private Vector3 SampleLocalPosition(SamplerBase sampler)
{
double rand = sampler.GetRandom();
double areaRand = rand * (m_Area0 * 2.0 + m_Area1 * 2.0 + m_Area2 * 2.0);
Vector2 sample = sampler.SampleUnitSquare();
if (areaRand < m_Area0)
{
return(new Vector3(-scale.x * 0.5 + scale.x * sample.x, -scale.y * 0.5 + scale.y * sample.y, -scale.z * 0.5));
}
else if (areaRand >= m_Area0 && areaRand < m_Area0 * 2.0)
{
return(new Vector3(-scale.x * 0.5 + scale.x * sample.x, -scale.y * 0.5 + scale.y * sample.y, scale.z * 0.5));
}
else if (areaRand >= m_Area0 * 2.0 && areaRand < m_Area0 * 2.0 + m_Area1)
{
return(new Vector3(-scale.x * 0.5, -scale.y * 0.5 + scale.y * sample.x, -scale.z * 0.5 + scale.z * sample.y));
}
else if (areaRand >= m_Area0 * 2.0 + m_Area1 && areaRand < m_Area0 * 2.0 + m_Area1 * 2.0)
{
return(new Vector3(scale.x * 0.5, -scale.y * 0.5 + scale.y * sample.x, -scale.z * 0.5 + scale.z * sample.y));
}
else if (areaRand >= m_Area0 * 2.0 + m_Area1 * 2.0 && areaRand < m_Area0 * 2.0 + m_Area1 * 2.0 + m_Area2)
{
return(new Vector3(-scale.x * 0.5 + scale.x * sample.x, -scale.y * 0.5, -scale.z * 0.5 + scale.z * sample.y));
}
else
{
return(new Vector3(-scale.x * 0.5 + scale.x * sample.x, scale.y * 0.5, -scale.z * 0.5 + scale.z * sample.y));
}
}
public Color Shade(Material material, SamplerBase sampler, Ray ray, RayCastHit hit)
{
if (hit.depth > m_PathTracer.tracingTimes)
{
if (material.IsEmissive() && m_PathTracer.sampleDirectLight && ray.isDiffuseRay)
{
return(Color.black);
}
return(material.GetEmissive(hit));
}
if (material.IsEmissive())
{
if (m_PathTracer.sampleDirectLight && hit.depth != 0 && ray.isDiffuseRay)
{
return(Color.black);
}
return(material.GetEmissive(hit));
}
float refractive = material.GetRefractive(hit);
float metallic = material.GetMetallic(hit);
float roughness = material.GetRoughness(hit);
float opacity = material.GetOpacity(hit);
Color albedo = material.GetAlbedo(hit);
Vector3 worldNormal = material.GetWorldNormal(hit);
float ndv = (float)Math.Max(0.0f, Vector3.Dot(worldNormal, -1.0 * ray.direction));
if (hit.isBackFace)
{
refractive = 1.0f / refractive;
}
float F0 = (1.0f - refractive) / (1.0f + refractive);
F0 = F0 * F0;
if (F0 > 0.04f)
{
F0 = 0.04f;
}
Color F0Col = Color.Lerp(new Color(F0, F0, F0), albedo, metallic);
Color fresnel = Fresnel.FresnelSchlick(ndv, F0Col, roughness);
float fl = fresnel.Average();
ShadingType shadingType = ShadingType.Reflect;
double russianRoulette = sampler.GetRandom();
if (fl > russianRoulette)
{
shadingType = ShadingType.Reflect;
}
else if (fl + (1.0f - fl) * (1.0f - opacity) > russianRoulette)
{
shadingType = ShadingType.Refract;
}
else
{
shadingType = ShadingType.Diffuse;
}
if (shadingType == ShadingType.Diffuse)
{
if (1.0f - metallic < float.Epsilon)
{
return(Color.black);
}
if (albedo.IsCloseToZero())
{
return(Color.black);
}
Vector3 sp = sampler.SampleHemiSphere();
Vector3 wi = Vector3.ONB(worldNormal, sp);
float pdf = (float)(sp.z / Math.PI);
double ndl = Vector3.Dot(worldNormal, wi);
if (ndl <= 0.0)
{
return(Color.black);
}
float brdf = (roughness < float.Epsilon ? m_LambertaianBRDF : m_DisneyDiffuseBRDF).SampleBRDF(sampler, ray.direction * -1.0, wi, hit.hit, worldNormal, roughness);
if (brdf < float.Epsilon)
{
return(Color.black);
}
Ray diffuseRay = new Ray(hit.hit, wi, true);
Color L = m_PathTracer.PathTracing(diffuseRay, sampler, hit.depth + 1);
return(albedo * L * brdf * (1.0f - metallic) * (float)ndl / pdf);
}
if (shadingType == ShadingType.Reflect)
{
if (albedo.IsCloseToZero())
{
return(Color.black);
}
Vector3 sp = sampler.SampleHemiSphere(roughness);
Vector3 spnormal = Vector3.ONB(worldNormal, sp);
Vector3 wo = ray.direction * -1.0;
Vector3 wi = Vector3.Reflect(wo, spnormal);
float pdf = (float)(sp.z / Math.PI);
double ndl = Vector3.Dot(worldNormal, wi);
if (ndl <= 0.0)
{
return(Color.black);
}
float brdf = m_CookTorranceBRDF.SampleBRDF(sampler, wo, wi, hit.hit, worldNormal, roughness);
if (brdf < float.Epsilon)
{
return(Color.black);
}
Ray specularRay = new Ray(hit.hit, wi, false);
Color L = m_PathTracer.PathTracing(specularRay, sampler, hit.depth + 1);
return(Color.Lerp(Color.white, fresnel, metallic) * L * brdf * (float)ndl / pdf);
}
if (shadingType == ShadingType.Refract)
{
}
return(Color.black);
//MaterialProperty property;
//property.worldNormal = material.GetWorldNormal(hit);
//property.opacity = material.GetOpacity(hit);
//property.metallic = material.GetMetallic(hit);
//property.roughness = material.GetRoughness(hit);
//property.albedo = material.GetAlbedo(hit);
//if (m_PathTracer.sampleDirectLight)
// result += ShadeDirectLights(property, sampler, ray, hit);
//result += material.GetOcclusion(hit) * ShadeAmbientLight(property, sampler, ray, hit);
//return result + material.GetEmissive(hit);
}