//linda Cobb

//winter 98/99

//http://www.timestocome.com

//opengl plotting routine for data







#include <stdio.h>

#include <math.h>

#include <GLUT/glut.h>                  //open gl libraries for graphics




void drawAxis(){



  typedef GLfloat point2[2];          //define a point array

  long int k, j;                      //loop control

  point2 p = {0.0, 0.0};              //begin here





 glColor3f(0.0, 0.0, 1.0);

  for(k=-250; k<250; k++){            //vertical axis

    p[0] = 0.0;

    p[1] = k;

    glBegin(GL_POINTS);

    glVertex2fv(p);

    glEnd();

  }





  glColor3f(0.0, 0.0, 1.0);           //horizontal axis

  for(k=-250; k<250; k++){

    p[0] = k;

    p[1] = 0.0;

    glBegin(GL_POINTS);

    glVertex2fv(p);

    glEnd();

  }





  //tick marks

  for(k=-250; k<250; k+=10){         //horizontal tick marks

    for(j=-5; j<5; j++){

      p[0] = k;

      p[1] = j;

      glBegin(GL_POINTS);

      glVertex2fv(p);

      glEnd();

    }

    

  }





  for(k=-250; k<250; k+=10){         //vertical tick marks

    for(j=-5; j<5; j++){

      p[0] = j;

      p[1] = k;

      glBegin(GL_POINTS);

      glVertex2fv(p);

      glEnd();

    }

    

  }



}







//plot data in an opengl window previously stored in array 

void myDisplay(){



 

  typedef GLfloat point2[2];          //define a point array

  long int k;                         //loop control

  point2 p = {0.0, 0.0};              //begin here

  extern  displayData[2][51];       //hold data to plot w/ opengl routines 

  

  glClear(GL_COLOR_BUFFER_BIT);       //clear window



  drawAxis();



  glColor3f(1.0, 0.0, 0.0);           //plot color (red)

  

  for(k=0; k < 51; k++){            //plot data

    p[0] = displayData[0][k]*100;     //x position (scale data so can see better...)

    p[1] = displayData[1][k]*100;     //y position

    glBegin(GL_POINTS);               //plot points

    glVertex2fv(p);

    glEnd();

  }



}









//initialize opengl window for plotting

void myinit(void){



  glClearColor(1.0, 1.0, 1.0, 0.0);    //backround color  (r,g,b, alpha)

  glColor3f(1.0, 0.0, 0.0);            //draw color (r, g, b)

  glMatrixMode(GL_PROJECTION);         //projection stack

  gluOrtho2D(-250.0, 250.0, -250.0, 250.0);  //2d coordinate system centered at (0,0)

  glMatrixMode(GL_MODELVIEW);          //model view stack 



}







plotData(int argc, char **argv){



    glutInit(&argc, argv);       

	glutInitWindowSize(500,500);

	glutInitDisplayMode(GLUT_RGB|GLUT_SINGLE);

	(void)glutCreateWindow("plot data");

	glutDisplayFunc(myDisplay);

	myinit();

    glutMainLoop();



}