From e3b8a01231d97930b8061b868538f9948445648b Mon Sep 17 00:00:00 2001
From: Peregrine05 <92183530+Peregrine05@users.noreply.github.com>
Date: Mon, 6 Nov 2023 01:04:47 +0100
Subject: [PATCH] Revert "Diffuse sampling fog"

---
 .../chunky/renderer/scene/PathTracer.java     | 74 ++++---------------
 1 file changed, 16 insertions(+), 58 deletions(-)

diff --git a/chunky/src/java/se/llbit/chunky/renderer/scene/PathTracer.java b/chunky/src/java/se/llbit/chunky/renderer/scene/PathTracer.java
index 924f219f2e..a5642ef704 100644
--- a/chunky/src/java/se/llbit/chunky/renderer/scene/PathTracer.java
+++ b/chunky/src/java/se/llbit/chunky/renderer/scene/PathTracer.java
@@ -256,65 +256,23 @@ private static boolean doParticleFogReflection(Ray ray, Ray next, VolumeMaterial
         cumulativeColor.z += emittance.z + ray.color.z * (directLightB * scene.sun.emittance.z + next.color.z);
       }
     } else {
-      double sun_az = scene.sun().getAzimuth();
-      double sun_alt = scene.sun().getAltitude();
-      Vector3 sun_dir = new Vector3(FastMath.cos(sun_az)*FastMath.cos(sun_alt), FastMath.sin(sun_alt), FastMath.sin(sun_az)*FastMath.cos(sun_alt));
-      double circle_radius = scene.sun().getSunRadius() * scene.sun().getDiffuseSampleRadius();
-      double sample_chance = scene.sun().getDiffuseSampleChance();
-      double sample_area = (1 - FastMath.cos(circle_radius))*2*Math.PI;
-      if(Math.abs(currentMat.anisotropy) < 0.99 && scene.getSunSamplingStrategy().isDiffuseSampling()) {
-        if(random.nextDouble() < sample_chance) {
-          // Generate random sun direction assuming sun is directly overhead
-          double ay = random.nextDouble(FastMath.cos(circle_radius), 1);
-          double phi = random.nextDouble(2*Math.PI);
-          double ax = FastMath.sqrt(1 - ay * ay)*FastMath.sin(phi);
-          double az = FastMath.sqrt(1 - ay * ay)*FastMath.cos(phi);
-          // Transform to actual sun position
-          double bx = ax * FastMath.sin(sun_alt) + ay * FastMath.cos(sun_alt);
-          double by = -ax * FastMath.cos(sun_alt) + ay * FastMath.sin(sun_alt);
-          double cx = bx * FastMath.cos(sun_az) - az * FastMath.sin(sun_az);
-          double cz = bx * FastMath.sin(sun_az) + az * FastMath.cos(sun_az);
-          next.d.set(cx, by, cz);
-          double pdf = phaseHG(inboundDirection.dot(next.d), currentMat.anisotropy);
-          hit |= pathTrace(scene, next, state, false);
-          if (hit) {
-            cumulativeColor.x += (emittance.x + ray.color.x * (next.color.x)) * pdf * sample_area / sample_chance;
-            cumulativeColor.y += (emittance.y + ray.color.y * (next.color.y)) * pdf * sample_area / sample_chance;
-            cumulativeColor.z += (emittance.z + ray.color.z * (next.color.z)) * pdf * sample_area / sample_chance;
-          }
-        } else {
-          while(true) {
-            double z = random.nextDouble(-1, 1);
-            double rho = FastMath.sqrt(1 - z * z);
-            double phi = random.nextDouble(2*Math.PI);
-            next.d.set(rho*FastMath.cos(phi), rho*FastMath.sin(phi), z);
-            if(next.d.dot(sun_dir) > FastMath.cos(circle_radius)) {
-              continue;
-            }
-            double pdf = phaseHG(inboundDirection.dot(next.d), currentMat.anisotropy);
-            hit |= pathTrace(scene, next, state, false);
-            if (hit) {
-              cumulativeColor.x += (emittance.x + ray.color.x * (next.color.x)) * pdf * (4*Math.PI - sample_area) / (1 - sample_chance);
-              cumulativeColor.y += (emittance.y + ray.color.y * (next.color.y)) * pdf * (4*Math.PI - sample_area) / (1 - sample_chance);
-              cumulativeColor.z += (emittance.z + ray.color.z * (next.color.z)) * pdf * (4*Math.PI - sample_area) / (1 - sample_chance);
-            }
-            break;
-          }
-        }
-      } else {
-        Vector3 outboundDirection = new Vector3();
-        double x1 = random.nextDouble();
-        double x2 = random.nextDouble();
-        henyeyGreensteinSampleP(currentMat.anisotropy, inboundDirection, outboundDirection, x1, x2);
-        next.d.set(outboundDirection);
-        next.d.normalize();
-        hit |= pathTrace(scene, next, state, false);
-        if (hit) {
-          cumulativeColor.x += emittance.x + ray.color.x * (next.color.x);
-          cumulativeColor.y += emittance.y + ray.color.y * (next.color.y);
-          cumulativeColor.z += emittance.z + ray.color.z * (next.color.z);
-        }
+      Vector4 rayColor = new Vector4(ray.color);
+
+      Vector3 outboundDirection = new Vector3();
+      double x1 = random.nextDouble();
+      double x2 = random.nextDouble();
+      henyeyGreensteinSampleP(currentMat.anisotropy, inboundDirection, outboundDirection, x1, x2);
+      next.d.set(outboundDirection);
+      next.d.normalize();
+
+      hit |= pathTrace(scene, next, state, false);
+      if (hit) {
+        cumulativeColor.x += emittance.x + ray.color.x * (next.color.x);
+        cumulativeColor.y += emittance.y + ray.color.y * (next.color.y);
+        cumulativeColor.z += emittance.z + ray.color.z * (next.color.z);
       }
+      ray.color.set(rayColor);
+
     }
     return hit;
   }