Added very simply osgparametric example which uses an OpenGL shader program

to create an animated parametric surface.

examples/osgparametric/GNUmakefile

@@ -0,0 +1,17 @@
+TOPDIR = ../..
+include $(TOPDIR)/Make/makedefs 
+
+CXXFILES =\
+	osgparametric.cpp\
+
+LIBS     += -losgProducer -lProducer -losgText -losgGA -losgDB -losgUtil -losg $(GL_LIBS) $(X_LIBS) $(OTHER_LIBS) 
+
+INSTFILES = \
+	$(CXXFILES)\
+	GNUmakefile.inst=GNUmakefile
+
+EXEC = osgparametric
+
+INC +=  $(X_INC)
+
+include $(TOPDIR)/Make/makerules 

examples/osgparametric/GNUmakefile.inst

@@ -0,0 +1,14 @@
+TOPDIR = ../..
+include $(TOPDIR)/Make/makedefs
+
+CXXFILES =\
+	osgparametric.cpp\
+
+LIBS     += -losgProducer -lProducer -losgDB -losgText -losgUtil -losg $(GL_LIBS) $(X_LIBS) $(OTHER_LIBS) 
+
+EXEC = osgparametric
+
+INC += $(PRODUCER_INCLUDE_DIR) $(X_INC)
+LDFLAGS  += $(PRODUCER_LIB_DIR)
+
+include $(TOPDIR)/Make/makerules

examples/osgparametric/osgparametric.cpp

@@ -0,0 +1,193 @@
+#include <osg/Vec3>
+#include <osg/Vec4>
+#include <osg/Quat>
+#include <osg/Matrix>
+#include <osg/ShapeDrawable>
+#include <osg/Geometry>
+#include <osg/Geode>
+#include <osg/Texture2D>
+
+#include <osgDB/FileUtils>
+#include <osgDB/ReadFile>
+
+#include <osgUtil/Optimizer>
+
+#include <osgProducer/Viewer>
+
+char vertexShaderSource[] = 
+    "uniform vec2  xCoeff; \n"
+    "uniform vec2  yCoeff; \n"
+    "\n"
+    "void main(void) \n"
+    "{ \n"
+    "\n"
+    "    gl_TexCoord[0] = gl_Vertex; \n"
+    "    gl_Vertex.z = gl_Vertex.x*xCoeff[0] + gl_Vertex.x*gl_Vertex.x* xCoeff[1] + \n"
+    "                  gl_Vertex.y*yCoeff[1] + gl_Vertex.y*gl_Vertex.y* yCoeff[1]; \n"
+    "    gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
+    "}\n";
+    
+char fragmentShaderSource[] = 
+    "uniform sampler2D baseTexture; \n"
+    "\n"
+    "void main(void) \n"
+    "{ \n"
+    "    gl_FragColor = texture2D( baseTexture, gl_TexCoord[0].xy); \n"
+    "}\n";
+
+
+class UniformVarying : public osg::Uniform::Callback
+{
+    virtual void operator () (osg::Uniform* uniform, osg::NodeVisitor* nv)
+    {
+        const osg::FrameStamp* fs = nv->getFrameStamp();
+        float value = sinf(fs->getReferenceTime());
+        uniform->set(osg::Vec2(value,-value));
+    }
+};
+
+osg::Node* createModel()
+{
+    osg::Geode* geode = new osg::Geode;
+    
+    osg::Geometry* geom = new osg::Geometry;
+    geode->addDrawable(geom);
+    
+    // dimensions for ~one million triangles :-)
+    unsigned int num_x = 708;
+    unsigned int num_y = 708;
+
+    osg::Vec3Array* vertices = new osg::Vec3Array( num_x * num_y );
+    
+    float dx = 1.0f/(float)(num_x-1);
+    float dy = 1.0f/(float)(num_y-1);
+    osg::Vec3 row(0.0f,0.0f,0.0);
+    
+    unsigned int vert_no = 0;
+    for(unsigned int iy=0; iy<num_y; ++iy)
+    {
+        osg::Vec3 column = row;
+        for(unsigned int ix=0;ix<num_x;++ix)
+        {
+            (*vertices)[vert_no++] = column;
+            column.x() += dx;
+        }        
+        row.y() += dy;
+    }
+
+    geom->setVertexArray(vertices);
+
+    for(unsigned int iy=0; iy<num_y-1; ++iy)
+    {
+        unsigned int element_no = 0;
+        osg::DrawElementsUInt* elements = new osg::DrawElementsUInt(GL_TRIANGLE_STRIP, num_x*2);
+        unsigned int index = iy * num_x;
+        for(unsigned int ix = 0; ix<num_x; ++ix)
+        {
+            (*elements)[element_no++] = index + num_x;
+            (*elements)[element_no++] = index++;
+        }
+        geom->addPrimitiveSet(elements);    
+    }
+    
+    geom->setUseVertexBufferObjects(true);
+    
+    
+    osg::StateSet* stateset = geom->getOrCreateStateSet();
+
+    osg::Program* program = new osg::Program;
+    stateset->setAttribute(program);
+
+    osg::Shader* vertex_shader = new osg::Shader(osg::Shader::VERTEX, vertexShaderSource);
+    program->addShader(vertex_shader);
+    
+
+    osg::Shader* fragment_shader = new osg::Shader(osg::Shader::FRAGMENT, fragmentShaderSource);
+    program->addShader(fragment_shader);
+
+
+    osg::Uniform* xCoeff = new osg::Uniform("xCoeff",osg::Vec2(1.0,-1.0f));
+    xCoeff->setUpdateCallback(new UniformVarying);
+    stateset->addUniform(xCoeff);
+
+    osg::Uniform* yCoeff = new osg::Uniform("yCoeff",osg::Vec2(-1.0f,1.0f));
+    stateset->addUniform(yCoeff);
+    
+    
+    stateset->setTextureAttributeAndModes(0,new osg::Texture2D(osgDB::readImageFile("lz.rgb")));
+
+    osg::Uniform* baseTextureSampler = new osg::Uniform("baseTexture",0);
+    stateset->addUniform(baseTextureSampler);
+    
+    return geode;
+
+}
+
+int main(int argc, char *argv[])
+{
+    // use an ArgumentParser object to manage the program arguments.
+    osg::ArgumentParser arguments(&argc,argv);
+
+    // set up the usage document, in case we need to print out how to use this program.
+    arguments.getApplicationUsage()->setDescription(arguments.getApplicationName()+" is the example which demonstrate support for ARB_vertex_program.");
+    arguments.getApplicationUsage()->setCommandLineUsage(arguments.getApplicationName()+" [options] filename ...");
+    arguments.getApplicationUsage()->addCommandLineOption("-h or --help","Display this information");
+   
+    // construct the viewer.
+    osgProducer::Viewer viewer(arguments);
+
+    // set up the value with sensible default event handlers.
+    viewer.setUpViewer(osgProducer::Viewer::STANDARD_SETTINGS);
+
+    // get details on keyboard and mouse bindings used by the viewer.
+    viewer.getUsage(*arguments.getApplicationUsage());
+
+    // if user request help write it out to cout.
+    if (arguments.read("-h") || arguments.read("--help"))
+    {
+        arguments.getApplicationUsage()->write(std::cout);
+        return 1;
+    }
+
+    // any option left unread are converted into errors to write out later.
+    arguments.reportRemainingOptionsAsUnrecognized();
+
+    // report any errors if they have occured when parsing the program aguments.
+    if (arguments.errors())
+    {
+        arguments.writeErrorMessages(std::cout);
+        return 1;
+    }
+
+    // load the nodes from the commandline arguments.
+    osg::Node* model = createModel();
+    if (!model)
+    {
+        return 1;
+    }
+
+    // add a viewport to the viewer and attach the scene graph.
+    viewer.setSceneData(model);
+    
+    // create the windows and run the threads.
+    viewer.realize();
+
+    while( !viewer.done() )
+    {
+        // wait for all cull and draw threads to complete.
+        viewer.sync();
+
+        // update the scene by traversing it with the the update visitor which will
+        // call all node update callbacks and animations.
+        viewer.update();
+         
+        // fire off the cull and draw traversals of the scene.
+        viewer.frame();
+        
+    }
+    
+    // wait for all cull and draw threads to complete before exit.
+    viewer.sync();
+
+    return 0;
+}