VkQueueFamilyOptimalImageTransferGranularityPropertiesKHR

The VkQueueFamilyOptimalImageTransferGranularityPropertiesKHR structure is defined as:

typedef struct VkQueueFamilyOptimalImageTransferGranularityPropertiesKHR {
    VkStructureType sType;
    void* pNext;
    VkExtent3D optimalImageTransferGranularity;
} VkQueueFamilyOptimalImageTransferGranularityPropertiesKHR;

pub struct QueueFamilyOptimalImageTransferGranularityPropertiesKHR {
    s_type: vk::StructureType,
    p_next: *mut c_void,
    optimal_image_transfer_granularity: vk::Extent3D,
}

• sType is a VkStructureType value identifying this structure.
• pNext is NULL or a pointer to a structure extending this structure.
• optimalImageTransferGranularity is the optimal granularity for image copy operations in this queue family.

If this structure is included in the pNext chain of the VkQueueFamilyProperties2 structure passed to vkGetPhysicalDeviceQueueFamilyProperties2, then it is filled with the optimal image transfer granularity for the specified queue family.

The value returned in optimalImageTransferGranularity has a unit of compressed texel blocks for images having a block-compressed format, and a unit of texels otherwise.

Possible values of optimalImageTransferGranularity are:

• (0,0,0) specifies that an image copy operation is optimal only when copying whole mip levels, i.e. all of the following conditions are met:
  • The x, y, and z members of a VkOffset3D are zero.
  • The width, height, and depth members of a VkExtent3D parameter match the width, height, and depth of the image subresource corresponding to the parameter, respectively.
• (A_x, A_y, A_z) where A_x, A_y, and A_z are all integer powers of two. An image copy operation is optimal when all of the following conditions are met:
  • width of a VkExtent3D parameter is an integer multiple of A_x, or else x + width equals the width of the image subresource corresponding to the parameter.
  • height of a VkExtent3D parameter is an integer multiple of A_y, or else y + height equals the height of the image subresource corresponding to the parameter.
  • depth of a VkExtent3D parameter is an integer multiple of A_z, or else z + depth equals the depth of the image subresource corresponding to the parameter.
  • If the format of the image corresponding to the parameters is one of the block-compressed formats then for the purposes of the above calculations the granularity must be scaled up by the compressed texel block dimensions.