How do I add new button functions

[Bobkk-k]

I want to implement the point cloud to be colored by categories, this is I currently according to the tutorial to write, but always report errors, can you help me？

[Bobkk-k]

else if (key == GLFW_KEY_I && modifiers == 0) {
    for (auto m : models_) {
        for (auto d : m->renderer()->points_drawables())
        {
            auto cloud = dynamic_cast<PointCloud*>(m);
            if (cloud)
            {
                auto colors = cloud->add_vertex_property<vec3>("v:color");
                auto categories = cloud->get_vertex_property<int>("v:category");
                for (auto v : cloud->vertices()) {
                    std::cout << v <<std::endl;
                    int category = categories[v];
                    /*srand(category);*/
                    colors[v] = random_color();
                }
            }
            d->set_coloring(Drawable::COLOR_PROPERTY, Drawable::VERTEX, "v:color");
        }
    }
}

[LiangliangNan]

What are the errors did you see? Better to post the error messages or snapshots here.

Besides, your code also has logical errors. colors[v] = random_color() is apparently not correct, because it assigns a random color for each vertex. The correct way to do it is to first generate a unique color for each category. Then for each vertex you assign the predefined color queried based on its category.

[Bobkk-k]

What are the errors did you see? Better to post the error messages or snapshots here.

Besides, your code also has logical errors. colors[v] = random_color() is apparently not correct, because it assigns a random color for each vertex. The correct way to do it is to first generate a unique color for each category. Then for each vertex you assign the predefined color queried based on its category.

Thanks to your reply. I'm sorry I didn't express my problem clearly, I main problem is I don't know which function to use to make vertexs colorize by its color property. set_coloringfunction seems dosen't work. But I have find a function to do this, it is update_color_buffer().

now I met a new problem. The update_color_buffer() function dosen't work, after I use set_uniform_coloring function. It seems once I use set uniform_coloring function, I can't colorize my vertexs by different colors. Thanks again！

[LiangliangNan]

Your previous question: You can call Drawable::update() function after calling to set_coloring(...) to actually transfer the color information to GPU. You will also need to call your viewer's update() function to update the display.

Your second question: Of course, because you asked to use uniform color for all vertices (because of the call to set_uniform_coloring()).

[Bobkk-k]

I got it. Thank you so much！！