Layer Weight node support for Blender Internal Render

3 files changed, 24 insertions, 1 deletions

diff --git a/source/blender/render/extern/include/RE_shader_ext.h b/source/blender/render/extern/include/RE_shader_ext.h
index 73867de6b2e..ae389fdfd2e 100644
--- a/source/blender/render/extern/include/RE_shader_ext.h
+++ b/source/blender/render/extern/include/RE_shader_ext.h
@@ -218,6 +218,8 @@ int multitex_nodes(struct Tex *tex, float texvec[3], float dxt[3], float dyt[3],
 float RE_lamp_get_data(struct ShadeInput *shi, struct Object *lamp_obj, float col[4], float lv[3], float *dist, float shadow[4]);
 void RE_instance_get_particle_info(struct ObjectInstanceRen *obi, float *index, float *age, float *lifetime, float co[3], float *size, float vel[3], float angvel[3]);
 
+float RE_fresnel_dielectric(float incoming[3], float normal[3], float eta);
+
 /* shaded view and bake */
 struct Render;
 struct Image;
diff --git a/source/blender/render/intern/include/shading.h b/source/blender/render/intern/include/shading.h
index 27867eadbb4..13f16ce0bd7 100644
--- a/source/blender/render/intern/include/shading.h
+++ b/source/blender/render/intern/include/shading.h
@@ -99,7 +99,7 @@ ListBase *get_lights(struct ShadeInput *shi);
 float lamp_get_visibility(struct LampRen *lar, const float co[3], float lv[3], float *dist);
 void lamp_get_shadow(struct LampRen *lar, ShadeInput *shi, float inp, float shadfac[4], int do_real);
 
-float	fresnel_fac(const float view[3], const float vn[3], float fresnel, float fac);
+float fresnel_fac(const float view[3], const float vn[3], float fresnel, float fac);
 
 /* rayshade.c */
 extern void shade_ray(struct Isect *is, struct ShadeInput *shi, struct ShadeResult *shr);
diff --git a/source/blender/render/intern/source/shadeoutput.c b/source/blender/render/intern/source/shadeoutput.c
index 3d6462e09a0..c4de95e863e 100644
--- a/source/blender/render/intern/source/shadeoutput.c
+++ b/source/blender/render/intern/source/shadeoutput.c
@@ -2151,3 +2151,24 @@ const float (*RE_render_current_get_matrix(int matrix_id))[4]
 	}
 	return NULL;
 }
+
+float RE_fresnel_dielectric(float incoming[3], float normal[3], float eta)
+{
+	/* compute fresnel reflectance without explicitly computing
+	 * the refracted direction */
+	float c = fabs(dot_v3v3(incoming, normal));
+	float g = eta * eta - 1.0 + c * c;
+	float result;
+
+	if (g > 0.0) {
+		g = sqrtf(g);
+		float A = (g - c) / (g + c);
+		float B = (c * (g + c) - 1.0) / (c * (g - c) + 1.0);
+		result = 0.5 * A * A * (1.0 + B * B);
+	}
+	else {
+		result = 1.0;  /* TIR (no refracted component) */
+	}
+
+	return result;
+}
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