ASSERT(size >= 0);
ASSERT(offset + size <= obj->Size);
+ if (!size)
+ return;
+
+ /*
+ * According to ARB_vertex_buffer_object specification, if data is null,
+ * then the contents of the buffer object's data store is undefined. We just
+ * ignore, and leave it unchanged.
+ */
+ if (!data)
+ return;
+
st_cond_flush_pipe_buffer_write(st_context(ctx), st_obj->buffer,
offset, size, data);
}
ASSERT(size >= 0);
ASSERT(offset + size <= obj->Size);
+ if (!size)
+ return;
+
st_cond_flush_pipe_buffer_read(st_context(ctx), st_obj->buffer,
offset, size, data);
}
pipe_buffer_reference( &st_obj->buffer, NULL );
- st_obj->buffer = pipe_buffer_create( pipe->screen, 32, buffer_usage, size );
+ if (size != 0) {
+ st_obj->buffer = pipe_buffer_create(pipe->screen, 32, buffer_usage, size);
+
+ if (!st_obj->buffer) {
+ return GL_FALSE;
+ }
- if (!st_obj->buffer) {
- return GL_FALSE;
+ if (data)
+ st_no_flush_pipe_buffer_write(st_context(ctx), st_obj->buffer, 0,
+ size, data);
+ return GL_TRUE;
}
- if (data)
- st_no_flush_pipe_buffer_write(st_context(ctx), st_obj->buffer, 0,
- size, data);
return GL_TRUE;
}
}
+/**
+ * Dummy data whose's pointer is used for zero length ranges.
+ */
+static long
+st_bufferobj_zero_length_range = 0;
+
+
/**
* Called via glMapBufferRange().
*/
if (access & GL_MAP_FLUSH_EXPLICIT_BIT)
flags |= PIPE_BUFFER_USAGE_FLUSH_EXPLICIT;
+ if (access & GL_MAP_UNSYNCHRONIZED_BIT)
+ flags |= PIPE_BUFFER_USAGE_UNSYNCHRONIZED;
+
/* ... other flags ...
*/
assert(offset < obj->Size);
assert(offset + length <= obj->Size);
- obj->Pointer = pipe_buffer_map_range(pipe->screen, st_obj->buffer, offset, length, flags);
+ /*
+ * We go out of way here to hide the degenerate yet valid case of zero
+ * length range from the pipe driver.
+ */
+ if (!length) {
+ obj->Pointer = &st_bufferobj_zero_length_range;
+ }
+ else {
+ obj->Pointer = pipe_buffer_map_range(pipe->screen, st_obj->buffer, offset, length, flags);
+ if (obj->Pointer) {
+ obj->Pointer = (ubyte *) obj->Pointer + offset;
+ }
+ }
+
if (obj->Pointer) {
- obj->Pointer = (ubyte *) obj->Pointer + offset;
obj->Offset = offset;
obj->Length = length;
obj->AccessFlags = access;
}
-
+
return obj->Pointer;
}
assert(length >= 0);
assert(offset + length <= obj->Length);
+ if (!length)
+ return;
+
pipe_buffer_flush_mapped_range(pipe->screen, st_obj->buffer,
obj->Offset + offset, length);
}
struct pipe_context *pipe = st_context(ctx)->pipe;
struct st_buffer_object *st_obj = st_buffer_object(obj);
- pipe_buffer_unmap(pipe->screen, st_obj->buffer);
+ if(obj->Length)
+ pipe_buffer_unmap(pipe->screen, st_obj->buffer);
+
obj->Pointer = NULL;
obj->Offset = 0;
obj->Length = 0;
struct st_buffer_object *dstObj = st_buffer_object(dst);
ubyte *srcPtr, *dstPtr;
+ if(!size)
+ return;
+
/* buffer should not already be mapped */
assert(!src->Pointer);
assert(!dst->Pointer);