public Color GetColorOnEntity(Entity.HitResult hitResult, Entity entity, Ray ray)
{
var emission = entity.EntityMaterial.Emission;
var ambient = entity.EntityMaterial.Ambient;
var finalColor = emission.Add(ambient);
// in case of precision issue
var checkPoint = hitResult.HitPoint + Epsilon * hitResult.HitNorm;
foreach (var light in Lights)
{
if (!light.HasLightOn(checkPoint, this))
{
continue;
}
var lightVec = light.GetLightVector(hitResult.HitPoint);
var lightReflect = Vector3.Reflect(lightVec, hitResult.HitNorm);
var attenuation = light.GetAttenuation(hitResult.HitPoint);
var diffuse = light.Diffuse.Moderate(entity.EntityMaterial.Diffuse);
var specular = light.Specular.Moderate(entity.EntityMaterial.Specular);
var diffuseCoef =
Math.Max(Vector3.Dot(-Vector3.Normalize(hitResult.HitNorm), Vector3.Normalize(lightVec)), 0);
var specularCoef =
Math.Max(Vector3.Dot(Vector3.Normalize(lightReflect), -Vector3.Normalize(ray.Direction)), 0);
specularCoef = (float)Math.Pow(specularCoef, entity.EntityMaterial.Shininess);
var lightColor = diffuse.Multiply(diffuseCoef).Add(specular.Multiply(specularCoef));
finalColor = finalColor.Add(lightColor.Multiply(attenuation));
}
return(finalColor);
}
public Color GetColor(Ray ray, int maxDepth)
{
if (maxDepth == 0)
{
return(Color.Black);
}
var minDistanceSquared = float.MaxValue;
Entity.HitResult realHitResult = null;
Entity realHitEntity = null;
foreach (var entity in Entities)
{
var hitResult = entity.GetHitResult(ray);
var distanceSquared = Vector3.DistanceSquared(hitResult.HitPoint, ray.Origin);
if (!hitResult.Hit || !(distanceSquared < minDistanceSquared))
{
continue;
}
minDistanceSquared = distanceSquared;
realHitResult = hitResult;
realHitEntity = entity;
}
if (realHitResult == null)
{
return(Color.Black);
}
var baseColor = Color.Black;
var reflectedColor = Color.Black;
if (realHitEntity.EntityMaterial.Reflectivity <= 1 - float.Epsilon)
{
baseColor = GetColorOnEntity(realHitResult, realHitEntity, ray);
}
if (realHitEntity.EntityMaterial.Reflectivity >= float.Epsilon)
{
// in case of precision issue
var direction = Vector3.Reflect(ray.Direction, realHitResult.HitNorm);
var origin = realHitResult.HitPoint + Epsilon * Vector3.Normalize(realHitResult.HitNorm);
var reflectedRay = new Ray(origin, direction);
reflectedColor = GetColor(reflectedRay, maxDepth - 1);
}
return(baseColor.Multiply(1 - realHitEntity.EntityMaterial.Reflectivity).Add(
reflectedColor.Multiply(realHitEntity.EntityMaterial.Reflectivity)
));
}
