DDA Line Drawing Algorithm using OPEN GL | Computer Graphics Lab Manual | Anna University Chennai | Final Year IT Department

11:PROGRAM:

#include

#include

#include

inline GLint round(const GLfloat a)

{

            return GLint (a+0.5);

}

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 lineDDA(GLint x0,GLint y0,GLint xend,GLint yend)

{

            GLint dx=xend-x0;

            GLint dy=yend-y0;

            GLint steps,k;

            GLfloat xIncrement,yIncrement,x=x0,y=y0;

            if(fabs(dx)>fabs(dy))

                        steps=fabs(dx);

            else

                        steps=fabs(dy);

            xIncrement=GLfloat(dx)/GLfloat(steps);

            yIncrement=GLfloat(dy)/GLfloat(steps);

            setPixel(round(x),round(y));

            for(k=0;k

            {

                        x+=xIncrement;

                        y+=yIncrement;

                        setPixel(round(x),round(y));

            }

}

void drawMyLine(void)

{

            glClear(GL_COLOR_BUFFER_BIT);

            glColor3f(1.0,0.0,0.0);

            glPointSize(4.0);

            GLint x0=100;

            GLint y0=100;

            GLint xend=200;

            GLint yend=200;

            lineDDA(x0,y0,xend,yend);

}

void main(int argc,char** argv)

{

            glutInit(&argc,argv);

            glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);

            glutInitWindowSize(500,500);

            glutInitWindowPosition(0,0);

            glutCreateWindow("DDA algorithm");

            init();

            glutDisplayFunc(drawMyLine);

            glutMainLoop();

}