Function loadG1

src/OpenLoco/src/Graphics/Gfx.cpp:75–159

0x0044733C

    // 0x0044733C
    void loadG1()
    {
        auto g1Path = Environment::getPath(Environment::PathId::g1);
        std::ifstream stream(g1Path, std::ios::in | std::ios::binary);
        if (!stream)
        {
            throw Exception::RuntimeError("Opening g1 file failed.");
        }

        G1Header header;
        if (!readData(stream, header))
        {
            throw Exception::RuntimeError("Reading g1 file header failed.");
        }

        if (header.numEntries != G1ExpectedCount::kDisc)
        {
            if (header.numEntries == G1ExpectedCount::kSteam)
            {
                Logging::verbose("Got Steam G1.DAT variant, will fix elements automatically.");
            }
            else
            {
                Logging::warn("G1 element count doesn't match expected value:\nExpected {}; Got {}", G1ExpectedCount::kDisc, header.numEntries);
            }
        }

        // Read element headers
        auto elements32 = std::vector<G1Element32>(header.numEntries);
        if (!readData(stream, elements32.data(), header.numEntries))
        {
            throw Exception::RuntimeError("Reading g1 element headers failed.");
        }
        auto elements = convertElements(elements32);

        // Read element data
        auto elementData = std::make_unique<std::byte[]>(header.totalSize);
        if (!readData(stream, elementData.get(), header.totalSize))
        {
            throw Exception::RuntimeError("Reading g1 elements failed.");
        }
        stream.close();

        // The steam G1.DAT is missing two localised tutorial icons, and a smaller font variant
        // This code copies the closest variants into their place, and moves other elements accordingly
        if (header.numEntries == G1ExpectedCount::kSteam)
        {
            // Temporarily convert offsets to absolute indexes
            for (size_t i = 0; i < elements.size(); i++)
            {
                if (elements[i].hasFlags(G1ElementFlags::hasZoomSprites))
                {
                    elements[i].zoomOffset = static_cast<int16_t>(i - elements[i].zoomOffset);
                }
            }

            elements.resize(G1ExpectedCount::kDisc);