private Color3 SampleLightDirectly(ISurfaceLight light, Color3 brdf, Intersection intersection)
{
var rPoint = light.GetRandomPoint(_rng, intersection); //get random point on light
var l = rPoint.Location - intersection.Location; //vector to light
var dist = l.LengthFast;
l.Normalize();
var lightRay = Ray.CreateFromIntersection(intersection, l, dist); //ray to light
var nlightDotL = Vector3.Dot(rPoint.Normal, -l); //light normal dot light
var nDotL = Vector3.Dot(intersection.SurfaceNormal, l); //normal dot light
if (nDotL > 0 && nlightDotL > 0 && !IntersectionHelper.DoesIntersect(lightRay, _scene.Objects, light))
{
var solidAngle = (nlightDotL * light.Area) / (dist * dist); //light area on hemisphere
return(light.Color * solidAngle * brdf * nDotL);
}
return(Color4.Black);
}
private Color3 SampleLightDirectly(ISurfaceLight light, Color3 brdf, Intersection intersection)
{
var rPoint = light.GetRandomPoint(_rng, intersection); //get random point on light
var l = rPoint.Location - intersection.Location; //vector to light
var dist = l.LengthFast;
l.Normalize();
var lightRay = Ray.CreateFromIntersection(intersection, l, dist); //ray to light
var nlightDotL = Vector3.Dot(rPoint.Normal, -l); //light normal dot light
var nDotL = Vector3.Dot(intersection.SurfaceNormal, l); //normal dot light
if (nDotL > 0 && nlightDotL > 0 && !IntersectionHelper.DoesIntersect(lightRay, _scene.Objects, light))
{
var solidAngle = (nlightDotL * light.Area) / (dist * dist); //light area on hemisphere
return light.Color * solidAngle * brdf * nDotL;
}
return Color4.Black;
}
