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copied!<p>The most straightforward method would be to create a VBO containing the worldspace points of all the lines you wish to draw with GL_LINES.</p> <p>The easiest is to use glDrawArrays. If you have extreme amounts of object pairs that need lines between (10.000s+) then it might make sense to store all the points in a VBO, and then use a IBO (index buffer) to say what points in the VBO are connected by a line.</p> <p>The line vertices would still have to be transformed by the view matrix.</p> <p>Here's an example: GLuint vao, vbo;</p> <pre><code>// generate and bind the vao glGenVertexArrays(1, &vao); glBindVertexArray(vao); // generate and bind the buffer object glGenBuffers(1, &vbo); glBindBuffer(GL_ARRAY_BUFFER, vbo); struct Point{ float x,y,z; Point(float x,float y,float z) : x(x), y(y), z(z) {} }; // create two points needed for a line. For more lines, just add another point-pair std::vector<Point> vertexData; vertexData.push_back( Point(-0.5, 0.f, 0.f) ); vertexData.push_back( Point(+0.5, 0.f, 0.f) ); // fill with data size_t numVerts = vertexData.size(); glBufferData(GL_ARRAY_BUFFER, sizeof(Point)*numVerts, &vertexData[0], GL_STATIC_DRAW); // set up generic attrib pointers glEnableVertexAttribArray(0); glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, numVerts*sizeof(Point), (char*)0 + 0*sizeof(GLfloat)); // "unbind" vao glBindVertexArray(0); // In your render-loop: glBindVertexArray(vao); glDrawArrays(GL_LINES, 0, numVerts); </code></pre> <p>If you need to add more point-pairs during runtime, update the std::vector, bind the VBO and call glBufferData.</p>

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