triangle-rasterization: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/lib64/piglit/bin/triangle-rasterization - from package: piglit

You may install the required package with command yum install {package}

Error in other languages:
triangle-rasterization: bevel nie gevind nie
triangle-rasterization: comandă negăsită
triangle-rasterization: comando não encontrado
triangle-rasterization: commande introuvable
triangle-rasterization: command not found
triangle-rasterization: käsku ei ole
triangle-rasterization: không tìm thấy lệnh
triangle-rasterization: komanda nerasta
triangle-rasterization: Kommando nicht gefunden.
triangle-rasterization: kommandot finns inte
triangle-rasterization: komut yok
triangle-rasterization: nie znaleziono polecenia
triangle-rasterization: níor aimsíodh an t-ordú
triangle-rasterization: no se encontró la orden
triangle-rasterization: no s'ha trobat l'ordre
triangle-rasterization: opdracht niet gevonden
triangle-rasterization: parancs nem található
triangle-rasterization: perintah tidak ditemukan
triangle-rasterization: príkaz nenájdený
triangle-rasterization: příkaz nenalezen
triangle-rasterization: команда не найдена
triangle-rasterization: командата не е открита
triangle-rasterization: 命令找不到
triangle-rasterization: コマンドが見つかりません