indice-aware calculate_tangents

Model3d.cpp

@@ -685,8 +685,8 @@ std::pair<int, int> TSubModel::Load( cParser &parser, bool dynamic )
 					    }
                     }
                     Vertices.resize( m_geometry.vertex_count ); // in case we had some degenerate triangles along the way
-                    gfx::calculate_tangents( Vertices, GL_TRIANGLES );
                     gfx::calculate_indices( Indices, Vertices );
+                    gfx::calculate_tangents( Vertices, Indices, GL_TRIANGLES );
                     // update values potentially changed by indexing
                     m_geometry.index_count = Indices.size();
                     m_geometry.vertex_count = Vertices.size();

geometrybank.cpp

@@ -67,7 +67,7 @@ basic_vertex::deserialize_packed( std::istream &s, bool const Tangent ) {
 // based on
 // Lengyel, Eric. “Computing Tangent Space Basis Vectors for an Arbitrary Mesh”.
 // Terathon Software, 2001. http://terathon.com/code/tangent.html
-void calculate_tangents(vertex_array &vertices, int type)
+void calculate_tangents(vertex_array &vertices, const index_array &indices, int type)
 {
     size_t vertex_count = vertices.size();
 
@@ -75,12 +75,14 @@ void calculate_tangents(vertex_array &vertices, int type)
         return;
 
     size_t triangle_count;
+    size_t tri_count_base = indices.empty() ? vertex_count : indices.size();
+
     if (type == GL_TRIANGLES)
-        triangle_count = vertex_count / 3;
+        triangle_count = tri_count_base / 3;
     else if (type == GL_TRIANGLE_STRIP)
-        triangle_count = vertex_count - 2;
+        triangle_count = tri_count_base - 2;
     else if (type == GL_TRIANGLE_FAN)
-        triangle_count = vertex_count - 2;
+        triangle_count = tri_count_base - 2;
     else
         return;
 
@@ -116,6 +118,12 @@ void calculate_tangents(vertex_array &vertices, int type)
             i3 = a + 2;
         }
 
+        if (!indices.empty()) {
+            i1 = indices[i1];
+            i2 = indices[i2];
+            i3 = indices[i3];
+        }
+
         const glm::vec3 &v1 = vertices[i1].position;
         const glm::vec3 &v2 = vertices[i2].position;
         const glm::vec3 &v3 = vertices[i3].position;
@@ -198,14 +206,10 @@ void calculate_indices( index_array &Indices, vertex_array &Vertices ) {
             ++matchiter;
             if( ( glm::all( glm::epsilonEqual( vertex.position, matchiter->position, matchtolerance ) ) )
              && ( glm::all( glm::epsilonEqual( vertex.normal,   matchiter->normal, matchtolerance ) ) )
-             && ( glm::all( glm::epsilonEqual( vertex.texture,  matchiter->texture, matchtolerance ) ) )
+             && ( glm::all( glm::epsilonEqual( vertex.texture,  matchiter->texture, matchtolerance ) ) ) ) {
-             && ( vertex.tangent.w == matchiter->tangent.w ) ) {
                 Indices[ matchidx ] = Indices[ idx ];
-                // HACK, TODO: tangent math winged/adapted from opengl-tutorial.org 13, check if it makes any sense
-                vertex.tangent += glm::vec4{ glm::vec3( matchiter->tangent ), 0.f };
             }
         }
-        vertex.tangent = { glm::normalize( glm::vec3{ vertex.tangent } ), vertex.tangent.w };
         indexedvertices.emplace_back( vertex );
     }
     // done indexing, swap the source vertex bank with the processed one

geometrybank.h

@@ -52,7 +52,7 @@ using basic_index = std::uint32_t;
 using vertex_array = std::vector<basic_vertex>;
 using index_array = std::vector<basic_index>;
 
-void calculate_tangents( vertex_array &vertices, int type );
+void calculate_tangents(vertex_array &vertices, const index_array &indices, int type );
 void calculate_indices( index_array &Indices, vertex_array &Vertices );
 
 // generic geometry bank class, allows storage, update and drawing of geometry chunks

opengl33renderer.cpp

@@ -1860,7 +1860,7 @@ gfx::geometry_handle opengl33_renderer::Insert( gfx::index_array &Indices, gfx::
 // creates a new geometry chunk of specified type from supplied data, in specified bank. returns: handle to the chunk or NULL
 gfx::geometry_handle opengl33_renderer::Insert(gfx::vertex_array &Vertices, gfx::geometrybank_handle const &Geometry, int const Type)
 {
-	gfx::calculate_tangents(Vertices, Type);
+    gfx::calculate_tangents(Vertices, gfx::index_array(), Type);
 
 	return m_geometry.create_chunk(Vertices, Geometry, Type);
 }
@@ -1868,7 +1868,7 @@ gfx::geometry_handle opengl33_renderer::Insert(gfx::vertex_array &Vertices, gfx:
 // replaces data of specified chunk with the supplied vertex data, starting from specified offset
 bool opengl33_renderer::Replace(gfx::vertex_array &Vertices, gfx::geometry_handle const &Geometry, int const Type, std::size_t const Offset)
 {
-	gfx::calculate_tangents(Vertices, Type);
+    gfx::calculate_tangents(Vertices, gfx::index_array(), Type);
 
 	return m_geometry.replace(Vertices, Geometry, Offset);
 }
@@ -1876,7 +1876,7 @@ bool opengl33_renderer::Replace(gfx::vertex_array &Vertices, gfx::geometry_handl
 // adds supplied vertex data at the end of specified chunk
 bool opengl33_renderer::Append(gfx::vertex_array &Vertices, gfx::geometry_handle const &Geometry, int const Type)
 {
-	gfx::calculate_tangents(Vertices, Type);
+    gfx::calculate_tangents(Vertices, gfx::index_array(), Type);
 
 	return m_geometry.append(Vertices, Geometry);
 }

vr/openvr_imp.cpp

@@ -154,7 +154,7 @@ void vr_openvr::begin_frame()
                                            glm::vec2(vertex->rfTextureCoord[0], vertex->rfTextureCoord[1])));
                 }
 
-                gfx::calculate_tangents(vertices, GL_TRIANGLES);
+                gfx::calculate_tangents(vertices, indices, GL_TRIANGLES);
 
                 submodel_name = std::string(component == -1 ? rendermodel_name : component_name);
                 sm = controllers[i]->model->AppendChildFromGeometry(submodel_name, "__root", vertices, indices);