if (texture->resource.format_flags & WINED3DFMT_FLAG_DECOMPRESS)
    {
        struct wined3d_format temp;

        temp.decompress = format->decompress;
        format = wined3d_get_format(gl_info, WINED3DFMT_B8G8R8A8_UNORM, WINED3DUSAGE_TEXTURE);
        f = *format;
        f.conv_byte_count = format->byte_count;
        f.upload = temp.decompress;
        format = &f;
        texture->resource.format_flags &= ~WINED3DFMT_FLAG_BLOCKS;
    }

    if (format->upload)
    {
        unsigned int dst_row_pitch, dst_slice_pitch;
        void *src_mem;

        if (texture->resource.format_flags & WINED3DFMT_FLAG_BLOCKS)
            ERR("Converting a block-based format.\n");

        f = *format;
        f.byte_count = format->conv_byte_count;
        format = &f;

        wined3d_format_calculate_pitch(format, 1, update_w, update_h, &dst_row_pitch, &dst_slice_pitch);

        if (!(converted_mem = heap_calloc(update_d, dst_slice_pitch)))
        {
            ERR("Failed to allocate upload buffer.\n");
            return;
        }

        src_mem = context_map_bo_address(context, &bo, src_slice_pitch,
                GL_PIXEL_UNPACK_BUFFER, WINED3D_MAP_READ);
        format->upload(src_mem, converted_mem, src_row_pitch, src_slice_pitch,
                dst_row_pitch, dst_slice_pitch, update_w, update_h, update_d);
        context_unmap_bo_address(context, &bo, GL_PIXEL_UNPACK_BUFFER);

        bo.buffer_object = 0;
        bo.addr = converted_mem;
        src_row_pitch = dst_row_pitch;
        src_slice_pitch = dst_slice_pitch;
    }