Method InitFromMemory

engine/Poseidon/Graphics/Textures/JpgImport.cpp:107–140

TextureSourceJPEG::~TextureSourceJPEG() = default;

bool TextureSourceJPEG::InitFromMemory(const uint8_t* data, size_t size, const char* nameForErrors)
{
    int w = 0, h = 0, channels = 0;
    stbi_uc* pixels = stbi_load_from_memory(data, static_cast<int>(size), &w, &h, &channels, 4 /*force RGBA*/);
    if (!pixels)
    {
        LOG_DEBUG(Graphics, "stbi_load_from_memory failed for {}: {}", nameForErrors ? nameForErrors : "?",
                  stbi_failure_reason());
        return false;
    }

    if (!IsPow2(w) || !IsPow2(h))
    {
        Poseidon::Foundation::WarningMessage("Image %s: dimensions %dx%d not 2^n", nameForErrors ? nameForErrors : "?",
                                             w, h);
        stbi_image_free(pixels);
        return false;
    }

    _w = w;
    _h = h;
    _rgba0.assign(pixels, pixels + static_cast<size_t>(w) * static_cast<size_t>(h) * 4);
    stbi_image_free(pixels);

    int maxDim = std::max(_w, _h);
    _mipmaps = Log2i(maxDim) + 1;
    // Keep a small floor — mip dimensions below 4 pixels carry no detail and the
    // old IJL path also skipped them.
    while (_mipmaps > 1 && ((_w >> (_mipmaps - 1)) < 4 || (_h >> (_mipmaps - 1)) < 4))
        --_mipmaps;

    _avgColor = ComputeAverage(_rgba0.data(), _w, _h);
    return true;
}

bool TextureSourceJPEG::Init(const char* name, PacLevelMem* mips, int maxMips)
{