Currently the drawIndexedQuads method uses [MTLRenderEncoder setVertexBytes] method to pass the vertex data to vertex shader function.

The method [MTLRenderEncoder setVertexBytes] can be used only for <= 4KB data.
In scenarios when the input vertex data is very large, it requires more number of setVertexBytes calls.
This can be avoided by using [MTLRenderEncoder setVertexBuffer] method instead, which would need only one call.

There are 2 other setVertexBytes calls in clearRTT, which can be replaced.