bool intersectBoundingSphere()

in src/Algorithm/fractals.c [483:512]

• 24 lines of code
• 4 McCabe index (conditional complexity)

bool intersectBoundingSphere(vec3 origin,
                            vec3 direction,
                            out float tmin,
                            out float tmax)
{
    bool hit = false;
    float b = dot(origin, direction);
    float c = dot(origin, origin) - boundingRadius;
    float disc = b*b - c;           // discriminant
    tmin = tmax = 0.0;

    if (disc > 0.0) {
        // Real root of disc, so intersection
        float sdisc = sqrt(disc);
        float t0 = -b - sdisc;          // closest intersection distance
        float t1 = -b + sdisc;          // furthest intersection distance

        if (t0 >= 0.0) {
            // Ray intersects front of sphere
            tmin = t0;
            tmax = t0 + t1;
        } else if (t0 < 0.0) {
            // Ray starts inside sphere
            tmax = t1;
        }
        hit = true;
    }

    return hit;
}