Define an out variable in the vertex shader that has type vec$4$ and is named position. Define an in variable in the fragment shader with the same name. Add a statement to assign the buffer position to the position variable.

In the fragment shader, change the code to compute fColor as follows.

If the x component of position is less than $0,$ set the r component of the fragment color to $\mathrm{.}25,$ otherwise set it to $1\mathrm{.}0$

If the y component of position is less than $0,$ set the g component of the fragment color to $\mathrm{.}25,$ otherwise set it to $1\mathrm{.}0$

If the z component of position is less than $0,$ set the b component of the fragment color to $\mathrm{.}25,$ otherwise set it to $1\mathrm{.}0$

Set the a component of the fragment color to $1$

Multiply the fragment color by s$\_$color.

The source code is the following :

#include

#include $"$GLM$/$gtc$/$type$\_$ptr$.$hpp$"$

#include

#include "learnopengl$/$shader$\_4722.$h$"$

#include $"$cs$4722/$artifact$.$h$"$

#include $"$cs$4722/$window$.$h$"$

#include $"$cs$4722/$buffer$\_$utilities.h$"$

static std::vector artifact$\_$list;

static Shader $*$shader;

void init$()$

$\{$

shader $=$ new Shader$("../$problemB$/$vertex$\_$shader.glsl$","../$problemB$/$fragment$\_$shader.glsl$")$;

shader$->$use$()$;

glEnable$($GL$\_$DEPTH$\_$TEST$)$;

auto$*$ shape $=$ new cs$4722$::cylinder$(\mathrm{.}4,21)$;

$/*$

$*$ Change the color$\_$set$\_$ of the shape to using two levels of gray.

$*$ This will give a darker$/$lighter pattern of the material color over the surface.

$*/$

auto gray$\_$level$0=\mathrm{.}80$;

auto gray$\_$level$1=\mathrm{.}90$;

shape$->$color$\_$set$\_=$ std::vector$(\{$cs$4722$::color$($gray$\_$level$0,$ gray$\_$level$0,$ gray$\_$level$0,1\mathrm{.}0),$

cs$4722$::color$($gray$\_$level$1,$ gray$\_$level$1,$ gray$\_$level$1,1\mathrm{.}0)\})$;

auto number $=5$;

auto d $=4\mathrm{.}0/(2*$ number $+1)$;

auto radius $=$ d $/4$;

auto base $=-1+3*$ radius;

for $($auto x $=0$; x $<$ number; $++$x$)$

$\{$

for $($auto y $=0$; y $<$ number; $++$y$)$

$\{$

for $($auto z $=0$; z $<$ number; $++$z$)$

$\{$

auto$*$ artf $=$ new cs$4722$::artifact$\_$rotating$()$;

artf$->$the$\_$shape $=$ shape;

artf$->$world$\_$transform.translate $=$ glm::vec$3($base $+$ x $*$ d$,$ base $+$ y $*$ d$,$ base $+$ z $*$ d$)$;

artf$->$world$\_$transform.scale $=$ glm::vec$3($radius$,$ radius, radius$)$;

artf$->$animation$\_$transform.rotation$\_$axis $=$ glm::vec$3(3*$ x $+1,3*$ y $+1,3*$ z $+1)$;

artf$->$animation$\_$transform.rotation$\_$center $=$

artf$->$world$\_$transform.matrix$()*$ glm::vec$4(-1,0,0,1)$;

artf$->$rotation$\_$rate $=$ M$\_$PI $/3*$ pow$($z$+1,\mathrm{.}5)$;

artifact$\_$list.push$\_$back$($artf$)$;

$\}$

$\}$

$\}$

cs$4722$::init$\_$buffers$($shader$->$ID$,$ artifact$\_$list, $"$b$\_$position", $"$b$\_$color"$)$;

$\}$

void render$()$

$\{$

static auto last$\_$time $=0\mathrm{.}0$;

auto time $=$ glfwGetTime$()$;

auto delta$\_$time $=$ time $-$ last$\_$time;

last$\_$time $=$ time;

$//$ uncomment the following few lines to see the frame rate computed two different ways

static double arate $=0\mathrm{.}0$;

auto x $=(100*$ arate $+1/$ delta$\_$time$)/101$;

arate $=$ x;

for $($auto artf : artifact$\_$list$)\{$

artf$->$animate$($time$,$ delta$\_$time$)$;

auto model$\_$matrix $=$ artf$->$animation$\_$transform.matrix$()*$ artf$->$world$\_$transform.matrix$()$;

shader$->$setMat$4("$u$\_$transform", model$\_$matrix$)$;

glDrawArrays$($GL$\_$TRIANGLES, artf$->$the$\_$shape$->$buffer$\_$start, artf$->$the$\_$shape$->$buffer$\_$size$)$;

$\}$

$\}$

int main$()$

$\{$

glfwInit$()$;

cs$4722$::set$\_$opengl$\_$version$(3,3)$;

GLFWwindow $*$window $=$ cs$4722$::setup$\_$window$("$Problem B$",\mathrm{.}6,1)$;

gladLoadGL$($glfwGetProcAddress$)$;

init$()$;

while $(!$glfwWindowShouldClose$($window$))$

$\{$

glClearBufferfv$($GL$\_$COLOR, $0,$ cs$4722$::x$11$::gray$50.$as$\_$float$\_$array$())$;

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

render$()$;

glfwSwapBuffers$($window$)$;

glfwPollEvents$()$;

$\}$

glfwDestroyWindow$($window$)$;

glfwTerminate$()$;

$\}$