Create perspective and orthographic displays of a $3$D scene. Use the tap of a keyboard key to allow a user to change the view of the scene between orthographic $(2$D$)$ and perspective $(3$D$)$ views at will. Hint: Check the glViewport and the glOrtho functions. For consistency, use the letter P keyboard key for perspective view and the letter O key for orthographic view. To do this work, switch the function call to retrieve either the perspective or orthographic projection matrix. Because of the nature of the projection methods, the camera settings will be different between perspective and orthographic projection. For orthographic projection, the camera will look directly at the $3$D object. The bottom plane should not be visible if the orthographic projection is correct.

Create code that follows a logical flow without syntax errors. The code you create has to be executable. The code that is included needs to be reached by the execution. You don$$t have to include everything in a single function. Your work should be well modularized.

Apply coding best practices in your creations. Pay particular attention to the way you format and comment your code. Program code should be easy to read and follow industry$-$standard code formatting practices, such as indentation and spacing. The source code should be brief and clear. Use descriptive comments.

#include "ViewManager.h$"$

$//$ GLM Math Header inclusions

#include

#include

#include

$//$ declaration of the global variables and defines

namespace$\{$

$//$ Variables for window width and height

const int WINDOW$\_$WIDTH $=1000$;

const int WINDOW$\_$HEIGHT $=800$;

const char$*$ g$\_$ViewName $=$ "view";

const char$*$ g$\_$ProjectionName $=$ "projection";

$//$ camera object used for viewing and interacting with

$//$ the $3$D scene

Camera$*$ g$\_$pCamera $=$ nullptr;

$//$ these variables are used for mouse movement processing

float gLastX $=$ WINDOW$\_$WIDTH $/2\mathrm{.}0$f;

float gLastY $=$ WINDOW$\_$HEIGHT $/2\mathrm{.}0$f;

bool gFirstMouse $=$ true;

$//$ time between current frame and last frame

float gDeltaTime $=0\mathrm{.}0$f;

float gLastFrame $=0\mathrm{.}0$f;

$//$ the following variable is false when orthographic projection

$//$ is off and true when it is on

bool bOrthographicProjection $=$ false;$\}$

$*$ ViewManager$()$

ViewManager::ViewManager$($

ShaderManager $*$pShaderManager$)\{$

$//$ initialize the member variables

m$\_$pShaderManager $=$ pShaderManager;

m$\_$pWindow $=$ NULL;

g$\_$pCamera $=$ new Camera$()$;

$//$ default camera view parameters

g$\_$pCamera$->$Position $=$ glm::vec$3(0\mathrm{.}0$f$,5\mathrm{.}0$f$,12\mathrm{.}0$f$)$;

g$\_$pCamera$->$Front $=$ glm::vec$3(0\mathrm{.}0$f$,-0\mathrm{.}5$f$,-2\mathrm{.}0$f$)$;

g$\_$pCamera$->$Up $=$ glm::vec$3(0\mathrm{.}0$f$,1\mathrm{.}0$f$,0\mathrm{.}0$f$)$;

g$\_$pCamera$->$Zoom $=80$;

g$\_$pCamera$->$MovementSpeed $=20$;$\}$

$*$ ~ViewManager$()$

ViewManager::~ViewManager$()\{$

$//$ free up allocated memory

m$\_$pShaderManager $=$ NULL;

m$\_$pWindow $=$ NULL;

if $($NULL $!=$ g$\_$pCamera$)\{$

delete g$\_$pCamera;

g$\_$pCamera $=$ NULL;$\}\}$

$*$ CreateDisplayWindow$()$

GLFWwindow$*$ ViewManager::CreateDisplayWindow$($const char$*$ windowTitle$)\{$

GLFWwindow$*$ window $=$ nullptr;

$//$ try to create the displayed OpenGL window

window $=$ glfwCreateWindow$($

WINDOW$\_$WIDTH,

WINDOW$\_$HEIGHT,

windowTitle,

NULL, NULL$)$;

if $($window $==$ NULL$)\{$

std::cout $<<$ "Failed to create GLFW window" $<<$ std::endl;

glfwTerminate$()$;

return NULL;$\}$

glfwMakeContextCurrent$($window$)$;

$//$ tell GLFW to capture all mouse events

glfwSetInputMode$($window$,$ GLFW$\_$CURSOR, GLFW$\_$CURSOR$\_$DISABLED$)$;

$//$ this callback is used to receive mouse moving events

glfwSetCursorPosCallback$($window$,$ &ViewManager::Mouse$\_$Position$\_$Callback$)$;

$//$ enable blending for supporting transparent rendering

glEnable$($GL$\_$BLEND$)$;

glBlendFunc$($GL$\_$SRC$\_$ALPHA, GL$\_$ONE$\_$MINUS$\_$SRC$\_$ALPHA$)$;

m$\_$pWindow $=$ window;

return$($window$)$;$\}$