From 7cc2d90725b75a19d73b7484935607c39851e6a5 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Fri, 17 Sep 2010 11:20:11 +0000
Subject: [PATCH] From Ulrich Hertlein, "I've added a command line switch
 '--testOcclusion' that enables display of other models in front and behind
 the outlined object."

---
 examples/osgoutline/osgoutline.cpp | 59 ++++++++++++++++++++++++++----
 1 file changed, 51 insertions(+), 8 deletions(-)

diff --git a/examples/osgoutline/osgoutline.cpp b/examples/osgoutline/osgoutline.cpp
index bd7811e91..e8055880b 100644
--- a/examples/osgoutline/osgoutline.cpp
+++ b/examples/osgoutline/osgoutline.cpp
@@ -5,6 +5,7 @@
  */
 
 #include <osg/Group>
+#include <osg/PositionAttitudeTransform>
 
 #include <osgDB/ReadFile>
 #include <osgViewer/Viewer>
@@ -16,19 +17,61 @@ int main(int argc, char** argv)
 {
     osg::ArgumentParser arguments(&argc,argv);
     arguments.getApplicationUsage()->setCommandLineUsage(arguments.getApplicationName()+" [options] <file>");
+    arguments.getApplicationUsage()->addCommandLineOption("--testOcclusion","Test occlusion by other objects");
     arguments.getApplicationUsage()->addCommandLineOption("-h or --help","Display this information");
-   
-    // create outline effect
-    osg::ref_ptr<osgFX::Outline> outline = new osgFX::Outline;
-    outline->setWidth(8);
-    outline->setColor(osg::Vec4(1,1,0,1));
+
+    bool testOcclusion = false;
+    while (arguments.read("--testOcclusion")) { testOcclusion = true; }
+
+    // load outlined object
+    std::string modelFilename = arguments.argc() > 1 ? arguments[1] : "dumptruck.osg";
+    osg::ref_ptr<osg::Node> outlineModel = osgDB::readNodeFile(modelFilename);
+    if (!outlineModel)
+    {
+        osg::notify(osg::FATAL) << "Unable to load model '" << modelFilename << "'\n";
+        return -1;
+    }
 
     // create scene
     osg::ref_ptr<osg::Group> root = new osg::Group;
-    root->addChild(outline.get());
 
-    osg::ref_ptr<osg::Node> model0 = osgDB::readNodeFile(arguments.argc() > 1 ? arguments[1] : "al.obj");
-    outline->addChild(model0.get());
+    {
+        // create outline effect
+        osg::ref_ptr<osgFX::Outline> outline = new osgFX::Outline;
+        root->addChild(outline.get());
+
+        outline->setWidth(8);
+        outline->setColor(osg::Vec4(1,1,0,1));
+        outline->addChild(outlineModel.get());
+    }
+
+    if (testOcclusion)
+    {
+        // load occluder
+        std::string occludedModelFilename = "cow.osg";
+        osg::ref_ptr<osg::Node> occludedModel = osgDB::readNodeFile(occludedModelFilename);
+        if (!occludedModel)
+        {
+            osg::notify(osg::FATAL) << "Unable to load model '" << occludedModelFilename << "'\n";
+            return -1;
+        }
+
+        // occluder offset
+        const osg::BoundingSphere& bsphere = outlineModel->getBound();
+        const osg::Vec3 occluderOffset = osg::Vec3(0,1,0) * bsphere.radius() * 1.2f;
+
+        // occluder behind outlined model
+        osg::ref_ptr<osg::PositionAttitudeTransform> modelTransform0 = new osg::PositionAttitudeTransform;
+        modelTransform0->setPosition(bsphere.center() + occluderOffset);
+        modelTransform0->addChild(occludedModel.get());
+        root->addChild(modelTransform0.get());
+
+        // occluder in front of outlined model
+        osg::ref_ptr<osg::PositionAttitudeTransform> modelTransform1 = new osg::PositionAttitudeTransform;
+        modelTransform1->setPosition(bsphere.center() - occluderOffset);
+        modelTransform1->addChild(occludedModel.get());
+        root->addChild(modelTransform1.get());
+    }
 
     // must have stencil buffer...
     osg::DisplaySettings::instance()->setMinimumNumStencilBits(1);