#include <GL/glut.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#define WINDOW "image"
#define UP 101
#define DOWN 103
#define RIGHT 102
#define LEFT 100
#define MAX 200
 
int NX, NY, NZ;

void do_byteswap_f32( float arr[], int nel ), global(), local( int, int, int );
void readnames( char[] ), readarray( float[], char[], int ), readjet();
void TimerFunction( int ), bitmap( char[], int, int );

float data[MAX][MAX*MAX], mxval, mnval, jet[MAX][MAX];
float globalmx=0, globalmn=100;
int win[MAX], ilev=1, howmany, sets, count=0, glo=0, usr=0, anim=0, logscale=0, nonegs=1, endian=0;
char initfns[MAX][MAX], fns[MAX][MAX][MAX];

void menu(int value){           // called when menu is opened on right click

 switch( value ){
  case 1: usr=glo=0;            // unset glo & usr, sets local max/min
          glutPostRedisplay();  // recall display func with new values 
          break;
  case 2: glo=1;                // enables global max/min  
          usr=0;                // unsets usr 
          mxval=globalmx;       // sets max to globalmx
          mnval=globalmn;       // sets min to globalmn
          glutPostRedisplay();  // recall display func with new values
          break;
  case 3: usr=1;                // switch to user-set max/min 
          glo=0;                // unset glo
          printf( "Max=" );  scanf( "%f", &mxval );  // prompt user for new max
          printf( "Min=" );  scanf( "%f", &mnval );  // prompt user for new min
          glutPostRedisplay();                       // recall display func with new values
          break;
  case 4: logscale=(logscale+1)%2;  // switch log scale on/off
          glutPostRedisplay();
          break;
  case 5: nonegs=(nonegs+1)%2;      // switch allowance of negatives on/off 
          glutPostRedisplay();
          break;
  case 6: endian=(endian+1)%2;      // switch between big/little endian
          glutPostRedisplay();
          break;
 }
}
void display(void){                 // called on glutPostRedisplay
 int i, j, ioff, q; 
 float r, g, b, k, y;
 double num, logmx, logmn;
 char str[MAX]; 

 for( q=0; q<sets; q++ ){    // runs display func for each subwindow
  glutSetWindow( win[q] );          // sets which subwindow to display to
  glClear( GL_COLOR_BUFFER_BIT );   // background to black
  if( glo || usr )                  // if global or user-set max/min 
   readarray( data[q], fns[q][count], ilev );  // read new array w/o calculating local max/min
  else                              // if local max/min is set 
   local( q, count, ilev );         // read new array and calculate local max/min

  if( logscale ){
   if( usr ){
    logmx=(double)mxval;
    logmn=(double)mnval;
   }
   else{
    logmx=log10( mxval );
    logmn=log10( mnval );
   }
  }

  ioff=0;                           // ioff will count both i&j b/c data is 1D
  for( j=0; j<NY; j++ ){            // cycles through y values
   for( i=0; i<NX; i++ ){           // cycles through x values
    r=g=b=0;                        // set color values to black
    if( data[q][ioff]==0 );           // if data=0, values stay black
    else{
     if( logscale ){
      num=(double)data[q][ioff];
      num=log10( num );
      if( num<logmn ) num=0;
      else{
       if( num>logmx ) num=63;
       else
        num=63*( num-logmn )/( logmx-logmn );
      }
     }
     else{
      if( data[q][ioff]<mnval )  num=0;   // if data is less than min, =min
      else{
       if( data[q][ioff]>mxval )  num=63; // if data is more than max, =max
       else
        num=63*( data[q][ioff]-mnval )/( mxval-mnval );  // scale num from 0-63 (not defined for 64)
      }
     }
     r=jet[(int)num][0];            // set red val
     g=jet[(int)num][1];            // set green val
     b=jet[(int)num][2];            // set blue val  
    }

    glColor3f( r, g, b );           // put r, g, b into effect
    glRectf( i, j, i+1, j+1 );      // draws a square for data value 
    ioff++;                    
   } 
  } 
  glColor3f( 1, 1, 1 );             // set color to white
  glRectf( NX, 0, NX+1, NY+1 );     // draws a border
  glRectf( 0, NY, NX, NY+1 );       // draws a border  
  for( i=0; i<64; i++ ){            // draws color bar    
   glColor3f( jet[i][0], jet[i][1], jet[i][2]);         // sets color
   k=(float)i;                      // turns i into a float
   y=(float)NY/64;                  // sets height of rectangles
   glRectf( NX+10, y*k, NX+20, (k+1)*y );               // draws rectangle 
  } 
  glColor3f( 1, 1, 1 );             // color to white

  if( logscale )
   sprintf( str, "%.2f", logmx );
  else
   sprintf( str, "%.1e", mxval );    // labels color bar with max val
  bitmap( str, NX+2, NY-1 );
  
  if( logscale )
   sprintf( str, "%.2f", logmn );
  else
   sprintf( str, "%.1e", mnval );    // labels color bar with min val
  bitmap( str, NX+2, 1 );

  sprintf( str, "Level %d", ilev ); // labels current level 
  bitmap( str, 1, NY+3 );

  sprintf( str, "Time %d", count+1 ); // labels current time 
  bitmap( str, 50, NY+3 );

  if( glo )                         // labels how max/min have been set
   sprintf( str, "Global" );        // if glo is set, display Global
  if( usr ) 
   sprintf( str, "User-set" );      // if usr is set, display User-set
  if( !usr && !glo ) 
   sprintf( str, "Local" );         // else display Local 
  bitmap( str, NX+12, NY+3 );
  
  if( anim ){                       // tell user if autoplay is on
   sprintf( str, "Autoplay" );
   bitmap( str, NX-25, NY+3 );
  }

  if( logscale ){
   sprintf( str, "Log Scale" );     // tell user if log scale is on
   bitmap( str, NX-25, NY+10 ); 
  }

  bitmap( fns[q][count], 1, NY+10 ); // labels current file
 
  glutSwapBuffers();                // double buffering set to animate smoothly
  glFlush(); 
 }
}

void bitmap( char str[], int x, int y ){  // called to display text onscreen
 int i;

 glRasterPos2f( x, y );             // set position of text
 for( i=0; i<strlen( str ); i++)    // display each character of str
  glutBitmapCharacter( GLUT_BITMAP_HELVETICA_12, str[i] );
}

void key( unsigned char key, int x, int y ){   // called on key press
 int i, tmp;
 
 switch(key){
  case 'q':   exit(0);              // quits on 'q'
              break;
  case 'r':   count=0;              // resets back to first time    
              ilev=1;               // and first level
              glutPostRedisplay();            
              break;
  case 'a':   anim=(anim+1)%2;      // turns anim on/off
              glutPostRedisplay();            
              break;
 } 
}

void TimerFunction( int value ){    // called when anim is set and arrow key is pressed
 int i;

 switch(value){                     // increments in the correct direction
  case DOWN : if( ilev<NZ ) 
               ilev++;              // if down arrow pressed, move down a level      
              break;
  case UP   : if( ilev>1 )    
               ilev--;              // if up arrow is pressed, move up a level
              break;
  case LEFT : if( count>0 )      
               count--;             // if left arrow is pressed, move back one time step 
              break;
  case RIGHT: if( count<howmany-1 )
               count++;             // if right arrow is pressed, moves forward one time step 
              break;
 }
 
 glutPostRedisplay();            

 if (anim )
  switch( value ){    
   case DOWN : if( ilev==NZ ) ilev=1;                   // if end reached, restart 
               glutTimerFunc( 100, TimerFunction, value ); // recalls itself
               break;
   case UP   : if( ilev==1 ) ilev=NZ;                   // if end reached, restart 
               glutTimerFunc( 100, TimerFunction, value ); // recalls itself 
               break;
   case LEFT : if( count==0 ) count=howmany-1;             // if end reached, restart 
               glutTimerFunc( 100, TimerFunction, value ); // recalls itself
               break;
   case RIGHT: if( count==howmany-1 ) count=0;             // if end reached, restart                 
               glutTimerFunc( 100, TimerFunction, value ); // recalls itself
               break;
  } 
}

void specialkey( int key, int x, int y ){
 int i;

 if( anim )                       // if animation is set, call the timer function
  glutTimerFunc( 100, TimerFunction, key);             // to scroll automatically

 switch(key){
  case DOWN   :  if( ilev<NZ )      // if you haven't reached the bottom
                  ilev++;              // keep going down
                 break;
  case UP     :  if( ilev>1 )          // if you haven't reached the top
                  ilev--;              // keep going up
                 break;
  case RIGHT  :  if( count<howmany-1 ) // if you haven't reached the last file
                  count++;             // keep going right
                 break;
  case LEFT   :  if( count>0 )         // if you haven't reached the first file
                  count--;             // keep going left
                 break;
 }
 glutPostRedisplay();            
}

void global(){                         // calculates the max/min for the total data set
 FILE* fp;
 int h, i, j;
 for( h=0; h<sets; h++)                // cycles through each window 
  for( i=0; i<howmany; i++ )           // cycles through each time 
   for( j=0; j<NZ; j++ ){              // cycles through each level for each file
    local( h, i, j );                  // calculates local max/min for specific data set 
    if( mxval > globalmx ) globalmx = mxval;   // sets highest value to globalmx
    if( mnval < globalmn ) globalmn = mnval;   // sets lowest value to globalmn
   }
}

void local( int i, int time, int lev ){        // calculates local max/min
 int j;
 
 mxval=0;  
 mnval=100;
 readarray( data[i], fns[i][time], lev );      // read new array of data
 for( j=0; j<NX*NY; j++ ){
  if( data[i][j] > mxval ) 
   mxval=data[i][j];                           // set largest val to mxval 
  if( data[i][j] < mnval && data[i][j]!=0 ) 
   mnval=data[i][j];                           // set smallest positive val to mnval 
 }
}

void readnames( char filename[] ){             // reads in list of filenames 
 FILE* fp;
 int i=0, j=0;
 
 fp=fopen( filename, "r" );                    // opens list of filenames
 while( !feof(fp) ){                           // reads until the end of the file 
  fscanf( fp, "%s", initfns[i] );              // places filename into an array of strings 
  i++;                                         // counts how many filenames there are  
 } 
 fclose( fp );                                 // close file
 sets=i-1;                                  // saves number of initial filenames 
 
 for(i=0; i<sets; i++){                     // goes through each read-in filename 
  fp=fopen( initfns[i], "r" );                 // opens each filename  
  j=0;
  while( !feof(fp) ){                          // reads in filenames from each filename 
   fscanf( fp, "%s", fns[i][j]);               
   j++;
  }
  fclose(fp);                                  // close file
 }
 howmany=j-1;                                  // saves number of data filenames  
}

void readjet(){               //reads in color scale values
 FILE* fp;
 int i, j; 
  
 fp=fopen( "jet.dat", "r" );  // opens file containing values
 for( i=0; i<64; i++ )        // reads in 64 sets of r, g, b values
  for( j=0; j<3; j++ )
   fscanf( fp, "%f", &jet[i][j] );
 fclose( fp );                // closes file
}

void readarray( float arr[], char filename[], int il ){   // reads new data
 FILE* fp;
 int i;
 
 fp=fopen( filename, "r" );                  // opens the file containing data
 fseek( fp, (il-1)*NX*NY*4, SEEK_SET );      // seeks to the correct place using ilev
 fread( arr, sizeof( arr[0] ), NX*NY, fp );  // reads in data to fill one level 
 fclose( fp );                               // close file

 if( nonegs ) 
  for( i=0; i<NX*NY; i++ )                    
   if( arr[i] < 0 ) 
    arr[i] = pow(10, -20);   // sets negative values to 10^-20 

 if( endian )
  do_byteswap_f32( arr, NX*NY );            // switches endian 
}

void do_byteswap_f32( float arr[], int nel ){ // switches endian

 int i;
 char src[4], trg[4];

 for( i=0; i<nel; i++ ){
  memcpy( src, &(arr[i]), 4 );
  trg[0]=src[3];
  trg[1]=src[2];
  trg[2]=src[1];
  trg[3]=src[0];
  memcpy( &(arr[i]), trg, 4 );
 }
}

void black(){
 glClear( GL_COLOR_BUFFER_BIT );
 glutSwapBuffers();
 glFlush(); 
}

int main( int argc, char *argv[] ){
 int i, setsx, setsy, tmpx, tmpy, winx, winy, parent;
 char filename[MAX];

 sscanf( argv[1], "%dx%d", &winx, &winy );  // reads screen resolution from command line
 winy-=60;  winx-=20;                     // adjusts resolution so edges won't get cut off             
 
 printf( "Please enter x, y and z dimensions.\n" );   
 scanf( "%d %d %d", &NX, &NY, &NZ );           // prompts user for NX, NY, NZ
 printf( "Please enter filename.\n" );
 scanf( "%s", filename );                         // prompts user for initial filenames 
 printf( "Please enter dimensions of data sets.\n" );
 scanf( "%dx%d", &setsx, &setsy );                 // prompts user for dimensions of subwindows

 readjet();                               // stores color values
 readnames( filename );                   // gets list of filenames to read from
 global();                                // calculates max and min for all data

 glutInit( &argc, argv );                 
 glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );   // sets rgb mode and double buffering
 glutInitWindowSize( winx, winy );                // parent window will cover screen
 glutInitWindowPosition( 10, 10 );                // location of parent window
 parent=glutCreateWindow( WINDOW );               // creates parent window

 glClearColor( 0, 0, 0, 0 );                      // sets clear color to black
 gluOrtho2D( 0, winx , winy, 0 );                 // sets(0,0) as top left corner 
 glutDisplayFunc( display );
 glutKeyboardFunc( key );                         // called on key press
 glutSpecialFunc( specialkey );                   // called on special key press (arrow keys)
 

 for( i=0; i<setsx*setsy; i++ ){
  tmpx = (i%setsx)*(winx/setsx);                  // x coordinate of top left corner of subwindow
  tmpy = (i/setsx)*(winy/setsy);                  // y coordinate of top left corner of subwindow 

  win[i]=glutCreateSubWindow( parent, tmpx, tmpy, winx/setsx, winy/setsy ); // creates subwindow
  gluOrtho2D( 0, NX+35, 0, NY+15 );               // sets how data is mapped to subwindow
  glutKeyboardFunc( key );                        // called on key press
  glutSpecialFunc( specialkey );                  // called on special key press (arrow keys)
  if( i >= sets )                                 // 
   glutDisplayFunc( black );
  else
   glutDisplayFunc( display );                     // sets display func for subwindow
  

  glutCreateMenu( menu );                                // adds a menu
   glutAddMenuEntry( "Local Color Scale", 1 );           // adds a menu entry 
   glutAddMenuEntry( "Global Color Scale", 2 );          // adds a menu entry 
   glutAddMenuEntry( "User-Set Color Scale", 3 );        // adds a menu entry 
   glutAddMenuEntry( "Log Scale (on/off)", 4 );          // adds a menu entry 
   glutAddMenuEntry( "Allow Negatives (on/off)", 5 );    // adds a menu entry
   glutAddMenuEntry( "Switch Endian (big/little) ", 6);  // adds a menu entry
  glutAttachMenu( GLUT_RIGHT_BUTTON );                   // menu called on right click
 }

 glutMainLoop();                                  // begin processing events
 return 0;
}