From Julien Valentin, "To sum up changes, I had:
-some extensions in GLExtensions - GL_TEXTURE_BUFFER as target in osg::StateSet - a VBO based transform feed back example " git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@14651 16af8721-9629-0410-8352-f15c8da7e697
This commit is contained in:
Robert Osfield
299
examples/osgtransformfeedback/osgtransformfeedback.cpp
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299
examples/osgtransformfeedback/osgtransformfeedback.cpp
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/* OpenSceneGraph example, osgtransformfeedback
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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/* file: examples/osgtransformfeedback/osgtransformfeedback.cpp
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* author: Julien Valentin 2013-10-01
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* copyright: (C) 2013
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* license: OpenSceneGraph Public License (OSGPL)
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*
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* A demo of GLSL geometry shaders using OSG transform feedback
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*
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*/
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#include <osg/GL2Extensions>
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#include <osg/Notify>
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#include <osg/ref_ptr>
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#include <osg/Geode>
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#include <osg/Geometry>
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#include <osg/Point>
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#include <osg/Vec3>
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#include <osg/Vec4>
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#include <osg/Program>
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#include <osg/Shader>
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#include <osg/BlendFunc>
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#include <osg/Uniform>
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#include <osgViewer/Viewer>
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#include <osg/BufferIndexBinding>
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#include <iostream>
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///////////////////////////////////////////////////////////////////////////
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class SineAnimation: public osg::Uniform::Callback
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{
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public:
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SineAnimation( float rate = 1.0f, float scale = 1.0f, float offset = 0.0f ) :
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_rate(rate), _scale(scale), _offset(offset)
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{}
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void operator()( osg::Uniform* uniform, osg::NodeVisitor* nv )
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{
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float angle = _rate * nv->getFrameStamp()->getSimulationTime();
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float value = sinf( angle ) * _scale + _offset;
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uniform->set( value );
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}
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private:
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const float _rate;
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const float _scale;
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const float _offset;
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};
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///////////////////////////////////////////////////////////////////////////
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static const char* RendervertSource =
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{
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"#version 120\n"
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"uniform float u_anim1;\n"
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"//in vec4 Vertex;\n"
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"varying vec4 v_color;\n"
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"void main(void)\n"
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"{\n"
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" v_color = gl_Vertex;\n"
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" gl_Position = gl_ModelViewProjectionMatrix *(gl_Vertex);\n"
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"}\n"
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};
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static const char* vertSource =
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{
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"#version 120\n"
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"#extension GL_EXT_geometry_shader4 : enable\n"
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"uniform float u_anim1;\n"
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//"in vec4 Vertex;\n"
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" varying out vec4 v_color;\n"
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//"out vec4 v_vertex;\n"
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"void main(void)\n"
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"{\n"
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//" v_color = Vertex;\n"
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//" v_vertex = Vertex;;//gl_ModelViewProjectionMatrix * Vertex;\n"
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" gl_Position = (gl_Vertex);\n"
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" v_color = gl_Vertex;\n"
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"}\n"
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};
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static const char* geomSource =
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{
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"#version 120\n"
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"#extension GL_EXT_geometry_shader4 : enable\n"
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// "layout(points) in;\n"\
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// "layout(points, max_vertices = 4) out;\n"
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"uniform float u_anim1;\n"
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" varying in vec4 v_color[];\n"
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//" varying in vec4 v_vertex[];\n"
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" varying vec4 out1;\n"
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"void main(void)\n"
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"{\n"
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" vec4 v =vec4( gl_PositionIn[0].xyz,1);\n"
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" out1 = v + vec4(u_anim1,0.,0.,0.);// gl_Position = v + vec4(u_anim1,0.,0.,0.); \n"
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" EmitVertex();\n"
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" EndPrimitive();\n"
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" out1 = v - vec4(u_anim1,0.,0.,0.); // gl_Position = v - vec4(u_anim1,0.,0.,0.); \n"
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" EmitVertex();\n"
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" EndPrimitive();\n"
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"\n"
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" out1= v + vec4(0.,1.0-u_anim1,0.,0.);// gl_Position = v + vec4(0.,1.0-u_anim1,0.,0.); \n"
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" EmitVertex();\n"
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" EndPrimitive();\n"
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" out1 = v - vec4(0.,1.0-u_anim1,0.,0.); //gl_Position = v - vec4(0.,1.0-u_anim1,0.,0.); \n"
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" EmitVertex();\n"
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" EndPrimitive();\n"
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"}\n"
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};
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static const char* fragSource =
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{
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"#version 120\n"
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"#extension GL_EXT_geometry_shader4 : enable\n"
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"uniform float u_anim1;\n"
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"varying vec4 v_color_out;\n"
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"void main(void)\n"
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"{\n"
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" gl_FragColor = vec4(1,0,0,1);//v_color_out;\n"
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"}\n"
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};
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osg::Program* createGeneratorShader()
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{
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osg::Program* pgm = new osg::Program;
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pgm->setName( "osg transformfeedback demo" );
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pgm->addShader( new osg::Shader( osg::Shader::VERTEX, vertSource ) );
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pgm->setParameter( GL_GEOMETRY_VERTICES_OUT_EXT, 4 );
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pgm->setParameter( GL_GEOMETRY_INPUT_TYPE_EXT, GL_POINTS );
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pgm->setParameter( GL_GEOMETRY_OUTPUT_TYPE_EXT, GL_POINTS );
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pgm->addShader( new osg::Shader( osg::Shader::GEOMETRY, geomSource ) );
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pgm->addTransformFeedBackVarying(std::string("out1"));
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pgm->setTransformFeedBackMode(GL_INTERLEAVED_ATTRIBS);
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return pgm;
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}
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osg::Program* createRenderShader()
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{
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osg::Program* pgm = new osg::Program;
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pgm->setName( "osg transformfeedback renderer demo" );
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pgm->addShader( new osg::Shader( osg::Shader::VERTEX, RendervertSource ) );
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pgm->addShader( new osg::Shader( osg::Shader::FRAGMENT, fragSource ) );
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return pgm;
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}
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//////////////////////////////////////////////////////////////////////////////////////
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class SomePointsRenderer;
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class SomePointsGenerator:public osg::Geometry
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{
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public:
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SomePointsGenerator();
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void setRenderer(osg::Geometry*renderer);
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GLuint getNumPrimitivesGenerated()const;
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protected:
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osg::Program * _program;
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osg::ref_ptr<osg::VertexBufferObject> genbuffer;//Renderer buffer
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osg::Vec4Array* vAry;
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virtual void drawImplementation( osg::RenderInfo& renderInfo ) const;
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};
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/////////////////////////////////////////////////////////////////////////////////////
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class SomePointsRenderer : public osg::Geometry
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{
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public:
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SomePointsRenderer(SomePointsGenerator*_generator)
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{
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setUseVertexBufferObjects(true);
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osg::Vec4Array* vAry2 = new osg::Vec4Array;
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vAry2->resize(_generator->getNumPrimitivesGenerated());
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setVertexArray(vAry2);
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addPrimitiveSet( new osg::DrawArrays( GL_LINES, 0,_generator->getNumPrimitivesGenerated()));
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osg::StateSet* sset = getOrCreateStateSet();
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///hacking rendering order
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/*osg::BlendFunc* bf = new
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osg::BlendFunc(osg::BlendFunc::SRC_ALPHA,
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osg::BlendFunc::ONE_MINUS_SRC_ALPHA );
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sset->setAttributeAndModes(bf);*/
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sset->setMode( GL_LIGHTING, osg::StateAttribute::OFF );
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getOrCreateVertexBufferObject();
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sset->setAttribute( createRenderShader() );
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}
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};
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///////////////////////////////////////////////////////////////////////////
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GLuint SomePointsGenerator::getNumPrimitivesGenerated()const
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{
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return vAry->size()*4;
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}
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void SomePointsGenerator::drawImplementation( osg::RenderInfo& renderInfo ) const
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{
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//get output buffer
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unsigned int contextID = renderInfo.getState()->getContextID();
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GLuint ubuff= genbuffer->getOrCreateGLBufferObject(contextID)->getGLObjectID();
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osg::GLExtensions* ext = renderInfo.getState()->get<osg::GLExtensions>();
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ext->glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0,ubuff);
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glEnable(GL_RASTERIZER_DISCARD);
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ext->glBeginTransformFeedback(GL_POINTS);
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osg::Geometry::drawImplementation( renderInfo );
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ext->glEndTransformFeedback();
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glDisable(GL_RASTERIZER_DISCARD);
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ext->glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0, 0);
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}
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SomePointsGenerator::SomePointsGenerator():osg::Geometry()
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{
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setUseVertexBufferObjects(true);
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osg::StateSet* sset = getOrCreateStateSet();
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sset->setMode( GL_LIGHTING, osg::StateAttribute::OFF );
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vAry = new osg::Vec4Array;;
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vAry->push_back( osg::Vec4(0,0,0,1) );
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vAry->push_back( osg::Vec4(0,1,0,1) );
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vAry->push_back( osg::Vec4(1,0,0,1) );
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vAry->push_back( osg::Vec4(1,1,0,1 ));
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addPrimitiveSet( new osg::DrawArrays( GL_POINTS, 0, vAry->size() ) );
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setVertexArray( vAry );
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_program=createGeneratorShader() ;
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sset->setAttribute(_program );
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// a generic cyclic animation value
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osg::Uniform* u_anim1( new osg::Uniform( "u_anim1", 0.9f ) );
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u_anim1->setUpdateCallback( new SineAnimation( 4, 0.5, 0.5 ) );
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sset->addUniform( u_anim1 );
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}
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void SomePointsGenerator::setRenderer(osg::Geometry* renderer)
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{
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genbuffer = renderer->getOrCreateVertexBufferObject();
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}
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///////////////////////////////////////////////////////////////////////////
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int main( int , char** )
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{
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osg::Geode* root( new osg::Geode );
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SomePointsGenerator * pate = new SomePointsGenerator();
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SomePointsRenderer* pate2 = new SomePointsRenderer(pate);
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pate->setRenderer( pate2);
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root->addDrawable( pate );
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root->addDrawable( pate2 );
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osgViewer::Viewer viewer;
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viewer.setSceneData( root );
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return viewer.run();
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}
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