Fix T38439: allow IOR in range [0, inf] instead of [1, inf] in Cycles.

The same can be achieved by flipping normals on the mesh, but it can be
convenient to do this in the shader.

5 files changed, 6 insertions, 6 deletions

diff --git a/intern/cycles/kernel/shaders/node_fresnel.osl b/intern/cycles/kernel/shaders/node_fresnel.osl
index ca463817840..8c59d5bb512 100644
--- a/intern/cycles/kernel/shaders/node_fresnel.osl
+++ b/intern/cycles/kernel/shaders/node_fresnel.osl
@@ -22,7 +22,7 @@ shader node_fresnel(
 	normal Normal = N,
 	output float Fac = 0.0)
 {
-	float f = max(IOR, 1.0 + 1e-5);
+	float f = max(IOR, 1e-5);
 	float eta = backfacing() ? 1.0 / f: f;
 	float cosi = dot(I, Normal);
 	Fac = fresnel_dielectric_cos(cosi, eta);
diff --git a/intern/cycles/kernel/shaders/node_glass_bsdf.osl b/intern/cycles/kernel/shaders/node_glass_bsdf.osl
index c79785f2d65..96934199621 100644
--- a/intern/cycles/kernel/shaders/node_glass_bsdf.osl
+++ b/intern/cycles/kernel/shaders/node_glass_bsdf.osl
@@ -25,7 +25,7 @@ shader node_glass_bsdf(
 	normal Normal = N,
 	output closure color BSDF = 0)
 {
-	float f = max(IOR, 1.0 + 1e-5);
+	float f = max(IOR, 1e-5);
 	float eta = backfacing() ? 1.0 / f: f;
 	float cosi = dot(I, Normal);
 	float Fr = fresnel_dielectric_cos(cosi, eta);
diff --git a/intern/cycles/kernel/shaders/node_refraction_bsdf.osl b/intern/cycles/kernel/shaders/node_refraction_bsdf.osl
index a4e9d0825db..f87b3a5dd86 100644
--- a/intern/cycles/kernel/shaders/node_refraction_bsdf.osl
+++ b/intern/cycles/kernel/shaders/node_refraction_bsdf.osl
@@ -24,7 +24,7 @@ shader node_refraction_bsdf(
 	normal Normal = N,
 	output closure color BSDF = 0)
 {
-	float f = max(IOR, 1.0 + 1e-5);
+	float f = max(IOR, 1e-5);
 	float eta = backfacing() ? 1.0 / f: f;
 
 	if (distribution == "Sharp")
diff --git a/intern/cycles/kernel/svm/svm_closure.h b/intern/cycles/kernel/svm/svm_closure.h
index 42e66a79978..2813e38d8f7 100644
--- a/intern/cycles/kernel/svm/svm_closure.h
+++ b/intern/cycles/kernel/svm/svm_closure.h
@@ -225,7 +225,7 @@ ccl_device void svm_node_closure_bsdf(KernelGlobals *kg, ShaderData *sd, float *
 				sc->N = N;
 				sc->data0 = param1;
 
-				float eta = fmaxf(param2, 1.0f + 1e-5f);
+				float eta = fmaxf(param2, 1e-5f);
 				sc->data1 = (sd->flag & SD_BACKFACING)? 1.0f/eta: eta;
 
 				/* setup bsdf */
@@ -247,7 +247,7 @@ ccl_device void svm_node_closure_bsdf(KernelGlobals *kg, ShaderData *sd, float *
 				break;
 #endif
 			/* index of refraction */
-			float eta = fmaxf(param2, 1.0f + 1e-5f);
+			float eta = fmaxf(param2, 1e-5f);
 			eta = (sd->flag & SD_BACKFACING)? 1.0f/eta: eta;
 
 			/* fresnel */
diff --git a/intern/cycles/kernel/svm/svm_fresnel.h b/intern/cycles/kernel/svm/svm_fresnel.h
index 0a3d576cfe1..5def52205eb 100644
--- a/intern/cycles/kernel/svm/svm_fresnel.h
+++ b/intern/cycles/kernel/svm/svm_fresnel.h
@@ -25,7 +25,7 @@ ccl_device void svm_node_fresnel(ShaderData *sd, float *stack, uint ior_offset,
 	float eta = (stack_valid(ior_offset))? stack_load_float(stack, ior_offset): __uint_as_float(ior_value);
 	float3 normal_in = stack_valid(normal_offset)? stack_load_float3(stack, normal_offset): sd->N;
 	
-	eta = fmaxf(eta, 1.0f + 1e-5f);
+	eta = fmaxf(eta, 1e-5f);
 	eta = (sd->flag & SD_BACKFACING)? 1.0f/eta: eta;
 
 	float f = fresnel_dielectric_cos(dot(sd->I, normal_in), eta);