picker_surface_mesh.h

 
/********************************************************************
 * Copyright (C) 2015 Liangliang Nan <liangliang.nan@gmail.com>
 * https://3d.bk.tudelft.nl/liangliang/
 *
 * This file is part of Easy3D. If it is useful in your research/work,
 * I would be grateful if you show your appreciation by citing it:
 * ------------------------------------------------------------------
 *      Liangliang Nan.
 *      Easy3D: a lightweight, easy-to-use, and efficient C++ library
 *      for processing and rendering 3D data.
 *      Journal of Open Source Software, 6(64), 3255, 2021.
 * ------------------------------------------------------------------
 *
 * Easy3D is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License Version 3
 * as published by the Free Software Foundation.
 *
 * Easy3D is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 ********************************************************************/
 
#ifndef EASY3D_GUI_PICKER_SURFACE_MESH_H
#define EASY3D_GUI_PICKER_SURFACE_MESH_H
 
#include <easy3d/gui/picker.h>
#include <easy3d/core/surface_mesh.h>
 
 
namespace easy3d {
 
    class ShaderProgram;
 
    class SurfaceMeshPicker : public Picker {
    public:
        explicit SurfaceMeshPicker(const Camera *cam);
        ~SurfaceMeshPicker() override = default;
 
        //------------------ sensitivity  ---------------------
 
        unsigned int resolution() const { return hit_resolution_; }
        void set_resolution(unsigned int r) { hit_resolution_ = r; }
 
        //--------------- pick a single element ---------------
 
        SurfaceMesh::Face pick_face(SurfaceMesh *model, int x, int y);
 
        SurfaceMesh::Vertex pick_vertex(SurfaceMesh *model, int x, int y);
 
        SurfaceMesh::Halfedge pick_edge(SurfaceMesh *model, int x, int y);
 
        SurfaceMesh::Vertex pick_vertex(SurfaceMesh *model, SurfaceMesh::Face picked_face, int x, int y);
 
        SurfaceMesh::Halfedge pick_edge(SurfaceMesh *model, SurfaceMesh::Face picked_face, int x, int y);
 
        //-------------------- query after picking ----------------------
 
        SurfaceMesh::Face picked_face() const;
 
        vec3 picked_point(SurfaceMesh *model, SurfaceMesh::Face picked_face, int x, int y) const;
 
 
        //------------------ multiple selection of faces ------------------
 
        std::vector<SurfaceMesh::Face> pick_faces(SurfaceMesh *model, const Rect &rect);
 
        std::vector<SurfaceMesh::Face> pick_faces(SurfaceMesh *model, const Polygon2 &plg);
 
    private:
        // selection implemented in GPU (using shader program)
        SurfaceMesh::Face pick_face_gpu(SurfaceMesh *model, int x, int y, ShaderProgram* program);
 
        // selection implemented in CPU (with OpenMP if supported)
        SurfaceMesh::Face pick_face_cpu(SurfaceMesh *model, int x, int y);
 
        Plane3 face_plane(SurfaceMesh *model, SurfaceMesh::Face face) const;
 
        static bool do_intersect(SurfaceMesh *model, SurfaceMesh::Face picked_face, const OrientedLine3 &line) {
            // Uses Plucker coordinates (see OrientedLine)
            Sign face_sign = ZERO;
            for (auto h : model->halfedges(picked_face)) {
                auto s = model->source(h);
                auto t = model->target(h);
                const OrientedLine3 edge_line(model->position(t), model->position(s));
                Sign sign = OrientedLine3::side(line, edge_line);
                if (sign != ZERO) {
                    if (face_sign != ZERO && sign != face_sign)
                        return false;
                    face_sign = sign;
                }
            }
            return true;
        }
 
    private:
        unsigned int hit_resolution_;     // in pixels
        SurfaceMesh::Face picked_face_;
    };
 
}
 
 
#endif  // EASY3D_GUI_PICKER_SURFACE_MESH_H