Function LoadGrfFileIndexed

src/gfxinit.cpp:82–106

* Load an old fashioned GRF file to replace already loaded sprites. * @param filename The name of the file to open. * @param index_tbl The offsets of each of the sprites. * @param needs_palette_remap Whether the colours in the GRF file need a palette remap. * @return The number of loaded sprites. */

 * @return The number of loaded sprites.
 */
static void LoadGrfFileIndexed(const std::string &filename, std::span<const std::pair<SpriteID, SpriteID>> index_tbl, bool needs_palette_remap)
{
	uint sprite_id = 0;

	SpriteFile &file = OpenCachedSpriteFile(filename, BASESET_DIR, needs_palette_remap);

	Debug(sprite, 2, "Reading indexed grf-file '{}'", filename);

	uint8_t container_ver = file.GetContainerVersion();
	if (container_ver == 0) UserError("Base grf '{}' is corrupt", filename);
	ReadGRFSpriteOffsets(file);
	if (container_ver >= 2) {
		/* Read compression. */
		uint8_t compression = file.ReadByte();
		if (compression != 0) UserError("Unsupported compression format");
	}

	for (const auto &pair : index_tbl) {
		for (SpriteID load_index = pair.first; load_index <= pair.second; ++load_index) {
			[[maybe_unused]] bool b = LoadNextSprite(load_index, file, sprite_id);
			assert(b);
			sprite_id++;
		}
	}
}

/**
 * Checks whether the MD5 checksums of the files are correct.