C++ OpenGL Glutsphere location issue - c++

Question

i have a problem regarding my OpenGL code, i try to use
glTranslatef
just to renew my glutsolidsphere location but whatever i try to change.. it make all other unnecessary object move to and it to to the edge of the windows screen setting but it turn out like this.."the image" .it move all my other object.. what wrong with my code?
/* * hello.c * This is a simple,
introductory OpenGL program. */
#include <GL/glut.h>
void display(void)
{
/* clear all pixels */
glClear (GL_COLOR_BUFFER_BIT);
/* draw white polygon (rectangle) with corners at
*(0.25, 0.25, 0.0) and (0.75, 0.75, 0.0) */
glColor3f (1.0, 0.0, 0.0);
glBegin(GL_TRIANGLES);
glVertex3f (0.50, 0.70, 0.0);
glVertex3f (0.40, 0.60, 0.0);
glVertex3f (0.60, 0.60, 0.0);
glEnd();
glFlush ();
glColor3f (0.0, 1.0, 0.0);
glBegin(GL_POLYGON);
glVertex3f (0.40, 0.20, 0.0);
glVertex3f (0.60, 0.20, 0.0);
glVertex3f (0.60, 0.40, 0.0);
glVertex3f (0.40, 0.40, 0.0);
glEnd();
glFlush ();
glColor3f (0.0, 1.0, 1.0);
glBegin(GL_POLYGON);
glVertex3f (0.30, 0.30, 0.0);
glVertex3f (0.32, 0.30, 0.0);
glVertex3f (0.40, 0.38, 0.0);
glVertex3f (0.40, 0.40, 0.0);
glVertex3f (0.30, 0.40, 0.0);
glEnd();
glFlush ();
glColor3f (0.0, 1.0, 1.0);
glBegin(GL_POLYGON);
glVertex3f (0.60, 0.38, 0.0);
glVertex3f (0.68, 0.30, 0.0);
glVertex3f (0.70, 0.30, 0.0);
glVertex3f (0.70, 0.40, 0.0);
glVertex3f (0.60, 0.40, 0.0);
glEnd();
glFlush ();
glColor3f (0.0, 0.0, 1.0);
glBegin(GL_LINE_STRIP);
glVertex3f (0.25, 0.24, 0.0);
glVertex3f (0.30, 0.29, 0.0);
glVertex3f (0.35, 0.24, 0.0);
glVertex3f (0.40, 0.29, 0.0);
glVertex3f (0.45, 0.24, 0.0);
glVertex3f (0.50, 0.29, 0.0);
glVertex3f (0.55, 0.24, 0.0);
glVertex3f (0.60, 0.29, 0.0);
glVertex3f (0.65, 0.24, 0.0);
glVertex3f (0.70, 0.29, 0.0);
glVertex3f (0.75, 0.24, 0.0);
glEnd();
glFlush ();
glColor3f (0.0, 1.0, 1.0);
glBegin(GL_LINE_STRIP);
glVertex3f (0.25, 0.19, 0.0);
glVertex3f (0.30, 0.24, 0.0);
glVertex3f (0.35, 0.19, 0.0);
glVertex3f (0.40, 0.24, 0.0);
glVertex3f (0.45, 0.19, 0.0);
glVertex3f (0.50, 0.24, 0.0);
glVertex3f (0.55, 0.19, 0.0);
glVertex3f (0.60, 0.24, 0.0);
glVertex3f (0.65, 0.19, 0.0);
glVertex3f (0.70, 0.24, 0.0);
glVertex3f (0.75, 0.19, 0.0);
glEnd();
glFlush ();
glColor3f (0.0, 0.0, 1.0);
glBegin(GL_LINE_STRIP);
glVertex3f (0.25, 0.14, 0.0);
glVertex3f (0.30, 0.19, 0.0);
glVertex3f (0.35, 0.14, 0.0);
glVertex3f (0.40, 0.19, 0.0);
glVertex3f (0.45, 0.14, 0.0);
glVertex3f (0.50, 0.19, 0.0);
glVertex3f (0.55, 0.14, 0.0);
glVertex3f (0.60, 0.19, 0.0);
glVertex3f (0.65, 0.14, 0.0);
glVertex3f (0.70, 0.19, 0.0);
glVertex3f (0.75, 0.14, 0.0);
glEnd();
glFlush ();
glColor3f (1.0, 1.0, 0.0);
glTranslatef(0.20,0.27,0.0);
glutSolidSphere(0.06, 20, 20);
glFlush ();
/* don't wait!
* start processing buffered OpenGL routines */
}
void init (void)
{
/* select clearing color */
glClearColor (1.0, 1.0, 1.0, 1.0);
/* initialize viewing values */
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.0, 1.0, 0.0, 1.0, -1.0, 1.0);
}
/*
* Declare initial window size, position, and display mode
* (single buffer and RGBA). Open window with "hello"
* in its title bar. Call initialization routines.
* Register callback function to display graphics.
* Enter main loop and process events. */
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
glutInitWindowSize (900, 600);
glutInitWindowPosition (50, 100);
glutCreateWindow ("hello");
init ();
glutDisplayFunc(display);
glutMainLoop();
return 0;
/* ANSI C requires main to return int. */
}

Answer 1

Most of OpenGL acts as a state machine, which means that settings "stick" until you change them again. This includes the transformation state. So when you call:
glTranslatef(0.20,0.27,0.0);
everything that you draw after this point will be translated. And if you call glTranslatef() multiple times, the transformations are accumulated, meaning that you will translate more and more.
If this is not the behavior you want, you have to restore the transformation to the previous state after you draw your sphere. The easiest way to do this is with glPushMatrix()/glPopMatrix(). Transformation matrices in legacy OpenGL are managed as a stack, and pushing/popping the matrix will restore the previous state.
The code around drawing the sphere will then look like this:
glPushMatrix();
glTranslatef(0.2f, 0.27f , 0.0f);
glutSolidSphere(0.06, 20, 20);
glPopMatrix();