers are only executed once, even if frame duping is used. * If frame duping is used, set_image should be used for the frames which should be duped instead. * * Command buffers passed to the frontend with set_command_buffers * must not actually be submitted to the GPU until retro_video_refresh_t is called. * The frontend must submit the command buffer before submitting any other command buffers * provided by set_command_buffers. */ retro_vulkan_set_command_buffers_t set_command_buffers; /* Waits on CPU for device activity for the current sync index to complete. * This is useful since the core will not have a relevant fence to sync with * when the frontend is submitting the command buffers. */ retro_vulkan_wait_sync_index_t wait_sync_index; /* If the core submits command buffers itself to any of the queues provided in this interface, * the core must lock and unlock the frontend from racing on the VkQueue. * Queue submission can happen on any thread. * Even if queue submission happens on the same thread as retro_run(), the lock/unlock * functions must still be called. * * NOTE: Queue submissions are heavy-weight. */ retro_vulkan_lock_queue_t lock_queue; retro_vulkan_unlock_queue_t unlock_queue; }; #endif