generate a line with DDA algorithm

dda.cpp

#include <GL/glut.h>
#include <GL/glu.h>
#include <cmath>

void init()
{
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(0.0, 500.0, 0.0, 500.0);
}

void lineWithDDA(int x0, int y0, int x1, int y1)
{
    int i, steps;
    float deltaX, deltaY, x, y;
    if (abs(x1 - x0) > abs(y1 - y0)) {
        steps = abs(x1 - x0);
    }
    else {
        steps = abs(y1 - y0);
    }
    deltaX = (x1 - x0) / steps;
    deltaY = (y1 - y0) / steps;
    x = x0;
    y = y0;

    glColor3f(1.0, 1.0, 1.0);
    glBegin(GL_POINTS);
        for (i = 0; i < steps; i++) {
            glVertex2i(x, y);
            x = x + deltaX;
            y = y + deltaY;
        }
    glEnd();
}


void display()
{
    glClear(GL_COLOR_BUFFER_BIT);
    lineWithDDA(200, 0, 100, 100);
    lineWithDDA(0, 0, 100, 100);
    glFlush();
}


int main(int argc, char **argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize(500, 500);
    glutInitWindowPosition(100, 100);
    glutCreateWindow("Generate Line");
    init();
    glutDisplayFunc(display);
    glutMainLoop();
    return 0;
}

This is very helpful! Thanks