CAUTION: glm no longer initializes mat4

[shatteredmoon]

This code assumes that new mat4 objects are initialized to the identity matrix. It looks like glm stopped doing this with version v0.9.9.0.

You can use GLM_FORCE_CTOR_INIT to construct an identity matrix

#define GLM_FORCE_CTOR_INIT
#include <glm/glm.hpp>