text: /*
   * The OpenGL code in this example is based on the "teapots" example in
   * "OpenGL Programming Guide" by Jackie Neider, Tom Davis, and Mason
   * Woo, Addison-Wesley, 1993. It can be obtained from ftp.sgi.com and
   * contains the following copyright notice:
   *
   * (c) Copyright 1993, Silicon Graphics, Inc.
   * ALL RIGHTS RESERVED
   * Permission to use, copy, modify, and distribute this software for
   * any purpose and without fee is hereby granted, provided that the
   * above copyright notice appear in all copies and that both the
   * copyright notice and this permission notice appear in supporting
   * documentation, and that the name of Silicon Graphics, Inc. not be
   * used in advertising or publicity pertaining to distribution of the
   * software without specific, written prior permission.
   *
   * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
   * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
   * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
   * FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL SILICON
   * GRAPHICS, INC. BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
   * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
   * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
   * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
   * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC. HAS BEEN
   * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
   * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
   * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
   *
   * US Government Users Restricted Rights
   * Use, duplication, or disclosure by the Government is subject to
   * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
   * (c)(1)(ii) of the Rights in Technical Data and Computer Software
   * clause at DFARS 252.227-7013 and/or in similar or successor
   * clauses in the FAR or the DOD or NASA FAR Supplement.
   * Unpublished-- rights reserved under the copyright laws of the
   * United States. Contractor/manufacturer is Silicon Graphics,
   * Inc., 2011 N. Shoreline Blvd., Mountain View, CA 94039-7311.
   *
   * OpenGL(TM) is a trademark of Silicon Graphics, Inc.
   */
  
  #include <QtWidgets>
  #include <QtOpenGL>
  
  #include "teapots.h"
  
  Teapots::Teapots(QWidget *parent)
      : QGLWidget(parent)
  {
      rubberBandIsShown = false;
  
      makeCurrent();
      fbObject = new QGLFramebufferObject(1024, 1024,
                                          QGLFramebufferObject::Depth);
      createGLTeapotObject();
  }
  
  Teapots::~Teapots()
  {
      makeCurrent();
      delete fbObject;
      glDeleteLists(glTeapotObject, 1);
  }
  
  void Teapots::initializeGL()
  {
      static const GLfloat ambient[] = { 0.0, 0.0, 0.0, 1.0 };
      static const GLfloat diffuse[] = { 1.0, 1.0, 1.0, 1.0 };
      static const GLfloat position[] = { 0.0, 3.0, 3.0, 0.0 };
      static const GLfloat lmodelAmbient[] = { 0.2, 0.2, 0.2, 1.0 };
      static const GLfloat localView[] = { 0.0 };
  
      glLightfv(GL_LIGHT0, GL_AMBIENT, ambient);
      glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse);
      glLightfv(GL_LIGHT0, GL_POSITION, position);
      glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lmodelAmbient);
      glLightModelfv(GL_LIGHT_MODEL_LOCAL_VIEWER, localView);
  
      glFrontFace(GL_CW);
      glEnable(GL_LIGHTING);
      glEnable(GL_LIGHT0);
      glEnable(GL_AUTO_NORMAL);
      glEnable(GL_NORMALIZE);
      glEnable(GL_DEPTH_TEST);
      glDepthFunc(GL_LESS);
  }
  
  void Teapots::resizeGL(int width, int height)
  {
      fbObject->bind();
  
      glDisable(GL_TEXTURE_2D);
      glEnable(GL_LIGHTING);
      glEnable(GL_DEPTH_TEST);
  
      glViewport(0, 0, width, height);
      glMatrixMode(GL_PROJECTION);
      glLoadIdentity();
      if (width <= height) {
          glOrtho(0.0, 20.0, 0.0, 20.0 * GLfloat(height) / GLfloat(width),
                  -10.0, 10.0);
      } else {
          glOrtho(0.0, 20.0 * GLfloat(width) / GLfloat(height), 0.0, 20.0,
                  -10.0, 10.0);
      }
      glMatrixMode(GL_MODELVIEW);
      drawTeapots();
  
      fbObject->release();
  }
  
  void Teapots::paintGL()
  {
      glDisable(GL_LIGHTING);
      glViewport(0, 0, width(), height());
      glMatrixMode(GL_PROJECTION);
      glLoadIdentity();
      glMatrixMode(GL_MODELVIEW);
      glLoadIdentity();
      glDisable(GL_DEPTH_TEST);
  
      glClear(GL_COLOR_BUFFER_BIT);
      glEnable(GL_TEXTURE_2D);
      glBindTexture(GL_TEXTURE_2D, fbObject->texture());
      glColor3f(1.0, 1.0, 1.0);
      GLfloat s = width() / GLfloat(fbObject->size().width());
      GLfloat t = height() / GLfloat(fbObject->size().height());
  
      glBegin(GL_QUADS);
      glTexCoord2f(0.0, 0.0);
      glVertex2f(-1.0, -1.0);
      glTexCoord2f(s, 0.0);
      glVertex2f(1.0, -1.0);
      glTexCoord2f(s, t);
      glVertex2f(1.0, 1.0);
      glTexCoord2f(0.0, t);
      glVertex2f(-1.0, 1.0);
      glEnd();
  
      if (rubberBandIsShown) {
          glMatrixMode(GL_PROJECTION);
          glOrtho(0, width(), height(), 0, 0, 100);
          glMatrixMode(GL_MODELVIEW);
  
          glDisable(GL_TEXTURE_2D);
          glEnable(GL_BLEND);
          glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
          glLineWidth(4.0);
          glColor4f(1.0, 1.0, 1.0, 0.2);
          glRecti(rubberBandCorner1.x(), rubberBandCorner1.y(),
                  rubberBandCorner2.x(), rubberBandCorner2.y());
          glColor4f(1.0, 1.0, 0.0, 0.5);
          glLineStipple(3, 0xAAAA);
          glEnable(GL_LINE_STIPPLE);
  
          glBegin(GL_LINE_LOOP);
          glVertex2i(rubberBandCorner1.x(), rubberBandCorner1.y());
          glVertex2i(rubberBandCorner2.x(), rubberBandCorner1.y());
          glVertex2i(rubberBandCorner2.x(), rubberBandCorner2.y());
          glVertex2i(rubberBandCorner1.x(), rubberBandCorner2.y());
          glEnd();
  
          glLineWidth(1.0);
          glDisable(GL_LINE_STIPPLE);
          glDisable(GL_BLEND);
      }
  }
  
  void Teapots::mousePressEvent(QMouseEvent *event)
  {
      rubberBandCorner1 = event->pos();
      rubberBandCorner2 = event->pos();
      rubberBandIsShown = true;
  }
  
  void Teapots::mouseMoveEvent(QMouseEvent *event)
  {
      if (rubberBandIsShown) {
          rubberBandCorner2 = event->pos();
          updateGL();
      }
  }
  
  void Teapots::mouseReleaseEvent(QMouseEvent * /* event */)
  {
      if (rubberBandIsShown) {
          rubberBandIsShown = false;
          updateGL();
      }
  }
  
  void Teapots::createGLTeapotObject()
  {
      static const int patch[][16] = {
          { 102, 103, 104, 105, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
            15 },
          { 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
            27 },
          { 24, 25, 26, 27, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39,
            40 },
          { 96, 96, 96, 96, 97, 98, 99, 100, 101, 101, 101, 101, 0, 1, 2,
            3 },
          { 0, 1, 2, 3, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115,
            116, 117 },
          { 118, 118, 118, 118, 124, 122, 119, 121, 123, 126, 125, 120,
            40, 39, 38, 37 },
          { 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55,
            56 },
          { 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 28, 65, 66,
            67 },
          { 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82,
            83 },
          { 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94,
            95 }
      };
      static const GLfloat cp[][3] = {
          { 0.2, 0, 2.7 }, { 0.2, -0.112, 2.7 }, { 0.112, -0.2, 2.7 },
          { 0, -0.2, 2.7 }, { 1.3375, 0, 2.53125 },
          { 1.3375, -0.749, 2.53125 }, { 0.749, -1.3375, 2.53125 },
          { 0, -1.3375, 2.53125 }, { 1.4375, 0, 2.53125 },
          { 1.4375, -0.805, 2.53125 }, { 0.805, -1.4375, 2.53125 },
          { 0, -1.4375, 2.53125 }, { 1.5, 0, 2.4 }, { 1.5, -0.84, 2.4 },
          { 0.84, -1.5, 2.4 }, { 0, -1.5, 2.4 }, { 1.75, 0, 1.875 },
          { 1.75, -0.98, 1.875 }, { 0.98, -1.75, 1.875 },
          { 0, -1.75, 1.875 }, { 2, 0, 1.35 }, { 2, -1.12, 1.35 },
          { 1.12, -2, 1.35 }, { 0, -2, 1.35 }, { 2, 0, 0.9 },
          { 2, -1.12, 0.9 }, { 1.12, -2, 0.9 }, { 0, -2, 0.9 },
          { -2, 0, 0.9 }, { 2, 0, 0.45 }, { 2, -1.12, 0.45 },
          { 1.12, -2, 0.45 }, { 0, -2, 0.45 }, { 1.5, 0, 0.225 },
          { 1.5, -0.84, 0.225 }, { 0.84, -1.5, 0.225 },
          { 0, -1.5, 0.225 }, { 1.5, 0, 0.15 }, { 1.5, -0.84, 0.15 },
          { 0.84, -1.5, 0.15 }, { 0, -1.5, 0.15 }, { -1.6, 0, 2.025 },
          { -1.6, -0.3, 2.025 }, { -1.5, -0.3, 2.25 }, { -1.5, 0, 2.25 },
          { -2.3, 0, 2.025 }, { -2.3, -0.3, 2.025 }, { -2.5, -0.3, 2.25 },
          { -2.5, 0, 2.25 }, { -2.7, 0, 2.025 }, { -2.7, -0.3, 2.025 },
          { -3, -0.3, 2.25 }, { -3, 0, 2.25 }, { -2.7, 0, 1.8 },
          { -2.7, -0.3, 1.8 }, { -3, -0.3, 1.8 }, { -3, 0, 1.8 },
          { -2.7, 0, 1.575 }, { -2.7, -0.3, 1.575 }, { -3, -0.3, 1.35 },
          { -3, 0, 1.35 }, { -2.5, 0, 1.125 }, { -2.5, -0.3, 1.125 },
          { -2.65, -0.3, 0.9375 }, { -2.65, 0, 0.9375 },
          { -2, -0.3, 0.9 }, { -1.9, -0.3, 0.6 }, { -1.9, 0, 0.6 },
          { 1.7, 0, 1.425 }, { 1.7, -0.66, 1.425 }, { 1.7, -0.66, 0.6 },
          { 1.7, 0, 0.6 }, { 2.6, 0, 1.425 }, { 2.6, -0.66, 1.425 },
          { 3.1, -0.66, 0.825 }, { 3.1, 0, 0.825 }, { 2.3, 0, 2.1 },
          { 2.3, -0.25, 2.1 }, { 2.4, -0.25, 2.025 }, { 2.4, 0, 2.025 },
          { 2.7, 0, 2.4 }, { 2.7, -0.25, 2.4 }, { 3.3, -0.25, 2.4 },
          { 3.3, 0, 2.4 }, { 2.8, 0, 2.475 }, { 2.8, -0.25, 2.475 },
          { 3.525, -0.25, 2.49375 }, { 3.525, 0, 2.49375 },
          { 2.9, 0, 2.475 }, { 2.9, -0.15, 2.475 },
          { 3.45, -0.15, 2.5125 }, { 3.45, 0, 2.5125 }, { 2.8, 0, 2.4 },
          { 2.8, -0.15, 2.4 }, { 3.2, -0.15, 2.4 }, { 3.2, 0, 2.4 },
          { 0, 0, 3.15 }, { 0.8, 0, 3.15 }, { 0.8, -0.45, 3.15 },
          { 0.45, -0.8, 3.15 }, { 0, -0.8, 3.15 }, { 0, 0, 2.85 },
          { 1.4, 0, 2.4 }, { 1.4, -0.784, 2.4 }, { 0.784, -1.4, 2.4 },
          { 0, -1.4, 2.4 }, { 0.4, 0, 2.55 }, { 0.4, -0.224, 2.55 },
          { 0.224, -0.4, 2.55 }, { 0, -0.4, 2.55 }, { 1.3, 0, 2.55 },
          { 1.3, -0.728, 2.55 }, { 0.728, -1.3, 2.55 }, { 0, -1.3, 2.55 },
          { 1.3, 0, 2.4 }, { 1.3, -0.728, 2.4 }, { 0.728, -1.3, 2.4 },
          { 0, -1.3, 2.4 }, { 0, 0, 0 }, { 1.425, -0.798, 0 },
          { 1.5, 0, 0.075 }, { 1.425, 0, 0 }, { 0.798, -1.425, 0 },
          { 0, -1.5, 0.075 }, { 0, -1.425, 0 }, { 1.5, -0.84, 0.075 },
          { 0.84, -1.5, 0.075 }
      };
      static const GLfloat tex[2][2][2] = {
          { { 0, 0 }, { 1, 0 } }, { { 0, 1 }, { 1, 1 } }
      };
  
      GLfloat p[4][4][3];
      GLfloat q[4][4][3];
      GLfloat r[4][4][3];
      GLfloat s[4][4][3];
      int grid = 14;
  
      makeCurrent();
  
      glTeapotObject = glGenLists(1);
  
      glNewList(glTeapotObject, GL_COMPILE);
      glPushMatrix();
      glRotatef(270.0, 1.0, 0.0, 0.0);
      glScalef(0.5, 0.5, 0.5);
      glTranslatef(0.0, 0.0, -1.5);
  
      for (int i = 0; i < 10; i++) {
          for (int j = 0; j < 4; j++) {
              for (int k = 0; k < 4; k++) {
                  for (int l = 0; l < 3; l++) {
                      p[j][k][l] = cp[patch[i][(j * 4) + k]][l];
                      q[j][k][l] = cp[patch[i][(j * 4) + (3 - k)]][l];
                      if (l == 1)
                          q[j][k][l] *= -1.0;
                      if (i < 6) {
                          r[j][k][l] = cp[patch[i][(j * 4) + (3 - k)]][l];
                          if (l == 0)
                              r[j][k][l] *= -1.0;
                          s[j][k][l] = cp[patch[i][(j * 4) + k]][l];
                          if (l <= 1)
                              s[j][k][l] *= -1.0;
                      }
                  }
              }
          }
          glMap2f(GL_MAP2_TEXTURE_COORD_2, 0, 1, 2, 2, 0, 1, 4, 2,
                  &tex[0][0][0]);
          glMap2f(GL_MAP2_VERTEX_3, 0, 1, 3, 4, 0, 1, 12, 4, &p[0][0][0]);
          glEnable(GL_MAP2_VERTEX_3);
          glEnable(GL_MAP2_TEXTURE_COORD_2);
          glMapGrid2f(grid, 0.0, 1.0, grid, 0.0, 1.0);
          glEvalMesh2(GL_LINE, 0, grid, 0, grid);
          glMap2f(GL_MAP2_VERTEX_3, 0, 1, 3, 4, 0, 1, 12, 4, &q[0][0][0]);
          glEvalMesh2(GL_LINE, 0, grid, 0, grid);
          if (i < 6) {
              glMap2f(GL_MAP2_VERTEX_3, 0, 1, 3, 4, 0, 1, 12, 4,
                      &r[0][0][0]);
              glEvalMesh2(GL_LINE, 0, grid, 0, grid);
              glMap2f(GL_MAP2_VERTEX_3, 0, 1, 3, 4, 0, 1, 12, 4,
                      &s[0][0][0]);
              glEvalMesh2(GL_LINE, 0, grid, 0, grid);
          }
      }
      glDisable(GL_MAP2_VERTEX_3);
      glDisable(GL_MAP2_TEXTURE_COORD_2);
      glPopMatrix();
      glEndList();
  }
  
  void Teapots::drawTeapot(GLfloat x, GLfloat y, GLfloat ambientR,
                           GLfloat ambientG, GLfloat ambientB,
                           GLfloat diffuseR, GLfloat diffuseG,
                           GLfloat diffuseB, GLfloat specularR,
                           GLfloat specularG, GLfloat specularB,
                           GLfloat shininess)
  {
      GLfloat matrix[4];
      matrix[3] = 1.0;
  
      glPushMatrix();
  
      glTranslatef(x, y, 0.0);
  
      matrix[0] = ambientR;
      matrix[1] = ambientG;
      matrix[2] = ambientB;
      glMaterialfv(GL_FRONT, GL_AMBIENT, matrix);
  
      matrix[0] = diffuseR;
      matrix[1] = diffuseG;
      matrix[2] = diffuseB;
      glMaterialfv(GL_FRONT, GL_DIFFUSE, matrix);
  
      matrix[0] = specularR;
      matrix[1] = specularG;
      matrix[2] = specularB;
      glMaterialfv(GL_FRONT, GL_SPECULAR, matrix);
  
      glMaterialf(GL_FRONT, GL_SHININESS, shininess * 128.0);
  
      glCallList(glTeapotObject);
  
      glPopMatrix();
  }
  
  void Teapots::drawTeapots()
  {
      glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  
      drawTeapot(2.0, 17.0, 0.0215, 0.1745, 0.0215, 0.07568, 0.61424,
                 0.07568, 0.633, 0.727811, 0.633, 0.6);
      drawTeapot(2.0, 14.0, 0.135, 0.2225, 0.1575, 0.54, 0.89, 0.63,
                 0.316228, 0.316228, 0.316228, 0.1);
      drawTeapot(2.0, 11.0, 0.05375, 0.05, 0.06625, 0.18275, 0.17,
                 0.22525, 0.332741, 0.328634, 0.346435, 0.3);
      drawTeapot(2.0, 8.0, 0.25, 0.20725, 0.20725, 1, 0.829, 0.829,
                 0.296648, 0.296648, 0.296648, 0.088);
      drawTeapot(2.0, 5.0, 0.1745, 0.01175, 0.01175, 0.61424, 0.04136,
                 0.04136, 0.727811, 0.626959, 0.626959, 0.6);
      drawTeapot(2.0, 2.0, 0.1, 0.18725, 0.1745, 0.396, 0.74151, 0.69102,
                 0.297254, 0.30829, 0.306678, 0.1);
  
      drawTeapot(6.0, 17.0, 0.329412, 0.223529, 0.027451, 0.780392,
                 0.568627, 0.113725, 0.992157, 0.941176, 0.807843,
                 0.21794872);
      drawTeapot(6.0, 14.0, 0.2125, 0.1275, 0.054, 0.714, 0.4284, 0.18144,
                 0.393548, 0.271906, 0.166721, 0.2);
      drawTeapot(6.0, 11.0, 0.25, 0.25, 0.25, 0.4, 0.4, 0.4, 0.774597,
                 0.774597, 0.774597, 0.6);
      drawTeapot(6.0, 8.0, 0.19125, 0.0735, 0.0225, 0.7038, 0.27048,
                 0.0828, 0.256777, 0.137622, 0.086014, 0.1);
      drawTeapot(6.0, 5.0, 0.24725, 0.1995, 0.0745, 0.75164, 0.60648,
                 0.22648, 0.628281, 0.555802, 0.366065, 0.4);
      drawTeapot(6.0, 2.0, 0.19225, 0.19225, 0.19225, 0.50754, 0.50754,
                 0.50754, 0.508273, 0.508273, 0.508273, 0.4);
  
      drawTeapot(10.0, 17.0, 0.0, 0.0, 0.0, 0.01, 0.01, 0.01, 0.50, 0.50,
                 0.50, 0.25);
      drawTeapot(10.0, 14.0, 0.0, 0.1, 0.06, 0.0, 0.50980392, 0.50980392,
                 0.50196078, 0.50196078, 0.50196078, 0.25);
      drawTeapot(10.0, 11.0, 0.0, 0.0, 0.0, 0.1, 0.35, 0.1, 0.45, 0.55,
                 0.45, 0.25);
      drawTeapot(10.0, 8.0, 0.0, 0.0, 0.0, 0.5, 0.0, 0.0, 0.7, 0.6, 0.6,
                 0.25);
      drawTeapot(10.0, 5.0, 0.0, 0.0, 0.0, 0.55, 0.55, 0.55, 0.70, 0.70,
                 0.70, 0.25);
      drawTeapot(10.0, 2.0, 0.0, 0.0, 0.0, 0.5, 0.5, 0.0, 0.60, 0.60,
                 0.50, 0.25);
  
      drawTeapot(14.0, 17.0, 0.02, 0.02, 0.02, 0.01, 0.01, 0.01, 0.4, 0.4,
                 0.4, 0.078125);
      drawTeapot(14.0, 14.0, 0.0, 0.05, 0.05, 0.4, 0.5, 0.5, 0.04, 0.7,
                 0.7, 0.078125);
      drawTeapot(14.0, 11.0, 0.0, 0.05, 0.0, 0.4, 0.5, 0.4, 0.04, 0.7,
                 0.04, 0.078125);
      drawTeapot(14.0, 8.0, 0.05, 0.0, 0.0, 0.5, 0.4, 0.4, 0.7, 0.04,
                 0.04, 0.078125);
      drawTeapot(14.0, 5.0, 0.05, 0.05, 0.05, 0.5, 0.5, 0.5, 0.7, 0.7,
                 0.7, 0.078125);
      drawTeapot(14.0, 2.0, 0.05, 0.05, 0.0, 0.5, 0.5, 0.4, 0.7, 0.7,
                 0.04, 0.078125);
  }
  