private Intersections MinIntersections(RayPacket256 rayPacket256, Scene scene)
{
Intersections mins = new Intersections(Intersections.NullDistance, Intersections.NullIndex);
for (int i = 0; i < scene.Things.Length; i++)
{
Vector256 <float> distance = scene.Things[i].Intersect(rayPacket256);
if (!Intersections.AllNullIntersections(distance))
{
var notNullMask = Compare(distance, Intersections.NullDistance, FloatComparisonMode.NotEqualOrderedNonSignaling);
var nullMinMask = Compare(mins.Distances, Intersections.NullDistance, FloatComparisonMode.EqualOrderedNonSignaling);
var lessMinMask = Compare(mins.Distances, distance, FloatComparisonMode.GreaterThanOrderedNonSignaling);
var minMask = And(notNullMask, Or(nullMinMask, lessMinMask));
var minDis = BlendVariable(mins.Distances, distance, minMask);
var minIndices = BlendVariable(mins.ThingIndices,
Vector256.Create(i),
minMask.AsInt32());
mins.Distances = minDis;
mins.ThingIndices = minIndices;
}
}
return(mins);
}
internal unsafe void RenderVectorized(Scene scene, int *rgb)
{
Camera camera = scene.Camera;
// Iterate y then x in order to preserve cache locality.
for (int y = 0; y < Height; y++)
{
int stride = y * Width;
for (int x = 0; x < Width; x += VectorPacket256.Packet256Size)
{
float fx = x;
Vector256 <float> Xs = Add(Vector256.Create(fx), ZeroToSeven);
var dirs = GetPoints(Xs, Vector256.Create((float)y), camera);
var rayPacket256 = new RayPacket256(camera.Pos, dirs);
var SoAcolors = TraceRay(rayPacket256, scene, 0);
var AoS = SoAcolors.Transpose();
var intAoS = AoS.ConvertToIntRGB();
int *output = &rgb[(x + stride) * 3]; // Each pixel has 3 fields (RGB)
{
Store(output, intAoS.Rs);
Store(output + 8, intAoS.Gs);
Store(output + 16, intAoS.Bs);
}
}
}
}
public override Vector256 <float> Intersect(RayPacket256 rayPacket256)
{
var denom = VectorPacket256.DotProduct(Norms, rayPacket256.Dirs);
var dist = Divide(Add(VectorPacket256.DotProduct(Norms, rayPacket256.Starts), Offsets), Subtract(Vector256 <float> .Zero, denom));
var gtMask = Compare(denom, Vector256 <float> .Zero, FloatComparisonMode.OrderedGreaterThanNonSignaling);
return(BlendVariable(dist, Intersections.NullDistance, gtMask));
}
private Vector256 <float> TestRay(RayPacket256 rayPacket256, Scene scene)
{
var isect = MinIntersections(rayPacket256, scene);
if (isect.AllNullIntersections())
{
return(Vector256 <float> .Zero);
}
var isNull = Compare(isect.Distances, Intersections.NullDistance, FloatComparisonMode.EqualOrderedNonSignaling);
return(BlendVariable(isect.Distances, Vector256 <float> .Zero, isNull));
}
public override Vector256 <float> Intersect(RayPacket256 rayPacket256)
{
var eo = Centers - rayPacket256.Starts;
var v = VectorPacket256.DotProduct(eo, rayPacket256.Dirs);
var zero = SetZeroVector256 <float>();
var vLessZeroMask = Compare(v, zero, FloatComparisonMode.LessThanOrderedNonSignaling);
var discs = Subtract(Multiply(Radiuses, Radiuses), Subtract(VectorPacket256.DotProduct(eo, eo), Multiply(v, v)));
var discLessZeroMask = Compare(discs, zero, FloatComparisonMode.LessThanOrderedNonSignaling);
var dists = BlendVariable(Subtract(v, Sqrt(discs)), zero, Or(vLessZeroMask, discLessZeroMask));
var isZero = Compare(dists, zero, FloatComparisonMode.EqualOrderedNonSignaling);
return(BlendVariable(dists, Intersections.NullDistance, isZero));
}
private ColorPacket256 Shade(Intersections isect, RayPacket256 rays, Scene scene, int depth)
{
var ds = rays.Dirs;
var pos = isect.Distances * ds + rays.Starts;
var normals = scene.Normals(isect.ThingIndices, pos);
var reflectDirs = ds - (Multiply(VectorPacket256.DotProduct(normals, ds), Vector256.Create(2f)) * normals);
var colors = GetNaturalColor(isect.ThingIndices, pos, normals, reflectDirs, scene);
if (depth >= MaxDepth)
{
return(colors + new ColorPacket256(.5f, .5f, .5f));
}
return(colors + GetReflectionColor(isect.ThingIndices, pos + (Vector256.Create(0.001f) * reflectDirs), normals, reflectDirs, scene, depth));
}
private ColorPacket256 TraceRay(RayPacket256 rayPacket256, Scene scene, int depth)
{
var isect = MinIntersections(rayPacket256, scene);
if (isect.AllNullIntersections())
{
return(ColorPacket256Helper.BackgroundColor);
}
var color = Shade(isect, rayPacket256, scene, depth);
var isNull = Compare(isect.Distances, Intersections.NullDistance, FloatComparisonMode.EqualOrderedNonSignaling);
var backgroundColor = ColorPacket256Helper.BackgroundColor.Xs;
return(new ColorPacket256(BlendVariable(color.Xs, backgroundColor, isNull),
BlendVariable(color.Ys, backgroundColor, isNull),
BlendVariable(color.Zs, backgroundColor, isNull)));
}
public abstract Vector256 <float> Intersect(RayPacket256 rayPacket256);
