private SampledSpectrum SampleLights(Scene scene, BSDF bsdf, ref Intersection intersection,
ref Vector3 leaving)
{
var lights = scene.Lights;
var spectrum = SampledSpectrum.Black();
foreach (var light in lights)
{
var nsamples = _strategy == LightSamplingStrategy.Multiple ? light.NSamples : 1;
var lightContribution = SampledSpectrum.Black();
for (var i = 0; i < nsamples; ++i)
{
Vector3 incoming;
VisibilityTester visibilityTester;
var lightSpectrum = light.Sample(ref intersection.Point, scene, out incoming, out visibilityTester);
if (lightSpectrum.IsBlack() || visibilityTester.Occluded())
{
continue;
}
var cosangle = Math.Abs(Vector3.Dot(incoming, intersection.NormalVector));
// we get the light coming to us from transmission + reflection
var distribution = bsdf.F(incoming, leaving, BxDF.BxDFType.All);
// we scale the light by the incident angle of light on the surface and by the distribution
// function from light to us and we add it to the spectrum
lightContribution += distribution * lightSpectrum * cosangle;
}
spectrum += lightContribution / nsamples;
}
return(spectrum);
}
public override SampledSpectrum Li(Scene scene, Ray ray, Renderer renderer, Sample sample, ref Intersection i)
{
var spectrum = SampledSpectrum.Black();
var lights = scene.Lights;
var bsdfAtPoint = i.GetBSDF();
// we want to get the radiance coming from the surface to us, but the ray comes from us
// to the surface
var leaving = -ray.Direction;
foreach (var light in lights)
{
Vector3 incoming;
VisibilityTester visibilityTester;
var lightSpectrum = light.Sample(ref i.Point, scene, out incoming, out visibilityTester);
// We compute the BSDF value only if the light is not black and it is not occluded. Note that it is important
// for the occlusion test to be after the test for black spectrum, because checking for intersection is an
// expansive operation.
if (!lightSpectrum.IsBlack() && !visibilityTester.Occluded())
{
var cosangle = Math.Abs(Vector3.Dot(incoming, i.NormalVector));
// we get the light coming to us from transmission + reflection
var bsdf = bsdfAtPoint.F(incoming, leaving, BxDF.BxDFType.All);
// we scale the light by the incident angle of light on the surface and by the distribution
// function from light to us and we add it to the spectrum
spectrum += bsdf * lightSpectrum * cosangle;
}
}
if (ray.Depth + 1 < MaxDepth)
{
spectrum += SpecularTransmit(ray, renderer, sample, bsdfAtPoint, ref i);
spectrum += SpecularReflect(ray, renderer, sample, bsdfAtPoint, ref i);
}
return(spectrum);
}
public FresnelBlend(SampledSpectrum d, SampledSpectrum s, MicrofacetDistribution dist)
: base(BxDFType.Reflection | BxDFType.Glossy)
{
_distribution = dist;
_rd = d;
_rs = s;
}
public Microfacet(SampledSpectrum reflectance, Fresnel f, MicrofacetDistribution d)
: base(BxDFType.Reflection | BxDFType.Glossy)
{
_spectrum = reflectance;
_distribution = d;
_fresnel = f;
}
public DiskLight(Transformation objectToWorld, float radius = 1, SampledSpectrum spectrum = null)
: base(objectToWorld, spectrum)
{
_radius = radius;
_normal = ObjectToWorld.TransformNormal(new Vector3(0, -1, 0)).Normalized();
NSamples = (uint)Math.Max(1, _radius / 4f);
}
public override SampledSpectrum Sample(Vector3 leaving, out Vector3 incoming)
{
var entering = CosTheta(ref leaving) > 0;
float ei, et;
if (entering)
{
ei = IndexOfRefractionIncident;
et = IndexOfRefractionTransmitted;
}
else
{
et = IndexOfRefractionIncident;
ei = IndexOfRefractionTransmitted;
}
var sinIncidentSquared = SinThetaSquared(ref leaving);
var eta = ei / et;
var sinTransmittedSquared = eta * eta * sinIncidentSquared;
var cosTransmitted = (float)Math.Sqrt(1 - sinTransmittedSquared);
if (entering)
{
cosTransmitted = -cosTransmitted;
}
var sinTOversinI = eta;
incoming = new Vector3(sinTOversinI * -leaving.X, sinTOversinI * -leaving.Y, cosTransmitted);
if (sinTransmittedSquared >= 1)
{
return(SampledSpectrum.Black());
}
var f = _fresnel.Evaluate(CosTheta(ref leaving));
return((new SampledSpectrum(1) - f) * _s / AbsCosTheta(ref incoming) * (et * et) / (ei * ei));
}
/// <summary>
/// Compute the fresnel reflectance for dielectric materials
/// </summary>
/// <param name="cosi">the angle between incoming ray and normal</param>
/// <param name="cost">the angle between outgoing ray and normal's inverse</param>
/// <param name="si">the index of refraction of the first medium</param>
/// <param name="st">the index of refraction of the second medium</param>
/// <returns>the reflectance</returns>
public static SampledSpectrum DielectricFresnel(float cosi, float cost, SampledSpectrum si, SampledSpectrum st)
{
var parallel = ((st * cosi) - (si * cost)) / ((st * cosi) + (si * cost));
var perpendicular = ((si * cosi) - (st * cost)) / ((si * cosi) + (st * cost));
return(parallel * parallel + perpendicular * perpendicular);
}
/// <summary>
/// Choose an incoming direction on the view from a BxDF matching a type
/// and returns its contribution
/// </summary>
/// <param name="leaving">the vector leaving the surface</param>
/// <param name="incoming">the vector arriving at the surface, the function will set it</param>
/// <param name="type">the type of scattering</param>
/// <returns></returns>
public SampledSpectrum Sample(Vector3 leaving, ref Vector3 incoming, BxDF.BxDFType type)
{
/* we randomly choose a BxDF that matches the type */
var matchingBxDFs = _bxdfs.Where(f => type.HasFlag(f.Type)).ToList(); // the list of bxdf matching the type
if (matchingBxDFs.Count == 0)
{
return(SampledSpectrum.Black());
}
// random selection over matching bxdfs
var bxdf =
matchingBxDFs.ElementAt(Math.Min((int)(StaticRandom.NextFloat() * matchingBxDFs.Count), matchingBxDFs.Count - 1));
var leavingLocal = WorldToLocal(ref leaving);
Vector3 incomingLocal;
// we sample the chosen bxdf
var spectrum = bxdf.Sample(leavingLocal, out incomingLocal);
// we transform the incoming ray returned by the sampling to world space
incoming = LocalToWorld(ref incomingLocal);
// is the reflection is not specular, we add contribution from other bxdfs of the same type
if (!bxdf.Type.HasFlag(BxDF.BxDFType.Reflection))
{
spectrum = _bxdfs.Where(b => type.HasFlag(b.Type))
.Aggregate(spectrum, (current, b) => current + b.F(incomingLocal, leavingLocal));
}
return(spectrum);
}
public SpecularTransmission(float indexOfRefractionIncident, float indexOfRefractionTransmitted,
SampledSpectrum s = null) : base(BxDFType.Transmission | BxDFType.Specular)
{
_fresnel = new FresnelDielectric(indexOfRefractionIncident, indexOfRefractionTransmitted);
_s = s ?? SampledSpectrum.Random();
IndexOfRefractionIncident = indexOfRefractionIncident;
IndexOfRefractionTransmitted = indexOfRefractionTransmitted;
}
public SampledSpectrum F(Vector3 incoming, Vector3 leaving, BxDF.BxDFType type)
{
var s = SampledSpectrum.Black();
var incomingLocal = WorldToLocal(ref incoming);
var leavingLocal = WorldToLocal(ref leaving);
return(_bxdfs.Where(bxdf => type.HasFlag(bxdf.Type))
.Aggregate(s, (current, bxdf) => current + bxdf.F(incomingLocal, leavingLocal)));
}
public OrenNayar(SampledSpectrum spectrum, float sigma) : base(BxDFType.Reflection | BxDFType.Diffuse)
{
var sig = MathHelper.DegreesToRadians(sigma);
var sigsqrd = sig * sig;
_a = 1f - (sigsqrd / (2 * (sigsqrd + 0.33f)));
_b = (0.45f * sigsqrd) / (sigsqrd + 0.09f);
_spectrum = spectrum;
}
public override void AddSample(Sample sample, SampledSpectrum spectrum)
{
var color = Colors[(int)sample.Y, (int)sample.X];
if (color != null)
{
color.AddSample(spectrum.ToRGB());
}
}
public ClementiteMaterial(Vector3 ka, Vector3 kd, Vector3 ks, uint ns, float d, uint illum)
{
_ka = SampledSpectrum.FromRGB(new[] { ka.X, ka.Y, ka.Z });
_kd = SampledSpectrum.FromRGB(new[] { kd.X, kd.Y, kd.Z });
_ks = SampledSpectrum.FromRGB(new[] { ks.X, ks.Y, ks.Z });
_ns = ns;
_illum = illum;
_d = d;
}
/// <summary>
/// This function is used to parse a .poule file.
/// </summary>
private void ParsePoule(Scene scene, string filename)
{
string[] lines = File.ReadAllLines(filename);
foreach (string str in lines)
{
if (_pointLightReg.Match(str).Success)
{
string[] array = str.Split(' ');
scene.Lights.Add(new PointLight(Transformation.Translation(
float.Parse(array[1], CultureInfo.InvariantCulture.NumberFormat),
float.Parse(array[2], CultureInfo.InvariantCulture.NumberFormat),
float.Parse(array[3], CultureInfo.InvariantCulture.NumberFormat)),
SampledSpectrum.White()));
}
else if (_diskLightReg.Match(str).Success)
{
string[] array = str.Split(' ');
scene.Lights.Add(new PointLight(Transformation.Translation(
float.Parse(array[1], CultureInfo.InvariantCulture.NumberFormat),
float.Parse(array[2], CultureInfo.InvariantCulture.NumberFormat),
float.Parse(array[3], CultureInfo.InvariantCulture.NumberFormat)),
SampledSpectrum.White()));
}
else if (_cameraReg.Match(str).Success)
{
string[] array = str.Split(' ');
_camera = new SimpleCamera(_screen,
Transformation.Compose(
Transformation.Translation(
Convert.ToInt32(array[1]),
Convert.ToInt32(array[2]),
Convert.ToInt32(array[3])
),
Transformation.RotateX(float.Parse(array[4], CultureInfo.InvariantCulture.NumberFormat)),
Transformation.RotateY(float.Parse(array[5], CultureInfo.InvariantCulture.NumberFormat)),
Transformation.RotateZ(float.Parse(array[6], CultureInfo.InvariantCulture.NumberFormat))
));
}
else if (_objReg.Match(str).Success == true)
{
string[] array = str.Split(' ');
try
{
string path = array[1].Replace(@"\\", @"\");
ParsingObj parser = new ParsingObj(path);
parser.AddToScene(scene);
}
catch (Exception e)
{
FileName.Text = e.Message;
}
}
}
}
public AccumulatedSpectrum Mul(ref SampledSpectrum sp)
{
if (storeInRgb)
{
this.rgbAcc *= sp.ToRgb();
}
else
{
this.spAcc *= sp;
}
return this;
}
public override SampledSpectrum F(Vector3 incoming, Vector3 leaving)
{
var diffuse = _rd * (float)(28f / (23 * Math.PI)) * (new SampledSpectrum(1) - _rs) *
(1f - (float)Math.Pow(1 - 0.5 * AbsCosTheta(ref incoming), 5)) *
(1f - (float)Math.Pow(1 - 0.5 * AbsCosTheta(ref leaving), 5));
var half = (incoming + leaving).Normalized();
var specular = new SampledSpectrum(_distribution.D(ref half)) /
(new SampledSpectrum(4 * AbsDot(ref incoming, ref leaving) *
Math.Max(AbsCosTheta(ref incoming), AbsCosTheta(ref leaving))) *
SchlickFresnel(Vector3.Dot(incoming, half)));
return(diffuse + specular);
}
public AccumulatedSpectrum Mul(ref RgbSpectrum rgb, SpectrumType t)
{
if (storeInRgb)
{
this.rgbAcc *= rgb;
}
else
{
this.spAcc *= new SampledSpectrum(ref rgb, t);
}
return this;
}
public override SampledSpectrum Li(Scene scene, Ray ray, Renderer renderer, Sample sample,
ref Intersection intersection)
{
var spectrum = SampledSpectrum.Black();
var bsdfAtPoint = intersection.GetBSDF();
var leaving = -ray.Direction;
spectrum += SampleLights(scene, bsdfAtPoint, ref intersection, ref leaving);
if (ray.Depth + 1 < MaxDepth)
{
spectrum += SpecularTransmit(ray, renderer, sample, bsdfAtPoint, ref intersection);
spectrum += SpecularReflect(ray, renderer, sample, bsdfAtPoint, ref intersection);
}
return(spectrum);
}
public SampledSpectrum SpecularTransmit(Ray ray, Renderer renderer, Sample sample, BSDF bsdf, ref Intersection i)
{
var leaving = -ray.Direction;
var incoming = new Vector3();
var f = bsdf.Sample(leaving, ref incoming, BxDF.BxDFType.Transmission | BxDF.BxDFType.Specular);
var angle = Math.Abs(Vector3.Dot(incoming.Normalized(), i.NormalVector));
if (f.IsBlack() || angle == 0f)
{
return(SampledSpectrum.Black());
}
var reflectedRay = new Ray(incoming.Normalized(), i.Point, 0.1f, Ray.DefaultEndValue, ray.Depth + 1);
var li = renderer.Li(sample, reflectedRay);
return(f * li * angle);
}
/// <summary>
/// Compute radiance for a sample
/// </summary>
/// <param name="sample"></param>
/// <param name="ray"></param>
/// <returns></returns>
public SampledSpectrum Li(Sample sample, Ray ray = null)
{
ray = ray ?? Camera.GenerateRay(sample);
var intersection = new Intersection();
var spectrum = SampledSpectrum.Black();
if (Scene.TryToIntersect(ray, ref intersection))
{
spectrum = Integrator.Li(Scene, ray, this, sample, ref intersection);
}
else
{
spectrum = Scene.Lights.Aggregate(spectrum, (current, light) => current + light.Le(ray));
}
return(spectrum);
}
/// <summary>
/// </summary>
/// <remarks>This function let us choose the incoming vector</remarks>
/// <param name="leaving"></param>
/// <param name="incoming"></param>
/// <returns></returns>
public override SampledSpectrum Sample(Vector3 leaving, out Vector3 incoming)
{
/* Since we are in the reflection system, rotating the vector by PI radians
* around the normal consists of negating its x component and its y component */
incoming = new Vector3(-leaving.X, -leaving.Y, leaving.Z);
var abscostheta = AbsCosTheta(ref incoming);
var reflectedLight = SampledSpectrum.Black();
if (_fresnel != null)
{
var reflectedAmount = _fresnel.Evaluate(CosTheta(ref incoming));
reflectedLight = _spectrum * reflectedAmount / abscostheta;
}
else
{
reflectedLight = _spectrum * _reflectiveness / abscostheta;
}
return(reflectedLight);
}
private void InitNewScene()
{
_scene = new Scene();
var screen = new raytracer.core.Screen(1024, 768);
_film = new MyFilm(screen, NSamples);
Camera camera = new SimpleCamera(screen,
Transformation.Translation((float)PositionX.Value, (float)PositionY.Value, (float)PositionZ.Value) *
Transformation.RotateX((float)(RotationX.Value % 360)) *
Transformation.RotateY((float)(RotationY.Value % 360)) *
Transformation.RotateZ((float)(RotationZ.Value % 360)));
_renderer = new Renderer(_scene,
new GridSampler(screen), camera, _film,
new WhittedIntegrator());
_scene.Lights.Add(new PointLight(Transformation.Translation(100, 650, -500), SampledSpectrum.White() * 2000000));
_scene.Lights.Add(new PointLight(Transformation.Translation(0, 0, -1000), SampledSpectrum.Random() * 200000));
SimpleObjParser(_scene, _file);
}
public TestMaterial(float?reflectiveness = null, SampledSpectrum spectrum = null)
{
_reflectiveness = reflectiveness ?? StaticRandom.NextFloat();
_spectrum = spectrum ?? SampledSpectrum.Random() * 0.3f;
}
/// <summary>
/// Create a light from a transformation
/// </summary>
/// <param name="objectToWorld">the light-to-world transformation</param>
/// <param name="spectrum">the spectrum of the light</param>
/// <param name="nsamples">the number of samples to take from the light</param>
protected Light(Transformation objectToWorld = null, SampledSpectrum spectrum = null, uint nsamples = 1)
{
ObjectToWorld = objectToWorld ?? Transformation.Identity;
Spectrum = spectrum ?? SampledSpectrum.White();
NSamples = Math.Max(1, nsamples);
}
/// <summary>
/// </summary>
/// <remarks>
/// This function returns nothing since it is nearly impossible to have
/// a correct incoming vector (there is only a single incoming vector)
/// </remarks>
/// <param name="incoming"></param>
/// <param name="leaving"></param>
/// <returns></returns>
public override SampledSpectrum F(Vector3 incoming, Vector3 leaving)
{
return(SampledSpectrum.Black());
}
/// <summary>
/// Create a specular reflection model based on Snell's laws.
/// </summary>
/// <param name="fresnel">the fresnel properties of the material</param>
/// <param name="spectrum">a scaling spectrum</param>
public SpecularReflection(Fresnel fresnel = null, SampledSpectrum spectrum = null)
: base(BxDFType.Reflection | BxDFType.Specular)
{
_spectrum = spectrum ?? new SampledSpectrum(1);
_fresnel = fresnel;
}
/// <summary>
/// Creates a specular reflection model based on unrealistic properties
/// </summary>
/// <param name="reflectiveness">the reflectiveness (between 0 and 1000)</param>
/// <param name="spectrum">a scaling spectrum</param>
public SpecularReflection(float reflectiveness = 1, SampledSpectrum spectrum = null)
: base(BxDFType.Reflection | BxDFType.Specular)
{
_spectrum = spectrum ?? new SampledSpectrum(1);
_reflectiveness = MathHelper.Clamp(reflectiveness, 0, 1000);
}
public LambertianReflection(SampledSpectrum spectrum) : base(BxDFType.Reflection | BxDFType.Diffuse)
{
_spectrum = spectrum ?? SampledSpectrum.Random();
}
/// <summary>
/// Return the spectrum of light when ray does not hit anything.
/// </summary>
/// <param name="ray">the ray</param>
/// <returns></returns>
public virtual SampledSpectrum Le(Ray ray)
{
return(SampledSpectrum.Black());
}
protected AreaLight(Transformation objectToWorld = null, SampledSpectrum spectrum = null, uint nsamples = 1)
: base(objectToWorld, spectrum, nsamples)
{
}
public GlassMaterial(float refractionIndex1, float refractionIndex2, SampledSpectrum spectrum = null)
{
_transmission = new SpecularTransmission(refractionIndex1, refractionIndex2, spectrum);
}
/// <summary> /// Adds the result of the ray casting (a spectrum) for the ray generated /// by a sample /// <seealso cref="CoefficientSpectrum" /> /// <seealso cref="Sample" /> /// </summary> /// <param name="sample">the sample from which the ray was generated</param> /// <param name="spectrum">the result of the casting of the ray in the scene</param> public abstract void AddSample(Sample sample, SampledSpectrum spectrum);
