Method nextFunctionValue

examples/Plotter/BigDataset/Model.cpp:109–154

}

qreal Model::nextFunctionValue()
{
    qreal fx = 0.0;

    switch (m_function) {
    case SineFunction:
        fx = sin(m_x);
        break;
    case TriangleFunction: {
        qreal x = fmod(m_x + 0.5 * M_PI, 2 * M_PI); // make it look like sine, only less round
        if (x < M_PI) {
            fx = -1.0 + x * (2.0 / M_PI);
        } else {
            fx = 3.0 - x * (2.0 / M_PI);
        }
        break;
    }
    case SquareFunction: {
        qreal x = fmod(m_x, 2 * M_PI);
        fx = x < M_PI ? 1 : -1;
        break;
    }
    case NoiseFunction:
        fx = -1.0 + qreal(QRandomGenerator::global()->generate()) * 2.0 / qreal(RAND_MAX);
        break;
    case SineOneDivFunction: {
        // we want this repeating and we want negative arguments, too.
        qreal x = fmod(m_x + 10, 20) - 10;
        if (qAbs(x) < 1e-6) {
            break;
        }
        fx = sin(1.0 / x);
        break;
    }
    case OneDivSineFunction: {
        qreal s = sin(m_x);
        fx = qAbs(s) > 1e-6 ? 1.0 / s : 0.0;
        break;
    }
    default:
        Q_ASSERT(false);
    }

    m_x += s_stepWidth;
    return fx;
}