const int CAMSHAKE_STILL = 0;
const int CAMSHAKE_ONE_HAND = 1;
const int CAMSHAKE_SLOW_WALK = 2;
const int CAMSHAKE_FAST_WALK = 3;

vec4 readShakeTrack(int track, float time)
{
    vec4 shake = texture2D(iShakeTexture, vec2((time * 30.) / 1024., (float(track) + 0.5) / 4.));
    shake *= vec4(298.9801894102875, 268.15706491470337, 0.04235362283476297, 1.0);
    shake += vec4(-120.21135719270364, -142.22203880491924, -1.5530782050492652e-11, 0.);
    return shake;
}

void applyShake(inout vec3 dir, vec4 shake)
{
    mat2 rollMatrix = mat2(cos(shake.z), sin(shake.z), -sin(shake.z), cos(shake.z));
    dir.xy = rollMatrix * dir.xy;
    dir.xy += shake.xy / 1920.;
    dir = normalize(dir);
}