如何将模板参数与“if”和“switch”语句一起使用？

问：

我目前正在用 Vulkan 用 C++ 编写游戏引擎，现在我正在努力将我的意大利面条代码简化为更直观的东西。作为此过程的一部分，我通用了一个描述符来创建引擎所需的多个组件，并且 由多个不同类型的对象继承。structstruct

这在 my 和 objects 之间不是问题，因为它们都具有 type 的成员变量。但是，我的对象的不同之处在于成员变量的类型。SSBOUBOVkDescriptorBufferInfoTextureVkDescriptorImageInfo

对象使用这两种类型，其在“vulkan_core.h”标头中的定义是：VkWriteDescriptorSet

typedef struct VkWriteDescriptorSet {
    VkStructureType                  sType;
    const void*                      pNext;
    VkDescriptorSet                  dstSet;
    uint32_t                         dstBinding;
    uint32_t                         dstArrayElement;
    uint32_t                         descriptorCount;
    VkDescriptorType                 descriptorType;
    const VkDescriptorImageInfo*     pImageInfo;   //to be provided by my Texture objects
    const VkDescriptorBufferInfo*    pBufferInfo;  //to be provided by my UBO/SSBO objects
    const VkBufferView*              pTexelBufferView;
} VkWriteDescriptorSet;

我尝试概括对象的创建如下：VkWriteDescriptorSet

template <typename T>
inline VkWriteDescriptorSet writeSet(const std::vector<T>& bufferInfo, std::array<size_t,2> dst) {
    VkWriteDescriptorSet writeInfo { VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET };

    /* Here I try to differentiate how the VkWriteDescriptorSet object is created */
    if (std::is_same<T, VkDescriptorImageInfo>::value) {
        writeInfo.pImageInfo = &bufferInfo[dst[1]];  //requires T == VkDescriptorImageInfo
    }
    else {
        writeInfo.pBufferInfo = &bufferInfo[dst[1]]; //requires T == VkDescriptorBufferInfo
    }

    /* Then the function fills out the rest of the object */

    return writeInfo;
}

上述内容在以下函数中调用：

void writeSets(uint32_t bindingCount) {    
    // The type of the vector below depends on the calling object (UBO/SSBO or Texture)
    std::vector</* VkDescriptorBufferInfo or VkDescriptorImageInfo */> bufferInfo(bindingCount);

    std::vector<VkWriteDescriptorSet> descriptorWrites(bindingCount);
    for (size_t i = 0; i < MAX_FRAMES_IN_FLIGHT; i++) {           
        /* loop does stuff */
        for (size_t j = 0; j < bindingCount; j++) {
            /* loop does more stuff */
            descriptorWrites[j] = writeSet(bufferInfo, { i, j }); // the generalized function is called
        }
        vkUpdateDescriptorSets(VkGPU::device, bindingCount, descriptorWrites.data(), 0, nullptr);
    }
}

不幸的是，我的程序无法编译并返回以下错误：

Severity: Error
Line: 27
Code: C2440
Description: '=': cannot convert from 'const _Ty *' to 'const VkDescriptorImageInfo *'

这最终引出了我的问题，如何在“if”和“switch”语句中使用模板参数？

编辑： 我尝试推广该函数的另一种方法是使用以下 switch 语句：VkDescriptorTypeenum

template <typename T>
inline VkWriteDescriptorSet writeSet(const std::vector<T>& bufferInfo, std::array<size_t,2> dst) {
    VkWriteDescriptorSet writeInfo { VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET };

    /* Here I try to differentiate how the VkWriteDescriptorSet object is created */
    switch (type) {
    case VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER:
        writeInfo.pImageInfo = &bufferInfo[dst[1]];  //requires T == VkDescriptorImageInfo
    default:
        writeInfo.pBufferInfo = &bufferInfo[dst[1]]; //requires T == VkDescriptorBufferInfo
    }

    /* Then the function fills out the rest of the object */

    return writeInfo;
}