hitectures for GPUs (graphics
processing units, the hardware that handles graphics), but most of them
involve batching commands and reordering them for performance. When layers
are used, they cause the rendering pipeline to have to switch render
target (from one layer to another). Render target switches can flush the
GPU's command buffer, which typically means that optimizations that one
could get with larger batching are lost. Render target switches also
generate a lot of memory churn because the GPU needs