/// <summary>
/// Creates a line starting at the projection of this.loc on the intersection between this and another Plane.
/// The direction of the line is that of the crossproduct of this.normal and anotherPlane.normal.
/// </summary>
/// <returns>A line along the intersection of this and anotherPlane, returns "null" if two planes are significantly parallel</returns>
/// <param name="anotherPlane">A plane to calculate the intersection with</param>
public Scientrace.Line getIntersectionLineWith(Scientrace.Plane anotherPlane)
{
Scientrace.UnitVector n1, n2;
n1 = this.getNorm();
n2 = anotherPlane.getNorm();
Vector tw = n1.crossProduct(n2);
if (tw.length < MainClass.SIGNIFICANTLY_SMALL)
{
//Console.WriteLine("WARNING: two planes do not intersect since they are parallel.");
return(null);
}
UnitVector intersection_direction = tw.tryToUnitVector();
Vector tl1 = n1.crossProduct(intersection_direction);
if (tl1.length == 0)
{
throw new Exception("Plane.getIntersectionLineWith/l1.length can never be zero. If this happens, notify the [email protected] about this..." + this.ToString() + anotherPlane.ToString());
}
// l1 lies in "this" plane, and is orthogonal to the intersectionline-direction
UnitVector l1 = tl1.tryToUnitVector();
// where l1, starting at this.loc, meets anotherPlane we found a location on the intersectionline.
Scientrace.Location retLoc = anotherPlane.lineThroughPlane(new Line(this.loc, l1));
if (retLoc == null)
{
Console.WriteLine("WARNING: retLoc == null; l1: " + l1.ToString() + " ; anotherPlane:" + anotherPlane.getNorm().ToString());
return(null);
}
return(new Line(retLoc, intersection_direction));
}
} // end func partialReflectRefract
public void initCreatedRefractTrace(Trace refractTrace, UnitVector surfaceNormal, Scientrace.Object3d fromObject3d, Scientrace.Object3d toObject3d)
{
double oldrefindex = fromObject3d.materialproperties.refractiveindex(this);
double newrefindex = toObject3d.materialproperties.refractiveindex(this);
//for definitions on the parameters below, check fullInternalReflects function.
UnitVector incoming_trace_direction = this.traceline.direction;
if (incoming_trace_direction.dotProduct(surfaceNormal) > 0)
{
surfaceNormal = surfaceNormal.negative();
}
Scientrace.UnitVector nnorm = surfaceNormal.negative();
Scientrace.Vector incoming_normal_projection = nnorm * (incoming_trace_direction.dotProduct(nnorm));
Vector L1 = incoming_trace_direction - incoming_normal_projection;
double L2 = (oldrefindex / newrefindex) * L1.length;
if (incoming_trace_direction == incoming_normal_projection)
{
//in case of normal incident light: do not refract.
refractTrace.traceline.direction = incoming_trace_direction;
return;
}
try {
refractTrace.traceline.direction = ((nnorm * Math.Sqrt(1 - Math.Pow(L2, 2)))
+ (L1.tryToUnitVector() * L2)).tryToUnitVector();
} catch (ZeroNonzeroVectorException) {
Console.WriteLine("WARNING: cannot define direction for refraction trace. Using surface normal instead. (L1: " + incoming_trace_direction.trico() + ", L2:" + incoming_normal_projection.trico() + ").");
refractTrace.traceline.direction = nnorm;
} //end try/catch
}
/// <summary>
/// When two vectors are parallel, the cross product cannot be normalised. This method hacks around that problem.
/// </summary>
/// <returns>A UnitVector</returns>
/// <param name="aVector">A second vector to which the result will be orthogonal.</param>
public UnitVector safeNormalisedCrossProduct(Scientrace.Vector aVector)
{
if (this.length * aVector.length == 0)
{
return(UnitVector.x1vector());
}
Vector crossVector = this.crossProduct(aVector);
if (crossVector.length == 0)
{
return(this.safeNormalisedCrossProduct(aVector.vectorDance()));
}
return(crossVector.tryToUnitVector());
}