private HitPoint FindClosestHitPoint(Ray ray)
{
var hitPoints = new List <HitPoint>();
if (AccelerationStructure)
{
BVHNode root = _accelerationStructure;
hitPoints.AddRange(FindHitpoints(ray, root));
}
else
{
for (int i = 0; i < _spheres.Length; i++)
{
var sphere = _spheres[i];
var hitPoint = FindHitpoint(ray, sphere);
if (hitPoint != null)
{
hitPoints.Add(hitPoint);
}
}
}
return(hitPoints.OrderBy(h => h.Ray.Lambda).FirstOrDefault());
}
public static void RecursivePrint(BVHNode node, Action <string> logger, int indent = 0)
{
if (node != null)
{
var sb = new StringBuilder();
for (int i = 0; i < indent; i++)
{
sb.Append(" ");
}
var indentStr1 = sb.ToString();
var indentStr2 = indentStr1 + " ";
var sphere = node.BoundingSphere;
logger(indentStr1 + FormatSphere(sphere));
foreach (var item in node.Items)
{
logger(indentStr2 + FormatSphere(item));
}
RecursivePrint(node.Left, logger, indent + 2);
RecursivePrint(node.Right, logger, indent + 2);
}
}
public static BVHNode BuildTopDown(IEnumerable <Sphere> spheres, Action <string> logger, bool print = false)
{
BVHNode rootNode = new BVHNode(spheres.ToArray());
BuildTopDown(rootNode, logger);
if (print)
{
RecursivePrint(rootNode, logger);
}
return(rootNode);
}
private List <HitPoint> FindHitpoints(Ray ray, BVHNode node)
{
var hitPoints = new List <HitPoint>();
var queue = new Queue <BVHNode>();
queue.Enqueue(node);
while (queue.Count > 0)
{
var current = queue.Dequeue();
if (current.Items.Length > 0)
{
foreach (var item in current.Items)
{
var hitPoint = FindHitpoint(ray, item);
if (hitPoint != null)
{
hitPoints.Add(hitPoint);
}
}
}
else
{
if (current.Left != null)
{
var boundingSphere = current.Left.BoundingSphere;
if (FindHitpoint(ray, boundingSphere) != null)
{
queue.Enqueue(current.Left);
}
}
if (current.Right != null)
{
var boundingSphere = current.Right.BoundingSphere;
if (FindHitpoint(ray, boundingSphere) != null)
{
queue.Enqueue(current.Right);
}
}
}
}
return(hitPoints);
}
private bool HasObjectInFrontOfLightSource(Vector3 hitPointVec, Vector3 pos)
{
var lVec = pos - hitPointVec;
var ray = new Ray(hitPointVec, lVec);
var length = Vector3.DistanceSquared(ray.StartVec, lVec);
if (AccelerationStructure)
{
BVHNode root = _accelerationStructure;
var hitPoints = FindHitpoints(ray, root);
foreach (var hitPoint in hitPoints)
{
var rayVec = hitPoint.Ray.Lambda * hitPoint.Ray.DirectionVec;
var scale = Vector3.DistanceSquared(hitPoint.Ray.StartVec, rayVec) / length;
if (scale <= 1)
{
return(true);
}
}
}
else
{
for (int i = 0; i < _spheres.Length; i++)
{
var sphere = _spheres[i];
var hitPoint = FindHitpoint(ray, sphere);
if (hitPoint != null)
{
var rayVec = hitPoint.Ray.Lambda * hitPoint.Ray.DirectionVec;
var scale = Vector3.DistanceSquared(hitPoint.Ray.StartVec, rayVec) / length;
if (scale <= 1)
{
return(true);
}
}
}
}
return(false);
}
private static void BuildTopDown(BVHNode node, Action <string> logger)
{
int iterations = 0;
var queue = new Queue <BVHNode>();
queue.Enqueue(node);
BVHNode current = null;
while (queue.Count > 0)
{
++iterations;
current = queue.Dequeue();
if (current.Items.Length > MinPartitionSize)
{
var boundingSphere = current.BoundingSphere;
var splitOrder = GetSplitOrder(boundingSphere.Center);
foreach (var split_dim in splitOrder)
{
var leftSpheres = new List <Sphere>();
var rightSpheres = new List <Sphere>();
var split_coord = 0.5f * ValueAt(boundingSphere.Center, split_dim);
foreach (var sphere in current.Items)
{
if (ValueAt(sphere.Center, split_dim) < split_coord)
{
leftSpheres.Add(sphere);
}
else
{
rightSpheres.Add(sphere);
}
}
var split_success
= leftSpheres.Count > 0 &&
rightSpheres.Count > 0;
if (split_success)
{
current.Left = new BVHNode(leftSpheres.ToArray());
queue.Enqueue(current.Left);
current.Right = new BVHNode(rightSpheres.ToArray());
queue.Enqueue(current.Right);
current.ClearItems();
break;
}
}
}
}
logger($"BVH constructed in '{iterations}' iterations.");
}
public string GetImageFileName(int width, int height, double dpiX, double dpiY, CancellationToken cancellationToken, string settingsSummary, string exportDirectory)
{
var sw = Stopwatch.StartNew();
OutputLogEveryXPixel = (width * height / 100);
if (AccelerationStructure)
{
_accelerationStructure = BVHNode.BuildTopDown(_spheres, _logger);
}
var bitmap = new BitmapImage(width, height, dpiX, dpiY);
var divideX = width / (float)2;
var alignX = 1 - divideX;
var divideY = height / (float)2;
var alignY = 1 - divideY;
int workDone = 0;
int totalWork = width * height;
if (Parallelize)
{
var options = new ParallelOptions()
{
CancellationToken = cancellationToken, MaxDegreeOfParallelism = Environment.ProcessorCount
};
Parallel.For(0, width, options, i =>
{
for (int j = 0; j < height; j++)
{
if (cancellationToken.IsCancellationRequested)
{
break;
}
if (AntiAliasing)
{
Vector3 result = Vector3.Zero;
for (int k = 0; k < AntiAliasingSampleSize; k++)
{
var dx = (float)_random.NextGaussian(0d, 0.5d);
var dy = (float)_random.NextGaussian(0d, 0.5d);
var x = (i + alignX + dx) / divideX;
var y = ((height - j) + alignY + dy) / divideY;
var rgb = GetColor(x, y);
result += rgb;
}
var avg_rgb = result * (1f / AntiAliasingSampleSize);
var c = Conversions.FromRGB(avg_rgb, GammaCorrect);
bitmap.Set(i, j, c);
}
else
{
var x = (i + alignX) / divideX;
var y = ((height - j) + alignY) / divideY;
var rgb = GetColor(x, y);
var c = Conversions.FromRGB(rgb, GammaCorrect);
bitmap.Set(i, j, c);
}
var value = Interlocked.Increment(ref workDone);
if (value % OutputLogEveryXPixel == 0)
{
var progress = (float)value / totalWork;
WriteOutput($"{(progress * 100):F3}% progress. Running {sw.Elapsed}. Remaining {TimeSpan.FromMilliseconds(sw.Elapsed.TotalMilliseconds / progress * (1f - progress))}.");
}
}
});
}
else
{
for (int i = 0; i < width; i++)
{
if (cancellationToken.IsCancellationRequested)
{
break;
}
for (int j = 0; j < height; j++)
{
if (cancellationToken.IsCancellationRequested)
{
break;
}
if (AntiAliasing)
{
Vector3 result = Vector3.Zero;
for (int k = 0; k < AntiAliasingSampleSize; k++)
{
var x = (i + alignX + (float)_random.NextGaussian(0d, 0.5d)) / divideX;
var y = ((height - j) + alignY + (float)_random.NextGaussian(0d, 0.5d)) / divideY;
var rgb = GetColor(x, y);
result += rgb;
}
var avg_rgb = result * (1f / AntiAliasingSampleSize);
var c = Conversions.FromRGB(avg_rgb, GammaCorrect);
bitmap.Set(i, j, c);
}
else
{
// Question: Why is it mirrored?
var x = (i + alignX) / divideX;
var y = ((height - j) + alignY) / divideY;
var rgb = GetColor(x, y);
var c = Conversions.FromRGB(rgb, GammaCorrect);
bitmap.Set(i, j, c);
}
++workDone;
if (workDone % OutputLogEveryXPixel == 0)
{
var progress = (float)workDone / totalWork;
WriteOutput($"{(progress * 100):F3}% progress. Running {sw.Elapsed}. Remaining {TimeSpan.FromMilliseconds(sw.Elapsed.TotalMilliseconds / progress * (1f - progress))}.");
}
}
}
}
if (cancellationToken.IsCancellationRequested)
{
WriteOutput("Operation canceled by user.");
return(null);
}
var imageSource = bitmap.GetImageSource();
sw.Stop();
return(SaveImage(imageSource, sw.Elapsed, settingsSummary, exportDirectory));
}