local_seam_leveling valid_pixel assertion failure.

[mali-tintash]

What is a possible cause of this resulting in false for local_seam_leveling. validity mask is never changed after global_seam_leveling, or am I mistaken?

And why do we need an assertion here, why not just skip? What makes it such a big violation?

valid = (w0 * w2 == 0.0f || validity_mask->at(floor_x, floor_y, 0) == 255) &&
                (w1 * w2 == 0.0f || validity_mask->at(floor_xp1, floor_y, 0) == 255) &&
                (w0 * w3 == 0.0f || validity_mask->at(floor_x, floor_yp1, 0) == 255) &&
                (w1 * w3 == 0.0f || validity_mask->at(floor_xp1, floor_yp1, 0) == 255);

taken from

bool TexturePatch::valid_pixel(math::Vec2f pixel) const {
    float x = pixel[0];
    float y = pixel[1];

    float const height = static_cast<float>(get_height());
    float const width = static_cast<float>(get_width());

    bool valid = (0.0f <= x && x < width && 0.0f <= y && y < height);
    if (valid && validity_mask != NULL){
        /* Only pixel which can be correctly interpolated are valid. */
        float cx = std::max(0.0f, std::min(width - 1.0f, x));
        float cy = std::max(0.0f, std::min(height - 1.0f, y));
        **int const floor_x = static_cast<int>(cx);
        int const floor_y = static_cast<int>(cy);**
        int const floor_xp1 = std::min(floor_x + 1, get_width() - 1);
        int const floor_yp1 = std::min(floor_y + 1, get_height() - 1);

        float const w1 = cx - static_cast<float>(floor_x);
        float const w0 = 1.0f - w1;
        float const w3 = cy - static_cast<float>(floor_y);
        float const w2 = 1.0f - w3;

        valid = (w0 * w2 == 0.0f || validity_mask->at(floor_x, floor_y, 0) == 255) &&
                (w1 * w2 == 0.0f || validity_mask->at(floor_xp1, floor_y, 0) == 255) &&
                (w0 * w3 == 0.0f || validity_mask->at(floor_x, floor_yp1, 0) == 255) &&
                (w1 * w3 == 0.0f || validity_mask->at(floor_xp1, floor_yp1, 0) == 255);
    }

    return valid;
}

[mali-tintash]

The assertion failed because I had removed 0.5 subtraction from the texCoords. It works fine when I put that back.