Luna::RHI::IBuffer::map

virtual RV map(usize read_begin, usize read_end, void **data)=0

Maps the resource data to system memory and enables CPU access to the resource data. Map/unmap operations are reference counted, for each map operation, you need to call unmap once to finally unmap the memory.

Parameters

• in read_begin

  The offset, in bytes, of the beginning of the data range that will be read by CPU.

• in read_end

  The offset, in bytes, of the ending of the data range that will be read by CPU.

• out data

  Returns the pointer to the mapped memory. The returned pointer is not offsetted by read_begin and always points to the beginning of the resource data, but only data in [pointer + read_begin, pointer + read_end) range is valid for reading from CPU.

If read_end <= read_begin, no data will be read by CPU, which is required if resource heap type is not MemoryType::readback.

If read_end is larger than the subresource size (like setting to USIZE_MAX), the read range will be clamped to [read_begin, resource_size).