ROTATION IN OpenGL

ROTATION IN OpenGL:

first of all we will create a window for drawing here is the code for creation of window here and naw draw a rectangle or triangle by using GL_QUADS function you can see that how to draw rectangle here 

for rotation we use the builtian function glRotatef()

syntax:

glRotatef(angle  ,  float x   ,  float y  ,   float z)

f indicate the it will take the value in floating point. it will take 4 perameter

example:

void Draw_triangle() {

glPushMatrix(); //Save the transformations performed thus far

glRotatef(-40.0, 0.0, 0.9, 0.0);

glBegin(GL_QUADS);        

       glColor3f(0.0f,1.0f,0.0f);    

       glVertex2f( 0.2, 0.49);    

       glVertex2f(0.4, 0.49);   

       glVertex2f(0.4, 0.76);    

       glVertex2f( 0.2, 0.76);    

       

glEnd();

glPopMatrix();

glFlush();

}

screen short:

Rotation