Constant VERTEX 

pub const VERTEX: &str = "#version 140
in vec3 position;
in vec2 texture_coords;
in vec3 normal;
in vec4 colour;

out vec3 v_position;
out vec2 uv;
out vec3 v_normal;
out vec4 v_colour;

uniform mat4 model;
uniform mat4 perspective;
uniform mat4 camera;
void main() {
    v_colour = colour;
    uv = texture_coords;
    mat3 norm_mat = transpose(inverse(mat3(camera * model)));
    v_normal = normalize(norm_mat * normal);
    gl_Position = perspective * camera * model * vec4(position, 1.0);
    v_position = gl_Position.xyz / gl_Position.w;
}";

simple vertex shader. uniform requires model: Mat4, perspective: Mat4 (use Mat4::view_matrix_3d() for 3d or Mat4::view_matrix_2d() for 2d/orthographic) and camera: Mat4 (inverse camera matrix. use Mat4::from_inverse_transform() or call .inverse() before feeding the matrix into to the shader)

If you are new to shaders or how things render I highly recomend you check out the glium tutorial book (https://github.com/glium/glium/tree/master/book) it is where this shader is from after all

WARNING! if ALL vertex bindings aren’t bound in the draw call your program will PANIC on most computers, HOWEVER, some don’t panic, which may lead you to FALSELY believe you program will run else where