/// <summary>
///
/// </summary>
/// <param name="element"></param>
/// <param name="position"></param>
/// <param name="norm"></param>
/// <param name="rayDirection"></param>
/// <param name="scene"></param>
/// <returns></returns>
private Color GetNaturalColor(SceneObject element, Vector position, Vector norm, Vector rayDirection, Scene scene)
{
var ret = new Color(0, 0, 0);
foreach (Light light in scene.Lights)
{
Vector lightDirection = light.Position - position;
Vector lightUnitVector = lightDirection.Normalise;
double intersectionDistance = scene.TestRay(new Ray() { Start = position, Direction = lightUnitVector });
bool isInShadow = !((intersectionDistance > lightDirection.Magnitude) || (intersectionDistance == 0));
if (!isInShadow)
{
double angleOfIllumination = Vector.Dot(lightUnitVector, norm);
Color lcolor = angleOfIllumination > 0 ? angleOfIllumination * light.Color : new Color(0, 0, 0);
double specular = Vector.Dot(lightUnitVector, rayDirection.Normalise);
Color scolor = specular > 0 ? Color.Times(Math.Pow(specular, element.Surface.Roughness), light.Color) : new Color(0, 0, 0);
ret = ret + (element.Surface.Diffuse(position) * lcolor) + (element.Surface.Specular(position) * scolor);
}
}
return ret;
}
/// <summary>
/// Get the color of an object at a point of intersection by tracing back to the light sources.
/// This creates shadows and adds color if the lights are off-white.
/// </summary>
/// <param name="element">The object being intersected</param>
/// <param name="position">The point of intersection on the object</param>
/// <param name="norm">The normal at the point of intersection</param>
/// <param name="reflectDirection">The direction of the light reflection off of the surface</param>
/// <param name="scene">The scene description</param>
/// <returns>The color of the object due to the scenes lighting</returns>
private Color GetNaturalColor(SceneObject element, Vector position, Vector norm, Vector reflectDirection, Scene scene)
{
var ret = new Color(0, 0, 0);
foreach (Light light in scene.Lights)
{
// Direction from the point of intersction to the light source
Vector lightDirection = light.Position - position;
Vector lightUnitVector = lightDirection.Normalise;
// Perform an intersection test in the direction of the light source to determine if we are in a shadow
double intersectionDistance = scene.TestRay(new Ray() { Start = position, Direction = lightUnitVector });
bool isInShadow = !((intersectionDistance > lightDirection.Magnitude) || (intersectionDistance == 0));
if (!isInShadow)
{
// Check the light is shining on the front of the object. Use the angle to determine
// the brightness of the light.
double angleOfIllumination = Vector.Dot(lightUnitVector, norm);
Color lightColor = angleOfIllumination > 0 ? angleOfIllumination * light.Color : new Color(0, 0, 0);
// Determine of the light is in the direction of a reflection, leading to a specular effect
double specular = Vector.Dot(lightUnitVector, reflectDirection.Normalise);
// Calculate color of object based on surface qualities
Color specularColor = specular > 0 ? Math.Pow(specular, element.Surface.Roughness) * light.Color : new Color(0, 0, 0);
ret = ret + (element.Surface.Diffuse(position) * lightColor) + (element.Surface.Specular(position) * specularColor);
}
}
return ret;
}
/// <summary>
///
/// </summary>
/// <param name="element"></param>
/// <param name="position"></param>
/// <param name="norm"></param>
/// <param name="rayDirection"></param>
/// <param name="scene"></param>
/// <param name="depth"></param>
/// <returns></returns>
private Color GetReflectionColor(SceneObject element, Vector position, Vector norm, Vector rayDirection, Scene scene, int depth)
{
return element.Surface.Reflectiveness(position) * this.TraceRay(new Ray() { Start = position, Direction = rayDirection }, scene, depth + 1);
}
/// <summary>
/// Calculate the color being reflected at a point of intersection
/// </summary>
/// <param name="element">The object being intersected</param>
/// <param name="position">The position on the objects surface</param>
/// <param name="norm">The normal at the point of intersection</param>
/// <param name="reflectDirection">The direction of the reflected ray</param>
/// <param name="scene">The scene description</param>
/// <param name="depth">The current depth of recursion</param>
/// <returns>The color being reflected</returns>
private Color GetReflectionColor(SceneObject element, Vector position, Vector norm, Vector reflectDirection, Scene scene, int depth)
{
// Only calculate reflected color if the surface is reflective
var reflectiveness = element.Surface.Reflectiveness(position);
if (reflectiveness > 0)
{
return reflectiveness * this.TraceRay(new Ray() { Start = position, Direction = reflectDirection }, scene, depth + 1);
}
return new Color(0, 0, 0);
}
