private ColorVector RenderDiffuse(ColorVector currentColor, IntersectionInfo intersectionInfo, ILight light)
{
if (RenderData.RenderDiffuse)
{
var v = (light.Position - intersectionInfo.Position).Normalize();
var l = v.Dot(intersectionInfo.Normal);
if (l > 0.0)
{
return(currentColor + intersectionInfo.Color * light.Color * l);
}
}
return(currentColor);
}
private ColorVector RenderHighlights(ColorVector currentColor, IShape shape, IntersectionInfo shadowIntersection,
ILight light)
{
if (RenderData.RenderHighlights && !shadowIntersection.IsHit && shape.GetMaterial().Gloss > 0.0)
{
var lv = (shape.Position - light.Position).Normalize();
var e = (Camera.Position - shape.Position).Normalize();
var h = (e - lv).Normalize();
var glossWeight = 0.0; // todo: pow(max(dot(info.Normal, h), 0.0), shininess)
return(currentColor + light.Color * glossWeight);
}
return(currentColor);
}
private ColorVector GetLightingColor(PosVector point, PosVector normal)
{
var lightColor = new ColorVector();
foreach (var light in Scene.Lights)
{
// if not shaded
if (IsViewable(light.Position, point))
{
var lightVector = light.Position - point;
lightColor = lightColor + (light.Color * Math.Abs(PosVector.CosVectors(normal, lightVector)));
}
}
return(lightColor);
}
private ColorVector GetSpecularColor(Ray ray, double p)
{
var lightColor = new ColorVector();
foreach (var light in Scene.Lights)
{
// if not shaded
if (IsViewable(light.Position, ray.Position))
{
var lightSourceVector = light.Position - ray.Position;
var cosLightSource = PosVector.CosVectors(ray.Direction, lightSourceVector);
if (cosLightSource > double.Epsilon)
{
lightColor = lightColor * p; // + (light.Color * Math.Pow(cosLightSource, p));
}
}
}
return(lightColor);
}
private ColorVector RenderReflection(ColorVector currentColor, IntersectionInfo intersectionInfo, Ray ray,
int depth)
{
if (RenderData.RenderReflection)
{
if (Scene.TryGetShape(intersectionInfo.ElementId, out var shape))
{
if (shape.GetMaterial().KReflection > 0.0)
{
var reflectionRay = GetReflectionRay(intersectionInfo.Position, intersectionInfo.Normal, ray.Direction);
var refl = TestIntersection(reflectionRay, shape.Id);
var reflColor = refl.IsHit && refl.Distance > 0.0
? RayTrace(refl, reflectionRay, depth + 1)
: Scene.Background.Color;
return(currentColor.Blend(reflColor, shape.GetMaterial().KReflection));
}
}
}
return(currentColor);
}
private ColorVector RenderRefraction(ColorVector currentColor, IntersectionInfo intersectionInfo, Ray ray,
int depth)
{
if (RenderData.RenderRefraction)
{
if (Scene.TryGetShape(intersectionInfo.ElementId, out var shape))
{
if (shape.GetMaterial().KTransparent > 0.0)
{
var refractionRay = GetRefractionRay(intersectionInfo.Position, intersectionInfo.Normal, ray.Direction,
shape.GetMaterial().Refraction);
var refr = shape.Intersect(refractionRay);
var refractedColor = Scene.Background.Color;
if (refr.IsHit)
{
if (Scene.TryGetShape(refr.ElementId, out var refrShape))
{
var elemRefractionRay = GetRefractionRay(refr.Position, refr.Normal, refractionRay.Direction,
refrShape.GetMaterial().Refraction);
var secondRefr = TestIntersection(elemRefractionRay, shape.Id);
if (secondRefr.IsHit && secondRefr.Distance > 0.0)
{
refractedColor = RayTrace(secondRefr, elemRefractionRay, depth + 1);
}
}
}
else
{
refractedColor = Scene.Background.Color;
}
return(currentColor.Blend(refractedColor, shape.GetMaterial().KTransparent));
}
}
}
return(currentColor);
}
private ColorVector CalculateColor(Ray ray, IntersectionInfo intInfo, double rayIntensity, int depth)
{
if (intInfo.IsHit && Scene.TryGetShape(intInfo.ElementId, out IShape shape))
{
var material = shape.GetMaterial();
var objectColor = intInfo.Color;
var ambientColor = new ColorVector();
var diffuseColor = new ColorVector();
var reflectedColor = new ColorVector();
var specularColor = new ColorVector();
var resultColor = new ColorVector();
double fogDensity = 0;
if (Scene.HasFogDensity)
{
fogDensity = Scene.GetFogDensity(intInfo.Distance);
}
if (material.KAmbient > double.Epsilon)
{
ambientColor = Scene.Background.Color.Mix(objectColor);
resultColor = resultColor.Mix(ambientColor);
}
if (material.KDiffuse > double.Epsilon)
{
diffuseColor = objectColor;
if (Scene.HasLights)
{
diffuseColor = diffuseColor.Mix(GetLightingColor(intInfo.Position, intInfo.Normal));
}
resultColor = resultColor.Blend(diffuseColor, material.KDiffuse);
}
if (material.KSpecular > double.Epsilon)
{
specularColor = Scene.Background.Color;
if (Scene.HasLights)
{
var reflectedRay = ReflectRay(ray, intInfo.Normal);
specularColor = GetSpecularColor(reflectedRay, material.Gloss);
}
resultColor = resultColor.Blend(specularColor, material.KSpecular);
}
if (material.KReflection > double.Epsilon)
{
// avoid deep recursion by tracing rays which have intensity greater than threshold
// and avoid infinite recursion by limiting number of recursive calls
if (rayIntensity > ThresholdRayIntensity && depth < MaxRayRecursionLevel)
{
var reflectedRay = ReflectRay(ray, intInfo.Normal);
reflectedColor = TraceRecursive(
reflectedRay,
rayIntensity * material.KReflection * (1 - fogDensity),
depth + 1);
}
else
{
reflectedColor = Scene.Background.Color;
}
resultColor = resultColor.Blend(reflectedColor, material.KReflection);
}
if (Scene.HasFogDensity)
{
resultColor = (Scene.Background.Color * fogDensity) + (resultColor * (1.0 - fogDensity));
}
return(resultColor);
}
else
{
return(Scene.Background.Color);
}
}
private Rgba32 ClampToPixel(ColorVector color)
{
var clamped = color.Clamp();
return(new Rgba32(ColorToByte(clamped.R), ColorToByte(clamped.G), ColorToByte(clamped.B)));
}