Function ReadGRFSpriteOffsets

src/spritecache.cpp:558–603

* Parse the sprite section of GRFs. * @param container_version Container version of the GRF we're currently processing. */

 * @param container_version Container version of the GRF we're currently processing.
 */
void ReadGRFSpriteOffsets(SpriteFile &file)
{
	_grf_sprite_offsets.clear();

	if (file.GetContainerVersion() >= 2) {
		/* Seek to sprite section of the GRF. */
		size_t data_offset = file.ReadDword();
		size_t old_pos = file.GetPos();
		file.SeekTo(data_offset, SEEK_CUR);

		GrfSpriteOffset offset{};

		/* Loop over all sprite section entries and store the file
		 * offset for each newly encountered ID. */
		SpriteID id, prev_id = 0;
		while ((id = file.ReadDword()) != 0) {
			if (id != prev_id) {
				_grf_sprite_offsets[prev_id] = offset;
				offset.file_pos = file.GetPos() - 4;
				offset.control_flags.Reset();
			}
			prev_id = id;
			uint length = file.ReadDword();
			if (length > 0) {
				SpriteComponents colour{file.ReadByte()};
				length--;
				if (length > 0) {
					uint8_t zoom = file.ReadByte();
					length--;
					if (colour.Any() && zoom == 0) { // ZoomLevel::Normal (normal zoom)
						offset.control_flags.Set((colour != SpriteComponent::Palette) ? SpriteCacheCtrlFlag::AllowZoomMin1x32bpp : SpriteCacheCtrlFlag::AllowZoomMin1xPal);
						offset.control_flags.Set((colour != SpriteComponent::Palette) ? SpriteCacheCtrlFlag::AllowZoomMin2x32bpp : SpriteCacheCtrlFlag::AllowZoomMin2xPal);
					}
					if (colour.Any() && zoom == 2) { // ZoomLevel::In2x (2x zoomed in)
						offset.control_flags.Set((colour != SpriteComponent::Palette) ? SpriteCacheCtrlFlag::AllowZoomMin2x32bpp : SpriteCacheCtrlFlag::AllowZoomMin2xPal);
					}
				}
			}
			file.SkipBytes(length);
		}
		if (prev_id != 0) _grf_sprite_offsets[prev_id] = offset;

		/* Continue processing the data section. */
		file.SeekTo(old_pos, SEEK_SET);
	}
}


/**