From Mike Weiblen, support for geometry shaders, and osgeometryshaders example to demonstrate them.

examples/CMakeLists.txt

@@ -70,6 +70,7 @@ IF(DYNAMIC_OPENSCENEGRAPH)
     ADD_SUBDIRECTORY(osgscribe)
     ADD_SUBDIRECTORY(osgsequence)
     ADD_SUBDIRECTORY(osgshaders)
+    ADD_SUBDIRECTORY(osggeometryshaders)
     ADD_SUBDIRECTORY(osgshaderterrain)
     ADD_SUBDIRECTORY(osgshadow)
     ADD_SUBDIRECTORY(osgshape)

examples/osggeometryshaders/CMakeLists.txt

@@ -0,0 +1,2 @@
+SET(TARGET_SRC osggeometryshaders.cpp )
+SETUP_EXAMPLE(osggeometryshaders)

examples/osggeometryshaders/osggeometryshaders.cpp

@@ -0,0 +1,191 @@
+/* OpenSceneGraph example, osgshaders2
+*
+*  Permission is hereby granted, free of charge, to any person obtaining a copy
+*  of this software and associated documentation files (the "Software"), to deal
+*  in the Software without restriction, including without limitation the rights
+*  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+*  copies of the Software, and to permit persons to whom the Software is
+*  furnished to do so, subject to the following conditions:
+*
+*  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+*  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+*  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+*  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+*  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+*  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+*  THE SOFTWARE.
+*/
+
+/* file:        examples/osgshaders2/osgshaders2.cpp
+ * author:      Mike Weiblen 2008-01-03
+ * copyright:   (C) 2008 Zebra Imaging
+ * license:     OpenSceneGraph Public License (OSGPL)
+ *
+ * A demo of GLSL geometry shaders using OSG
+ * Tested on Dell Precision M4300 w/ NVIDIA Quadro FX 360M
+*/
+
+
+#include <osg/Notify>
+#include <osg/ref_ptr>
+#include <osg/Geode>
+#include <osg/Geometry>
+#include <osg/Point>
+#include <osg/Vec3>
+#include <osg/Vec4>
+#include <osg/Program>
+#include <osg/Shader>
+#include <osg/Uniform>
+#include <osgViewer/Viewer>
+
+// play with these #defines to see their effect
+#define ENABLE_GLSL
+#define ENABLE_GEOMETRY_SHADER
+
+///////////////////////////////////////////////////////////////////////////
+
+#ifdef ENABLE_GLSL
+
+class SineAnimation: public osg::Uniform::Callback
+{
+public:
+    SineAnimation( float rate = 1.0f, float scale = 1.0f, float offset = 0.0f ) :
+            _rate(rate), _scale(scale), _offset(offset)
+    {}
+
+    void operator()( osg::Uniform* uniform, osg::NodeVisitor* nv )
+    {
+        float angle = _rate * nv->getFrameStamp()->getSimulationTime();
+        float value = sinf( angle ) * _scale + _offset;
+        uniform->set( value );
+    }
+
+private:
+    const float _rate;
+    const float _scale;
+    const float _offset;
+};
+
+///////////////////////////////////////////////////////////////////////////
+
+static const char* vertSource = {
+"#version 120\n"
+"#extension GL_EXT_geometry_shader4 : enable\n"
+"uniform float u_anim1;\n"
+"varying vec4 v_color;\n"
+"void main(void)\n"
+"{\n"
+"    v_color = gl_Vertex;\n"
+"    gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
+"}\n"
+};
+
+static const char* geomSource = {
+"#version 120\n"
+"#extension GL_EXT_geometry_shader4 : enable\n"
+"uniform float u_anim1;\n"
+"varying vec4 v_color;\n"
+"void main(void)\n"
+"{\n"
+"    vec4 v = gl_PositionIn[0];\n"
+"    v_color = v;\n"
+"\n"
+"    gl_Position = v + vec4(u_anim1,0.,0.,0.);  EmitVertex();\n"
+"    gl_Position = v - vec4(u_anim1,0.,0.,0.);  EmitVertex();\n"
+"    EndPrimitive();\n"
+"\n"
+"    gl_Position = v + vec4(0.,1.0-u_anim1,0.,0.);  EmitVertex();\n"
+"    gl_Position = v - vec4(0.,1.0-u_anim1,0.,0.);  EmitVertex();\n"
+"    EndPrimitive();\n"
+"}\n"
+};
+
+
+static const char* fragSource = {
+"#version 120\n"
+"#extension GL_EXT_geometry_shader4 : enable\n"
+"uniform float u_anim1;\n"
+"varying vec4 v_color;\n"
+"void main(void)\n"
+"{\n"
+"    gl_FragColor = v_color;\n"
+"}\n"
+};
+
+osg::Program* createShader()
+{
+    osg::Program* pgm = new osg::Program;
+    pgm->setName( "osgshader2 demo" );
+
+    pgm->addShader( new osg::Shader( osg::Shader::VERTEX,   vertSource ) );
+    pgm->addShader( new osg::Shader( osg::Shader::FRAGMENT, fragSource ) );
+
+#ifdef ENABLE_GEOMETRY_SHADER
+    pgm->addShader( new osg::Shader( osg::Shader::GEOMETRY, geomSource ) );
+    pgm->setParameter( GL_GEOMETRY_VERTICES_OUT_EXT, 4 );
+    pgm->setParameter( GL_GEOMETRY_INPUT_TYPE_EXT, GL_POINTS );
+    pgm->setParameter( GL_GEOMETRY_OUTPUT_TYPE_EXT, GL_LINE_STRIP );
+#endif
+
+    return pgm;
+}
+
+#endif
+
+///////////////////////////////////////////////////////////////////////////
+
+class SomePoints : public osg::Geometry
+{
+public:
+    SomePoints()
+    {
+        osg::Vec4Array* cAry = new osg::Vec4Array;
+        setColorArray( cAry );
+        setColorBinding( osg::Geometry::BIND_OVERALL );
+        cAry->push_back( osg::Vec4(1,1,1,1) );
+
+        osg::Vec3Array* vAry = new osg::Vec3Array;
+        setVertexArray( vAry );
+        vAry->push_back( osg::Vec3(0,0,0) );
+        vAry->push_back( osg::Vec3(0,1,0) );
+        vAry->push_back( osg::Vec3(1,0,0) );
+        vAry->push_back( osg::Vec3(1,1,0) );
+        vAry->push_back( osg::Vec3(0,0,1) );
+        vAry->push_back( osg::Vec3(0,1,1) );
+        vAry->push_back( osg::Vec3(1,0,1) );
+        vAry->push_back( osg::Vec3(1,1,1) );
+
+        addPrimitiveSet( new osg::DrawArrays( GL_POINTS, 0, vAry->size() ) );
+
+        osg::StateSet* sset = getOrCreateStateSet();
+        sset->setMode( GL_LIGHTING, osg::StateAttribute::OFF );
+
+        // if things go wrong, fall back to big points
+        osg::Point* p = new osg::Point;
+        p->setSize(6);
+        sset->setAttribute( p );
+
+#ifdef ENABLE_GLSL
+        sset->setAttribute( createShader() );
+
+        // a generic cyclic animation value
+        osg::Uniform* u_anim1( new osg::Uniform( "u_anim1", 0.0f ) );
+        u_anim1->setUpdateCallback( new SineAnimation( 4, 0.5, 0.5 ) );
+        sset->addUniform( u_anim1 );
+#endif
+    }
+};
+
+///////////////////////////////////////////////////////////////////////////
+
+int main( int argc, char *argv[] )
+{
+    osg::Geode* root( new osg::Geode );
+    root->addDrawable( new SomePoints );
+
+    osgViewer::Viewer viewer;
+    viewer.setSceneData( root );
+    return viewer.run();
+}
+
+// vim: set sw=4 ts=8 et ic ai: