Collada importer: Add support for line strip primitives

code/ColladaParser.cpp

@@ -2231,7 +2231,7 @@ void ColladaParser::ReadIndexData( Mesh* pMesh)
     }
 
 #ifdef ASSIMP_BUILD_DEBUG
-	if (primType != Prim_TriFans && primType != Prim_TriStrips &&
+	if (primType != Prim_TriFans && primType != Prim_TriStrips && primType != Prim_LineStrip &&
         primType != Prim_Lines) { // this is ONLY to workaround a bug in SketchUp 15.3.331 where it writes the wrong 'count' when it writes out the 'lines'.
         ai_assert(actualPrimitives == numPrimitives);
     }
@@ -2400,6 +2400,10 @@ size_t ColladaParser::ReadPrimitives( Mesh* pMesh, std::vector<InputChannel>& pP
         size_t numberOfVertices = indices.size() / numOffsets;
         numPrimitives = numberOfVertices - 2;
     }
+    if (pPrimType == Prim_LineStrip) {
+        size_t numberOfVertices = indices.size() / numOffsets;
+        numPrimitives = numberOfVertices - 1;
+    }
 
     pMesh->mFaceSize.reserve( numPrimitives);
     pMesh->mFacePosIndices.reserve( indices.size() / numOffsets);
@@ -2416,6 +2420,11 @@ size_t ColladaParser::ReadPrimitives( Mesh* pMesh, std::vector<InputChannel>& pP
                 for (size_t currentVertex = 0; currentVertex < numPoints; currentVertex++)
                     CopyVertex(currentVertex, numOffsets, numPoints, perVertexOffset, pMesh, pPerIndexChannels, currentPrimitive, indices);
                 break;
+            case Prim_LineStrip:
+                numPoints = 2;
+                for (size_t currentVertex = 0; currentVertex < numPoints; currentVertex++)
+                    CopyVertex(currentVertex, numOffsets, 1, perVertexOffset, pMesh, pPerIndexChannels, currentPrimitive, indices);
+                break;
             case Prim_Triangles:
                 numPoints = 3;
                 for (size_t currentVertex = 0; currentVertex < numPoints; currentVertex++)