1 files changed, 40 insertions, 28 deletions

diff --git a/intern/cycles/kernel/svm/musgrave.h b/intern/cycles/kernel/svm/musgrave.h
index 521c96d9f37..8bf172f0981 100644
--- a/intern/cycles/kernel/svm/musgrave.h
+++ b/intern/cycles/kernel/svm/musgrave.h
@@ -119,13 +119,12 @@ ccl_device_noinline_cpu float noise_musgrave_hybrid_multi_fractal_1d(
 {
   float p = co;
   float pwHL = powf(lacunarity, -H);
-  float pwr = pwHL;
 
-  float value = snoise_1d(p) + offset;
-  float weight = gain * value;
-  p *= lacunarity;
+  float pwr = 1.0f;
+  float value = 0.0f;
+  float weight = 1.0f;
 
-  for (int i = 1; (weight > 0.001f) && (i < float_to_int(octaves)); i++) {
+  for (int i = 0; (weight > 0.001f) && (i < float_to_int(octaves)); i++) {
     if (weight > 1.0f) {
       weight = 1.0f;
     }
@@ -138,8 +137,12 @@ ccl_device_noinline_cpu float noise_musgrave_hybrid_multi_fractal_1d(
   }
 
   float rmd = octaves - floorf(octaves);
-  if (rmd != 0.0f) {
-    value += rmd * ((snoise_1d(p) + offset) * pwr);
+  if ((rmd != 0.0f) && (weight > 0.001f)) {
+    if (weight > 1.0f) {
+      weight = 1.0f;
+    }
+    float signal = (snoise_1d(p) + offset) * pwr;
+    value += rmd * weight * signal;
   }
 
   return value;
@@ -290,13 +293,12 @@ ccl_device_noinline_cpu float noise_musgrave_hybrid_multi_fractal_2d(
 {
   float2 p = co;
   float pwHL = powf(lacunarity, -H);
-  float pwr = pwHL;
 
-  float value = snoise_2d(p) + offset;
-  float weight = gain * value;
-  p *= lacunarity;
+  float pwr = 1.0f;
+  float value = 0.0f;
+  float weight = 1.0f;
 
-  for (int i = 1; (weight > 0.001f) && (i < float_to_int(octaves)); i++) {
+  for (int i = 0; (weight > 0.001f) && (i < float_to_int(octaves)); i++) {
     if (weight > 1.0f) {
       weight = 1.0f;
     }
@@ -309,8 +311,12 @@ ccl_device_noinline_cpu float noise_musgrave_hybrid_multi_fractal_2d(
   }
 
   float rmd = octaves - floorf(octaves);
-  if (rmd != 0.0f) {
-    value += rmd * ((snoise_2d(p) + offset) * pwr);
+  if ((rmd != 0.0f) && (weight > 0.001f)) {
+    if (weight > 1.0f) {
+      weight = 1.0f;
+    }
+    float signal = (snoise_2d(p) + offset) * pwr;
+    value += rmd * weight * signal;
   }
 
   return value;
@@ -461,13 +467,12 @@ ccl_device_noinline_cpu float noise_musgrave_hybrid_multi_fractal_3d(
 {
   float3 p = co;
   float pwHL = powf(lacunarity, -H);
-  float pwr = pwHL;
 
-  float value = snoise_3d(p) + offset;
-  float weight = gain * value;
-  p *= lacunarity;
+  float pwr = 1.0f;
+  float value = 0.0f;
+  float weight = 1.0f;
 
-  for (int i = 1; (weight > 0.001f) && (i < float_to_int(octaves)); i++) {
+  for (int i = 0; (weight > 0.001f) && (i < float_to_int(octaves)); i++) {
     if (weight > 1.0f) {
       weight = 1.0f;
     }
@@ -480,8 +485,12 @@ ccl_device_noinline_cpu float noise_musgrave_hybrid_multi_fractal_3d(
   }
 
   float rmd = octaves - floorf(octaves);
-  if (rmd != 0.0f) {
-    value += rmd * ((snoise_3d(p) + offset) * pwr);
+  if ((rmd != 0.0f) && (weight > 0.001f)) {
+    if (weight > 1.0f) {
+      weight = 1.0f;
+    }
+    float signal = (snoise_3d(p) + offset) * pwr;
+    value += rmd * weight * signal;
   }
 
   return value;
@@ -632,13 +641,12 @@ ccl_device_noinline_cpu float noise_musgrave_hybrid_multi_fractal_4d(
 {
   float4 p = co;
   float pwHL = powf(lacunarity, -H);
-  float pwr = pwHL;
 
-  float value = snoise_4d(p) + offset;
-  float weight = gain * value;
-  p *= lacunarity;
+  float pwr = 1.0f;
+  float value = 0.0f;
+  float weight = 1.0f;
 
-  for (int i = 1; (weight > 0.001f) && (i < float_to_int(octaves)); i++) {
+  for (int i = 0; (weight > 0.001f) && (i < float_to_int(octaves)); i++) {
     if (weight > 1.0f) {
       weight = 1.0f;
     }
@@ -651,8 +659,12 @@ ccl_device_noinline_cpu float noise_musgrave_hybrid_multi_fractal_4d(
   }
 
   float rmd = octaves - floorf(octaves);
-  if (rmd != 0.0f) {
-    value += rmd * ((snoise_4d(p) + offset) * pwr);
+  if ((rmd != 0.0f) && (weight > 0.001f)) {
+    if (weight > 1.0f) {
+      weight = 1.0f;
+    }
+    float signal = (snoise_4d(p) + offset) * pwr;
+    value += rmd * weight * signal;
   }
 
   return value;