const void *
ImageBuf::retile (int x, int y, int z, ImageCache::Tile* &tile,
int &tilexbegin, int &tileybegin, int &tilezbegin) const
{
int tw = spec().tile_width, th = spec().tile_height;
int td = std::max (1, spec().tile_depth);
if (tile == NULL || x < tilexbegin || x >= (tilexbegin+tw) ||
y < tileybegin || y >= (tileybegin+th) ||
z < tilezbegin || z >= (tilezbegin+td)) {
// not the same tile as before
if (tile)
m_imagecache->release_tile (tile);
int xtile = (x-spec().x) / tw;
int ytile = (y-spec().y) / th;
int ztile = (z-spec().z) / td;
tilexbegin = spec().x + xtile*tw;
tileybegin = spec().y + ytile*th;
tilezbegin = spec().z + ztile*td;
tile = m_imagecache->get_tile (m_name, subimage(), miplevel(), x, y, z);
}
size_t offset = ((y - tileybegin) * tw) + (x - tilexbegin);
offset += ((z - tilezbegin) * tw * th);
offset *= spec().pixel_bytes();
TypeDesc format;
return (const char *)m_imagecache->tile_pixels (tile, format) + offset;
}
bool
ImageBuf::copy (const ImageBuf &src)
{
if (! m_spec_valid && ! m_pixels_valid) {
// uninitialized
if (! src.m_spec_valid && ! src.m_pixels_valid)
return true; // uninitialized=uninitialized is a nop
// uninitialized = initialized : set up *this with local storage
reset (src.name(), src.spec());
}
bool selfcopy = (&src == this);
if (cachedpixels()) {
if (selfcopy) { // special case: self copy of ImageCache loads locally
return read (subimage(), miplevel(), true /*force*/);
}
reset (src.name(), src.spec());
// Now it has local pixels
}
if (selfcopy)
return true;
if (localpixels()) {
if (m_clientpixels) {
// app-owned memory
if (spec().width != src.spec().width ||
spec().height != src.spec().height ||
spec().depth != src.spec().depth ||
spec().nchannels != src.spec().nchannels) {
// size doesn't match, fail
return false;
}
this->copy_metadata (src);
} else {
// locally owned memory -- we can fully resize it
reset (src.name(), src.spec());
}
return this->copy_pixels (src);
}
return false; // all other cases fail
}