FFmpeg/libavutil/vulkan_loader.h

/*
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef AVUTIL_VULKAN_LOADER_H
#define AVUTIL_VULKAN_LOADER_H

#include <stdio.h>

#include "avassert.h"
#include "vulkan_functions.h"

/* Macro to turn a function name into a loader struct */
#define PFN_LOAD_INFO(req_inst, req_dev, ext_flag, name) \
    {                                                    \
        req_inst,                                        \
        req_dev,                                         \
        offsetof(FFVulkanFunctions, name),               \
        ext_flag,                                        \
    },

static inline uint64_t ff_vk_extensions_to_mask(const char * const *extensions,
                                                int nb_extensions)
{
    static const struct ExtensionMap {
        const char *name;
        FFVulkanExtensions flag;
    } extension_map[] = {
        { VK_EXT_EXTERNAL_MEMORY_DMA_BUF_EXTENSION_NAME,   FF_VK_EXT_EXTERNAL_DMABUF_MEMORY },
        { VK_EXT_IMAGE_DRM_FORMAT_MODIFIER_EXTENSION_NAME, FF_VK_EXT_DRM_MODIFIER_FLAGS     },
        { VK_KHR_EXTERNAL_MEMORY_FD_EXTENSION_NAME,        FF_VK_EXT_EXTERNAL_FD_MEMORY     },
        { VK_KHR_EXTERNAL_SEMAPHORE_FD_EXTENSION_NAME,     FF_VK_EXT_EXTERNAL_FD_SEM        },
        { VK_EXT_EXTERNAL_MEMORY_HOST_EXTENSION_NAME,      FF_VK_EXT_EXTERNAL_HOST_MEMORY   },
        { VK_EXT_DEBUG_UTILS_EXTENSION_NAME,               FF_VK_EXT_DEBUG_UTILS            },
        { VK_EXT_PHYSICAL_DEVICE_DRM_EXTENSION_NAME,       FF_VK_EXT_DEVICE_DRM             },
        { VK_EXT_SHADER_ATOMIC_FLOAT_EXTENSION_NAME,       FF_VK_EXT_ATOMIC_FLOAT           },
        { VK_KHR_COOPERATIVE_MATRIX_EXTENSION_NAME,        FF_VK_EXT_COOP_MATRIX            },
#ifdef _WIN32
        { VK_KHR_EXTERNAL_MEMORY_WIN32_EXTENSION_NAME,     FF_VK_EXT_EXTERNAL_WIN32_MEMORY  },
        { VK_KHR_EXTERNAL_SEMAPHORE_WIN32_EXTENSION_NAME,  FF_VK_EXT_EXTERNAL_WIN32_SEM     },
#endif
        { VK_EXT_DESCRIPTOR_BUFFER_EXTENSION_NAME,         FF_VK_EXT_DESCRIPTOR_BUFFER,     },
        { VK_KHR_VIDEO_QUEUE_EXTENSION_NAME,               FF_VK_EXT_VIDEO_QUEUE            },
        { VK_KHR_VIDEO_DECODE_QUEUE_EXTENSION_NAME,        FF_VK_EXT_VIDEO_DECODE_QUEUE     },
        { VK_KHR_VIDEO_DECODE_H264_EXTENSION_NAME,         FF_VK_EXT_VIDEO_DECODE_H264      },
        { VK_KHR_VIDEO_DECODE_H265_EXTENSION_NAME,         FF_VK_EXT_VIDEO_DECODE_H265      },
        { "VK_MESA_video_decode_av1",                      FF_VK_EXT_VIDEO_DECODE_AV1       },
    };

    FFVulkanExtensions mask = 0x0;

    for (int i = 0; i < nb_extensions; i++) {
        for (int j = 0; j < FF_ARRAY_ELEMS(extension_map); j++) {
            if (!strcmp(extensions[i], extension_map[j].name)) {
                mask |= extension_map[j].flag;
                continue;
            }
        }
    }

    return mask;
}

/**
 * Function loader.
 * Vulkan function from scratch loading happens in 3 stages - the first one
 * is before any initialization has happened, and you have neither an instance
 * structure nor a device structure. At this stage, you can only get the bare
 * minimals to initialize an instance.
 * The second stage is when you have an instance. At this stage, you can
 * initialize a VkDevice, and have an idea of what extensions each device
 * supports.
 * Finally, in the third stage, you can proceed and load all core functions,
 * plus you can be sure that any extensions you've enabled during device
 * initialization will be available.
 */
static inline int ff_vk_load_functions(AVHWDeviceContext *ctx,
                                       FFVulkanFunctions *vk,
                                       uint64_t extensions_mask,
                                       int has_inst, int has_dev)
{
    AVVulkanDeviceContext *hwctx = ctx->hwctx;

    static const struct FunctionLoadInfo {
        char req_inst;
        char req_dev;
        uint16_t struct_offset;
        FFVulkanExtensions ext_flag;
    } vk_load_info[] = {
        FN_LIST(PFN_LOAD_INFO)
#ifdef _WIN32
        FN_LIST_WIN32(PFN_LOAD_INFO)
#endif
    };
    // Concatenate the names to avoid relocations. The resulting string
    // will end with \0\0
#define FUNC_NAME(req_inst, req_dev, ext_flag, name) "vk"#name"\0"
    const char *name =
        FN_LIST(FUNC_NAME)
#ifdef _WIN32
        FN_LIST_WIN32(FUNC_NAME)
#endif
    ;
#undef FUNC_NAME

    for (int i = 0; i < FF_ARRAY_ELEMS(vk_load_info); name += strlen(name) + 1, i++) {
        const struct FunctionLoadInfo *load = &vk_load_info[i];
        static const char extensions[][4] = { "", "EXT", "KHR" };
        PFN_vkVoidFunction fn;

        if (load->req_dev  && !has_dev)
            continue;
        if (load->req_inst && !has_inst)
            continue;

        for (int j = 0; j < FF_ARRAY_ELEMS(extensions); j++) {
            char ext_name[128];
            av_unused int n;

            n = snprintf(ext_name, sizeof(ext_name), "%s%s", name, extensions[j]);
            av_assert1(n < sizeof(ext_name));

            if (load->req_dev)
                fn = vk->GetDeviceProcAddr(hwctx->act_dev, ext_name);
            else if (load->req_inst)
                fn = hwctx->get_proc_addr(hwctx->inst, ext_name);
            else
                fn = hwctx->get_proc_addr(NULL, ext_name);

            if (fn)
                break;
        }

        if (!fn && ((extensions_mask &~ FF_VK_EXT_NO_FLAG) & load->ext_flag)) {
            av_log(ctx, AV_LOG_ERROR, "Loader error, function \"%s\" indicated "
                   "as supported, but got NULL function pointer!\n", name);
            return AVERROR_EXTERNAL;
        }

        *(PFN_vkVoidFunction *)((uint8_t *)vk + load->struct_offset) = fn;
    }
    av_assert1(*name == '\0');

    return 0;
}

#endif /* AVUTIL_VULKAN_LOADER_H */