/* OpenSceneGraph example, osgtransformfeedback * * 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/osgtransformfeedback/osgtransformfeedback.cpp * author: Julien Valentin 2013-10-01 * copyright: (C) 2013 * license: OpenSceneGraph Public License (OSGPL) * * A demo of GLSL geometry shaders using OSG transform feedback * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /////////////////////////////////////////////////////////////////////////// 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* RendervertSource = { "#version 120\n" "uniform float u_anim1;\n" "//in vec4 Vertex;\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* vertSource = { "#version 120\n" "#extension GL_EXT_geometry_shader4 : enable\n" "uniform float u_anim1;\n" " varying out vec4 v_color;\n" "void main(void)\n" "{\n" " gl_Position = (gl_Vertex);\n" " v_color = gl_Vertex;\n" "}\n" }; static const char* geomSource = { "#version 120\n" "#extension GL_EXT_geometry_shader4 : enable\n" "uniform float u_anim1;\n" " varying in vec4 v_color[];\n" " varying vec4 out1;\n" "void main(void)\n" "{\n" " vec4 v =vec4( gl_PositionIn[0].xyz,1);\n" " out1 = v + vec4(u_anim1,0.,0.,0.);// gl_Position = v + vec4(u_anim1,0.,0.,0.); \n" " EmitVertex();\n" " EndPrimitive();\n" " out1 = v - vec4(u_anim1,0.,0.,0.); // gl_Position = v - vec4(u_anim1,0.,0.,0.); \n" " EmitVertex();\n" " EndPrimitive();\n" "\n" " out1= v + vec4(0.,1.0-u_anim1,0.,0.);// gl_Position = v + vec4(0.,1.0-u_anim1,0.,0.); \n" " EmitVertex();\n" " EndPrimitive();\n" " out1 = v - vec4(0.,1.0-u_anim1,0.,0.); //gl_Position = v - vec4(0.,1.0-u_anim1,0.,0.); \n" " 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_out;\n" "void main(void)\n" "{\n" " gl_FragColor = vec4(1,0,0,1);//v_color_out;\n" "}\n" }; osg::Program* createGeneratorShader() { osg::Program* pgm = new osg::Program; pgm->setName( "osg transformfeedback demo" ); pgm->addShader( new osg::Shader( osg::Shader::VERTEX, vertSource ) ); 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_POINTS ); pgm->addShader( new osg::Shader( osg::Shader::GEOMETRY, geomSource ) ); pgm->addTransformFeedBackVarying(std::string("out1")); pgm->setTransformFeedBackMode(GL_INTERLEAVED_ATTRIBS); return pgm; } osg::Program* createRenderShader() { osg::Program* pgm = new osg::Program; pgm->setName( "osg transformfeedback renderer demo" ); pgm->addShader( new osg::Shader( osg::Shader::VERTEX, RendervertSource ) ); pgm->addShader( new osg::Shader( osg::Shader::FRAGMENT, fragSource ) ); return pgm; } ////////////////////////////////////////////////////////////////////////////////////// class SomePointsRenderer; class SomePointsGenerator:public osg::Geometry { public: SomePointsGenerator(); void setRenderer(osg::Geometry*renderer); GLuint getNumPrimitivesGenerated()const; protected: osg::Program * _program; osg::ref_ptr genbuffer;//Renderer buffer osg::Vec4Array* vAry; virtual void drawImplementation( osg::RenderInfo& renderInfo ) const; }; ///////////////////////////////////////////////////////////////////////////////////// class SomePointsRenderer : public osg::Geometry { public: SomePointsRenderer(SomePointsGenerator*_generator) { setUseVertexBufferObjects(true); osg::Vec4Array* vAry2 = new osg::Vec4Array; vAry2->resize(_generator->getNumPrimitivesGenerated()); setVertexArray(vAry2); addPrimitiveSet( new osg::DrawArrays( GL_LINES, 0,_generator->getNumPrimitivesGenerated())); osg::StateSet* sset = getOrCreateStateSet(); ///hacking rendering order /*osg::BlendFunc* bf = new osg::BlendFunc(osg::BlendFunc::SRC_ALPHA, osg::BlendFunc::ONE_MINUS_SRC_ALPHA ); sset->setAttributeAndModes(bf);*/ sset->setMode( GL_LIGHTING, osg::StateAttribute::OFF ); getOrCreateVertexBufferObject(); sset->setAttribute( createRenderShader() ); } }; /////////////////////////////////////////////////////////////////////////// GLuint SomePointsGenerator::getNumPrimitivesGenerated()const { return vAry->size()*4; } void SomePointsGenerator::drawImplementation( osg::RenderInfo& renderInfo ) const { //get output buffer unsigned int contextID = renderInfo.getState()->getContextID(); GLuint ubuff= genbuffer->getOrCreateGLBufferObject(contextID)->getGLObjectID(); osg::GLExtensions* ext = renderInfo.getState()->get(); ext->glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0,ubuff); glEnable(GL_RASTERIZER_DISCARD); ext->glBeginTransformFeedback(GL_POINTS); osg::Geometry::drawImplementation( renderInfo ); ext->glEndTransformFeedback(); glDisable(GL_RASTERIZER_DISCARD); ext->glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0, 0); } SomePointsGenerator::SomePointsGenerator():osg::Geometry() { setUseVertexBufferObjects(true); osg::StateSet* sset = getOrCreateStateSet(); sset->setMode( GL_LIGHTING, osg::StateAttribute::OFF ); vAry = new osg::Vec4Array;; vAry->push_back( osg::Vec4(0,0,0,1) ); vAry->push_back( osg::Vec4(0,1,0,1) ); vAry->push_back( osg::Vec4(1,0,0,1) ); vAry->push_back( osg::Vec4(1,1,0,1 )); addPrimitiveSet( new osg::DrawArrays( GL_POINTS, 0, vAry->size() ) ); setVertexArray( vAry ); _program=createGeneratorShader() ; sset->setAttribute(_program ); // a generic cyclic animation value osg::Uniform* u_anim1( new osg::Uniform( "u_anim1", 0.9f ) ); u_anim1->setUpdateCallback( new SineAnimation( 4, 0.5, 0.5 ) ); sset->addUniform( u_anim1 ); } void SomePointsGenerator::setRenderer(osg::Geometry* renderer) { genbuffer = renderer->getOrCreateVertexBufferObject(); } /////////////////////////////////////////////////////////////////////////// int main( int , char** ) { osg::Geode* root( new osg::Geode ); SomePointsGenerator * pate = new SomePointsGenerator(); SomePointsRenderer* pate2 = new SomePointsRenderer(pate); pate->setRenderer( pate2); root->addDrawable( pate ); root->addDrawable( pate2 ); osgViewer::Viewer viewer; viewer.setSceneData( root ); return viewer.run(); }