/*   []----------------------------------------[]
      |                Glut.inc                |
     []----------------------------------------[]
      |                                        |
      |   AUTHOR:    MFSomers 2005.            |
      |   USE:       All glut stuff for main   |
      |               code ready to be         |
      |               included if needed ...   |
      |                                        |
     []----------------------------------------[]
*/

// Copyright (C) 2005 M.F. Somers, Theoretical Chemistry Department, Leiden University
//
// This is free software; you can redistribute it and/or modify it under the terms of
// the GNU General Public License as published by the Free Software Foundation.
//
// http://www.gnu.org/licenses/gpl.txt

#if defined(__linux__)
#   include "glut.h"
#elif defined(_WIN32) || defined(WIN32)
#   include "glut.h"
# elif defined(__APPLE__) && defined(__MACH__)
#   include <GLUT/glut.h>
# elif defined(__APPLE__)
#   include "glut.h"
# elif defined(FREEBSD)
#   include "glut.h"
# else
#   error No GLUT support for this platform ...
#endif

/* ----------------------------------------------------------------------- */

int    Glut_CurrentMouseXPos,
       Glut_CurrentMouseYPos,
       Glut_LeftMouseButtonPressed,
       Glut_RightMouseButtonPressed = 0;

/* ----------------------------------------------------------------------- */
/* Called whenever glut needs to render the scene                          */

void Glut_RenderScene( void )
{
 RenderOpenGLScene( Dynamics -> GetFinalStateParticlesPointer(), TheInputData.Colors, Dynamics -> TheBox, Dynamics -> Periodicity );
 glutSwapBuffers();
}

/* ----------------------------------------------------------------------- */
/* Called whenever glut is doing nothing and we can do a time step or so   */

void Glut_Idle( void )
{
 
 if( OpenGL_DynamicsRunning && !Dynamics -> StopTrajectory )
  DoSomeOfTheWork( Dynamics );

 if( Dynamics -> StopTrajectory )
 {
  DumpFinalStateAndCleanup( Dynamics, TheInputData, 1 );

  if( StdOutFileName[ 0 ] ) fclose( StdOutFilePointer );   // only close if they have been redirected ...
  if( StdErrFileName[ 0 ] ) fclose( StdErrFilePointer );

  exit( 0 );
 }
 
 if( ( CPU_SECONDS() - OpenGL_LastRefreshTime >= 0.035 ) || OpenGL_RefreshScreen )           // do 25-30 frames/s roughly
  glutPostRedisplay();
}

/* ----------------------------------------------------------------------- */
/* Called whenever the window is resized                                   */

void Glut_ChangeSizeOfWindow( int Width, int Height ) 
{
 ResizeOpenGLScene( Width, Height, Dynamics -> TheBox );
}

/* ----------------------------------------------------------------------- */
/* Called when mouse is activly (with button down) moved */

void Glut_ActiveMouseMovementHandler( int MousePosX, int MousePosY )
{
 int dX = MousePosX - Glut_CurrentMouseXPos;
 int dY = MousePosY - Glut_CurrentMouseYPos;
 int HasBeenUpdated = 0;
 int dPhi, dTheta, dZoom;
 
 dPhi = dTheta = dZoom = 0;
 
 if( Glut_LeftMouseButtonPressed )
 {
  // check if moving mouse to the left
  if( dX < -OPENGL_MOUSE_TRIGGER )       
  {
   --dPhi;
   HasBeenUpdated = 1;
  }   
  
  // check if moving mouse to the right
  if( dX > OPENGL_MOUSE_TRIGGER )
  {
   ++dPhi;
   HasBeenUpdated = 1; 
  }
   
  // check if moving mouse upwards
  if( dY < -OPENGL_MOUSE_TRIGGER )
  {
   --dTheta;
   HasBeenUpdated = 1;
  }
  
  // check if moving mouse downwards
  if( dY > OPENGL_MOUSE_TRIGGER )
  {
   ++dTheta;
   HasBeenUpdated = 1;
  }
   
 }
 
 if( Glut_RightMouseButtonPressed )
 {
  // check if moving mouse upwards
  if( dY < -OPENGL_MOUSE_TRIGGER )
  {
   --dZoom;
   HasBeenUpdated = 1;
  }
  
  // check if moving mouse downwards
  if( dY > OPENGL_MOUSE_TRIGGER )
  {
   ++dZoom;
   HasBeenUpdated = 1;
  }
   
 }
 
 if( HasBeenUpdated )
 {
  OpenGL_ModelOrientationPhi += ( double )( dPhi ) * OPENGL_DELTA_ANGLE;
  OpenGL_ModelOrientationTheta += ( double )( dTheta ) * OPENGL_DELTA_ANGLE;
  OpenGL_ModelOrientationZoomF += ( double )( dZoom ) * OPENGL_DELTA_ZOOM;
  ChangeViewPointOfOpenGLScene( OpenGL_ModelOrientationPhi, OpenGL_ModelOrientationTheta, OpenGL_ModelOrientationZoomF );
  glutPostRedisplay();    
 }
 
}

/* ----------------------------------------------------------------------- */
/* Called when mouse is pasivly (without button down) moved                */

void Glut_PassiveMouseMovementHandler( int MousePosX, int MousePosY )
{
 Glut_CurrentMouseXPos = MousePosX;
 Glut_CurrentMouseYPos = MousePosY;
}

/* ----------------------------------------------------------------------- */
/* Called when a mouse button event is encoutered                          */

void Glut_MouseButtonHandler( int Button, int State, int MousePosX, int MousePosY )
{
 if( State == GLUT_DOWN )
 {
  if( Button == GLUT_LEFT_BUTTON ) Glut_LeftMouseButtonPressed = 1;
  if( Button == GLUT_RIGHT_BUTTON ) Glut_RightMouseButtonPressed = 1;
 } 
 
 if( State == GLUT_UP )
 {
  if( Button == GLUT_LEFT_BUTTON ) Glut_LeftMouseButtonPressed = 0;
  if( Button == GLUT_RIGHT_BUTTON ) Glut_RightMouseButtonPressed = 0; 
 }
}

/* ----------------------------------------------------------------------- */
/* Called whenever a key stroke is hit                                     */

void Glut_KeyboardHandler( unsigned char Key, int MouseXPos, int MouseYPos )
{
 if( Key == 27 )
 {
  Dynamics -> StopTrajectory = 1;
  return;
 }
 
 // stop rendering for a while and take snap-shot of current situation
 
 if( OpenGL_DynamicsRunning )
  DumpFinalStateAndCleanup( Dynamics, TheInputData, 0 );
  
 OpenGL_DynamicsRunning = !OpenGL_DynamicsRunning; 
}

/* ----------------------------------------------------------------------- */
/* Called by main program to setup glut rendering if needed                */

void SetupGlutRendering( int argc, char *argv[] )
{
 if( !TheInputData.DoDynamics ) return;

 // init glut
 glutInit( &argc, argv );
 glutInitDisplayMode( GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA );
 glutInitWindowPosition( 100, 100 );
 glutInitWindowSize( 320, 320 );
 glutCreateWindow( "3D model view" );

 // set call-backs for glut 
 glutDisplayFunc( Glut_RenderScene );
 glutIdleFunc( Glut_Idle );
 glutReshapeFunc( Glut_ChangeSizeOfWindow );
 glutKeyboardFunc( Glut_KeyboardHandler );
 glutMotionFunc( Glut_ActiveMouseMovementHandler );
 glutPassiveMotionFunc( Glut_PassiveMouseMovementHandler );
 glutMouseFunc( Glut_MouseButtonHandler );
 
 // setup the OpenGL default global state
 SetupOpenGLScene( 320, 320, TheInputData.TheBox );
  
 // now enter the glut main event loop
 glutMainLoop();	    
}

/* ----------------------------------------------------------------------- */