typedef double Matrix3x3[9];
std::string read_file(const std::string &filename);
-GLhandleARB compile_shader(const std::string &shader_src, GLenum type);
+GLuint compile_shader(const std::string &shader_src, GLenum type);
void multiply_3x3_matrices(const Matrix3x3 a, const Matrix3x3 b, Matrix3x3 result);
void invert_3x3_matrix(const Matrix3x3 m, Matrix3x3 result);
void print_3x3_matrix(const Matrix3x3 m);