texture: prevent warning about invalid comparaison (id is GLuint, but -1 is just integer)
texture: prevent warning about invalid comparaison (id is GLuint, but -1 is just integer)

matham/kivy,kivy/kivy,inclement/kivy,inclement/kivy,rnixx/kivy,kivy/kivy,kivy/kivy,akshayaurora/kivy,matham/kivy,akshayaurora/kivy,inclement/kivy,matham/kivy,rnixx/kivy,matham/kivy,rnixx/kivy,akshayaurora/kivy