public static (LightRay reflection, LightRay refraction, bool isFullRefraction) ReflectAndRefract(LightRay ray, Vector2 normal, Vector2 point, float n1, float n2)
{
var incidenceAngle = (float)(Math.Atan2(normal.Y, normal.X) - Math.Atan2(-ray.Direction.Y, -ray.Direction.X));
while (Math.Abs(incidenceAngle) > Math.PI / 2f)
{
incidenceAngle = incidenceAngle - 2f * (float)Math.PI * Math.Sign(incidenceAngle);
}
var refractionAngle = (float)Math.Asin(Math.Sin(incidenceAngle) * n1 / n2);
float reflCoeficent = (float)(Math.Sin(Math.Abs(incidenceAngle) - Math.Abs(refractionAngle)) /
(Math.Sin(Math.Abs(incidenceAngle) + Math.Abs(refractionAngle))));
bool isFullReflection = false;
if (float.IsNaN(refractionAngle))
{
isFullReflection = true;
reflCoeficent = 1;
}
if (incidenceAngle == 0f)
{
reflCoeficent = 0;
isFullReflection = false;
}
var reflectionDirection = Vector2.Reflect(ray.Direction, normal);
var reflection = new LightRay(point, reflectionDirection, ray.Intensity * reflCoeficent * reflCoeficent);
var refraction = new LightRay(point, Vector2.Transform(-normal, Matrix3x2.CreateRotation(-refractionAngle)), ray.Intensity - reflection.Intensity);
return(reflection, refraction, isFullReflection);
}
HandleSide(LightRay ray, ILine side, bool isInner, bool ignoreFirst = false)
{
var hit = side.Intersection(ray, ignoreFirst);
if (hit)
{
Vector2 normal;
var n = refractiveIndex(hit.Y);
if (isInner)
{
normal = -side.Normal(hit.Y);
n = 1f / n;
}
else
{
normal = side.Normal(hit.Y);
}
var(reflection, refraction, isFullReflection) = ReflectAndRefract(ray, normal, hit.Point, 1, n);
return(hit, refraction, reflection, isFullReflection);
}
return(hit, ray, ray, false);
}
public void HandleRay(LightRay ray, List <RayHit <LightRay> > hits, List <LightRay> rays)
{
Stack <(LightRay ray, int indexOfSender)> raysToHandle = new Stack <(LightRay ray, int index)>();
raysToHandle.Push((ray, -1));
List <LightRay> tmpRays = new List <LightRay>();
List <RayHit <LightRay> > tmpHits = new List <RayHit <LightRay> >();
while (raysToHandle.Count > 0)
{
(LightRay r, int currentIndex) = raysToHandle.Pop();
int[] mayIntersect = { currentIndex - 1, currentIndex + 1 };
foreach (var i in mayIntersect)
{
tmpHits.Clear();
tmpRays.Clear();
if (i >= 0 && i < lenses.Count)
{
lenses[i].HandleRay(r, tmpHits, tmpRays);
if (tmpHits.Count > 0)
{
foreach (var rayToHandle in tmpRays)
{
raysToHandle.Push((rayToHandle, i));
}
foreach (var hit in tmpHits)
{
hits.Add(hit);
}
break;
}
else
{
rays.Add(r);
}
}
}
}
}
public abstract void HandleRay(LightRay ray, List <RayHit <LightRay> > hits, List <LightRay> secondaryRays);
public override void HandleRay(LightRay rayToHandle, List <RayHit <LightRay> > hits, List <LightRay> secondaryRays)
{
Stack <LightRay> raysToHandle = new Stack <LightRay>();
ILine side = toLeft(rayToHandle.Origin) ? leftSurface : rightSurface;
ILine otherSide = toRight(rayToHandle.Origin) ? leftSurface : rightSurface;
var(hit, innerRefraction, mainReflection, fullRef) = HandleSide(rayToHandle, side, false);
if (hit)
{
if (!float.IsNaN(mainReflection.Intensity) && mainReflection.Intensity > 0f)
{
secondaryRays.Add(mainReflection);
}
hits.Add(hit);
if (fullRef)
{
return;
}
raysToHandle.Push(innerRefraction);
int reflectionDepth = 0;
bool reflectsOnSameSide = false;
bool previousHit = false;
// all are inside
while (raysToHandle.Count > 0 && reflectionDepth < 128)
{
var ray = raysToHandle.Pop();
var(newHit, newRefraction, newReflection, fullref) = HandleSide(ray, otherSide, true, reflectsOnSameSide);
reflectsOnSameSide = false;
if (newHit)
{
previousHit = true;
reflectionDepth++;
if (newReflection.Intensity >= 0.001f)
{
raysToHandle.Push(newReflection);
}
hits.Add(newHit);
if (fullref)
{
}
else
{
if (newRefraction.Intensity >= 0.001f)
{
secondaryRays.Add(newRefraction);
}
}
}
else
{
if (previousHit == false)
{
throw new Exception();
}
raysToHandle.Push(ray);
reflectsOnSameSide = true;
previousHit = false;
}
flipSides();
}
}
void flipSides()
{
var tmp = side;
side = otherSide;
otherSide = tmp;
}
}