update Collada Importer: reworked export and import of Materials

- added import of transparency and emission into principled BSDF Shader
- added support for importing all default collada material parameters

  * diffuse
  * emission
  * index_of_refraction
  * shininess (mapped to BSDF Roughness)
  * reflectivity (mapped to BSDF Metallic)
  * transparency + transparent mapped to BSDF Alpha)
  * ambient (creates unconnected texture node)
  * specular (creates unconnected texture node)
  * reflective(creates unconnected texture node)

- added support for exporting collada material parameters:

  * diffuse
  * emission
  * index_of_refraction
  * shininess (mapped to BSDF Roughness)
  * reflectivity (mapped to BSDF Metallic)
  * transparency + transparent mapped to BSDF Alpha)

- prepared support for exporting the following parameters
  but currently commented out:

  * ambient (creates unconnected texture node)
  * specular (creates unconnected texture node)
  * reflective(creates unconnected texture node)

  Problem: For now we only allow export of principled BSDF based
  materials. I am not sure from where to get ambient, specular
  and reflective as those values are not included in the
  principled BSDF Shader (wip).

1 files changed, 70 insertions, 45 deletions

diff --git a/source/blender/collada/collada_utils.cpp b/source/blender/collada/collada_utils.cpp
index 50dc1d8d658..dd5611c4bef 100644
--- a/source/blender/collada/collada_utils.cpp
+++ b/source/blender/collada/collada_utils.cpp
@@ -1321,92 +1321,110 @@ void bc_add_default_shader(bContext *C, Material *ma)
 
 COLLADASW::ColorOrTexture bc_get_base_color(Material *ma)
 {
-  bNode *master_shader = bc_get_master_shader(ma);
-  if (ma->use_nodes && master_shader) {
-    return bc_get_base_color(master_shader);
+  Color default_color = {0.8, 0.8, 0.8, 1.0};
+  bNode *shader = bc_get_master_shader(ma);
+  if (ma->use_nodes && shader) {
+    return bc_get_cot_from_shader(shader, "Base Color", default_color);
   }
   else {
-    return bc_get_cot(ma->r, ma->g, ma->b, ma->a);
+    return bc_get_cot(default_color);
   }
 }
 
-COLLADASW::ColorOrTexture bc_get_base_color(bNode *shader)
+COLLADASW::ColorOrTexture bc_get_emission(Material *ma)
 {
-  bNodeSocket *socket = nodeFindSocket(shader, SOCK_IN, "Base Color");
-  if (socket) {
-    bNodeSocketValueRGBA *dcol = (bNodeSocketValueRGBA *)socket->default_value;
-    float *col = dcol->value;
-    return bc_get_cot(col[0], col[1], col[2], col[3]);
+  Color default_color = {0, 0, 0, 1};
+  bNode *shader = bc_get_master_shader(ma);
+  if (ma->use_nodes && shader) {
+    return bc_get_cot_from_shader(shader, "Emission", default_color);
   }
   else {
-    return bc_get_cot(0.8, 0.8, 0.8, 1.0); /* default white */
+    return bc_get_cot(default_color); /* default black */
   }
 }
 
-COLLADASW::ColorOrTexture bc_get_emission(Material *ma)
+COLLADASW::ColorOrTexture bc_get_ambient(Material *ma)
+{
+  Color default_color = {0, 0, 0, 1.0};
+  return bc_get_cot(default_color);
+}
+
+COLLADASW::ColorOrTexture bc_get_specular(Material *ma)
+{
+  Color default_color = {0, 0, 0, 1.0};
+  return bc_get_cot(default_color);
+}
+
+COLLADASW::ColorOrTexture bc_get_reflective(Material *ma)
+{
+  Color default_color = {0, 0, 0, 1.0};
+  return bc_get_cot(default_color);
+}
+
+double bc_get_alpha(Material *ma)
 {
+  double alpha = ma->a; /* fallback if no socket found */
   bNode *master_shader = bc_get_master_shader(ma);
   if (ma->use_nodes && master_shader) {
-    return bc_get_emission(master_shader);
-  }
-  else {
-    return bc_get_cot(0, 0, 0, 1); /* default black */
+    bc_get_float_from_shader(master_shader, alpha, "Alpha");
   }
+  return alpha;
 }
 
-COLLADASW::ColorOrTexture bc_get_emission(bNode *shader)
+double bc_get_ior(Material *ma)
 {
-  bNodeSocket *socket = nodeFindSocket(shader, SOCK_IN, "Emission");
-  if (socket) {
-    bNodeSocketValueRGBA *dcol = (bNodeSocketValueRGBA *)socket->default_value;
-    float *col = dcol->value;
-    return bc_get_cot(col[0], col[1], col[2], col[3]);
-  }
-  else {
-    return bc_get_cot(0, 0, 0, 1); /* default black */
+  double ior = -1; /* fallback if no socket found */
+  bNode *master_shader = bc_get_master_shader(ma);
+  if (ma->use_nodes && master_shader) {
+    bc_get_float_from_shader(master_shader, ior, "IOR");
   }
+  return ior;
 }
 
-bool bc_get_reflectivity(bNode *shader, double &reflectivity)
+double bc_get_shininess(Material *ma)
 {
-  bNodeSocket *socket = nodeFindSocket(shader, SOCK_IN, "Specular");
-  if (socket) {
-    bNodeSocketValueFloat *ref = (bNodeSocketValueFloat *)socket->default_value;
-    reflectivity = (double)ref->value;
-    return true;
+  double ior = -1; /* fallback if no socket found */
+  bNode *master_shader = bc_get_master_shader(ma);
+  if (ma->use_nodes && master_shader) {
+    bc_get_float_from_shader(master_shader, ior, "Roughness");
   }
-  return false;
+  return ior;
 }
 
-double bc_get_alpha(Material *ma)
+double bc_get_reflectivity(Material *ma)
 {
-  double alpha = ma->a; /* fallback if no socket found */
+  double reflectivity = ma->spec; /* fallback if no socket found */
   bNode *master_shader = bc_get_master_shader(ma);
   if (ma->use_nodes && master_shader) {
-    bc_get_alpha(master_shader, alpha);
+    bc_get_float_from_shader(master_shader, reflectivity, "Metallic");
   }
-  return alpha;
+  return reflectivity;
 }
 
-bool bc_get_alpha(bNode *shader, double &alpha)
+double bc_get_float_from_shader(bNode *shader, double &val, std::string nodeid)
 {
-  bNodeSocket *socket = nodeFindSocket(shader, SOCK_IN, "Alpha");
+  bNodeSocket *socket = nodeFindSocket(shader, SOCK_IN, nodeid.c_str());
   if (socket) {
     bNodeSocketValueFloat *ref = (bNodeSocketValueFloat *)socket->default_value;
-    alpha = (double)ref->value;
+    val = (double)ref->value;
     return true;
   }
   return false;
 }
 
-double bc_get_reflectivity(Material *ma)
+COLLADASW::ColorOrTexture bc_get_cot_from_shader(bNode *shader,
+                                                 std::string nodeid,
+                                                 Color &default_color)
 {
-  double reflectivity = ma->spec; /* fallback if no socket found */
-  bNode *master_shader = bc_get_master_shader(ma);
-  if (ma->use_nodes && master_shader) {
-    bc_get_reflectivity(master_shader, reflectivity);
+  bNodeSocket *socket = nodeFindSocket(shader, SOCK_IN, nodeid.c_str());
+  if (socket) {
+    bNodeSocketValueRGBA *dcol = (bNodeSocketValueRGBA *)socket->default_value;
+    float *col = dcol->value;
+    return bc_get_cot(col);
+  }
+  else {
+    return bc_get_cot(default_color); /* default black */
   }
-  return reflectivity;
 }
 
 bNode *bc_get_master_shader(Material *ma)
@@ -1428,3 +1446,10 @@ COLLADASW::ColorOrTexture bc_get_cot(float r, float g, float b, float a)
   COLLADASW::ColorOrTexture cot(color);
   return cot;
 }
+
+COLLADASW::ColorOrTexture bc_get_cot(Color col)
+{
+  COLLADASW::Color color(col[0], col[1], col[2], col[3]);
+  COLLADASW::ColorOrTexture cot(color);
+  return cot;
+}