Simple GLSL lighting

shader.frag

#version 150

layout(std140) uniform Camera
{
    mat4 view_matrix;
    mat4 projection_matrix;
} camera;

layout(std140) uniform Light
{
    vec4 position;
    vec4 direction;

    vec4 diffuse;
    vec4 specular;
    vec4 ambient;

    float shininess;
    float attenuation;
    float spot_cutoff, spot_exponent;
} light;

in vec4 pos;
in vec4 nor;
in vec2 uv;

out vec4 color;

void main()
{
    vec4 light_vec = (camera.view_matrix * light.position) -  pos;
    vec4 light_dir = normalize(light_vec);

    float spot_cos = dot(-light_dir, camera.view_matrix * light.direction);
    float spot = ((spot_cos < light.spot_cutoff) ? 0.0 : pow(spot_cos, light.spot_exponent));

    float light_attenuation = (1.0 / (1.0 + light.attenuation * dot(light_vec, light_vec)));

    vec4 eye_vec = vec4(normalize(pos.xyz), 0.0);

    float diffuse = max(0.0, dot(nor, light_dir));
    float specular = pow(max(0.0, dot(reflect(light_dir, nor), eye_vec)), light.shininess);

    gl_FragColor =
        light.ambient +
        light_attenuation *
        spot *
        (diffuse * light.diffuse + specular * light.specular);
}

shader.vert

#version 150

layout(std140) uniform Camera
{
    mat4 view_matrix;
    mat4 projection_matrix;
} camera;

in vec4 position;
in vec4 normal;
in vec4 texcoord;

in mat4 model_matrix;
in mat4 normal_matrix;

out vec4 pos;
out vec4 nor;
out vec2 uv;

void main()
{
    pos = camera.view_matrix * model_matrix * position;
    nor = camera.view_matrix * normal_matrix * normal;
    uv = texcoord.xy;

    gl_Position = camera.projection_matrix * pos;
}