values aid the graphics driver in optimizing access to buffer
objects by declaring the primary provider and consumer of data for the buffer.
|• ||draw-usage declares that the buffer will be supplied with data from CPU memory and read from by the GPU for vertex or texture image data.|
|• ||read-usage declares that the buffer will be supplied with data from other GPU resources and read from primarily by the CPU.|
|• ||copy-usage declares that the buffer will both receive and supply data primarily for other GPU resources.|
is only a declaration and does not actually control access to the underlying buffer data.See alsobuffer-kind