Bresenham's Line Drawing Algorithm using OpenGL | Computer Graphics Lab Manual | Anna University Chennai | Final Year IT Department

12:PROGRAM:

#include

#include

#include

void init(void)

{

            glClearColor(1.0,1.0,1.0,0.0);

            glMatrixMode(GL_PROJECTION);

            gluOrtho2D(0.0,300.0,0.0,300.0);

}

void setPixel(GLint xcoord,GLint ycoord)

{

            glBegin(GL_POINTS);

            glVertex2i(xcoord,ycoord);

            glEnd();

            glFlush();

}

void line(GLint x0,GLint y0,GLint xend,GLint yend)

{

            GLint dx=fabs(xend-x0);

            GLint dy=fabs(yend-y0);

            GLint p=2*dy-dx;

            GLint twody=2*dy;

            GLint twodyminusdx=2*(dy-dx);

            GLint x,y;

            if(x0>xend)

            {

                        x=xend;

                        y=yend;

                        xend=x;

            }

            else

            {

                        x=x0;

                        y=y0;

            }

            setPixel(x,y);

            while(x

            {

                        x++;

                        if(p<0 font="">

                                    p+=twody;

                        else

                        {

                                    y++;

                                    p+=twodyminusdx;

                        }

                        setPixel(x,y);

            }

}

void drawMyLine(void)

{

            glClear(GL_COLOR_BUFFER_BIT);

            glColor3f(0.0,1.0,0.0);

            glPointSize(4.0);

            GLint x0=10;

            GLint y0=15;

            GLint xend=250;

            GLint yend=100;

            line(x0,y0,xend,yend);

}

void main(int argc,char** argv)

{

            glutInit(&argc,argv);

            glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);

            glutInitWindowSize(400,400);

            glutInitWindowPosition(0,0);

            glutCreateWindow("Bresenham's algorithm");

            init();

            glutDisplayFunc(drawMyLine);

            glutMainLoop();

}