/// <summary>
/// Method that check is a light ray originated in Point point reaches the Point observerPoint.
/// Needed for the point light renderer.
/// </summary>
/// <param name="point">point where the ray originates</param>
/// <param name="observerPoint">the point the ray should reach</param>
/// <returns></returns>
public bool isPointVisible(Point point, Point observerPoint)
{
Vec direction = point - observerPoint;
float directionNorm = direction.getNorm();
Ray ray = new Ray(observerPoint, direction, tm: ((float) 1e-2 / directionNorm), tM: 1.0f);
foreach (var shape in shapes)
{
if (shape.quickRayIntersection(ray)) return false;
}
return true;
}
public override Color computeRadiance(Ray ray)
{
HitRecord? hitRecord = this.world.rayIntersection(ray);
if (hitRecord == null) return this.backgroundColor;
Material hitMaterial = hitRecord?.shape?.material!;
Color resultColor = this.ambientColor;
foreach (PointLight curLight in world.lightSources)
{
if (this.world.isPointVisible(curLight.position, (Point)hitRecord?.worldPoint!))
{
Vec distanceVec = (Point)hitRecord?.worldPoint! - curLight.position;
float distance = distanceVec.getNorm();
Vec inDir = distanceVec * (1f / distance);
float cosTheta = MathF.Max(0f, Utility.NormalizedDot(-ray.dir, (Vec)hitRecord?.normal.toVec()!));
float distanceFactor;
if (curLight.linearRadius > 0)
distanceFactor = (curLight.linearRadius / distance) * (curLight.linearRadius / distance);
else
distanceFactor = 1f;
Color emittedColor = (Color)hitMaterial?.emittedRadiance.getColor(hitRecord.Value.surfacePoint)!;
Color brdfColor = (Color)hitMaterial?.brdf.Eval(
(Normal)hitRecord?.normal!,
inDir,
-ray.dir,
(Vec2D)hitRecord?.surfacePoint!)!;
resultColor += (emittedColor + brdfColor) * curLight.color * cosTheta * distanceFactor;
}
}
return resultColor;
}
