vkMapMemory，返回"Access is denied."错误

Question

我一直在开发一个基于Vulkan的图形引擎，在尝试创建缓冲区时，我遇到了vkMapMemory()函数的问题。在下面所示的代码中，程序返回一个"0"；访问被拒绝"；(-103741819或C0000005(错误。vkMapMemory()调用内部发生错误，我无法检查其返回的VkResult。

void createVertexBuffer(size_t sizeOfBuffer, void * _vertices , VkBuffer * _vertexBuffer, VkDeviceMemory * _vertexBufferMemory)
{
VkDeviceSize bufferSize = sizeOfBuffer;

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);

void* data;
if(vkMapMemory(_device, *_vertexBufferMemory, 0, bufferSize, 0, &data) != VK_SUCCESS)
printf("This is not printed");
memcpy(data, _vertices, sizeOfBuffer);
vkUnmapMemory(_device, *_vertexBufferMemory);

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(_device, stagingBuffer, NULL);
vkFreeMemory(_device, stagingBufferMemory, NULL);

return;
}

更多信息：

• sizeOfBuffer在这种情况下等于96
• _vertices数组大小实际上也等于96，因为它看起来是这样的：

_vertices[0][0] -1.000000 0.000000
_vertices[0][1] -1.000000 0.000000
_vertices[0][2] 0.000000 0.000000
_vertices[1][0] 1.000000 0.000000
_vertices[1][1] -1.000000 0.000000
_vertices[1][2] 0.000000 0.000000
_vertices[2][0] 1.000000 0.000000
_vertices[2][1] 1.000000 0.000000
_vertices[2][2] 0.000000 0.000000
_vertices[3][0] -1.000000 0.000000
_vertices[3][1] 1.000000 0.000000
_vertices[3][2] 0.000000 0.000000

• 三行的大小等于24，因为(sizeof(glm::vec3)=12)和三行包含两个glm::vec3结构：

typedef struct MKTAGA2 {
glm::vec3 position;
glm::vec3 color;
} MKTAGA;

Answer 1

我本来应该映射stagingBufferMemory的时候却在映射_vertexBufferMemory这是固定代码：

void createVertexBuffer(size_t sizeOfBuffer, void * _vertices , VkBuffer * _vertexBuffer, VkDeviceMemory * _vertexBufferMemory)
{
VkDeviceSize bufferSize = sizeOfBuffer;

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);

void* data;
vkMapMemory(_device, stagingBufferMemory, 0, bufferSize, 0, &data);
memcpy(data, _vertices, sizeOfBuffer);
vkUnmapMemory(_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(_device, stagingBuffer, NULL);
vkFreeMemory(_device, stagingBufferMemory, NULL);

return;
}