[3053648] Obj: segfault when first line is a material.

Add test file to reproduce the issues. Thanks to Ingo Kresse for providing the patch.

git-svn-id: https://assimp.svn.sourceforge.net/svnroot/assimp/trunk@807 67173fc5-114c-0410-ac8e-9d2fd5bffc1f

code/ObjFileParser.cpp

@@ -633,6 +633,11 @@ void ObjFileParser::createMesh()
 //	Returns true, if a new mesh must be created.
 bool ObjFileParser::needsNewMesh( const std::string &rMaterialName )
 {
+	if(m_pModel->m_pCurrentMesh == 0)
+	{
+		// No mesh data yet
+		return true;
+	}
 	bool newMat = false;
 	int matIdx = getMaterialIndex( rMaterialName );
 	int curMatIdx = m_pModel->m_pCurrentMesh->m_uiMaterialIndex;

test/models/OBJ/segment.mtl

@@ -0,0 +1,22 @@
+# Blender3D MTL File: 
+# Material Count: 2
+newmtl Orange
+Ns 96.078431
+Ka 0.000000 0.000000 0.000000
+Kd 0.739482 0.420173 0.148173
+Ks 0.500000 0.500000 0.500000
+Ni 1.000000
+d 1.000000
+illum 2
+
+
+newmtl Silver
+Ns 96.078431
+Ka 0.000000 0.000000 0.000000
+Kd 0.480000 0.480000 0.480000
+Ks 0.500000 0.500000 0.500000
+Ni 1.000000
+d 1.000000
+illum 2
+
+

test/models/OBJ/segment.source.txt

@@ -0,0 +1,4 @@
+Obj exported from Blender
+
+http://toychest.in.tum.de/wiki/projects:kuka_lwr
+License: Creative-Commons-by-Attribution-3.0