21CSL66 Program 1

#include <GL/glut.h>
#include <stdio.h>   // For printf and scanf
#include <stdlib.h>  // For abs function

// Bresenham's line drawing algorithm
void drawLine(int x0, int y0, int x1, int y1) {
    int dx = abs(x1 - x0);
    int dy = abs(y1 - y0);
    int sx = (x0 < x1) ? 1 : -1;
    int sy = (y0 < y1) ? 1 : -1;
    int err = dx - dy;

    while (1) {
        glBegin(GL_POINTS);
        glVertex2i(x0, y0);
        glEnd();

        if (x0 == x1 && y0 == y1) break;

        int e2 = 2 * err;
        if (e2 > -dy) {
            err -= dy;
            x0 += sx;
        }
        if (e2 < dx) {
            err += dx;
            y0 += sy;
        }
    }
}

// OpenGL display callback
void display() {
    int x1, x2, y1, y2;

    printf("Enter coordinates for x1 and y1: ");
    scanf("%d %d", &x1, &y1);
    printf("Enter coordinates for x2 and y2: ");
    scanf("%d %d", &x2, &y2);

    glClear(GL_COLOR_BUFFER_BIT);

    // Draw line using Bresenham's algorithm
    glColor3f(1.0f, 1.0f, 1.0f);
    drawLine(x1, y1, x2, y2);

    glFlush();
}

// OpenGL initialization
void initializeOpenGL(int argc, char** argv) {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize(800, 600);
    glutCreateWindow("Bresenham's Line Algorithm");

    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(0, 800, 0, 600);

    glutDisplayFunc(display);
}

// Main function
int main(int argc, char** argv) {
    initializeOpenGL(argc, argv);
    glutMainLoop();
    return 0;
}

braham@braham:~/Desktop/program$ g++ program1.cpp -lGL -lGLU -lglut -o program1
braham@braham:~/Desktop/program$ ./program1
Enter coordinates for x1 and y1: 50 50
Enter coordinates for x2 and y2: 500 500