From 12e1732f72bba6905da834a565885d4e8ecf9dc9 Mon Sep 17 00:00:00 2001
From: Alexander Romanov <a.romanov@blend4web.com>
Date: Thu, 15 Dec 2016 15:03:28 +0300
Subject: Layer Weight node support for Blender Internal Render

---
 .../nodes/shader/nodes/node_shader_fresnel.c       | 23 +--------------
 .../nodes/shader/nodes/node_shader_layer_weight.c  | 34 ++++++++++++++++++++--
 2 files changed, 33 insertions(+), 24 deletions(-)

(limited to 'source/blender/nodes')

diff --git a/source/blender/nodes/shader/nodes/node_shader_fresnel.c b/source/blender/nodes/shader/nodes/node_shader_fresnel.c
index 917a06b3536..d5e11795fc0 100644
--- a/source/blender/nodes/shader/nodes/node_shader_fresnel.c
+++ b/source/blender/nodes/shader/nodes/node_shader_fresnel.c
@@ -51,27 +51,6 @@ static int node_shader_gpu_fresnel(GPUMaterial *mat, bNode *UNUSED(node), bNodeE
 	return GPU_stack_link(mat, "node_fresnel", in, out, GPU_builtin(GPU_VIEW_POSITION));
 }
 
-static float 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;
-}
-
 static void node_shader_exec_fresnel(void *data, int UNUSED(thread), bNode *UNUSED(node), bNodeExecData *UNUSED(execdata), bNodeStack **in, bNodeStack **out)
 {
 	ShadeInput *shi = ((ShaderCallData *)data)->shi;
@@ -88,7 +67,7 @@ static void node_shader_exec_fresnel(void *data, int UNUSED(thread), bNode *UNUS
 	if(shi->use_world_space_shading)
 		mul_mat3_m4_v3((float (*)[4])RE_render_current_get_matrix(RE_VIEW_MATRIX), n);
 
-	out[0]->vec[0] = fresnel_dielectric(shi->view, n, shi->flippednor ? 1/eta : eta);
+	out[0]->vec[0] = RE_fresnel_dielectric(shi->view, n, shi->flippednor ? 1/eta : eta);
 }
 
 /* node type definition */
diff --git a/source/blender/nodes/shader/nodes/node_shader_layer_weight.c b/source/blender/nodes/shader/nodes/node_shader_layer_weight.c
index 8cbc587e339..90e2625b961 100644
--- a/source/blender/nodes/shader/nodes/node_shader_layer_weight.c
+++ b/source/blender/nodes/shader/nodes/node_shader_layer_weight.c
@@ -45,23 +45,53 @@ static int node_shader_gpu_layer_weight(GPUMaterial *mat, bNode *UNUSED(node), b
 {
 	if (!in[1].link)
 		in[1].link = GPU_builtin(GPU_VIEW_NORMAL);
-	else
+	else if (GPU_material_use_world_space_shading(mat)) {
 		GPU_link(mat, "direction_transform_m4v3", in[1].link, GPU_builtin(GPU_VIEW_MATRIX), &in[1].link);
+	}
 
 	return GPU_stack_link(mat, "node_layer_weight", in, out, GPU_builtin(GPU_VIEW_POSITION));
 }
 
+static void node_shader_exec_layer_weight(void *data, int UNUSED(thread), bNode *UNUSED(node), bNodeExecData *UNUSED(execdata), bNodeStack **in, bNodeStack **out)
+{
+	ShadeInput *shi = ((ShaderCallData *)data)->shi;
+	float blend = in[0]->vec[0];
+	float eta = max_ff(1 - blend, 0.00001);
+
+	float n[3];
+	if (in[1]->hasinput) {
+		copy_v3_v3(n, in[1]->vec);
+	}
+	else {
+		copy_v3_v3(n, shi->vn);
+	}
+
+	if (shi->use_world_space_shading)
+		mul_mat3_m4_v3((float (*)[4])RE_render_current_get_matrix(RE_VIEW_MATRIX), n);
+
+	out[0]->vec[0] = RE_fresnel_dielectric(shi->view, n, shi->flippednor ? eta : 1/eta);
+
+	float facing = fabs(dot_v3v3(shi->view, n));
+	if (blend != 0.5) {
+		CLAMP(blend, 0.0, 0.99999);
+		blend = (blend < 0.5) ? 2.0 * blend : 0.5 / (1.0 - blend);
+		facing = pow(facing, blend);
+	}
+	out[1]->vec[0] = 1.0 - facing;
+}
+
 /* node type definition */
 void register_node_type_sh_layer_weight(void)
 {
 	static bNodeType ntype;
 
 	sh_node_type_base(&ntype, SH_NODE_LAYER_WEIGHT, "Layer Weight", NODE_CLASS_INPUT, 0);
-	node_type_compatibility(&ntype, NODE_NEW_SHADING);
+	node_type_compatibility(&ntype, NODE_NEW_SHADING | NODE_OLD_SHADING);
 	node_type_socket_templates(&ntype, sh_node_layer_weight_in, sh_node_layer_weight_out);
 	node_type_init(&ntype, NULL);
 	node_type_storage(&ntype, "", NULL, NULL);
 	node_type_gpu(&ntype, node_shader_gpu_layer_weight);
+	node_type_exec(&ntype, NULL, NULL, node_shader_exec_layer_weight);
 
 	nodeRegisterType(&ntype);
 }
-- 
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