Method getSquareValue

core/2d/AutoPolygon.cpp:230–254

}

unsigned int AutoPolygon::getSquareValue(unsigned int x, unsigned int y, const Rect& rect, float threshold)
{
    /*
     checking the 2x2 pixel grid, assigning these values to each pixel, if not transparent
     +---+---+
     | 1 | 2 |
     +---+---+
     | 4 | 8 | <- current pixel (curx,cury)
     +---+---+
     */
    unsigned int sv = 0;
    // NOTE: due to the way we pick points from texture, rect needs to be smaller, otherwise it goes outside 1 pixel
    auto fixedRect = Rect(rect.origin, rect.size - Vec2(2, 2));

    Vec2 tl = Vec2(x - 1.0f, y - 1.0f);
    sv += (fixedRect.containsPoint(tl) && getAlphaByPos(tl) > threshold) ? 1 : 0;
    Vec2 tr = Vec2(x - 0.0f, y - 1.0f);
    sv += (fixedRect.containsPoint(tr) && getAlphaByPos(tr) > threshold) ? 2 : 0;
    Vec2 bl = Vec2(x - 1.0f, y - 0.0f);
    sv += (fixedRect.containsPoint(bl) && getAlphaByPos(bl) > threshold) ? 4 : 0;
    Vec2 br = Vec2(x - 0.0f, y - 0.0f);
    sv += (fixedRect.containsPoint(br) && getAlphaByPos(br) > threshold) ? 8 : 0;
    AXASSERT(sv != 0 && sv != 15, "square value should not be 0, or 15");
    return sv;
}

std::vector<ax::Vec2> AutoPolygon::marchSquare(const Rect& rect, const Vec2& start, float threshold)
{