cse422_class 01

#include <GL/glut.h>
#include <stdio.h>
#include <GL/gl.h>

void init(void)
{
  glClearColor(0.0,0.0,0.0,0.0); //GLfloat red,green,blue,alpha initial value 0 alpha values used by glclear to clear the color buffers
  glMatrixMode(GL_PROJECTION);  // To specify which matrix is the current matrix & projection applies subsequent matrix to projecton matrix stack
  glLoadIdentity();
  // glOrtho(0.0, 1.0, 0.0, 1.0, -1.0, 1.0);
  gluOrtho2D(0.0,200.0,0.0,200.0); // Orthographic representation; multiply the current matrix by an orthographic matrix 2D= left right,bottom,top equivalent near=-1,far=1
}


void display(){
    // wirte code here

    glClear(GL_COLOR_BUFFER_BIT);
    glColor3f(0,1,0);
    glBegin(GL_TRIANGLES);

    glVertex2d(10,10);
    glVertex2d(30,10);
    glVertex2d(50,10);

    glEnd();
    glFlush();

    glutSwapBuffers();
}

void display2(){
    glClear(GL_COLOR_BUFFER_BIT);

    glColor3f(1,0,0);
    glBegin(GL_POLYGON);

    glVertex2d(100,100);
    glVertex2d(300,300);
    glVertex2d(100,300);
    glVertex2d(300,100);

    glEnd();
    glFlush();

    glutSwapBuffers();
}

int main(int argc,char **argv){

    glutInit(&argc,argv);
    glutInitDisplayMode ( GLUT_RGB | GLUT_DOUBLE );

    glutInitWindowPosition(0,0);
    glutInitWindowSize(500,500);
    glutCreateWindow("Lab Final");
    init();
    glutDisplayFunc(display2);
    glutMainLoop();
    return 0;
}