Memcpy发生访问冲突失败-Vulkan复制到顶点缓冲区

Question

我正在尝试将一些数据传递给Vulkan中的GPU。 AFAIK，做到这一点的唯一方法是使用memcpy。这适用于较小的向量，但是对于较大的模型，尝试执行此操作时会遇到访问冲突异常。相同的方法在同一台机器上的另一个实现中工作。我应该找什么？谢谢

这里是代码

void VulkanAllocator::createVertexBuffer(std::vector<HE2_Vertex>* vertices, VkBuffer& vertexBuffer, VkDeviceMemory& vertexBufferMemory)
{
VkDeviceSize bufferSize = sizeof(HE2_Vertex) * vertices->size();

VkBuffer stagingBuffer;
VkDeviceMemory stagingBufferMemory;

createBuffer(bufferSize, VK_BUFFER_USAGE_TRANSFER_SRC_BIT, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT, stagingBuffer, stagingBufferMemory);

VkMemoryRequirements memReqs;

vkGetBufferMemoryRequirements(vdi->device, stagingBuffer, &memReqs);


void* data;

if (vkMapMemory(vdi->device, stagingBufferMemory, 0, (size_t)memReqs.size, 0, &data) != VK_SUCCESS)
{
    throw std::exception("Bad Memory map!");
}

memcpy(data, vertices->data(), (size_t)memReqs.size); //Crash after this line


vkUnmapMemory(vdi->device, stagingBufferMemory);

createBuffer(bufferSize, VK_BUFFER_USAGE_TRANSFER_DST_BIT | VK_BUFFER_USAGE_VERTEX_BUFFER_BIT,
    VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT, vertexBuffer, vertexBufferMemory);

copyBuffer(stagingBuffer, vertexBuffer, bufferSize);

vkDestroyBuffer(vdi->device, stagingBuffer, nullptr);
vkFreeMemory(vdi->device, stagingBufferMemory, nullptr);
}

并且CreateBuffer看起来像这样

void VulkanAllocator::createBuffer(VkDeviceSize size, VkBufferUsageFlags usage, VkMemoryPropertyFlags properties, VkBuffer& buffer, VkDeviceMemory& bufferMemory)
{
    VkBufferCreateInfo bufferInfo = {};
bufferInfo.sType = VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO;
bufferInfo.size = size;
bufferInfo.usage = usage;
bufferInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE;

if (vkCreateBuffer(vdi->device, &bufferInfo, nullptr, &buffer) != VK_SUCCESS)
{
    throw std::runtime_error("Unable to create vertex buffer");
}

VkMemoryRequirements memRequirements;

vkGetBufferMemoryRequirements(vdi->device, buffer, &memRequirements);

VkMemoryAllocateInfo allocInfo = {};

allocInfo.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
allocInfo.allocationSize = memRequirements.size;
allocInfo.memoryTypeIndex = findMemoryType(memRequirements.memoryTypeBits, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT);

if (vkAllocateMemory(vdi->device, &allocInfo, nullptr, &bufferMemory) != VK_SUCCESS)
{
    throw std::runtime_error("failed to allocate vertex buffer memory");
}

vkBindBufferMemory(vdi->device, buffer, bufferMemory, 0);
}

向量的创建是这样的（如果您经历过https://vulkan-tutorial.com/，则可能是在识别我的重构）。 HE2_Model仅包含HE2_Vertex s的向量和uint32_t s的向量。我不知道是否相关，但是我还没有为HE2_Vertex编写副本构造函数。

HE2_Model *模型=新的HE2_Model（）;

//Using tiny_obj_loader to pull in from a file
tinyobj::attrib_t attrib;
std::vector<tinyobj::shape_t> shapes;
std::vector<tinyobj::material_t> materials;

std::string warn, err;

if (!tinyobj::LoadObj(&attrib, &shapes, &materials, &warn, &err, filename.c_str()))
{
    throw std::runtime_error("Couldn't load model!");
}

std::unordered_map<HE2_Vertex, uint32_t> uniqueVertices = { };

for (const auto& shape : shapes)
{
    for (const auto& index : shape.mesh.indices)
    {
        HE2_Vertex vertex = {};

        vertex.pos = {
            attrib.vertices[3 * index.vertex_index + 0],
            attrib.vertices[3 * index.vertex_index + 1],
            attrib.vertices[3 * index.vertex_index + 2] };


        vertex.texCoord = {
            attrib.texcoords[2 * index.texcoord_index + 0],
            1.0f - attrib.texcoords[2 * index.texcoord_index + 1] };

        if (uniqueVertices.count(vertex) == 0)
        {
            uniqueVertices[vertex] = static_cast<uint32_t>(model->vertices.size());
            model->vertices.push_back(vertex);
        }

        model->indices.push_back(uniqueVertices[vertex]);
    }
}


HE2_Instance::renderBackend->onAddModel(model);

return model;

Answer 1

这是崩溃的行：

memcpy(data, vertices->data(), (size_t)memReqs.size); //Crash after this line

[您在评论中说，“ Memreqs的大小略大于bufferSize”，即memReqs.size大于向量的全部大小[bufferSize] sizeof(HE2_Vertex) * vertices->size();，因此您的memcpy将是从vertices-> data（）中读取的数据超出了允许的范围，这是未定义的行为，有时会崩溃。您应该改用它：

memcpy(data, vertices->data(), (size_t)bufferSize);

（（可能还会添加类似assert(bufferSize <= memReqs.size);的东西）] >>

Answer 2

非常令人震惊的是，此问题通过重建得以解决。我在一个Visual Studio解决方案中有多个项目，而我只需要学习不依赖项目依赖项，那么我始终需要处理的内存错误和异常的第一件事就是重建每个项目。对于任何具有怪异的访问冲突和行为等的人，最重要的技巧-重建重建重建!!!