We would end up with the offset from the start of the mapping rather than
the offset from the start of the buffer.
/* a real buffer obj: Ptr is an offset, not a pointer*/
GLsizeiptr offset;
assert(exec->vtx.bufferobj->Pointer); /* buf should be mapped */
- offset = (GLbyte *) data - (GLbyte *) exec->vtx.bufferobj->Pointer;
+ offset = (GLbyte *) data -
+ (GLbyte *) exec->vtx.bufferobj->Pointer +
+ exec->vtx.bufferobj->Offset;
assert(offset >= 0);
arrays[attr].Ptr = (void *) offset;
}