Function ReadSprite

src/spritecache.cpp:455–534

* Read a sprite from disk. * @param sc Location of sprite. * @param id Sprite number. * @param sprite_type Type of sprite. * @param allocator Allocator function to use. * @param encoder Sprite encoder to use. * @return Read sprite data. */

 * @return Read sprite data.
 */
static void *ReadSprite(const SpriteCache *sc, SpriteID id, SpriteType sprite_type, SpriteAllocator &allocator, SpriteEncoder *encoder)
{
	/* Use current blitter if no other sprite encoder is given. */
	if (encoder == nullptr) encoder = BlitterFactory::GetCurrentBlitter();

	SpriteFile &file = *sc->file;
	size_t file_pos = sc->file_pos;

	assert(sprite_type != SpriteType::Recolour);
	assert(IsMapgenSpriteID(id) == (sprite_type == SpriteType::MapGen));
	assert(sc->type == sprite_type);

	Debug(sprite, 9, "Load sprite {}", id);

	SpriteLoader::SpriteCollection sprite;
	ZoomLevels sprite_avail;
	ZoomLevels avail_8bpp;
	ZoomLevels avail_32bpp;

	SpriteLoaderGrf sprite_loader(file.GetContainerVersion());
	if (sprite_type != SpriteType::MapGen && encoder->Is32BppSupported()) {
		/* Try for 32bpp sprites first. */
		sprite_avail = sprite_loader.LoadSprite(sprite, file, file_pos, sprite_type, true, sc->control_flags, avail_8bpp, avail_32bpp);
	}
	if (sprite_avail.None()) {
		sprite_avail = sprite_loader.LoadSprite(sprite, file, file_pos, sprite_type, false, sc->control_flags, avail_8bpp, avail_32bpp);
		if (sprite_type == SpriteType::Normal && avail_32bpp.Any() && !encoder->Is32BppSupported() && sprite_avail.None()) {
			/* No 8bpp available, try converting from 32bpp. */
			SpriteLoaderMakeIndexed make_indexed(sprite_loader);
			sprite_avail = make_indexed.LoadSprite(sprite, file, file_pos, sprite_type, true, sc->control_flags, sprite_avail, avail_32bpp);
		}
	}

	if (sprite_avail.None()) {
		if (sprite_type == SpriteType::MapGen) return nullptr;
		if (id == SPR_IMG_QUERY) UserError("Okay... something went horribly wrong. I couldn't load the fallback sprite. What should I do?");
		return (void*)GetRawSprite(SPR_IMG_QUERY, SpriteType::Normal, &allocator, encoder);
	}

	if (sprite_type == SpriteType::MapGen) {
		/* Ugly hack to work around the problem that the old landscape
		 *  generator assumes that those sprites are stored uncompressed in
		 *  the memory, and they are only read directly by the code, never
		 *  send to the blitter. So do not send it to the blitter (which will
		 *  result in a data array in the format the blitter likes most), but
		 *  extract the data directly and store that as sprite.
		 * Ugly: yes. Other solution: no. Blame the original author or
		 *  something ;) The image should really have been a data-stream
		 *  (so type = 0xFF basically). */
		const auto &root_sprite = sprite.Root();
		uint num = root_sprite.width * root_sprite.height;

		Sprite *s = allocator.Allocate<Sprite>(sizeof(*s) + num);
		s->width = root_sprite.width;
		s->height = root_sprite.height;
		s->x_offs = root_sprite.x_offs;
		s->y_offs = root_sprite.y_offs;