Section $2\mathrm{.}6$

OpenGL Geometric

PRIMITIVES

$($a$)$

$($b$)$

Figure $2\mathrm{.}32$: $($a$)$ Square

annulus $-$ the region

between two bounding

squares $-$ and a possible

triangulation $($b$)$ A

partially triangulated

shape. I want to generate these $2$ diagrams in output using open gl$.$ i have generated first diagram and its code is mentioned below. i want you to write a single program for generating both graphics. Here is code for first one.

$//////////////////////////////////////////////////////////////////////$

$//$ squareAnnulus$\_$modified.cpp

$//$

$//$ This program draws a square annulus as a wireframe $($only boundaries$)$

$//$ using glVertex$3$f$()$ for specifying vertices, confined to the upper

$//$ middle half of the window.

$//$

$//$ Sumanta Guha

$//////////////////////////////////////////////////////////////////////$

#include

#include

#include

$//$ Drawing routine.

void drawScene$($void$)$

$\{$

glClear$($GL$\_$COLOR$\_$BUFFER$\_$BIT$)$;

$//$ Draw outer square boundary.

glColor$3$f$(0\mathrm{.}0,0\mathrm{.}0,0\mathrm{.}0)$; $//$ Set color to black.

glBegin$($GL$\_$LINE$\_$LOOP$)$;

glVertex$3$f$(10\mathrm{.}0,10\mathrm{.}0,0\mathrm{.}0)$; $//$ Bottom left.

glVertex$3$f$(10\mathrm{.}0,90\mathrm{.}0,0\mathrm{.}0)$; $//$ Top left.

glVertex$3$f$(90\mathrm{.}0,90\mathrm{.}0,0\mathrm{.}0)$; $//$ Top right.

glVertex$3$f$(90\mathrm{.}0,10\mathrm{.}0,0\mathrm{.}0)$; $//$ Bottom right.

glEnd$()$;

$//$ Draw inner square boundary.

glBegin$($GL$\_$LINE$\_$LOOP$)$;

glVertex$3$f$(30\mathrm{.}0,30\mathrm{.}0,0\mathrm{.}0)$; $//$ Bottom left.

glVertex$3$f$(30\mathrm{.}0,70\mathrm{.}0,0\mathrm{.}0)$; $//$ Top left.

glVertex$3$f$(70\mathrm{.}0,70\mathrm{.}0,0\mathrm{.}0)$; $//$ Top right.

glVertex$3$f$(70\mathrm{.}0,30\mathrm{.}0,0\mathrm{.}0)$; $//$ Bottom right.

glEnd$()$;

$//$ Draw square annulus triangles.

glBegin$($GL$\_$LINES$)$;

$//$ Bottom side.

glVertex$3$f$(10\mathrm{.}0,10\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(30\mathrm{.}0,30\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(30\mathrm{.}0,30\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(50\mathrm{.}0,10\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(50\mathrm{.}0,10\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(70\mathrm{.}0,30\mathrm{.}0,0\mathrm{.}0)$;

$//$ Left side.

glVertex$3$f$(10\mathrm{.}0,90\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(30\mathrm{.}0,70\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(30\mathrm{.}0,70\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(10\mathrm{.}0,50\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(10\mathrm{.}0,50\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(30\mathrm{.}0,30\mathrm{.}0,0\mathrm{.}0)$;

$//$ Top side.

glVertex$3$f$(90\mathrm{.}0,90\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(70\mathrm{.}0,70\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(70\mathrm{.}0,70\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(50\mathrm{.}0,90\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(50\mathrm{.}0,90\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(30\mathrm{.}0,70\mathrm{.}0,0\mathrm{.}0)$;

$//$ Right side.

glVertex$3$f$(90\mathrm{.}0,10\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(70\mathrm{.}0,30\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(70\mathrm{.}0,30\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(90\mathrm{.}0,50\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(90\mathrm{.}0,50\mathrm{.}0,0\mathrm{.}0)$;

glVertex$3$f$(70\mathrm{.}0,70\mathrm{.}0,0\mathrm{.}0)$;

glEnd$()$;

glFlush$()$;

$\}$

$//$ Initialization routine.

void setup$($void$)$

$\{$

glClearColor$(1\mathrm{.}0,1\mathrm{.}0,1\mathrm{.}0,0\mathrm{.}0)$;

$\}$

$//$ OpenGL window reshape routine.

void resize$($int w$,$ int h$)$

$\{$

glViewport$(0,$ h $/2,$ w $/2,$ h $/2)$; $//$ Set viewport to upper middle half of the window.

glMatrixMode$($GL$\_$PROJECTION$)$;

glLoadIdentity$()$;

glOrtho$(0\mathrm{.}0,100\mathrm{.}0,0\mathrm{.}0,100\mathrm{.}0,-1\mathrm{.}0,1\mathrm{.}0)$; $//$ Orthographic projection.

glMatrixMode$($GL$\_$MODELVIEW$)$;

glLoadIdentity$()$;

$\}$

$//$ Main routine.

int main$($int argc, char$**$ argv$)$

$\{$

glutInit$($&argc, argv$)$;

glutInitContextVersion$(4,3)$;

glutInitContextProfile$($GLUT$\_$COMPATIBILITY$\_$PROFILE$)$;

glutInitDisplayMode$($GLUT$\_$SINGLE $|$ GLUT$\_$RGBA$)$;

glutInitWindowSize$(500,500)$;

glutInitWindowPosition$(100,100)$;

glutCreateWindow$("$squareAnnulus$\_$modified.cpp$")$;

glutDisplayFunc$($drawScene$)$;

glutReshapeFunc$($resize$)$;

glewExperimental $=$ GL$\_$TRUE;

glewInit$()$;

setup$()$;

glutMainLoop$()$;

return $0$;

$\}$ REMEMBER, YOUR code should run properly in visual studio.