fix bidir seed bug

pgrit · Aug 28, 2024 · 19d301f · 19d301f
1 parent b5a49e0
commit 19d301f
Show file tree

Hide file tree

Showing 3 changed files with 5 additions and 12 deletions.
diff --git a/SeeSharp/Integrators/Bidir/BidirBase.cs b/SeeSharp/Integrators/Bidir/BidirBase.cs
@@ -186,7 +186,6 @@ public override void Render(Scene scene) {
 
         ProgressBar progressBar = new(prefix: "Rendering...");
         progressBar.Start(NumIterations);
-        RNG camSeedGen = new(BaseSeedCamera);
         RenderTimer timer = new();
         Stopwatch lightTracerTimer = new();
         Stopwatch pathTracerTimer = new();
@@ -211,7 +210,7 @@ public override void Render(Scene scene) {
                 LightPaths.NumPaths = NumLightPaths.Value;
 
                 lightTracerTimer.Start();
-                LightPaths.TraceAllPaths(iter,
+                LightPaths.TraceAllPaths(BaseSeedLight, iter,
                     (origin, primary, nextDirection) => NextEventPdf(primary, origin));
                 ProcessPathCache();
                 lightTracerTimer.Stop();

diff --git a/SeeSharp/Integrators/Bidir/LightPathCache.cs b/SeeSharp/Integrators/Bidir/LightPathCache.cs
@@ -16,12 +16,6 @@ public class LightPathCache {
     /// </summary>
     public int MaxDepth;
 
-    /// <summary>
-    /// Seed that is hashed with the iteration and path index to generate a random number sequence
-    /// for each light path.
-    /// </summary>
-    public uint BaseSeed = 0xC030114u;
-
     /// <summary>
     /// The scene that is being rendered
     /// </summary>
@@ -124,11 +118,12 @@ public virtual (Ray, RgbColor, float) SampleBackground(ref RNG rng) {
     /// <summary>
     /// Resets the path cache and populates it with a new set of light paths.
     /// </summary>
+    /// <param name="seed">Base seed for the random number generator, hashed with the iteration to obtain the actual seed.</param>
     /// <param name="iter">Index of the current iteration, used to seed the random number generator.</param>
     /// <param name="nextEventPdfCallback">
     /// Delegate that is invoked to compute the next event sampling density
     /// </param>
-    public virtual void TraceAllPaths(uint iter, LightPathWalk.NextEventPdfCallback nextEventPdfCallback) {
+    public virtual void TraceAllPaths(uint seed, uint iter, LightPathWalk.NextEventPdfCallback nextEventPdfCallback) {
         if (PathCache == null)
             PathCache = new PathCache(NumPaths, Math.Min(MaxDepth + 1, 10));
         else if (NumPaths != PathCache.NumPaths) {
@@ -141,7 +136,7 @@ public virtual void TraceAllPaths(uint iter, LightPathWalk.NextEventPdfCallback
         LightPathWalk walkModifier = new(PathCache, nextEventPdfCallback);
 
         Parallel.For(0, NumPaths, idx => {
-            var rng = new RNG(BaseSeed, (uint)idx, iter);
+            var rng = new RNG(seed, (uint)idx, iter);
             TraceLightPath(ref rng, idx, walkModifier);
         });
 

diff --git a/SeeSharp/Integrators/Bidir/PhotonMapper.cs b/SeeSharp/Integrators/Bidir/PhotonMapper.cs
@@ -54,14 +54,13 @@ public override void Render(Scene scene) {
             MaxDepth = MaxDepth,
             NumPaths = NumLightPaths,
             Scene = scene,
-            BaseSeed = BaseSeedLight
         };
 
         if (photonMap == null) photonMap = new();
 
         for (uint iter = 0; iter < NumIterations; ++iter) {
             scene.FrameBuffer.StartIteration();
-            lightPaths.TraceAllPaths(iter, null);
+            lightPaths.TraceAllPaths(BaseSeedLight, iter, null);
             ProcessPathCache();
             TraceAllCameraPaths(iter);
             scene.FrameBuffer.EndIteration();