private Texture loadTexture2D(final String path, final Texture.MinificationFilter minFilter) {
    if (_dataCache.containsTexture(path)) {
      return _dataCache.getTexture(path);
    }

    final Texture texture;
    if (_textureLocator == null) {
      texture =
          TextureManager.load(
              path,
              minFilter,
              _compressTextures
                  ? TextureStoreFormat.GuessCompressedFormat
                  : TextureStoreFormat.GuessNoCompressedFormat,
              true);
    } else {
      final ResourceSource source = _textureLocator.locateResource(path);
      texture =
          TextureManager.load(
              source,
              minFilter,
              _compressTextures
                  ? TextureStoreFormat.GuessCompressedFormat
                  : TextureStoreFormat.GuessNoCompressedFormat,
              true);
    }
    _dataCache.addTexture(path, texture);

    return texture;
  }
 @SuppressWarnings("unchecked")
 public void unbindMaterials(final Element bindMaterial) {
   if (bindMaterial == null || bindMaterial.getChildren().isEmpty()) {
     return;
   }
   for (final Element instance :
       (List<Element>)
           bindMaterial.getChild("technique_common").getChildren("instance_material")) {
     _dataCache.unbindMaterial(instance.getAttributeValue("symbol"));
   }
 }
  @SuppressWarnings("unchecked")
  public void bindMaterials(final Element bindMaterial) {
    if (bindMaterial == null || bindMaterial.getChildren().isEmpty()) {
      return;
    }

    for (final Element instance :
        (List<Element>)
            bindMaterial.getChild("technique_common").getChildren("instance_material")) {
      final Element matNode =
          _colladaDOMUtil.findTargetWithId(instance.getAttributeValue("target"));
      if (matNode != null && "material".equals(matNode.getName())) {
        _dataCache.bindMaterial(instance.getAttributeValue("symbol"), matNode);
      } else {
        logger.warning(
            "instance material target not found: " + instance.getAttributeValue("target"));
      }

      // TODO: need to store bound vert data as local data. (also unstore on unbind.)
    }
  }
  /**
   * Find and apply the given material to the given Mesh.
   *
   * @param materialName our material name
   * @param mesh the mesh to apply material to.
   */
  public void applyMaterial(final String materialName, final Mesh mesh) {
    if (materialName == null) {
      logger.warning("materialName is null");
      return;
    }

    Element mat = _dataCache.getBoundMaterial(materialName);
    if (mat == null) {
      logger.warning("material not bound: " + materialName + ", trying search with id.");
      mat = _colladaDOMUtil.findTargetWithId(materialName);
    }
    if (mat == null || !"material".equals(mat.getName())) {
      logger.warning("material not found: " + materialName);
      return;
    }

    final String originalMaterial = mat.getAttributeValue("id");
    MaterialInfo mInfo = null;
    if (!_dataCache.getMaterialInfoMap().containsKey(originalMaterial)) {
      mInfo = new MaterialInfo();
      mInfo.setMaterialName(originalMaterial);
      _dataCache.getMaterialInfoMap().put(originalMaterial, mInfo);
    }
    _dataCache.getMeshMaterialMap().put(mesh, originalMaterial);

    final Element child = mat.getChild("instance_effect");
    final Element effectNode = _colladaDOMUtil.findTargetWithId(child.getAttributeValue("url"));
    if (effectNode == null) {
      logger.warning(
          "material effect not found: "
              + mat.getChild("instance_material").getAttributeValue("url"));
      return;
    }

    if ("effect".equals(effectNode.getName())) {
      /*
       * temp cache for textures, we do not want to add textures twice (for example, transparant map might point
       * to diffuse texture)
       */
      final HashMap<String, Texture> loadedTextures = new HashMap<String, Texture>();
      final Element effect = effectNode;
      // XXX: For now, just grab the common technique:
      if (effect.getChild("profile_COMMON") != null) {
        if (mInfo != null) {
          mInfo.setProfile("COMMON");
        }
        final Element technique = effect.getChild("profile_COMMON").getChild("technique");
        String type = "blinn";
        if (technique.getChild(type) == null) {
          type = "phong";
          if (technique.getChild(type) == null) {
            type = "lambert";
            if (technique.getChild(type) == null) {
              type = "constant";
              if (technique.getChild(type) == null) {
                ColladaMaterialUtils.logger.warning(
                    "COMMON material has unusuable techinque. " + child.getAttributeValue("url"));
                return;
              }
            }
          }
        }
        final Element blinnPhongLambert = technique.getChild(type);
        if (mInfo != null) {
          mInfo.setTechnique(type);
        }
        final MaterialState mState = new MaterialState();

        // TODO: implement proper transparency handling
        Texture diffuseTexture = null;
        ColorRGBA transparent = new ColorRGBA(1.0f, 1.0f, 1.0f, 1.0f);
        float transparency = 1.0f;
        boolean useTransparency = false;
        String opaqueMode = "A_ONE";

        /*
         * place holder for current property, we import material properties in fixed order (for texture order)
         */
        Element property = null;
        /* Diffuse property */
        property = blinnPhongLambert.getChild("diffuse");
        if (property != null) {
          final Element propertyValue = (Element) property.getChildren().get(0);
          if ("color".equals(propertyValue.getName())) {
            final ColorRGBA color = _colladaDOMUtil.getColor(propertyValue.getText());
            mState.setDiffuse(MaterialFace.FrontAndBack, color);
          } else if ("texture".equals(propertyValue.getName()) && _loadTextures) {
            diffuseTexture =
                populateTextureState(mesh, propertyValue, effect, loadedTextures, mInfo, "diffuse");
          }
        }
        /* Ambient property */
        property = blinnPhongLambert.getChild("ambient");
        if (property != null) {
          final Element propertyValue = (Element) property.getChildren().get(0);
          if ("color".equals(propertyValue.getName())) {
            final ColorRGBA color = _colladaDOMUtil.getColor(propertyValue.getText());
            mState.setAmbient(MaterialFace.FrontAndBack, color);
          } else if ("texture".equals(propertyValue.getName()) && _loadTextures) {
            populateTextureState(mesh, propertyValue, effect, loadedTextures, mInfo, "ambient");
          }
        }
        /* Transparent property */
        property = blinnPhongLambert.getChild("transparent");
        if (property != null) {
          final Element propertyValue = (Element) property.getChildren().get(0);
          if ("color".equals(propertyValue.getName())) {
            transparent = _colladaDOMUtil.getColor(propertyValue.getText());
            // TODO: use this
            useTransparency = true;
          } else if ("texture".equals(propertyValue.getName()) && _loadTextures) {
            populateTextureState(mesh, propertyValue, effect, loadedTextures, mInfo, "transparent");
          }
          opaqueMode = property.getAttributeValue("opaque", "A_ONE");
        }
        /* Transparency property */
        property = blinnPhongLambert.getChild("transparency");
        if (property != null) {
          final Element propertyValue = (Element) property.getChildren().get(0);
          if ("float".equals(propertyValue.getName())) {
            transparency = Float.parseFloat(propertyValue.getText().replace(",", "."));
            // TODO: use this
            if (_flipTransparency) {
              transparency = 1f - transparency;
            }
            useTransparency = true;
          } else if ("texture".equals(propertyValue.getName()) && _loadTextures) {
            populateTextureState(
                mesh, propertyValue, effect, loadedTextures, mInfo, "transparency");
          }
        }
        /* Emission property */
        property = blinnPhongLambert.getChild("emission");
        if (property != null) {
          final Element propertyValue = (Element) property.getChildren().get(0);
          if ("color".equals(propertyValue.getName())) {
            mState.setEmissive(
                MaterialFace.FrontAndBack, _colladaDOMUtil.getColor(propertyValue.getText()));
          } else if ("texture".equals(propertyValue.getName()) && _loadTextures) {
            populateTextureState(mesh, propertyValue, effect, loadedTextures, mInfo, "emissive");
          }
        }
        /* Specular property */
        property = blinnPhongLambert.getChild("specular");
        if (property != null) {
          final Element propertyValue = (Element) property.getChildren().get(0);
          if ("color".equals(propertyValue.getName())) {
            mState.setSpecular(
                MaterialFace.FrontAndBack, _colladaDOMUtil.getColor(propertyValue.getText()));
          } else if ("texture".equals(propertyValue.getName()) && _loadTextures) {
            populateTextureState(mesh, propertyValue, effect, loadedTextures, mInfo, "specular");
          }
        }
        /* Shininess property */
        property = blinnPhongLambert.getChild("shininess");
        if (property != null) {
          final Element propertyValue = (Element) property.getChildren().get(0);
          if ("float".equals(propertyValue.getName())) {
            float shininess = Float.parseFloat(propertyValue.getText().replace(",", "."));
            if (shininess >= 0.0f && shininess <= 1.0f) {
              final float oldShininess = shininess;
              shininess *= 128;
              logger.finest(
                  "Shininess - "
                      + oldShininess
                      + " - was in the [0,1] range. Scaling to [0, 128] - "
                      + shininess);
            } else if (shininess < 0 || shininess > 128) {
              final float oldShininess = shininess;
              shininess = MathUtils.clamp(shininess, 0, 128);
              logger.warning(
                  "Shininess must be between 0 and 128. Shininess "
                      + oldShininess
                      + " was clamped to "
                      + shininess);
            }
            mState.setShininess(MaterialFace.FrontAndBack, shininess);
          } else if ("texture".equals(propertyValue.getName()) && _loadTextures) {
            populateTextureState(mesh, propertyValue, effect, loadedTextures, mInfo, "shininess");
          }
        }
        /* Reflectivity property */
        float reflectivity = 1.0f;
        property = blinnPhongLambert.getChild("reflectivity");
        if (property != null) {
          final Element propertyValue = (Element) property.getChildren().get(0);
          if ("float".equals(propertyValue.getName())) {
            reflectivity = Float.parseFloat(propertyValue.getText().replace(",", "."));
          }
        }
        /* Reflective property. Texture only */
        property = blinnPhongLambert.getChild("reflective");
        if (property != null) {
          final Element propertyValue = (Element) property.getChildren().get(0);
          if ("texture".equals(propertyValue.getName()) && _loadTextures) {
            final Texture reflectiveTexture =
                populateTextureState(
                    mesh, propertyValue, effect, loadedTextures, mInfo, "reflective");

            reflectiveTexture.setEnvironmentalMapMode(Texture.EnvironmentalMapMode.SphereMap);
            reflectiveTexture.setApply(ApplyMode.Combine);

            reflectiveTexture.setCombineFuncRGB(CombinerFunctionRGB.Interpolate);
            // color 1
            reflectiveTexture.setCombineSrc0RGB(CombinerSource.CurrentTexture);
            reflectiveTexture.setCombineOp0RGB(CombinerOperandRGB.SourceColor);
            // color 2
            reflectiveTexture.setCombineSrc1RGB(CombinerSource.Previous);
            reflectiveTexture.setCombineOp1RGB(CombinerOperandRGB.SourceColor);
            // interpolate param will come from alpha of constant color
            reflectiveTexture.setCombineSrc2RGB(CombinerSource.Constant);
            reflectiveTexture.setCombineOp2RGB(CombinerOperandRGB.SourceAlpha);

            reflectiveTexture.setConstantColor(new ColorRGBA(1, 1, 1, reflectivity));
          }
        }

        /*
         * An extra tag defines some materials not part of the collada standard. Since we're not able to parse
         * we simply extract the textures from the element (such that shaders etc can at least pick up on them)
         */
        property = technique.getChild("extra");
        if (property != null) {
          getTexturesFromElement(mesh, property, effect, loadedTextures, mInfo);
        }

        // XXX: There are some issues with clarity on how to use alpha blending in OpenGL FFP.
        // The best interpretation I have seen is that if transparent has a texture == diffuse,
        // Turn on alpha blending and use diffuse alpha.

        // check to make sure we actually need this.
        // testing separately for a transparency of 0.0 is to hack around erroneous exports, since
        // usually
        // there is no use in exporting something with 100% transparency.
        if ("A_ONE".equals(opaqueMode) && ColorRGBA.WHITE.equals(transparent) && transparency == 1.0
            || transparency == 0.0) {
          useTransparency = false;
        }

        if (useTransparency) {
          if (diffuseTexture != null) {
            final BlendState blend = new BlendState();
            blend.setBlendEnabled(true);
            blend.setTestEnabled(true);
            blend.setSourceFunction(BlendState.SourceFunction.SourceAlpha);
            blend.setDestinationFunction(BlendState.DestinationFunction.OneMinusSourceAlpha);
            mesh.setRenderState(blend);
          } else {
            final BlendState blend = new BlendState();
            blend.setBlendEnabled(true);
            blend.setTestEnabled(true);
            transparent.setAlpha(transparent.getAlpha() * transparency);
            blend.setConstantColor(transparent);
            blend.setSourceFunction(BlendState.SourceFunction.ConstantAlpha);
            blend.setDestinationFunction(BlendState.DestinationFunction.OneMinusConstantAlpha);
            mesh.setRenderState(blend);
          }

          mesh.getSceneHints().setRenderBucketType(RenderBucketType.Transparent);
        }

        if (mInfo != null) {
          if (useTransparency) {
            mInfo.setUseTransparency(useTransparency);
            if (diffuseTexture == null) {
              mInfo.setTransparency(transparent.getAlpha() * transparency);
            }
          }
          mInfo.setMaterialState(mState);
        }
        mesh.setRenderState(mState);
      }
    } else {
      ColladaMaterialUtils.logger.warning(
          "material effect not found: "
              + mat.getChild("instance_material").getAttributeValue("url"));
    }
  }