Vulkan API调试函数指针类型错误

Question

在过去的几天里一直困在这个问题上。我正在尝试使用Vulkan的调试层，我成功地获取了PFN_vkCreateDebugReportCallbackEXT和PFN_vkDestroyDebugReportCallbackEXT的函数指针。

但是，当创建要用作vkCreateDebugReportCallback参数的结构时，我对结构的pfnCallback部分有问题。

Visual在试图编译时给了我这个错误，并且我尝试了按如下方式进行类型转换：

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。

什么应该起作用？

从教科书https://www.packtpub.com/application-development/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它们的存储库这里所示。

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头文件中的定义相同，即vulkan.h。

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;

错误

严重程度代码描述项目文件行源抑制状态错误C2440 '='：无法从'VkBool32 (__cdecl *)(VkDebugReportFlagsEXT、VkDebugReportObjectTypeEXT、uint64_t、std::size_t、uint32_t、const char *、const char *、void *‘)转换为'PFN_vkDebugReportCallbackEXT’vulkanproject VkBool32 287构建

我的代码

完整的项目可在我的Github 存储库中获得

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

你为什么要选这个函数？？你不应该！函数已经必须是必需的类型。

我还在我的示例项目中以编程方式进行调试，并且它可以工作，因此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" );

因此，扫描您的代码--我看到了以下问题：

1. 你是铸造函数类型。
2. PFN_vkDebugReportCallbackEXT::msgCode是int32_t而不是uint32_t
3. 您可能不应该从回调返回VK_TRUE，除非您知道自己在做什么。
4. 为什么会有*instance和VkInstance&?？这没有任何意义。是把手。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，你真的想要VK_DEBUG_REPORT_DEBUG_BIT_EXT吗？考虑到你也不接受INFO，这是一个奇怪的选择。

1和2应该可以解决你眼前的问题。