Justify development choices for your $3$D scene. Think about why you chose your selected objects. The selected objects are the desk top monitor and keyboard, cell phone, sticky notes, pen, and the jar. Also consider how you were able to program for the required functionality. Explain how a user can navigate your $3$D scene. Explain how you set up to control the virtual camera for your $3$D scene using different input devices. Explain the custom functions in your program that you are using to make your code more modular and organized. Ask yourself, what does the function you developed do and how is it reusable?

$*$ Mouse$\_$Position$\_$Callback$()$

void ViewManager::Process$\_$Input$($GLFWwindow$*$ window$)\{$

if $($glfwGetKey$($window$,$ GLFW$\_$KEY$\_$ESCAPE$)==$ GLFW$\_$PRESS$)\{$

glfwSetWindowShouldClose$($window$,$ true$)$;$\}$

if $($glfwGetKey$($window$,$ GLFW$\_$KEY$\_$P$)==$ GLFW$\_$PRESS$)\{$

bOrthographicProjection $=$ false;$\}$

else if $($glfwGetKey$($window$,$ GLFW$\_$KEY$\_$O$)==$ GLFW$\_$PRESS$)\{$

bOrthographicProjection $=$ true;$\}\}$

glm::mat$4$ ViewManager::GetProjectionMatrix$()\{$

if $($bOrthographicProjection$)\{$

$//$ Define orthographic projection parameters $($left$,$ right, bottom, top, near, far$)$

return glm::ortho$(-2\mathrm{.}0$f$,2\mathrm{.}0$f$,-1\mathrm{.}0$f$,1\mathrm{.}0$f$,0\mathrm{.}1$f$,100\mathrm{.}0$f$)$;$\}$

else $\{$

$//$ Use perspective projection with default camera settings

return glm::perspective$($glm::radians$($g$\_$pCamera$->$Zoom$),($GLfloat$)$WINDOW$\_$WIDTH $/($GLfloat$)$WINDOW$\_$HEIGHT, $0\mathrm{.}1$f$,100\mathrm{.}0$f$)$;$\}\}$

void ViewManager::Mouse$\_$Scroll$\_$Callback$($GLFWwindow$*$ window, double xOffset, double yOffset$)\{$

$//$ Update the camera's zoom level based on the mouse scroll offset

g$\_$pCamera$->$ProcessMouseScroll$($yOffset$)$;$\}$

void ViewManager::Mouse$\_$Position$\_$Callback$($GLFWwindow$*$ window, double xMousePos, double yMousePos$)\{$

if $($gFirstMouse$)\{$

gLastX $=$ xMousePos;

gLastY $=$ yMousePos;

gFirstMouse $=$ false;$\}$

$//$ calculate the X offset and Y offset values for moving the $3$D camera accordingly

float xOffset $=$ xMousePos $-$ gLastX;

float yOffset $=$ gLastY $-$ yMousePos; $//$ reversed since y$-$coordinates go from bottom to top

$//$ set the current positions into the last position variables

gLastX $=$ xMousePos;

gLastY $=$ yMousePos;

$//$ move the $3$D camera according to the calculated offsets

g$\_$pCamera$->$ProcessMouseMovement$($xOffset$,$ yOffset$)$;$\}$

$*$ ProcessKeyboardEvents$()$

void ViewManager::ProcessKeyboardEvents$()\{$

$//$ close the window if the escape key has been pressed

if $($glfwGetKey$($m$\_$pWindow, GLFW$\_$KEY$\_$ESCAPE$)==$ GLFW$\_$PRESS$)\{$

glfwSetWindowShouldClose$($m$\_$pWindow, true$)$;$\}$

$//$ process camera zooming in and out

if $($glfwGetKey$($m$\_$pWindow, GLFW$\_$KEY$\_$W$)==$ GLFW$\_$PRESS$)\{$

g$\_$pCamera$->$ProcessKeyboard$($FORWARD$,$ gDeltaTime$)$;$\}$

if $($glfwGetKey$($m$\_$pWindow, GLFW$\_$KEY$\_$S$)==$ GLFW$\_$PRESS$)\{$

g$\_$pCamera$->$ProcessKeyboard$($BACKWARD$,$ gDeltaTime$)$;$\}$

$//$ process camera panning left and right

if $($glfwGetKey$($m$\_$pWindow, GLFW$\_$KEY$\_$A$)==$ GLFW$\_$PRESS$)\{$

g$\_$pCamera$->$ProcessKeyboard$($LEFT$,$ gDeltaTime$)$;$\}$

if $($glfwGetKey$($m$\_$pWindow, GLFW$\_$KEY$\_$D$)==$ GLFW$\_$PRESS$)\{$

g$\_$pCamera$->$ProcessKeyboard$($RIGHT$,$ gDeltaTime$)$;$\}$

$//$ Process camera upward and downward movement

if $($glfwGetKey$($m$\_$pWindow, GLFW$\_$KEY$\_$Q$)==$ GLFW$\_$PRESS$)\{$

g$\_$pCamera$->$ProcessKeyboard$($UP$,$ gDeltaTime$)$;$\}$

if $($glfwGetKey$($m$\_$pWindow, GLFW$\_$KEY$\_$E$)==$ GLFW$\_$PRESS$)\{$

g$\_$pCamera$->$ProcessKeyboard$($DOWN$,$ gDeltaTime$)$;$\}\}$

$*$ PrepareSceneView$()$

void ViewManager::PrepareSceneView$()\{$

glm::mat$4$ view;

glm::mat$4$ projection;

$//$ per$-$frame timing

float currentFrame $=$ glfwGetTime$()$;

gDeltaTime $=$ currentFrame $-$ gLastFrame;

gLastFrame $=$ currentFrame;

$//$ process any keyboard events that may be waiting in the

$//$ event queue

ProcessKeyboardEvents$()$;

$//$ get the current view matrix from the camera

view $=$ g$\_$pCamera$->$GetViewMatrix$()$;

$//$ define the current projection matrix

projection $=$ glm::perspective$($glm::radians$($g$\_$pCamera$->$Zoom$),($GLfloat$)$WINDOW$\_$WIDTH $/($GLfloat$)$WINDOW$\_$HEIGHT, $0\mathrm{.}1$f$,100\mathrm{.}0$f$)$;

$//$ if the shader manager object is valid

if $($NULL $!=$ m$\_$pShaderManager$)\{$

$//$ set the view matrix into the shader for proper rendering

m$\_$pShaderManager$->$setMat$4$Value$($g$\_$ViewName, view$)$;

$//$ set the view matrix into the shader for proper rendering

m$\_$pShaderManager$->$setMat$4$Value$($g$\_$ProjectionName, projection$)$;

$//$ set the view position of the camera into the shader for proper rendering

m$\_$pShaderManager$->$setVec$3$Value$("$viewPosition$",$ g$\_$pCamera$->$Position$)$;$\}\}$