The following is a code block in OpenGL #include 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, 1.0, 1.0): glBegin(GL_POLYGON): glVertex3f (0.25, 0.25, 0.0): glVertex3f (0.75, 0.25, 0.0): glVertex3f (0.75, 0.75, 0.0): glVertex3f (0.25, 0.75, 0.0): glEnd(): /* don't wait! * start processing buffered OpenGL routines /* glFlush(): } i) Explain the function of openGL software ii) What is the purpose of the code block presented iii) What is the function of each statement in the code block