#include <GL/glut.h>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <time.h> 
#define WINDSIZEX 100
#define WINDSIZEY 100
#define RANGE  WINDSIZEX*2.0/3.0 
#define ERRORGENE 0.004044

void init(void)
{

   glClearColor(0.0, 0.0, 0.0, 0.0);

   glColor3f(1.0, 0.0, 0.0);
    glDisable(GL_DITHER);
    glEnable(GL_LINE_SMOOTH);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE);
}




static void test(void)
{   GLfloat *buf;
    buf = (GLfloat *)malloc(WINDSIZEX*WINDSIZEY*3*sizeof(GLfloat));
    GLfloat v1[2], v2[2];
     GLfloat angle, X, Y, sum,limit,saveSum,range;
    GLfloat width;
   GLint k,j;
 // glGetFloatv(GL_LINE_WIDTH_RANGE, widthRange);
 //  glGetFloatv(GL_LINE_WIDTH_GRANULARITY, &widthGranularity);
    width = 1.0 ;
    
    srand( (unsigned)time( NULL ) ); 
     v1[0] = 0.0;
     v1[1] = 0.0;
        v2[0] =  WINDSIZEX/4.0;
        v2[1] = 0.0;
        angle = rand()%360;
 // width = (width+widthGranularity < widthRange[1]) ?
   //              width + widthGranularity : 1.0;
        glLineWidth(width);
        saveSum = v2[0]*width ;
    for (k = 0; k < 8; k++) {
            glClear(GL_COLOR_BUFFER_BIT);

            glPushMatrix();
            
            X =rand()%RANGE+WINDSIZEY/3.0;
            Y = rand()%RANGE+WINDSIZEY/3.0;
           
            glTranslatef(X, Y, 0.0);
            glRotatef(angle, 0, 0, 1);

            glBegin(GL_LINES);
                glVertex2fv(v1);
                glVertex2fv(v2);
            glEnd();

            glPopMatrix();
            glFlush();

            glReadPixels(0, 0, 100, 100, GL_RGB,GL_FLOAT, buf);
            for (j = 0; j < 100*100*3; j += 3) {
	
                sum += buf[j];
             }
             limit = 2.0 * (0.25 + ERRORGENE)*(v2[0] + width);
            printf ("\n coverage  is %f  idea coverage is is %f error margin is %f \n",
                  sum,saveSum,limit); 
            if (abs(saveSum-sum) > limit) {
               printf ("\nthis case run failed, the translate cause Aliasing\n ");
        
              exit(-1) ;


              }

       }
   printf ("test ok ");
}







void display(void)
{
   glViewport(0, 0, WINDSIZEX, WINDSIZEY);
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   gluOrtho2D(0, WINDSIZEX, 0, WINDSIZEY);
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();

   test();
}





int  main(int argc, char** argv)
{    
   // GLfloat *buf;
  //  buf = (GLfloat *)malloc(WINDSIZEX*WINDSIZEY*3*sizeof(GLfloat));
   
  
   glutInit(&argc, argv);
   glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
   glutInitWindowSize(WINDSIZEX, WINDSIZEY);
   glutInitWindowPosition(100, 100);
   glutCreateWindow(argv[0]);
   init();
  printf ("init ok");
   glutDisplayFunc(display);
   glutMainLoop();
   return 0 ;
}