graphics_utility.h

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/*
**  graphics_utility.h
**
**  This is part of Shiokaze, a research-oriented fluid solver for computer graphics.
**  Created by Ryoichi Ando <rand@nii.ac.jp> on Jan 15, 2018.
**
**  Permission is hereby granted, free of charge, to any person obtaining a copy of
**  this software and associated documentation files (the "Software"), to deal in
**  the Software without restriction, including without limitation the rights to use,
**  copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
**  Software, and to permit persons to whom the Software is furnished to do so,
**  subject to the following conditions:
**
**  The above copyright notice and this permission notice shall be included in all copies
**  or substantial portions of the Software.
**
**  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
**  INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
**  PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
**  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
**  CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
**  OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
//
#ifndef SHKZ_GRAPHICS_UTILITY_H
#define SHKZ_GRAPHICS_UTILITY_H
//
#include <cmath>
#include <shiokaze/graphics/graphics_engine.h>
#include <shiokaze/core/console.h>
#include <shiokaze/math/vec.h>
//
SHKZ_BEGIN_NAMESPACE
//
class graphics_utility {
private:
    using ge = graphics_engine;
public:
    template<class T> static void draw_circle ( graphics_engine &g, const T *p, double r, ge::MODE mode, unsigned num_v=20 ) {
        g.begin(mode);
        for( unsigned t=0; t<num_v; t++ ) {
            double theta = 2.0 * M_PI * t / (double)num_v;
            g.vertex2(p[0]+r*cos(theta),p[1]+r*sin(theta));
        }
        g.end();
    }
    template<class T> static void draw_arrow( graphics_engine &g, const T *p0, const T *p1 ) {
        double y_vec_x = p1[0]-p0[0];
        double y_vec_y = p1[1]-p0[1];
        double y_vec_len = hypot(y_vec_x,y_vec_y);
        if( y_vec_len ) {
            //
            y_vec_x /= y_vec_len;
            y_vec_y /= y_vec_len;
            //
            double x_vec_x = -y_vec_y;
            double x_vec_y = y_vec_x;
            double k = 0.25*y_vec_len;
            //
            g.begin(ge::MODE::LINES);
            g.vertex2v(p0);
            g.vertex2v(p1);
            g.end();
            //
            vec2d p2(p1[0]+k*0.8*x_vec_x-k*y_vec_x,p1[1]+k*0.8*x_vec_y-k*y_vec_y);
            vec2d p3(p1[0]-k*0.8*x_vec_x-k*y_vec_x,p1[1]-k*0.8*x_vec_y-k*y_vec_y);
            vec2d mid = (vec2d(p1[0],p1[1])+p2+p3)/3.0;
            g.begin(ge::MODE::TRIANGLES);
            g.vertex2v(p1);
            g.vertex2v(p2.v);
            g.vertex2v(mid.v);
            g.end();
            g.begin(ge::MODE::TRIANGLES);
            g.vertex2v(p1);
            g.vertex2v(p3.v);
            g.vertex2v(mid.v);
            g.end();
        }
    }
    static void draw_wired_box( graphics_engine &g, double scale=1.0 ) {
        const double p0[] = { 0.0, 0.0, 0.0 };
        const double p1[] = { scale, scale, scale };
        draw_wired_box(g,p0,p1);
    }
    template<class T> static void draw_wired_box( graphics_engine &g, const T *p0, const T *p1 ) {
        //
        g.begin(ge::MODE::LINE_LOOP);
        g.vertex3(p0[0],p0[1],p0[2]);
        g.vertex3(p1[0],p0[1],p0[2]);
        g.vertex3(p1[0],p1[1],p0[2]);
        g.vertex3(p0[0],p1[1],p0[2]);
        g.end();
        //
        g.begin(ge::MODE::LINE_LOOP);
        g.vertex3(p0[0],p0[1],p1[2]);
        g.vertex3(p1[0],p0[1],p1[2]);
        g.vertex3(p1[0],p1[1],p1[2]);
        g.vertex3(p0[0],p1[1],p1[2]);
        g.end();
        //
        g.begin(ge::MODE::LINES);
        g.vertex3(p0[0],p0[1],p0[2]);
        g.vertex3(p0[0],p0[1],p1[2]);
        g.vertex3(p0[0],p1[1],p0[2]);
        g.vertex3(p0[0],p1[1],p1[2]);
        g.vertex3(p1[0],p1[1],p0[2]);
        g.vertex3(p1[0],p1[1],p1[2]);
        g.vertex3(p1[0],p0[1],p0[2]);
        g.vertex3(p1[0],p0[1],p1[2]);
        g.end();
    }
};
//
SHKZ_END_NAMESPACE
//
#endif
//