OSG使用OpenGL3.3 几何着色器例子

淩亂°似流年 2023-10-18 00:57 147阅读 0赞

#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;
    }