Method UploadToGPU

engine/PoseidonGL33/TextureGL33_Loading.cpp:39–146

    if (interpolate && IsCompressedInterpolationFormat(format))
        return PacARGB1555;
    return format;
}

void TextureGL33::InitDesc(TextureDescGL33& desc, int levelMin, bool enableDXT)
{
    memset(&desc, 0, sizeof(desc));

    PacFormat format = UploadFormatForTextureGL33(_mipmaps[levelMin].DstFormat(), _interpolate);
    InitGLPixelFormat(desc, format, enableDXT);

    desc.w = _mipmaps[levelMin]._w;
    desc.h = _mipmaps[levelMin]._h;
    desc.nMipmaps = _nMipmaps - levelMin;
}

int TextureGL33::TotalSize(int levelMin) const
{
    int totalSize = 0;
    for (int i = levelMin; i < _nMipmaps; i++)
    {
        const PacLevelMem& mip = _mipmaps[i];
        totalSize += MipmapSizeGL33(UploadFormatForTextureGL33(_mipmaps[levelMin].DstFormat(), _interpolate), mip._w,
                                    mip._h);
    }
    return totalSize;
}

int TextureGL33::UploadToGPU(SurfaceInfoGL33& surface, int levelMin)
{
    if (!_src)
    {
        RptF("No texture source for %s", Name());
        return -1;
    }

    unsigned int tex = surface.GetTexture();
    if (!tex)
        return -1;

    // Upload via the dedicated upload unit so cached unit-0/1 bindings
    // tracked by ApplyPassState/_lastHandle remain accurate (otherwise a
    // demand-load between two draws of the same texture leaves GL bound to
    // the just-uploaded handle while the cache claims the previous binding,
    // and the next ApplyPassState skips the rebind — visible as the
    // M113-track-wheel "blink").
    GL33Bind::Tex2D(EngineGL33::kUploadUnit - GL_TEXTURE0, tex);
    glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

    // Capture the format once at level-min and reuse for every mip.
    // Per-mip DstFormat() can occasionally diverge from the level-min
    // (mixed-format PAAs are rare but legal), and CreateSurface in
    // TextureGL33_Init.cpp allocates *every* mip level with the
    // level-min format — uploading a sub-image with a different
    // compressed internalFormat trips GL_INVALID_OPERATION (0x0502).
    // Treat level-min as authoritative; the data buffer for each mip
    // is the right size for that format (size math below uses it).
    const PacFormat sharedFmt = UploadFormatForTextureGL33(_mipmaps[levelMin].DstFormat(), _interpolate);