Method drawCardinalSpline

core/2d/DrawNode.cpp:471–534

}

void DrawNode::drawCardinalSpline(const PointArray* configIn,
                                  float tension,
                                  unsigned int segments,
                                  const Color4F& color,
                                  float thickness,
                                  bool closed)
{
    if (thickness <= 0.0f)
    {
        AXLOGW("{}: thickness <= 0", __FUNCTION__);
        return;
    }

    // Don't change the original PointArray
    PointArray* config = configIn->clone();

    if (closed && config->count() > 2)
    {
        config->addControlPoint(config->getControlPointAtIndex(0));
        config->addControlPoint(config->getControlPointAtIndex(1));
        config->insertControlPoint(config->getControlPointAtIndex(config->count() - 3), 0);
        config->insertControlPoint(config->getControlPointAtIndex(config->count() - 4), 0);
    }

    ssize_t p;
    float lt;
    float deltaT = 1.0f / config->count();

    axstd::pod_vector<Vec2> _vertices{static_cast<size_t>(segments)};

    for (unsigned int i = 0; i < segments; i++)
    {
        float dt = (float)i / segments;
        p        = static_cast<ssize_t>(dt / deltaT);

        // Check last control point reached
        if (p >= (config->count() - 1))
        {
            _vertices[i] = config->getControlPointAtIndex(config->count() - 1);
            segments     = i + 1;
            _vertices.resize(segments);
            break;
        }

        // Interpolate
        Vec2 pp0 = config->getControlPointAtIndex(p - 1);
        Vec2 pp1 = config->getControlPointAtIndex(p + 0);
        Vec2 pp2 = config->getControlPointAtIndex(p + 1);
        Vec2 pp3 = config->getControlPointAtIndex(p + 2);

        lt           = (dt - deltaT * (float)p) / deltaT;
        _vertices[i] = cardinalSplineAt(pp0, pp1, pp2, pp3, tension, lt);
    }

    // Dont draw the first and the last point
    if (closed && config->count() > 2)
    {
        auto seg = static_cast<int>(segments / (config->count() - 2));