How to rotate a computer drawing in 90 degrees - c++

Question

I have created a bunny and a duck image in my blank window. My plan was to display it twice: once by itself and another image like it rotated at a 90 degrees. I've tried creating the image a second time and turning the image by changing values, but was difficult and couldn't work at all. Which axes needs to be used to rotate an image in a plane and the right way to accomplish it.
void myInit(void){
glClearColor(1.0, 1.0, 1.0, 0); // the background is white
glColor3f(0.0f, 0.0f, 0.0f); // set drawing color
gluOrtho2D(0.0, (GLdouble) screenWidth, 0.0, (GLdouble) screenHeight);
}
void drawBunny(){
glClear(GL_COLOR_BUFFER_BIT);
// draw the outline of box (bunny)
glLineWidth(2);
glBegin(GL_LINE_LOOP);
glVertex2i(50,50);
glVertex2i(150,50);
glVertex2i(150,100);
glVertex2i(50,100);
glEnd();
//draw bunny tail
glLineWidth(1);
glBegin(GL_LINE_STRIP);
glVertex2i(50,50);
glVertex2i(50,35);//2nd wider top/bottom
glVertex2i(70,35);//1st- shrink tail left/right
glVertex2i(70,50);//1st- shrink tail left/right
glEnd();
// draw first ear
glBegin(GL_LINE_LOOP);
glVertex2i(175,85);
glVertex2i(175,100);
glVertex2i(150,100);
glVertex2i(150,85);
glEnd();
//draw second ear
glBegin(GL_LINE_LOOP);
glVertex2i(175,70);
glVertex2i(175,100);
glVertex2i(150,100);
glVertex2i(150,70);
glEnd();
// draw the head
glBegin(GL_LINE_LOOP);
glVertex2i(150,100);
glVertex2i(150,110);
glVertex2i(125,110);
glVertex2i(125,100);
glEnd();
// draw first feet
glBegin(GL_LINE_LOOP);
glVertex2i(110,60);
glVertex2i(110,75);
glVertex2i(30,75); //decrease value increase feet
glVertex2i(30,60);
glEnd();
//draw second feet
glBegin(GL_LINE_LOOP);
glVertex2i(50,100);
glVertex2i(50,85);
glVertex2i(30,85); //decrease value increase feet
glVertex2i(30,100);
glEnd();
//* draw eyes
glBegin(GL_LINE_LOOP);
glVertex2i(140,100);
glVertex2i(140,105);
glVertex2i(135,105);
glVertex2i(135,100);
glEnd();
glFlush();
}
int main (int argc, char** argv){
glutInit(&argc, argv); // initialize the toolkit
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); // set display mode
glutInitWindowPosition(100,150); // set window position
glutInitWindowSize(screenWidth,screenHeight); // set window size
glutCreateWindow("House"); // create & open window
glutDisplayFunc(drawBunny); // register redraw function
myInit();
glutMainLoop(); // loop forever
}

Answer 1

write a display function which consist of 2 bunnies and rotate them :
void display()
{
glLoadIdentity();
glClear(GL_COLOR_BUFFER_BIT);
drawBunny();
glPushMatrix();
glRotatef(degreetoreturn,x,y,z); // Adjust parameters according to what you need
drawBunny();
glPopMatrix();
glutSwapBuffers();
}
Delete glClear() function and glFlush() functions from your drawBunny function. And finally in your main function change this line :
glutDisplayFunc(drawBunny); // register redraw function
to
glutDisplayFunc(display); // register redraw function