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gears.cc

3-D gear wheels demo.

// -*- C++ -*-
/*
 * 3-D gear wheels.  This program is in the public domain.
 *
 * Brian Paul
 */

/* Conversion to gtkglextmm by Naofumi Yasufuku */

#include <iostream>
#include <cstdlib>
#include <cmath>

#include <gtkmm.h>

#include <gtkglmm.h>

#ifdef G_OS_WIN32
#define WIN32_LEAN_AND_MEAN 1
#include <windows.h>
#endif

#include <GL/gl.h>
#include <GL/glu.h>


//
// OpenGL frame buffer configuration utilities.
//

struct GLConfigUtil
{
  static void print_gl_attrib(const Glib::RefPtr<const Gdk::GL::Config>& glconfig,
                              const char* attrib_str,
                              int attrib,
                              bool is_boolean);

  static void examine_gl_attrib(const Glib::RefPtr<const Gdk::GL::Config>& glconfig);
};

//
// Print a configuration attribute.
//
void GLConfigUtil::print_gl_attrib(const Glib::RefPtr<const Gdk::GL::Config>& glconfig,
                                   const char* attrib_str,
                                   int attrib,
                                   bool is_boolean)
{
  int value;

  if (glconfig->get_attrib(attrib, value))
    {
      std::cout << attrib_str << " = ";
      if (is_boolean)
        std::cout << (value == true ? "true" : "false") << std::endl;
      else
        std::cout << value << std::endl;
    }
  else
    {
      std::cout << "*** Cannot get "
                << attrib_str
                << " attribute value\n";
    }
}

//
// Print configuration attributes.
//
void GLConfigUtil::examine_gl_attrib(const Glib::RefPtr<const Gdk::GL::Config>& glconfig)
{
  std::cout << "\nOpenGL visual configurations :\n\n";

  std::cout << "glconfig->is_rgba() = "
            << (glconfig->is_rgba() ? "true" : "false")
            << std::endl;
  std::cout << "glconfig->is_double_buffered() = "
            << (glconfig->is_double_buffered() ? "true" : "false")
            << std::endl;
  std::cout << "glconfig->is_stereo() = "
            << (glconfig->is_stereo() ? "true" : "false")
            << std::endl;
  std::cout << "glconfig->has_alpha() = "
            << (glconfig->has_alpha() ? "true" : "false")
            << std::endl;
  std::cout << "glconfig->has_depth_buffer() = "
            << (glconfig->has_depth_buffer() ? "true" : "false")
            << std::endl;
  std::cout << "glconfig->has_stencil_buffer() = "
            << (glconfig->has_stencil_buffer() ? "true" : "false")
            << std::endl;
  std::cout << "glconfig->has_accum_buffer() = "
            << (glconfig->has_accum_buffer() ? "true" : "false")
            << std::endl;

  std::cout << std::endl;

  print_gl_attrib(glconfig, "Gdk::GL::USE_GL",           Gdk::GL::USE_GL,           true);
  print_gl_attrib(glconfig, "Gdk::GL::BUFFER_SIZE",      Gdk::GL::BUFFER_SIZE,      false);
  print_gl_attrib(glconfig, "Gdk::GL::LEVEL",            Gdk::GL::LEVEL,            false);
  print_gl_attrib(glconfig, "Gdk::GL::RGBA",             Gdk::GL::RGBA,             true);
  print_gl_attrib(glconfig, "Gdk::GL::DOUBLEBUFFER",     Gdk::GL::DOUBLEBUFFER,     true);
  print_gl_attrib(glconfig, "Gdk::GL::STEREO",           Gdk::GL::STEREO,           true);
  print_gl_attrib(glconfig, "Gdk::GL::AUX_BUFFERS",      Gdk::GL::AUX_BUFFERS,      false);
  print_gl_attrib(glconfig, "Gdk::GL::RED_SIZE",         Gdk::GL::RED_SIZE,         false);
  print_gl_attrib(glconfig, "Gdk::GL::GREEN_SIZE",       Gdk::GL::GREEN_SIZE,       false);
  print_gl_attrib(glconfig, "Gdk::GL::BLUE_SIZE",        Gdk::GL::BLUE_SIZE,        false);
  print_gl_attrib(glconfig, "Gdk::GL::ALPHA_SIZE",       Gdk::GL::ALPHA_SIZE,       false);
  print_gl_attrib(glconfig, "Gdk::GL::DEPTH_SIZE",       Gdk::GL::DEPTH_SIZE,       false);
  print_gl_attrib(glconfig, "Gdk::GL::STENCIL_SIZE",     Gdk::GL::STENCIL_SIZE,     false);
  print_gl_attrib(glconfig, "Gdk::GL::ACCUM_RED_SIZE",   Gdk::GL::ACCUM_RED_SIZE,   false);
  print_gl_attrib(glconfig, "Gdk::GL::ACCUM_GREEN_SIZE", Gdk::GL::ACCUM_GREEN_SIZE, false);
  print_gl_attrib(glconfig, "Gdk::GL::ACCUM_BLUE_SIZE",  Gdk::GL::ACCUM_BLUE_SIZE,  false);
  print_gl_attrib(glconfig, "Gdk::GL::ACCUM_ALPHA_SIZE", Gdk::GL::ACCUM_ALPHA_SIZE, false);

  std::cout << std::endl;
}


//
// Gears scene.
//

class GearsScene : public Gtk::GL::DrawingArea
{
public:
  explicit GearsScene(bool is_sync = true);
  virtual ~GearsScene();

protected:
  void gear(GLfloat inner_radius,
            GLfloat outer_radius,
            GLfloat width,
            GLint   teeth,
            GLfloat tooth_depth);

protected:
  // signal handlers:
  virtual void on_realize();
  virtual bool on_configure_event(GdkEventConfigure* event);
  virtual bool on_expose_event(GdkEventExpose* event);
  virtual bool on_map_event(GdkEventAny* event);
  virtual bool on_unmap_event(GdkEventAny* event);
  virtual bool on_visibility_notify_event(GdkEventVisibility* event);
  virtual bool on_idle();

public:
  // Invalidate whole window.
  void invalidate() {
    get_window()->invalidate_rect(get_allocation(), false);
  }

  // Update window synchronously (fast).
  void update()
  { get_window()->process_updates(false); }

protected:
  // idle signal connection:
  sigc::connection m_ConnectionIdle;

public:
  // get & set view rotation values.
  void get_view_rot(GLfloat& x, GLfloat& y, GLfloat& z)
  { x = m_ViewRotX; y = m_ViewRotY; z = m_ViewRotZ; }

  void set_view_rot(GLfloat x, GLfloat y, GLfloat z)
  { m_ViewRotX = x; m_ViewRotY = y; m_ViewRotZ = z; }

protected:
  // OpenGL scene related variables:
  GLint m_Gear1;
  GLint m_Gear2;
  GLint m_Gear3;

  GLfloat m_ViewRotX;
  GLfloat m_ViewRotY;
  GLfloat m_ViewRotZ;

  GLfloat m_Angle;

  bool m_IsSync;

protected:
  // frame rate evaluation stuff:
  Glib::Timer m_Timer;
  int m_Frames;
};

GearsScene::GearsScene(bool is_sync)
  : m_Gear1(0), m_Gear2(0), m_Gear3(0),
    m_ViewRotX(20.0), m_ViewRotY(30.0), m_ViewRotZ(0.0),
    m_Angle(0.0), m_IsSync(is_sync),
    m_Frames(0)
{
  //
  // Configure OpenGL-capable visual.
  //

  Glib::RefPtr<Gdk::GL::Config> glconfig;

  // Try double-buffered visual
  glconfig = Gdk::GL::Config::create(Gdk::GL::MODE_RGB    |
                                     Gdk::GL::MODE_DEPTH  |
                                     Gdk::GL::MODE_DOUBLE);
  if (!glconfig)
    {
      std::cerr << "*** Cannot find the double-buffered visual.\n"
                << "*** Trying single-buffered visual.\n";

      // Try single-buffered visual
      glconfig = Gdk::GL::Config::create(Gdk::GL::MODE_RGB   |
                                         Gdk::GL::MODE_DEPTH);
      if (!glconfig)
        {
          std::cerr << "*** Cannot find any OpenGL-capable visual.\n";
          std::exit(1);
        }
    }

  // print frame buffer attributes.
  GLConfigUtil::examine_gl_attrib(glconfig);

  //
  // Set OpenGL-capability to the widget.
  //

  set_gl_capability(glconfig);

  // Add events.
  add_events(Gdk::VISIBILITY_NOTIFY_MASK);
}

GearsScene::~GearsScene()
{
}

/*
 * Draw a gear wheel.  You'll probably want to call this function when
 * building a display list since we do a lot of trig here.
 *
 * Input:  inner_radius - radius of hole at center
 * outer_radius - radius at center of teeth
 * width - width of gear
 * teeth - number of teeth
 * tooth_depth - depth of tooth
 */

void GearsScene::gear(GLfloat inner_radius,
                      GLfloat outer_radius,
                      GLfloat width,
                      GLint   teeth,
                      GLfloat tooth_depth)
{
  GLint i;
  GLfloat r0, r1, r2;
  GLfloat angle, da;
  GLfloat u, v, len;

  r0 = inner_radius;
  r1 = outer_radius - tooth_depth / 2.0;
  r2 = outer_radius + tooth_depth / 2.0;

  da = 2.0 * G_PI / teeth / 4.0;

  glShadeModel(GL_FLAT);

  glNormal3f(0.0, 0.0, 1.0);

  /* draw front face */
  glBegin(GL_QUAD_STRIP);
  for (i = 0; i <= teeth; i++) {
    angle = i * 2.0 * G_PI / teeth;
    glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
    glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
    if (i < teeth) {
      glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
      glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
    }
  }
  glEnd();

  /* draw front sides of teeth */
  glBegin(GL_QUADS);
  da = 2.0 * G_PI / teeth / 4.0;
  for (i = 0; i < teeth; i++) {
    angle = i * 2.0 * G_PI / teeth;

    glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
    glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
    glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5);
    glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
  }
  glEnd();

  glNormal3f(0.0, 0.0, -1.0);

  /* draw back face */
  glBegin(GL_QUAD_STRIP);
  for (i = 0; i <= teeth; i++) {
    angle = i * 2.0 * G_PI / teeth;
    glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
    glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
    if (i < teeth) {
      glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
      glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
    }
  }
  glEnd();

  /* draw back sides of teeth */
  glBegin(GL_QUADS);
  da = 2.0 * G_PI / teeth / 4.0;
  for (i = 0; i < teeth; i++) {
    angle = i * 2.0 * G_PI / teeth;

    glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
    glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5);
    glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
    glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
  }
  glEnd();

  /* draw outward faces of teeth */
  glBegin(GL_QUAD_STRIP);
  for (i = 0; i < teeth; i++) {
    angle = i * 2.0 * G_PI / teeth;

    glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
    glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
    u = r2 * cos(angle + da) - r1 * cos(angle);
    v = r2 * sin(angle + da) - r1 * sin(angle);
    len = sqrt(u * u + v * v);
    u /= len;
    v /= len;
    glNormal3f(v, -u, 0.0);
    glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
    glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
    glNormal3f(cos(angle), sin(angle), 0.0);
    glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5);
    glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5);
    u = r1 * cos(angle + 3 * da) - r2 * cos(angle + 2 * da);
    v = r1 * sin(angle + 3 * da) - r2 * sin(angle + 2 * da);
    glNormal3f(v, -u, 0.0);
    glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
    glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
    glNormal3f(cos(angle), sin(angle), 0.0);
  }

  glVertex3f(r1 * cos(0), r1 * sin(0), width * 0.5);
  glVertex3f(r1 * cos(0), r1 * sin(0), -width * 0.5);

  glEnd();

  glShadeModel(GL_SMOOTH);

  /* draw inside radius cylinder */
  glBegin(GL_QUAD_STRIP);
  for (i = 0; i <= teeth; i++) {
    angle = i * 2.0 * G_PI / teeth;
    glNormal3f(-cos(angle), -sin(angle), 0.0);
    glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
    glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
  }
  glEnd();

}

void GearsScene::on_realize()
{
  // We need to call the base on_realize()
  Gtk::DrawingArea::on_realize();

  //
  // Get GL::Drawable.
  //

  Glib::RefPtr<Gdk::GL::Drawable> gldrawable = get_gl_drawable();

  //
  // GL calls.
  //

  // *** OpenGL BEGIN ***
  if (!gldrawable->gl_begin(get_gl_context()))
    return;

  static GLfloat pos[4] = {5.0, 5.0, 10.0, 0.0};
  static GLfloat red[4] = {0.8, 0.1, 0.0, 1.0};
  static GLfloat green[4] = {0.0, 0.8, 0.2, 1.0};
  static GLfloat blue[4] = {0.2, 0.2, 1.0, 1.0};

  glLightfv(GL_LIGHT0, GL_POSITION, pos);
  glEnable(GL_CULL_FACE);
  glEnable(GL_LIGHTING);
  glEnable(GL_LIGHT0);
  glEnable(GL_DEPTH_TEST);

  // Make the gears.
  m_Gear1 = glGenLists(1);
  glNewList(m_Gear1, GL_COMPILE);
  glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, red);
  gear(1.0, 4.0, 1.0, 20, 0.7);
  glEndList();

  m_Gear2 = glGenLists(1);
  glNewList(m_Gear2, GL_COMPILE);
  glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green);
  gear(0.5, 2.0, 2.0, 10, 0.7);
  glEndList();

  m_Gear3 = glGenLists(1);
  glNewList(m_Gear3, GL_COMPILE);
  glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, blue);
  gear(1.3, 2.0, 0.5, 10, 0.7);
  glEndList();

  glEnable(GL_NORMALIZE);

  std::cout << "GL_RENDERER   = " << glGetString(GL_RENDERER)   << std::endl;
  std::cout << "GL_VERSION    = " << glGetString(GL_VERSION)    << std::endl;
  std::cout << "GL_VENDOR     = " << glGetString(GL_VENDOR)     << std::endl;
  std::cout << "GL_EXTENSIONS = " << glGetString(GL_EXTENSIONS) << std::endl;
  std::cout << std::endl;

  gldrawable->gl_end();
  // *** OpenGL END ***

  // Start timer.
  m_Timer.start();
}

bool GearsScene::on_configure_event(GdkEventConfigure* event)
{
  //
  // Get GL::Drawable.
  //

  Glib::RefPtr<Gdk::GL::Drawable> gldrawable = get_gl_drawable();

  //
  // GL calls.
  //

  // *** OpenGL BEGIN ***
  if (!gldrawable->gl_begin(get_gl_context()))
    return false;

  GLfloat h = (GLfloat)(get_height()) / (GLfloat)(get_width());

  glViewport(0, 0, get_width(), get_height());
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  glFrustum(-1.0, 1.0, -h, h, 5.0, 60.0);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  glTranslatef(0.0, 0.0, -40.0);

  gldrawable->gl_end();
  // *** OpenGL END ***

  return true;
}

bool GearsScene::on_expose_event(GdkEventExpose* event)
{
  //
  // Get GL::Drawable.
  //

  Glib::RefPtr<Gdk::GL::Drawable> gldrawable = get_gl_drawable();

  //
  // GL calls.
  //

  // *** OpenGL BEGIN ***
  if (!gldrawable->gl_begin(get_gl_context()))
    return false;

  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

  glPushMatrix();
    glRotatef(m_ViewRotX, 1.0, 0.0, 0.0);
    glRotatef(m_ViewRotY, 0.0, 1.0, 0.0);
    glRotatef(m_ViewRotZ, 0.0, 0.0, 1.0);

    glPushMatrix();
      glTranslatef(-3.0, -2.0, 0.0);
      glRotatef(m_Angle, 0.0, 0.0, 1.0);
      glCallList(m_Gear1);
    glPopMatrix();

    glPushMatrix();
      glTranslatef(3.1, -2.0, 0.0);
      glRotatef(-2.0 * m_Angle - 9.0, 0.0, 0.0, 1.0);
      glCallList(m_Gear2);
    glPopMatrix();

    glPushMatrix();
      glTranslatef(-3.1, 4.2, 0.0);
      glRotatef(-2.0 * m_Angle - 25.0, 0.0, 0.0, 1.0);
      glCallList(m_Gear3);
    glPopMatrix();

  glPopMatrix();

  // Swap buffers.
  if (gldrawable->is_double_buffered())
    gldrawable->swap_buffers();
  else
    glFlush();

  gldrawable->gl_end();
  // *** OpenGL END ***

  //
  // Print frame rate.
  //

  ++m_Frames;

  double seconds = m_Timer.elapsed();
  if (seconds >= 5.0)
    {
      // std::cout.setf(std::ios_base::fixed, std::ios_base::floatfield);
      std::cout.setf(std::ios::fixed, std::ios::floatfield);
      std::cout.precision(3);
      std::cout << m_Frames << " frames in "
                << seconds << " seconds = "
                << (m_Frames / seconds) << " FPS\n";
      m_Timer.reset();
      m_Frames = 0;
    }

  return true;
}

bool GearsScene::on_map_event(GdkEventAny* event)
{
  if (!m_ConnectionIdle.connected())
    m_ConnectionIdle = Glib::signal_idle().connect(
      sigc::mem_fun(*this, &GearsScene::on_idle), GDK_PRIORITY_REDRAW);

  return true;
}

bool GearsScene::on_unmap_event(GdkEventAny* event)
{
  if (m_ConnectionIdle.connected())
    m_ConnectionIdle.disconnect();

  return true;
}

bool GearsScene::on_visibility_notify_event(GdkEventVisibility* event)
{
  if (event->state == GDK_VISIBILITY_FULLY_OBSCURED)
    {
      if (m_ConnectionIdle.connected())
        m_ConnectionIdle.disconnect();
    }
  else
    {
      if (!m_ConnectionIdle.connected())
        m_ConnectionIdle = Glib::signal_idle().connect(
          sigc::mem_fun(*this, &GearsScene::on_idle), GDK_PRIORITY_REDRAW);
    }

  return true;
}

bool GearsScene::on_idle()
{
  m_Angle += 2.0;

  // Invalidate the whole window.
  invalidate();

  // Update window synchronously (fast).
  if (m_IsSync)
    update();

  return true;
}


//
// The application class.
//

class Gears : public Gtk::Window
{
public:
  explicit Gears(bool is_sync = true);
  virtual ~Gears();

protected:
  // signal handlers:
  void on_button_quit_clicked();
  virtual bool on_key_press_event(GdkEventKey* event);

protected:
  // member widgets:
  Gtk::VBox m_VBox;
  GearsScene m_GearsScene;
  Gtk::Button m_ButtonQuit;
};

Gears::Gears(bool is_sync)
  : m_VBox(false, 0), m_GearsScene(is_sync), m_ButtonQuit("Quit")
{
  //
  // Top-level window.
  //

  set_title("Gears");

  // Get automatically redrawn if any of their children changed allocation.
  set_reallocate_redraws(true);

  add(m_VBox);

  //
  // Gears scene.
  //

  m_GearsScene.set_size_request(300, 300);

  m_VBox.pack_start(m_GearsScene);

  //
  // Simple quit button.
  //

  m_ButtonQuit.signal_clicked().connect(
    sigc::mem_fun(*this, &Gears::on_button_quit_clicked));

  m_VBox.pack_start(m_ButtonQuit, Gtk::PACK_SHRINK, 0);

  //
  // Show window.
  //

  show_all();
}

Gears::~Gears()
{
}

void Gears::on_button_quit_clicked()
{
  Gtk::Main::quit();
}

bool Gears::on_key_press_event(GdkEventKey* event)
{
  GLfloat x, y, z;

  m_GearsScene.get_view_rot(x, y, z);

  switch (event->keyval)
    {
    case GDK_z:
      z += 5.0;
      break;
    case GDK_Z:
      z -= 5.0;
      break;
    case GDK_Up:
      x += 5.0;
      break;
    case GDK_Down:
      x -= 5.0;
      break;
    case GDK_Left:
      y += 5.0;
      break;
    case GDK_Right:
      y -= 5.0;
      break;
    case GDK_Escape:
      Gtk::Main::quit();
      break;
    default:
      return true;
    }

  m_GearsScene.set_view_rot(x, y, z);

  m_GearsScene.invalidate();

  return true;
}


//
// Main.
//

int main(int argc, char** argv)
{
  Gtk::Main kit(argc, argv);

  //
  // Init gtkglextmm.
  //

  Gtk::GL::init(argc, argv);

  //
  // Parse arguments.
  //

  bool is_sync = true;

  for (int i = 1; i < argc; ++i) {
    if (std::strcmp(argv[i], "--async") == 0)
      is_sync = false;
  }

  //
  // Instantiate and run the application.
  //

  Gears gears(is_sync);

  kit.run(gears);

  return 0;
}
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