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Bresenham.c
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Bresenham.c
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#include <windows.h>
#include <GL/glut.h>
#include <stdio.h>
float a,b,c,d,x,y;
void init()
{
gluOrtho2D(-20,20,-20,20);
}
void Bresenham(int a,int b,int c,int d)
{
x=a;
y=b;
double dx=(b-a);double dy=(d-c);
double m=dy/dx;
glBegin(GL_LINE_STRIP);glColor3f(0.0f, 0.0f, 1.0f);
glVertex2d(x,y);
if(m<=1) //slope is less than 1
{
double decision=2*dy-dx;
for(int i=x;i<c;i++)
{
if(decision<=0)
decision+=2*dy;
else
{
decision+=2*dy-2*dx;
y=y+1;
}
x=x+1;
glVertex2d(x,y);
}
}
else
{ // slope>=1
double decision=2*dx-dy;
for(int i=y;i<d;i++)
{
if(decision<=0)
decision+=2*dx;
else
{
decision+=2*dx-2*dy;
x=x+1;
}
y=y+1;
glVertex2d(x,y);
}
}
glEnd();
glFlush();
}
void display() {
Bresenham(a, b, c, d);
}
int main(int argc, char** argv)
{
printf("Enter co-ordinates: \n");
printf(" Enter x1 = ");
scanf("%f", &a);
printf(" Enter y1 = ");
scanf("%f", &b);
printf(" Enter x2 = ");
scanf("%f", &c);
printf(" Enter y2 = ");
scanf("%f", &d);
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE);
glutInitWindowSize(400, 300);
glutInitWindowPosition(100, 100);
glutCreateWindow("Bresenham");
init();
glutDisplayFunc(display);
glutMainLoop();
return 0;
}