1/*
2 * Copyright 2011-2013 Blender Foundation
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "stdcycles.h"
18
19shader node_normal_map(normal NormalIn = N,
20                       float Strength = 1.0,
21                       color Color = color(0.5, 0.5, 1.0),
22                       string space = "tangent",
23                       string attr_name = "geom:tangent",
24                       string attr_sign_name = "geom:tangent_sign",
25                       output normal Normal = NormalIn)
26{
27  color mcolor = 2.0 * color(Color[0] - 0.5, Color[1] - 0.5, Color[2] - 0.5);
28  int is_backfacing = backfacing();
29
30  if (space == "tangent") {
31    vector tangent;
32    vector ninterp;
33    float tangent_sign;
34    float is_smooth;
35
36    getattribute("geom:is_smooth", is_smooth);
37    if (!is_smooth) {
38      ninterp = normalize(transform("world", "object", Ng));
39
40      /* the normal is already inverted, which is too soon for the math here */
41      if (is_backfacing) {
42        ninterp = -ninterp;
43      }
44    }
45
46    // get _unnormalized_ interpolated normal and tangent
47    if (getattribute(attr_name, tangent) && getattribute(attr_sign_name, tangent_sign) &&
48        (!is_smooth || getattribute("geom:N", ninterp))) {
49      // apply normal map
50      vector B = tangent_sign * cross(ninterp, tangent);
51      Normal = normalize(mcolor[0] * tangent + mcolor[1] * B + mcolor[2] * ninterp);
52
53      // transform to world space
54      Normal = normalize(transform("object", "world", Normal));
55    }
56    else {
57      Normal = normal(0, 0, 0);
58    }
59  }
60  else if (space == "object") {
61    Normal = normalize(transform("object", "world", vector(mcolor)));
62  }
63  else if (space == "world") {
64    Normal = normalize(vector(mcolor));
65  }
66  else if (space == "blender_object") {
67    /* strange blender convention */
68    mcolor[1] = -mcolor[1];
69    mcolor[2] = -mcolor[2];
70
71    Normal = normalize(transform("object", "world", vector(mcolor)));
72  }
73  else if (space == "blender_world") {
74    /* strange blender convention */
75    mcolor[1] = -mcolor[1];
76    mcolor[2] = -mcolor[2];
77
78    Normal = normalize(vector(mcolor));
79  }
80
81  /* invert normal for backfacing polygons */
82  if (is_backfacing) {
83    Normal = -Normal;
84  }
85
86  if (Strength != 1.0)
87    Normal = normalize(NormalIn + (Normal - NormalIn) * max(Strength, 0.0));
88
89  Normal = ensure_valid_reflection(Ng, I, Normal);
90}
91