c++ - Vulkan API 调试函数指针类型转换错误

Question

这几天一直被这个问题困扰。我正在尝试使用 Vulkan API 的调试层我已经成功获取了 PFN_vkCreateDebugReportCallbackEXT 和 PFN_vkDestroyDebugReportCallbackEXT 的函数指针。

但是在创建用作 vkCreateDebugReportCallback 参数的结构时，我遇到了结构的 pfnCallback 部分的问题。

Visual studio 在尝试编译时给我这个错误，我尝试按如下方式对其进行类型转换:

dbgReportCreateInfo.pfnCallback = (PFN_vkDebugReportCallbackEXT) debugFunction;

和

dbgReportCreateInfo.pfnCallback = reinterpret_cast<PFN_vkDebugReportCallbackEXT>(debugFunction);

当调用 vkCreateDebugReportCallback 函数时，这两者都会导致内存访问冲突。

应该做什么

来自课本Learning Vulkan和提供的存储库中结构的 PFN_vkDebugReportCallbackEXT pfn 部分的正确声明应该如其存储库中所示 here .

VKAPI_ATTR VkBool32 VKAPI_CALL debugFunction(
    VkFlags                    msgFlags, 
    VkDebugReportObjectTypeEXT objType, 
    uint64_t                   srcObject, 
    size_t                     location, 
    uint32_t                   msgCode, 
    const char *               layerPrefix, 
    const char *               msg, 
    void *                     userData);

Vulkan 头文件

这与 Vulkan 头文件 vulkan.h 中的定义相同

typdef uint32_t VkBool32;

typedef VkBool32 (VKAPI_PTR *PFN_vkDebugReportCallbackEXT)(
    VkDebugReportFlagsEXT                       flags,
    VkDebugReportObjectTypeEXT                  objectType,
    uint64_t                                    object,
    size_t                                      location,
    int32_t                                     messageCode,
    const char*                                 pLayerPrefix,
    const char*                                 pMessage,
    void*                                       pUserData);


typedef struct VkDebugReportCallbackCreateInfoEXT {
    VkStructureType                 sType;
    const void*                     pNext;
    VkDebugReportFlagsEXT           flags;
    PFN_vkDebugReportCallbackEXT    pfnCallback;
    void*                           pUserData;
} VkDebugReportCallbackCreateInfoEXT;

Visual Studio 错误

Severity Code Description Project File Line Source Suppression State Error C2440 '=': cannot convert from 'VkBool32 (__cdecl *)(VkDebugReportFlagsEXT,VkDebugReportObjectTypeEXT,uint64_t,std::size_t,uint32_t,const char *,const char *,void *)' to 'PFN_vkDebugReportCallbackEXT' vulkanproject C:\Users\Alec\workspace\cpp\vulkanproject\source\VulkanLayerAndExtension.cpp 287 Build

我的代码

我的 Github 中提供了完整的项目 repository

VulkanLayerAndExtension.h

class VulkanLayerAndExtension {
    // Some stuff before
    VkResult createDebugReportCallback();
    void destroyDebugReportCallback();
    static VKAPI_ATTR VkBool32 VKAPI_CALL debugFunction(VkDebugReportFlagsEXT msgFlags,
        VkDebugReportObjectTypeEXT objType,
        uint64_t srcObject,
        size_t location,
        uint32_t msgCode,
        const char * layerPrefix,
        const char * msg,
        void * userData);

private:
    PFN_vkCreateDebugReportCallbackEXT dbgCreateDebugReportCallback;
    PFN_vkDestroyDebugReportCallbackEXT dbgDestroyDebugReportCallback;
    VkDebugReportCallbackEXT debugReportCallback;
public:
    VkDebugReportCallbackCreateInfoEXT dbgReportCreateInfo = {};

VulkanLayerAndExtension.cpp

// stuff before

VKAPI_ATTR VkBool32 VKAPI_CALL
VulkanLayerAndExtension::debugFunction(VkDebugReportFlagsEXT msgFlags, VkDebugReportObjectTypeEXT objType, uint64_t srcObject, size_t location, uint32_t msgCode, const char * layerPrefix, const char * msg, void * userData)
{
    std::cout << "[VK_DEBUG_REPORT] ";
    if (msgFlags & VK_DEBUG_REPORT_ERROR_BIT_EXT) {
        std::cout << "ERROR";
    }
    else if (msgFlags & VK_DEBUG_REPORT_WARNING_BIT_EXT) {
        std::cout << "WARNING";
    }
    else if (msgFlags & VK_DEBUG_REPORT_INFORMATION_BIT_EXT) {
        std::cout << "INFORMATION";
    }
    else if (msgFlags & VK_DEBUG_REPORT_PERFORMANCE_WARNING_BIT_EXT) {
        std::cout << "PERFORMANCE";
    }
    else if (msgFlags & VK_DEBUG_REPORT_DEBUG_BIT_EXT) {
        std::cout << "DEBUG";
    }
    else {
        return VK_FALSE;
    }
    std::cout << ": [" << layerPrefix << "] Code" << msgCode << ":" << msg << std::endl;
    return VK_TRUE;
}

VkResult VulkanLayerAndExtension::createDebugReportCallback()
{
    VkResult result;

    VulkanApplication * appObj = VulkanApplication::GetInstance();
    VkInstance* instance = &appObj->instanceObj.instance;

    // Get vkCreateDebugReportCallbackEXT API
    dbgCreateDebugReportCallback = (PFN_vkCreateDebugReportCallbackEXT) vkGetInstanceProcAddr(*instance, "vkCreateDebugReportCallbackEXT");
    if (!dbgCreateDebugReportCallback) {
        std::cout << "Error: GetInstanceProcAddr unable to locate vkCreateDebugReportCallbackEXT function.\n";
        return VK_ERROR_INITIALIZATION_FAILED;
    }
    std::cout << "GetInstanceProcAddr loaded dbgCreateDebugReportCallback function.\n";

    // Get vkDestroyDebugReportCallbackEXT API
    dbgDestroyDebugReportCallback = (PFN_vkDestroyDebugReportCallbackEXT)vkGetInstanceProcAddr(*instance, "vkDestroyDebugReportCallbackEXT");
    if (!dbgDestroyDebugReportCallback) {
        std::cout << "Error: GetInstanceProcAddr unable to locate vkDestroyDebugReportCallbackEXT function.\n";
        return VK_ERROR_INITIALIZATION_FAILED;
    }
    std::cout << "GetInstanceProcAddr loaded dbgDestroyDebugReportCallback function.\n";

    dbgReportCreateInfo.sType = VK_STRUCTURE_TYPE_DEBUG_REPORT_CREATE_INFO_EXT;
    // Type error occurs on this line below
    dbgReportCreateInfo.pfnCallback =   VulkanLayerAndExtension::debugFunction;
    dbgReportCreateInfo.pUserData =     NULL;
    dbgReportCreateInfo.pNext =         NULL;
    dbgReportCreateInfo.flags =         VK_DEBUG_REPORT_WARNING_BIT_EXT |
                                        VK_DEBUG_REPORT_PERFORMANCE_WARNING_BIT_EXT |
                                        VK_DEBUG_REPORT_ERROR_BIT_EXT |
                                        VK_DEBUG_REPORT_DEBUG_BIT_EXT;

    // Create the debug report callback object
    result = dbgCreateDebugReportCallback(*instance, &dbgReportCreateInfo, NULL, &debugReportCallback);
    if (result == VK_SUCCESS) {
        std::cout << "Debug report callback object created successfully.\n";
    }

    return result;
}

void VulkanLayerAndExtension::destroyDebugReportCallback()
{
    VulkanApplication * appObj = VulkanApplication::GetInstance();
    VkInstance & instance = appObj->instanceObj.instance;
    if (debugReportCallback) {
        dbgDestroyDebugReportCallback(instance, debugReportCallback, NULL);
    }
}

Answer 1

你为什么要转换函数？？你不应该!该函数必须是所需的类型。

我还在 my example project 中以编程方式进行调试, 它有效，所以让我们在这里进行比较:

VKAPI_ATTR VkBool32 VKAPI_CALL genericDebugCallback(
    VkDebugReportFlagsEXT msgFlags,
    VkDebugReportObjectTypeEXT objType,
    uint64_t srcObject,
    size_t /*location*/,
    int32_t msgCode,
    const char* pLayerPrefix,
    const char* pMsg,
    void* /*pUserData*/
){
    // just print everything
    return VK_FALSE;
}

//// elsewhere
VkDebugReportCallbackCreateInfoEXT debugCreateInfo{
    VK_STRUCTURE_TYPE_DEBUG_REPORT_CREATE_INFO_EXT,
    nullptr,
    debugAmount,
    genericDebugCallback,
    nullptr
};

VkDebugReportCallbackEXT debug;
VkResult errorCode = vkCreateDebugReportCallbackEXT( instance, &debugCreateInfo, nullptr, &debug );
RESULT_HANDLER( errorCode, "vkCreateDebugReportCallbackEXT" );

所以扫描你的代码我发现了这些问题:

1. 您正在转换函数类型。
2. PFN_vkDebugReportCallbackEXT::msgCode 是 int32_t 而不是 uint32_t
3. 除非您知道自己在做什么，否则您可能不应该从回调中返回 VK_TRUE。
4. 为什么有*instance还有VkInstance&？？没有意义。它是一个 Handlebars 。直接使用VkInstance；没有指针，没有取消引用，也不需要引用。
5. 在 dbgReportCreateInfo.flags 中，您真的想要 VK_DEBUG_REPORT_DEBUG_BIT_EXT 吗？考虑到您不接受 INFO，这个选择有点奇怪。

1 和 2 应该可以解决您眼前的问题。