private Color CalculateRecursiveColor()

in System.Numerics/SIMD/RayTracer/Camera.cs [288:349]
50 lines of code
10 McCabe index (conditional complexity)

        private Color CalculateRecursiveColor(Intersection intersection, Scene scene, int depth)
        {
            // Ambient light:
            var color = Color.Lerp(Color.Black, intersection.Color * scene.AmbientLightColor, scene.AmbientLightIntensity);

            foreach (Light light in scene.Lights)
            {
                var lightContribution = new Color();
                var towardsLight = (light.Position - intersection.Point).Normalized();
                var lightDistance = Util.Distance(intersection.Point, light.Position);

                // Accumulate diffuse lighting:
                var lightEffectiveness = Vector3.Dot(towardsLight, intersection.Normal);
                if (lightEffectiveness > 0.0f)
                {
                    lightContribution = lightContribution + (intersection.Color * light.GetIntensityAtDistance(lightDistance) * light.Color * lightEffectiveness);
                }

                // Render shadow
                var shadowRay = new Ray(intersection.Point, towardsLight);
                Intersection shadowIntersection;
                if (TryCalculateIntersection(shadowRay, scene, intersection.ObjectHit, out shadowIntersection) && shadowIntersection.Distance < lightDistance)
                {
                    var transparency = shadowIntersection.ObjectHit.Material.Transparency;
                    var lightPassThrough = Util.Lerp(.25f, 1.0f, transparency);
                    lightContribution = Color.Lerp(lightContribution, Color.Zero, 1 - lightPassThrough);
                }

                color += lightContribution;
            }

            if (depth < ReflectionDepth)
            {
                // Reflection ray
                var objectReflectivity = intersection.ObjectHit.Material.Reflectivity;
                if (objectReflectivity > 0.0f)
                {
                    var reflectionRay = GetReflectionRay(intersection.Point, intersection.Normal, intersection.ImpactDirection);
                    Intersection reflectionIntersection;
                    if (TryCalculateIntersection(reflectionRay, scene, intersection.ObjectHit, out reflectionIntersection))
                    {
                        color = Color.Lerp(color, CalculateRecursiveColor(reflectionIntersection, scene, depth + 1), objectReflectivity);
                    }
                }

                // Refraction ray
                var objectRefractivity = intersection.ObjectHit.Material.Refractivity;
                if (objectRefractivity > 0.0f)
                {
                    var refractionRay = GetRefractionRay(intersection.Point, intersection.Normal, intersection.ImpactDirection, objectRefractivity);
                    Intersection refractionIntersection;
                    if (TryCalculateIntersection(refractionRay, scene, intersection.ObjectHit, out refractionIntersection))
                    {
                        var refractedColor = CalculateRecursiveColor(refractionIntersection, scene, depth + 1);
                        color = Color.Lerp(color, refractedColor, 1 - (intersection.ObjectHit.Material.Opacity));
                    }
                }
            }

            color = color.Limited;
            return color;
        }