OSG使用OpenGL3.3 几何着色器例子

#include <osgViewer/Viewer> #include <osg/Geometry> #include <osg/Material> #include <osgDB/ReadFile> #include <osg/Image> #include <osg/Texture2D> #include <osg/Texture1D> void configureShaders(osg::StateSet* stateSet) { const std::string vertexSource = "#version 330\n" "\n" "layout (location = 0) in vec4 Position;\n" "layout (location = 1) in vec4 color;\n" "layout (location = 2) in vec3 Normal;\n" "layout (location = 3) in vec2 Texcoord;\n" "uniform mat3 osg_NormalMatrix;\n" "out vec4 vcolor;\n" "out vec3 Norm;\n" "out vec2 texcoord;\n" "void main()\n" "{\n" " gl_Position = Position;\n" " vcolor = color;\n" " Norm = osg_NormalMatrix * Normal; \n" " texcoord = Texcoord; \n" "} \n"; osg::Shader* vShader = new osg::Shader(osg::Shader::VERTEX, vertexSource); const std::string geomSource = "#version 330 \n" "layout(triangles) in; \n" "layout(triangle_strip) out; \n" "layout(max_vertices = 9) out; \n" "uniform mat4 osg_ModelViewProjectionMatrix; \n" /*<数组大小为3，，下标索引为0,1,2>*/ "in vec4 vcolor[];\n" "in vec3 Norm[]; \n" "in vec2 texcoord[]; \n "/*<数组大小为3，下标索引为0,1,2>*/ "out vec2 tex; \n" "out vec4 fcolor; \n" "out vec3 norm; \n" "uniform sampler2D Tex;\n" "uniform sampler1D Tex1D;\n" "void main(void) \n" "{ \n" /*<绘制四边形>*/ " for (int i = 0; i < gl_in.length(); i++) \n" " { \n" " gl_Position = osg_ModelViewProjectionMatrix*gl_in[i].gl_Position; \n" " tex=texcoord[i]; \n" " fcolor=vcolor[i]; \n"/*<设置每个顶点颜色都不一样>*/ " norm=Norm[i]; \n" " EmitVertex(); \n" " } \n" " EndPrimitive(); \n" " gl_Position = osg_ModelViewProjectionMatrix*gl_in[0].gl_Position; \n" " tex=texcoord[0]; \n" " fcolor=vcolor[0]; \n"/*<设置每个顶点颜色都不一样>*/ " norm=Norm[0]; \n" " EmitVertex(); \n" " gl_Position = osg_ModelViewProjectionMatrix*gl_in[2].gl_Position; \n" " tex=texcoord[2]; \n" " fcolor=vcolor[2]; \n"/*<设置每个顶点颜色都不一样>*/ " norm=Norm[2]; \n" " EmitVertex(); \n" " gl_Position = osg_ModelViewProjectionMatrix*vec4(1.0,0.0,0.0,1.0); \n"/*<TempVertex[0]不是原点>*/ " tex=texcoord[1]; \n" " fcolor=vcolor[2]; \n"/*<设置每个顶点颜色都不一样>*/ " norm=Norm[0]; \n" " EmitVertex(); \n" " EndPrimitive(); \n" "} \n"; osg::Shader* gShader = new osg::Shader(osg::Shader::GEOMETRY, geomSource); const std::string fragmentSource = "#version 330 \n" " \n" "layout (location = 0) out vec4 fragData; \n" " \n" "uniform sampler2D Texture;\n" "in vec4 fcolor; \n" "in vec3 norm; \n" "in vec2 tex; \n" "void main() \n" "{ \n" "vec4 textureColor=texture(Texture,tex) * fcolor;\n" " fragData = textureColor; \n" "} \n"; osg::Shader* fShader = new osg::Shader(osg::Shader::FRAGMENT, fragmentSource); osg::Program* program = new osg::Program; program->addShader(vShader); program->addShader(gShader); program->addShader(fShader); stateSet->setAttribute(program); } void main() { osg::ref_ptr<osg::Group> root = new osg::Group; /*<顶点坐标>*/ osgViewer::Viewer viewer; osg::ref_ptr<osg::Vec3Array> vertices = new osg::Vec3Array; vertices->push_back(osg::Vec3(0.0f, 0.0f, 0.0f)); vertices->push_back(osg::Vec3(0.0f, 0.0f, 1.0f)); vertices->push_back(osg::Vec3(1.0f, 0.0f, 1.0f)); /*<顶点颜色>*/ osg::ref_ptr<osg::Vec4Array> V_C = new osg::Vec4Array; V_C->push_back(osg::Vec4(0.0, 1.0, 1.0, 1.0)); V_C->push_back(osg::Vec4(0.0, 0.0, 1.0, 1.0)); V_C->push_back(osg::Vec4(1.0, 1.0, 1.0, 1.0)); V_C->push_back(osg::Vec4(0.0, 1.0, 0.0, 1.0)); /*<顶点法线>*/ osg::ref_ptr<osg::Vec3Array> V_N = new osg::Vec3Array; V_N->push_back(osg::Vec3(0.0, 1.0, 0.0)); /*<顶点纹理坐标>*/ osg::ref_ptr<osg::Vec2Array> V_T = new osg::Vec2Array; V_T->push_back(osg::Vec2(0.0, 0.0)); V_T->push_back(osg::Vec2(1.0, 0.0)); V_T->push_back(osg::Vec2(1.0, 1.0)); V_T->push_back(osg::Vec2(0.0, 1.0)); osg::ref_ptr<osg::Geometry> geom = new osg::Geometry(); /*<设置顶点>*/ geom->setVertexArray(vertices); /*<顶点颜色>*/ geom->setVertexAttribArray(1, V_C); geom->setVertexAttribBinding(1, osg::Geometry::BIND_PER_VERTEX); /*<顶点法线>*/ geom->setVertexAttribArray(2, V_N); geom->setVertexAttribBinding(2, osg::Geometry::BIND_OVERALL); /*<顶点纹理坐标>*/ geom->setTexCoordArray(0, V_T); /*<纹理载入>*/ osg::ref_ptr<osg::Image> image1 = osgDB::readImageFile("Images/brick.jpg"); if (!image1) { std::cout << " cannot Open image !!" << std::endl; } osg::ref_ptr<osg::Texture2D> texture1 = new osg::Texture2D(); texture1->setDataVariance(osg::Object::DYNAMIC); texture1->setImage(image1.get()); geom->getOrCreateStateSet()->setTextureAttributeAndModes(0, texture1.get(), osg::StateAttribute::ON); geom->getOrCreateStateSet()->addUniform(new osg::Uniform("Texture", 0)); geom->getOrCreateStateSet()->addUniform(new osg::Uniform("Tex", 0)); geom->addPrimitiveSet(new osg::DrawArrays(GL_TRIANGLES, 0, 3)); configureShaders(geom->getOrCreateStateSet()); root->addChild(geom); /*<版本指定>*/ const int width(800), height(450); const std::string version("3.1"); osg::ref_ptr< osg::GraphicsContext::Traits > traits = new osg::GraphicsContext::Traits(); traits->x = 50; traits->y = 30; traits->width = width; traits->height = height; traits->windowDecoration = true; traits->doubleBuffer = true; traits->glContextVersion = version; osg::ref_ptr< osg::GraphicsContext > gc = osg::GraphicsContext::createGraphicsContext(traits.get()); if (!gc.valid()) { osg::notify(osg::FATAL) << "Unable to create OpenGL v" << version << " context." << std::endl; return; } // Create a Camera that uses the above OpenGL context. osg::Camera* cam = viewer.getCamera(); cam->setGraphicsContext(gc.get()); // Must set perspective projection for fovy and aspect. cam->setProjectionMatrix(osg::Matrix::perspective(30., (double)width / (double)height, 1., 100.)); // Unlike OpenGL, OSG viewport does *not* default to window dimensions. cam->setViewport(new osg::Viewport(0, 0, width, height)); // for non GL3/GL4 and non GLES2 platforms we need enable the osg_ uniforms that the shaders will use, // you don't need thse two lines on GL3/GL4 and GLES2 specific builds as these will be enable by default. gc->getState()->setUseModelViewAndProjectionUniforms(true); gc->getState()->setUseVertexAttributeAliasing(true); viewer.setSceneData(root.get()); viewer.run(); return; }