cgMapBuffer

> # NAME

> cgMapBuffer - map buffer into application's address space

> # SYNOPSIS

>       #include <Cg/cg.h>

>       void * cgMapBuffer( CGbuffer buffer,
>                           CGbufferaccess access );

> # PARAMETERS

> buffer

>   The buffer which will be mapped into the application's address space.

> access

>   An enumerant indicating the operations the client may perform on the data store through the pointer while the buffer data is mapped.

>   The following enumerants are allowed:

>   CG_MAP_READ

>     The application can read but not write through the data pointer.

>   CG_MAP_WRITE

>     The application can write but not read through the data pointer.

>   CG_MAP_READ_WRITE

>     The application can read and write through the data pointer.

>   CG_MAP_WRITE_DISCARD

>     Same as CG_MAP_READ_WRITE if using a GL buffer.

>   CG_MAP_WRITE_NO_OVERWRITE

>     Same as CG_MAP_READ_WRITE if using a GL buffer.

> # RETURN VALUES

> Returns a pointer through which the application can read or write the buffer's data store.

> Returns NULL if an error occurs.

> # DESCRIPTION

> cgMapBuffer maps a buffer into the application's address space for memory-mapped updating of the buffer's data. The application should call cgUnmapBuffer|cgUnmapBuffer when it's done updating or querying the buffer.

> # EXAMPLES

>         unsigned char *bufferPtr = cgMapBuffer( myBuffer, CG_MAP_READ_WRITE );
>         memcpy( ptr, bufferPtr, size );
>         cgUnmapBuffer( myBuffer );

> # ERRORS

> CG_INVALID_BUFFER_HANDLE_ERROR is generated if buffer is not a valid buffer.

> CG_INVALID_ENUMERANT_ERROR is generated if access is not CG_READ_ONLY, CG_WRITE_ONLY, or CG_READ_WRITE.

> CG_BUFFER_ALREADY_MAPPED_ERROR is generated if buffer is already mapped.

> # HISTORY

> cgMapBuffer was introduced in Cg 2.0.

> # SEE ALSO

> cgUnmapBuffer, cgSetBufferData, cgSetBufferSubData, cgSetParameter