tmat4x3< float, highp > highp_mat4x3
4 columns of 3 components matrix of high precision floating-point numbers.
tmat4x3< float, lowp > lowp_mat4x3
4 columns of 3 components matrix of low precision floating-point numbers.
tmat4x3< float, mediump > mediump_mat4x3
4 columns of 3 components matrix of medium precision floating-point numbers.
OpenGL Mathematics (glm.g-truc.net)