private double[] IntersectRaySphere(DoublePoint3D cameraPosition, DoublePoint3D viewVector, Sphere sphere)
{
var oc = cameraPosition - sphere.Center; //vector from camera to sphere center
var a = viewVector.ScalMultiply(viewVector); //viewVector length
var b = 2 * oc.ScalMultiply(viewVector);
var c = oc.ScalMultiply(oc) - sphere.Radius * sphere.Radius;
var discriminant = b * b - 4 * a * c;
if (discriminant < 0)
{
return new double[] { Inf, Inf }
}
;
var root1 = (-b + Math.Sqrt(discriminant)) / (2 * a);
var root2 = (-b - Math.Sqrt(discriminant)) / (2 * a);
return(new double[] { root1, root2 });
}
private DoublePoint3D ReflectRay(DoublePoint3D fallingVector, DoublePoint3D normalVector)
{
return(2 * normalVector * normalVector.ScalMultiply(fallingVector) - fallingVector);
}
private float ComputeLightning(DoublePoint3D intersectPoint, DoublePoint3D normalVector, DoublePoint3D vector, int specular)
{
var result = 0f;
var interval = new double[] { 0.001, Inf };
foreach (LightSource light in LightSources)
{
if (light.ToString().Contains("Ambient"))
{
result += light.Intense;
}
else
{
DoublePoint3D lightVector;
if (light.ToString().Contains("Point"))
{
lightVector = (light as PointLight).Coord - intersectPoint;
}
else
{
lightVector = (light as DirectLight).Vector;
}
//Shadows
Closest shadow = ClosestIntersection(intersectPoint, lightVector, interval);
float transparency = 1;
while (shadow.Object != -1)
{
if ((GraphicalObjects[shadow.Object].Transparency == 0) || (transparency == 0))
{
transparency = 0;
break;
}
transparency *= GraphicalObjects[shadow.Object].Transparency;
shadow = ClosestIntersection(intersectPoint + shadow.Point * lightVector, lightVector, interval);
}
if (transparency == 0)
{
continue;
}
//Diffusal Illumination
var scal = normalVector.ScalMultiply(lightVector);
if (scal > 0)
{
result += (float)(light.Intense * scal / (normalVector.Length() * lightVector.Length()));
}
//Specular Illumination
if (specular != -1)
{
var refleclectedVector = ReflectRay(lightVector, normalVector);
scal = refleclectedVector.ScalMultiply(vector);
if (scal > 0)
{
result += (float)(transparency * (light.Intense * Math.Pow(scal / (refleclectedVector.Length() * vector.Length()), specular)));
}
}
}
}
return(result);
}
