public override void Transform(Mat4x4D forward, Mat4x4D inverse)
{
Vec4D center = forward * GetCenter();
Normal = (inverse.Transpose3x3() * Normal).Normalize();
OriginDistance = center.Dot(Normal);
}
private DoubleColor GetColor(Ray ray, ref DebugRay[] debug)
{
Hit prevHit = default;
Hit hit = default;
DoubleColor tint = new DoubleColor(1);
for (int i = 0; i <= Scene.Recursion; i++)
{
// Periodically normalize the direction vector to prevent compounding error
if (i % 3 == 0)
{
ray = Ray.Directional(ray.Origin, ray.Direction);
}
hit = Scene.RayTrace(ray, prevHit);
DebugRay debugRay = debug != null ? debug[i] = new DebugRay()
{
Hit = hit
} : null;
if (hit == default)
{
if (debugRay != null)
{
debugRay.Type = BounceType.Missed;
}
// Return emission or -1 for instant misses
if (i == 0)
{
return(DoubleColor.Placeholder);
}
// Return miss color for misses
return(Scene.AmbientRGB);
}
if (Scene.DebugGeom)
{
if (debugRay != null)
{
debugRay.Type = BounceType.Debug;
}
return(hit.Primitive.Specular + hit.Primitive.Diffuse + hit.Primitive.Emission);
}
if (i >= Scene.Recursion)
{
if (debugRay != null)
{
debugRay.Type = BounceType.RecursionComplete;
}
break;
}
Ray outRay = Ray.Zero;
Vec4D roughNormal = RandomShine(hit.Normal, hit.Primitive.Shininess);
double diffLum = hit.Primitive.Diffuse.Luminance;
double specLum = hit.Primitive.Specular.Luminance;
double refrLum = hit.Primitive.Refraction.Luminance;
double emisLum = hit.Primitive.Emission.Luminance;
double cos = -roughNormal.Dot(ray.Direction);
double cosOut = 0;
double iorRatio = 0;
// Calculate ratio of reflection to transmission on this hit
if ((refrLum > 0 | specLum > 0) && hit.Primitive.RefractiveIndex != 0 && cos >= 0)
{
double iorIn;
double iorOut;
if (hit.Inside)
{
iorIn = hit.Primitive.RefractiveIndex;
iorOut = Scene.AirRefractiveIndex;
}
else
{
iorIn = Scene.AirRefractiveIndex;
iorOut = hit.Primitive.RefractiveIndex;
}
iorRatio = iorIn / iorOut;
double sinOut = iorRatio * Math.Sqrt(1 - (cos * cos));
// Skip refraction when we get total internal reflection
if (sinOut >= 1)
{
refrLum = 0;
if (debugRay != null)
{
debugRay.FresnelRatio = 1;
}
}
else
{
cosOut = Math.Sqrt(1 - (sinOut * sinOut));
double ratioSWave = ((iorOut * cos) - (iorIn * cosOut)) / ((iorOut * cos) + (iorIn * cosOut));
double ratioPWave = ((iorIn * cos) - (iorOut * cosOut)) / ((iorIn * cos) + (iorOut * cosOut));
double ratio = ((ratioSWave * ratioSWave) + (ratioPWave * ratioPWave)) / 2;
specLum *= ratio;
refrLum *= 1 - ratio;
if (debugRay != null)
{
debugRay.FresnelRatio = ratio;
}
}
}
else
{
refrLum = 0;
}
double totalLum = diffLum + specLum + refrLum + emisLum;
if (totalLum <= 0)
{
if (debugRay != null)
{
debugRay.Type = BounceType.PureBlack;
}
break;
}
if (i >= Scene.Recursion)
{
if (debugRay != null)
{
debugRay.Type = BounceType.RecursionComplete;
}
break;
}
DoubleColor newTint = DoubleColor.Black;
double rayRand = Rand.NextDouble() * totalLum;
// Choose whether to do a specular bounce based on brightness of specular
if (refrLum != 0 && (rayRand -= refrLum) <= 0)
{
// Transmission implementation
if (debugRay != null)
{
debugRay.Type = BounceType.Transmitted;
}
Vec4D outDir = (roughNormal * -cosOut) + ((ray.Direction + (roughNormal * cos)) * iorRatio);
outRay = new Ray(hit.Position, outDir);
newTint = hit.Primitive.Refraction;
// Only tint on entering the object, and don't count the recursivity
if (hit.Inside)
{
newTint = new DoubleColor(1);
}
}
else if (specLum != 0 && (rayRand -= specLum) <= 0)
{
if (debugRay != null)
{
debugRay.Type = BounceType.SpecularFail;
}
// Specular reflection
Vec4D outDir = Reflection(roughNormal, ray.Direction, cos);
// Determine whether the rough normal reflection is heading outward before continuing
if (outDir.Dot(hit.Normal) > 0)
{
if (debugRay != null)
{
debugRay.Type = BounceType.Specular;
}
outRay = new Ray(hit.Position, outDir);
newTint = hit.Primitive.Specular;
}
}
else if (diffLum != 0 && (rayRand -= diffLum) <= 0)
{
// Diffuse reflection
if (debugRay != null)
{
debugRay.Type = BounceType.Diffuse;
}
double z = (2 * Math.Acos(Rand.NextDouble())) / Math.PI;
double theta = Rand.NextDouble() * Math.PI * 2;
outRay = new Ray(hit.Position, Vec4D.CreateHorizon(hit.Normal, z, theta));
newTint = hit.Primitive.Diffuse;
}
else
{
// Emission
if (debugRay != null)
{
debugRay.Type = BounceType.Emission;
}
Util.Assert(hit.Primitive.Emission != DoubleColor.Black, "Emission being returned with no luminance");
// Break out of the loop to return emission early
break;
}
if (outRay == Ray.Zero)
{
break;
}
prevHit = hit;
ray = outRay;
// Since we limit the total brightness of the reflection through our bounce selection above,
// normalize to the total luminosity of our combined luminosities
newTint = newTint * Math.Max(totalLum, 1);
tint = tint * newTint;
//color = color.add(hit.Primitive.Emission.mult(tint));
}
return(tint * hit.Primitive.Emission);
}