compute()

vec2f fl::RosePath::compute ( float alpha )

overridevirtual

Implements fl::XYPathGenerator.

Definition at line 112 of file xypath_impls.cpp.

                                   {
    // Parametric equation for a rose curve (rhodonea)
    // α in [0,1] → (x,y) on the rose curve
 
    // Map alpha to the full range needed for the rose
    // For a complete rose, we need to go through k*PI radians where k is:
    // - k = n if n is odd and d is 1
    // - k = 2n if n is even and d is 1
    // - k = n*d if n and d are coprime
    // For simplicity, we'll use 2*PI*n as a good approximation
    float theta = alpha * 2.0f * PI * params().n;
 
    // Calculate the radius using the rose formula: r = cos(n*θ/d)
    // We use cosine for a rose that starts with a petal at theta=0
    float r = cosf(params().n * theta / params().d);
 
    // Scale to ensure the rose fits within [-1, 1] range
    // The absolute value ensures we get the proper shape
    r = fabsf(r);
 
    // Convert polar coordinates (r, theta) to Cartesian (x, y)
    float x = r * cosf(theta);
    float y = r * sinf(theta);
 
    return vec2f(x, y);
}

References fl::RosePathParams::n, params(), PI, x, and y.

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