#include <GL/glut.h>
 
void displayTriangle(void) {
    glClear(GL_COLOR_BUFFER_BIT);
    glColor3f(0.0, 0.0, 0.8);
    glBegin(GL_POLYGON);
        glVertex3f(-1.0, -0.5, -0.4);
        glVertex3f(1.0, -0.5, -0.4);
        glVertex3f(0.0, 0.5, -0.4);
    glEnd();
    glFlush();
}
 
int main(int argc, char** argv) {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE);
    glutInitWindowSize(640, 450);
    glutInitWindowPosition(200, 200);
    glutCreateWindow("Helló Világ!");
    glutDisplayFunc(displayTriangle);
    glutMainLoop();
    return 0;
}