/// <summary>This is a slerp that mimics a camera operator's movement in that
/// it chooses a path that avoids the lower hemisphere, as defined by
/// the up param</summary>
/// <param name="vA">First direction</param>
/// <param name="vB">Second direction</param>
/// <param name="t">Interpolation amoun t</param>
/// <param name="up">Defines the up direction</param>
public static Vector3 SlerpWithReferenceUp(
Vector3 vA, Vector3 vB, float t, Vector3 up)
{
float dA = vA.magnitude;
float dB = vB.magnitude;
if (dA < Epsilon || dB < Epsilon)
{
return(Vector3.Lerp(vA, vB, t));
}
Vector3 dirA = vA / dA;
Vector3 dirB = vB / dB;
Quaternion qA = Quaternion.LookRotation(dirA, up);
Quaternion qB = Quaternion.LookRotation(dirB, up);
Quaternion q = UnityQuaternionExtensions.SlerpWithReferenceUp(qA, qB, t, up);
Vector3 dir = q * Vector3.forward;
return(dir * Mathf.Lerp(dA, dB, t));
}
/// <summary>Intelligently blend the contents of two states.</summary>
/// <param name="stateA">The first state, corresponding to t=0</param>
/// <param name="stateB">The second state, corresponding to t=1</param>
/// <param name="t">How much to interpolate. Internally clamped to 0..1</param>
/// <returns>Linearly interpolated CameraState</returns>
public static CameraState Lerp(CameraState stateA, CameraState stateB, float t)
{
t = Mathf.Clamp01(t);
float adjustedT = t;
CameraState state = new CameraState();
state.Lens = LensSettings.Lerp(stateA.Lens, stateB.Lens, t);
state.ReferenceUp = Vector3.Slerp(stateA.ReferenceUp, stateB.ReferenceUp, t);
state.RawPosition = Vector3.Lerp(stateA.RawPosition, stateB.RawPosition, t);
state.ShotQuality = Mathf.Lerp(stateA.ShotQuality, stateB.ShotQuality, t);
state.PositionCorrection = Vector3.Lerp(
stateA.PositionCorrection, stateB.PositionCorrection, t);
// GML todo: is this right? Can it introduce a roll?
state.OrientationCorrection = Quaternion.Slerp(
stateA.OrientationCorrection, stateB.OrientationCorrection, t);
Vector3 dirTarget = Vector3.zero;
if (!stateA.HasLookAt || !stateB.HasLookAt)
{
state.ReferenceLookAt = kNoPoint; // can't interpolate if undefined
}
else
{
// Re-interpolate FOV to preserve target composition, if possible
float fovA = stateA.Lens.FieldOfView;
float fovB = stateB.Lens.FieldOfView;
if (!state.Lens.Orthographic && !Mathf.Approximately(fovA, fovB))
{
LensSettings lens = state.Lens;
lens.FieldOfView = state.InterpolateFOV(
fovA, fovB,
Mathf.Max((stateA.ReferenceLookAt - stateA.CorrectedPosition).magnitude, stateA.Lens.NearClipPlane),
Mathf.Max((stateB.ReferenceLookAt - stateB.CorrectedPosition).magnitude, stateB.Lens.NearClipPlane), t);
state.Lens = lens;
// Make sure we preserve the screen composition through FOV changes
adjustedT = Mathf.Abs((lens.FieldOfView - fovA) / (fovB - fovA));
}
// Linear interpolation of lookAt target point
state.ReferenceLookAt = Vector3.Lerp(
stateA.ReferenceLookAt, stateB.ReferenceLookAt, adjustedT);
// If orientations are different, use LookAt to blend them
float angle = Quaternion.Angle(stateA.RawOrientation, stateB.RawOrientation);
if (angle > UnityVectorExtensions.Epsilon)
{
dirTarget = state.ReferenceLookAt - state.CorrectedPosition;
}
}
// Clever orientation interpolation
if (dirTarget.AlmostZero())
{
// Don't know what we're looking at - can only slerp
state.RawOrientation = UnityQuaternionExtensions.SlerpWithReferenceUp(
stateA.RawOrientation, stateB.RawOrientation, t, state.ReferenceUp);
}
else
{
// Rotate while preserving our lookAt target
dirTarget = dirTarget.normalized;
if ((dirTarget - state.ReferenceUp).AlmostZero() ||
(dirTarget + state.ReferenceUp).AlmostZero())
{
// Looking up or down at the pole
state.RawOrientation = UnityQuaternionExtensions.SlerpWithReferenceUp(
stateA.RawOrientation, stateB.RawOrientation, t, state.ReferenceUp);
}
else
{
// Put the target in the center
state.RawOrientation = Quaternion.LookRotation(dirTarget, state.ReferenceUp);
// Blend the desired offsets from center
Vector2 deltaA = -stateA.RawOrientation.GetCameraRotationToTarget(
stateA.ReferenceLookAt - stateA.CorrectedPosition, stateA.ReferenceUp);
Vector2 deltaB = -stateB.RawOrientation.GetCameraRotationToTarget(
stateB.ReferenceLookAt - stateB.CorrectedPosition, stateB.ReferenceUp);
state.RawOrientation = state.RawOrientation.ApplyCameraRotation(
Vector2.Lerp(deltaA, deltaB, adjustedT), state.ReferenceUp);
}
}
// Accumulate the custom blendables and apply the weights
for (int i = 0; i < stateA.NumCustomBlendables; ++i)
{
CustomBlendable b = stateA.GetCustomBlendable(i);
b.m_Weight *= (1 - t);
if (b.m_Weight > UnityVectorExtensions.Epsilon)
{
state.AddCustomBlendable(b);
}
}
for (int i = 0; i < stateB.NumCustomBlendables; ++i)
{
CustomBlendable b = stateB.GetCustomBlendable(i);
b.m_Weight *= t;
if (b.m_Weight > UnityVectorExtensions.Epsilon)
{
state.AddCustomBlendable(b);
}
}
return(state);
}
