/// <summary>
/// Trace single ray in a given direction.
/// </summary>
/// <param name="origin"></param>
/// <param name="direction"></param>
/// <param name="depth">Current recursion level.</param>
/// <param name="lastReflected">The object from ray was cast.</param>
/// <returns></returns>
Color TraceSingleRay(Vector <double> origin, Vector <double> direction, uint depth = 0, ICollidable lastReflected = null)
{
if (depth >= MaxDepth)
{
return(Skybox.GetColorInDirection(direction));
}
var nearest = GetNearestEntity(origin, direction, lastReflected);
// If nearest entity is null it means that ray hasn't collide with anything
if (nearest.Entity == null)
{
return(Skybox.GetColorInDirection(direction) * new Color(0.5, 0.5, 0.5));
}
// Point of collision.
var point = origin + nearest.Distance * direction;
var entity = nearest.Entity;
var material = entity.Material;
var fragment = entity.GetMaterialFragmentInPoint(point);
var localColor = material.GetColor(fragment);
var diffuseColor = GetDiffuseColor(entity, point);
// If reflection coefficient is zero no further casting is needed
var reflectionColor = Color.Zero;
if (material.ReflectionCoefficient > double.Epsilon)
{
reflectionColor = GetReflectionColor(entity, point, direction, depth);
}
return(localColor * (diffuseColor + material.ReflectionCoefficient * reflectionColor));
}