Fix T70605: incorrect darken and lighten rgb mix mode

Differential Revision: https://developer.blender.org/D6058

Reviewers: brecht, fclem

2 files changed, 4 insertions, 4 deletions

diff --git a/intern/cycles/kernel/shaders/node_mix.osl b/intern/cycles/kernel/shaders/node_mix.osl
index 8caea6803ed..9fbd3391ade 100644
--- a/intern/cycles/kernel/shaders/node_mix.osl
+++ b/intern/cycles/kernel/shaders/node_mix.osl
@@ -91,12 +91,12 @@ color node_mix_diff(float t, color col1, color col2)
 
 color node_mix_dark(float t, color col1, color col2)
 {
-  return min(col1, col2) * t + col1 * (1.0 - t);
+  return mix(col1, min(col1, col2), t);
 }
 
 color node_mix_light(float t, color col1, color col2)
 {
-  return max(col1, col2 * t);
+  return mix(col1, max(col1, col2), t);
 }
 
 color node_mix_dodge(float t, color col1, color col2)
diff --git a/intern/cycles/kernel/svm/svm_color_util.h b/intern/cycles/kernel/svm/svm_color_util.h
index 0f571eb7253..1a0fa03305e 100644
--- a/intern/cycles/kernel/svm/svm_color_util.h
+++ b/intern/cycles/kernel/svm/svm_color_util.h
@@ -92,12 +92,12 @@ ccl_device float3 svm_mix_diff(float t, float3 col1, float3 col2)
 
 ccl_device float3 svm_mix_dark(float t, float3 col1, float3 col2)
 {
-  return min(col1, col2) * t + col1 * (1.0f - t);
+  return interp(col1, min(col1, col2), t);
 }
 
 ccl_device float3 svm_mix_light(float t, float3 col1, float3 col2)
 {
-  return max(col1, col2 * t);
+  return interp(col1, max(col1, col2), t);
 }
 
 ccl_device float3 svm_mix_dodge(float t, float3 col1, float3 col2)