fltk/test/CubeView.cxx

//
// CubeView class implementation for the Fast Light Tool Kit (FLTK).
//
// Copyright 1998-2021 by Bill Spitzak and others.
//
// This library is free software. Distribution and use rights are outlined in
// the file "COPYING" which should have been included with this file.  If this
// file is missing or damaged, see the license at:
//
//     https://www.fltk.org/COPYING.php
//
// Please see the following page on how to report bugs and issues:
//
//     https://www.fltk.org/bugs.php
//

// Note to editor: the following code can and should be copied
// to the fluid tutorial in 'documentation/src/fluid.dox'
// *without* '#if HAVE_GL' preprocessor statements, leaving
// only those parts where the condition is true.

// [\code in documentation/src/fluid.dox]
#include "CubeView.h"
#include <math.h>

#if HAVE_GL
CubeView::CubeView(int x, int y, int w, int h, const char *l)
  : Fl_Gl_Window(x, y, w, h, l)
#else
CubeView::CubeView(int x, int y, int w, int h, const char *l)
  : Fl_Box(x, y, w, h, l)
#endif /* HAVE_GL */
{
  Fl::use_high_res_GL(1);
  vAng = 0.0;
  hAng = 0.0;
  size = 10.0;
  xshift = 0.0;
  yshift = 0.0;

  /* The cube definition. These are the vertices of a unit cube
   * centered on the origin.*/

  boxv0[0] = -0.5; boxv0[1] = -0.5; boxv0[2] = -0.5;
  boxv1[0] =  0.5; boxv1[1] = -0.5; boxv1[2] = -0.5;
  boxv2[0] =  0.5; boxv2[1] =  0.5; boxv2[2] = -0.5;
  boxv3[0] = -0.5; boxv3[1] =  0.5; boxv3[2] = -0.5;
  boxv4[0] = -0.5; boxv4[1] = -0.5; boxv4[2] =  0.5;
  boxv5[0] =  0.5; boxv5[1] = -0.5; boxv5[2] =  0.5;
  boxv6[0] =  0.5; boxv6[1] =  0.5; boxv6[2] =  0.5;
  boxv7[0] = -0.5; boxv7[1] =  0.5; boxv7[2] =  0.5;

#if !HAVE_GL
  label("OpenGL is required for this demo to operate.");
  align(FL_ALIGN_WRAP | FL_ALIGN_INSIDE);
#endif /* !HAVE_GL */
}

#if HAVE_GL
void CubeView::drawCube() {
/* Draw a colored cube */
#define ALPHA 0.5
  glShadeModel(GL_FLAT);

  glBegin(GL_QUADS);
    glColor4f(0.0, 0.0, 1.0, ALPHA);
    glVertex3fv(boxv0);
    glVertex3fv(boxv1);
    glVertex3fv(boxv2);
    glVertex3fv(boxv3);

    glColor4f(1.0, 1.0, 0.0, ALPHA);
    glVertex3fv(boxv0);
    glVertex3fv(boxv4);
    glVertex3fv(boxv5);
    glVertex3fv(boxv1);

    glColor4f(0.0, 1.0, 1.0, ALPHA);
    glVertex3fv(boxv2);
    glVertex3fv(boxv6);
    glVertex3fv(boxv7);
    glVertex3fv(boxv3);

    glColor4f(1.0, 0.0, 0.0, ALPHA);
    glVertex3fv(boxv4);
    glVertex3fv(boxv5);
    glVertex3fv(boxv6);
    glVertex3fv(boxv7);

    glColor4f(1.0, 0.0, 1.0, ALPHA);
    glVertex3fv(boxv0);
    glVertex3fv(boxv3);
    glVertex3fv(boxv7);
    glVertex3fv(boxv4);

    glColor4f(0.0, 1.0, 0.0, ALPHA);
    glVertex3fv(boxv1);
    glVertex3fv(boxv5);
    glVertex3fv(boxv6);
    glVertex3fv(boxv2);
  glEnd();

  glColor3f(1.0, 1.0, 1.0);
  glBegin(GL_LINES);
    glVertex3fv(boxv0);
    glVertex3fv(boxv1);

    glVertex3fv(boxv1);
    glVertex3fv(boxv2);

    glVertex3fv(boxv2);
    glVertex3fv(boxv3);

    glVertex3fv(boxv3);
    glVertex3fv(boxv0);

    glVertex3fv(boxv4);
    glVertex3fv(boxv5);

    glVertex3fv(boxv5);
    glVertex3fv(boxv6);

    glVertex3fv(boxv6);
    glVertex3fv(boxv7);

    glVertex3fv(boxv7);
    glVertex3fv(boxv4);

    glVertex3fv(boxv0);
    glVertex3fv(boxv4);

    glVertex3fv(boxv1);
    glVertex3fv(boxv5);

    glVertex3fv(boxv2);
    glVertex3fv(boxv6);

    glVertex3fv(boxv3);
    glVertex3fv(boxv7);
  glEnd();
} // drawCube

void CubeView::draw() {
  if (!valid()) {
    glLoadIdentity();
    glViewport(0, 0, pixel_w(), pixel_h());
    glOrtho(-10, 10, -10, 10, -20050, 10000);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  }

  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

  glPushMatrix();

  glTranslatef((GLfloat)xshift, (GLfloat)yshift, 0);
  glRotatef((GLfloat)hAng, 0, 1, 0);
  glRotatef((GLfloat)vAng, 1, 0, 0);
  glScalef(float(size), float(size), float(size));

  drawCube();

  glPopMatrix();
}
// [\endcode in documentation/src/fluid.dox]

#endif /* HAVE_GL */