private static KdNode MakeLeaf(List <IShape> shapes)
{
return(new KdNode(KdNodePlane.NoPlane, PosVector.NewDefault(), shapes, null, null));
}
/*
* Using Surface Area Heuristic (SAH) for finding best split pane
* SAH = 0.5 * voxel_surface_area * number_of_objects_in_voxel
* splitted_SAH = split_cost
* + 0.5 * left_voxel_surface_area * number_of_objects_in_left_voxel
* + 0.5 * right_voxel_surface_area * number_of_objects_in_right_voxel
* Finding coordinate of split plane (XY, XZ or YZ) which minimizing SAH
* If can't find optimal split plane - returns NONE
* see: http://stackoverflow.com/a/4633332/653511
*/
private static (KdNodePlane, PosVector) FindPlane(List <IShape> shapes, BoundingBox bbox, int depth)
{
var finalPlane = KdNodePlane.NoPlane;
var finalPos = PosVector.NewDefault();
if (depth >= MaxTreeDepth || shapes.Count <= NumObjectsInLeaf)
{
return(KdNodePlane.NoPlane, PosVector.NewDefault());
}
double hx = bbox.BoxMax.X - bbox.BoxMin.X;
double hy = bbox.BoxMax.Y - bbox.BoxMin.Y;
double hz = bbox.BoxMax.Z - bbox.BoxMin.Z;
// calculate square of each side of initial bounding box
double sxy = hx * hy;
double sxz = hx * hz;
double syz = hy * hz;
double ssum = sxy + sxz + syz;
// normalize square of each side of initial bounding box to satisfy following relationship:
// sxy + sxz + syz = 1
sxy = sxy / ssum;
sxz = sxz / ssum;
syz = syz / ssum;
int maxSplits = 5; // max splits of bounding box
double splitCost = 5.0;
// assum that at beginning best SAH has initial bounding box
// SAH = 0.5 * square * objectsCount
// square of initial bounding box is sxy + sxz + syz = 1
double bestSah = Convert.ToDouble(shapes.Count);
// initial bounding box doesn't have split plane
finalPlane = KdNodePlane.NoPlane;
var currentSplitCoord = PosVector.NewDefault();
// find split surface which have the least SAH
// trying to minimize SAH by splitting across XY plane
double sSplit = sxy;
double sNonSplit = sxz + syz;
for (int i = 1; i < maxSplits; i++)
{
double l = Convert.ToDouble(i) / Convert.ToDouble(maxSplits);
double r = 1.0 - l;
// current coordinate of split surface
currentSplitCoord = new PosVector(currentSplitCoord.X, currentSplitCoord.Y, bbox.BoxMin.Z + l * hz);
var(vl, vr) = SplitBoundingBox(bbox, KdNodePlane.XY, currentSplitCoord);
var currentSah = (sSplit + l * sNonSplit) * Convert.ToDouble(NumShapesInBoundingBox(shapes, vl)) +
(sSplit + r * sNonSplit) * Convert.ToDouble(NumShapesInBoundingBox(shapes, vr)) +
splitCost;
if (currentSah < bestSah)
{
bestSah = currentSah;
finalPlane = KdNodePlane.XY;
finalPos = currentSplitCoord;
}
}
// trying to minimize SAH by splitting across XZ plane
sSplit = sxz;
sNonSplit = sxy + syz;
for (int i = 1; i < maxSplits; i++)
{
double l = Convert.ToDouble(i) / Convert.ToDouble(maxSplits);
double r = 1.0 - l;
// current coordinate of split surface
currentSplitCoord = new PosVector(currentSplitCoord.X, bbox.BoxMin.Y + l * hy, currentSplitCoord.Z);
var(vl, vr) = SplitBoundingBox(bbox, KdNodePlane.XZ, currentSplitCoord);
var currentSah = (sSplit + l * sNonSplit) * Convert.ToDouble(NumShapesInBoundingBox(shapes, vl)) +
(sSplit + r * sNonSplit) * Convert.ToDouble(NumShapesInBoundingBox(shapes, vr)) +
splitCost;
if (currentSah < bestSah)
{
bestSah = currentSah;
finalPlane = KdNodePlane.XZ;
finalPos = currentSplitCoord;
}
}
// trying to minimize SAH by splitting across YZ plane
sSplit = syz;
sNonSplit = sxy + sxz;
for (int i = 1; i < maxSplits; i++)
{
double l = Convert.ToDouble(i) / Convert.ToDouble(maxSplits);
double r = 1.0 - l;
// current coordinate of split surface
currentSplitCoord = new PosVector(bbox.BoxMin.X + l * hy, currentSplitCoord.Y, currentSplitCoord.Z);
var(vl, vr) = SplitBoundingBox(bbox, KdNodePlane.YZ, currentSplitCoord);
var currentSah = (sSplit + l * sNonSplit) * Convert.ToDouble(NumShapesInBoundingBox(shapes, vl)) +
(sSplit + r * sNonSplit) * Convert.ToDouble(NumShapesInBoundingBox(shapes, vr)) +
splitCost;
if (currentSah < bestSah)
{
bestSah = currentSah;
finalPlane = KdNodePlane.YZ;
finalPos = currentSplitCoord;
}
}
return(finalPlane, finalPos);
}
public static NffParserResult ParseFile(string path, int numThreads, int rayTraceDepth, int resolutionX,
int resolutionY)
{
var background = new Background(new ColorVector(0.0, 0.0, 0.0), 0.0);
var lights = new List <Light>();
var shapes = new List <Shape>();
var cameraAt = PosVector.NewDefault();
var cameraFrom = PosVector.NewDefault();
var cameraUp = PosVector.NewDefault();
var lookingFor = LookingFor.Instruction;
var currentMaterial = new SolidMaterial(0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, new ColorVector(0.0, 0.0, 0.0));
var polyVectors = new List <PosVector>();
var currentItemCounter = 0;
var lines = File.ReadAllLines(path);
foreach (var line in lines)
{
var split = line.Split(' ', '\t');
switch (lookingFor)
{
case LookingFor.Instruction:
{
var instruction = split[0];
if (instruction == "b")
{
// background color
background =
new Background(new ColorVector(double.Parse(split[1]), double.Parse(split[2]), double.Parse(split[3])),
0.0);
}
else if (instruction == "v")
{
// viewpoint location
lookingFor = LookingFor.ViewpointFrom;
}
else if (instruction == "l")
{
// positional light
var colorVector = split.Length == 7
? new ColorVector(double.Parse(split[4]), double.Parse(split[5]), double.Parse(split[6]))
: new ColorVector(1.0, 1.0, 1.0);
lights.Add(
new PointLight(new PosVector(double.Parse(split[1]), double.Parse(split[2]), double.Parse(split[3])),
colorVector));
}
else if (instruction == "f")
{
// println!("reading f: {}", num);
// object material properties
// "f" red green blue Kd Ks Shine T index_of_refraction
// Kd Diffuse component
// Ks Specular
// Shine Phong cosine power for highlights
// T Transmittance (fraction of contribution of the transmitting ray).
// Usually, 0 <= Kd <= 1 and 0 <= Ks <= 1, though it is not required that Kd + Ks = 1. Note that transmitting objects (T > 0) are considered to have two sides for algorithms that need these (normally, objects have one side).
// todo: i don't think i'm assigning the correct values into my solidmaterial yet
currentMaterial = new SolidMaterial(
0.0, // kAmbient
double.Parse(split[4]), // kDiffuse
double.Parse(split[5]), // kSpecular
double.Parse(split[7]), // kReflection
double.Parse(split[8]), // kTransparent
double.Parse(split[8]), // refraction -- todo: which is which here?
double.Parse(split[6]), // gloss
new ColorVector(double.Parse(split[1]), double.Parse(split[2]), double.Parse(split[3]))
);
}
else if (instruction == "c")
{
// cone or cylinder
}
else if (instruction == "s")
{
// sphere
shapes.Add(new SphereShape(
new PosVector(double.Parse(split[1]), double.Parse(split[2]), double.Parse(split[3])),
double.Parse(split[4]),
currentMaterial
));
}
else if (instruction == "p")
{
// polygon
currentItemCounter = int.Parse(split[1]);
polyVectors = new List <PosVector>();
lookingFor = LookingFor.Polygon;
}
else if (instruction == "pp")
{
// polygon patch
}
else if (instruction == "#")
{
// comment
}
}
break;
case LookingFor.Polygon:
{
if (currentItemCounter > 0)
{
currentItemCounter--;
polyVectors.Add(new PosVector(double.Parse(split[0]), double.Parse(split[1]), double.Parse(split[2])));
}
if (currentItemCounter == 0)
{
if (polyVectors.Count >= 3)
{
var firstVert = polyVectors[0];
var prevVert = polyVectors[1];
var thisVert = polyVectors[2];
shapes.Add(new TriangleShape(firstVert, prevVert, thisVert, currentMaterial, currentMaterial));
for (var i = 3; i < polyVectors.Count; i++)
{
prevVert = thisVert;
thisVert = polyVectors[i];
shapes.Add(new TriangleShape(firstVert, prevVert, thisVert, currentMaterial, currentMaterial));
}
}
lookingFor = LookingFor.Instruction;
}
}
break;
case LookingFor.ViewpointFrom:
{
cameraFrom = new PosVector(double.Parse(split[1]), double.Parse(split[2]), double.Parse(split[3]));
lookingFor = LookingFor.ViewpointAt;
}
break;
case LookingFor.ViewpointAt:
{
cameraAt = new PosVector(double.Parse(split[1]), double.Parse(split[2]), double.Parse(split[3]));
lookingFor = LookingFor.ViewpointUp;
}
break;
case LookingFor.ViewpointUp:
{
cameraUp = new PosVector(double.Parse(split[1]), double.Parse(split[2]), double.Parse(split[3]));
lookingFor = LookingFor.ViewpointAngle;
}
break;
case LookingFor.ViewpointAngle:
{
// todo: implement
lookingFor = LookingFor.ViewpointHither;
}
break;
case LookingFor.ViewpointHither:
{
// todo: implement
lookingFor = LookingFor.ViewpointResolution;
}
break;
case LookingFor.ViewpointResolution:
{
//resolutionX = int.Parse(split[1]);
//resolutionY = int.Parse(split[2]);
lookingFor = LookingFor.Instruction;
}
break;
}
}
return(new NffParserResult(Scene.Create(background, shapes, lights),
new RenderData(resolutionX, resolutionY, rayTraceDepth, numThreads, true),
new Camera(cameraFrom, cameraAt, cameraUp, 50.0)));
}
