Use absolute paths to lookup materials, fixes karts with identical texture names being in conflict. Also, when a texture is misisng, log an error but don't abort

src/graphics/material.cpp

@@ -65,6 +65,8 @@ Material::Material(const XMLNode *node, bool deprecated)
         throw std::runtime_error("[Material] No texture name specified "
                                  "in file\n");
     }
+    m_full_path = file_manager->getFileSystem()->getAbsolutePath(
+        file_manager->searchTexture(m_texname).c_str()).c_str();
     init();
 
     node->get("lazy-load", &m_lazy_load);
@@ -404,6 +406,8 @@ Material::Material(const std::string& fname, bool is_full_path,
 
     m_texname = fname;
     init();
+    m_full_path = file_manager->getFileSystem()->getAbsolutePath(
+        file_manager->searchTexture(m_texname).c_str()).c_str();
 
     if (load_texture)
         install(is_full_path, complain_if_not_found);

src/graphics/material.hpp

@@ -85,6 +85,8 @@ private:
     /** Name of the texture. */
     std::string      m_texname;
 
+    std::string      m_full_path;
+
     /** If true, the texture will not automatically be loaded and bound
      *  at load time, it must be loaded elsewhere. This is used to store
      *  material settings for font textures, without loading fonts for
@@ -288,6 +290,9 @@ public:
     // ------------------------------------------------------------------------
     const std::string&
           getTexFname        () const { return m_texname;            }
+    // ------------------------------------------------------------------------
+    const std::string&
+          getTexFullPath     () const { return m_full_path;          }
 
     // ------------------------------------------------------------------------
     bool  isTransparent      () const

src/graphics/material_manager.cpp

@@ -69,8 +69,17 @@ Material* MaterialManager::getMaterialFor(video::ITexture* t,
     if (t == NULL)
         return m_default_material;
 
-    const std::string image = StringUtils::getBasename(core::stringc(t->getName()).c_str());
+    core::stringc img_path = core::stringc(t->getName());
+    const std::string image = StringUtils::getBasename(img_path.c_str());
     // Search backward so that temporary (track) textures are found first
+    for (int i = (int)m_materials.size() - 1; i >= 0; i--)
+    {
+        std::string full_path = m_materials[i]->getTexFullPath();
+        if (m_materials[i]->getTexFullPath() == img_path.c_str())
+        {
+            return m_materials[i];
+        }
+    }
     for(int i = (int)m_materials.size()-1; i>=0; i-- )
     {
         if (m_materials[i]->getTexFname()==image)

src/graphics/stkmesh.cpp

@@ -283,8 +283,9 @@ SetTexture(GLMesh &mesh, unsigned i, bool isSrgb, const std::string &matname)
 {
     if (!mesh.textures[i])
     {
-        Log::fatal("STKMesh", "Missing texture %d for material %s", i, matname.c_str());
+        Log::error("STKMesh", "Missing texture %d for material %s", i, matname.c_str());
-        return;
+        // use unicolor texture to replace missing texture
+        mesh.textures[i] = getUnicolorTexture(video::SColor(255, 127, 127, 127));
     }
     compressTexture(mesh.textures[i], isSrgb);
     if (CVS->isAZDOEnabled())