Memory Management

In DirectX 12, the application is responsible for much of the graphics memory management much as it is for system memory. This includes managing CPU/GPU synchronization and ensuring that resources are not modified by the CPU while the GPU is using them or vice-versa.

For the DirectX Tool Kit for DirectX 12 this is primarily handled through two classes: GraphicsMemory and ResourceUploadBatch.

Constant buffers

The primary use of the GraphicsMemory class is to allocate constant buffers from a D3D12_HEAP_TYPE_UPLOAD heap. CBs can persist for many frames, or be used for a single frame, but they must remain unchanged until their usage is completed. GraphicsMemory tracks this using a per-frame fence which is reclaimed each frame as they complete during the Present loop. CBs are in memory shared between the CPU and GPU as they are used for communication between CPU code and GPU shaders.

Index/Vertex buffers

UNDER DEVELOPMENT

Textures

Typically textures are created as ID3D12Resource interfaces as committed memory in the D3D12_HEAP_TYPE_DEFAULT heap, requiring a D3D12_HEAP_TYPE_UPLOAD heap to transfer data from the CPU to the GPU memory which is often managed by the ResourceUploadBatch class. For more information see Textures.