Correct Delta Calculations

[Pottus]

This was always one thing I wanted with FCNPC was delta playback since it was not supported correctly. I am just pasting my code snippet for the solution to this problem and perhaps someone could do an official implementation with some tweaks.

It takes 3 parameters

Position to start playback
const CVector& vecPoint

float* fQuaternion
Passed from the script with but there is a probably a better way to reference this
FCNPC_GetQuaternion(npcid, rw, rx, ry, rz);

Lets you specify rotation offset angle for play back
float zoff

Some more notes:
Recordings should be made at 0, 0, 0 you could do say a series of attack punches then play that back anywhere at any angle, other use is recording jumping down off a ledge.

`bool CPlayback::Initialize(const CVector& vecPoint, float* fQuaternion, float zoff)
{
if (m_iRecordId == INVALID_RECORD_ID) {
return false;
}

m_recordData = pServer->GetRecordManager()->Get(m_iRecordId);

if (vecPoint != CVector()) {
	int iSize = static_cast<int>(m_recordData.v_dwTime.size());

	if (m_recordData.iPlaybackType == PLAYBACK_TYPE_DRIVER) {
		CVector vecPointOffset = m_recordData.v_vehicleSyncData[0].vecPosition - vecPoint;

		for (int i = 0; i < iSize; i++) {
			m_recordData.v_vehicleSyncData[i].vecPosition -= vecPointOffset;
		}
	}



	else if (m_recordData.iPlaybackType == PLAYBACK_TYPE_ONFOOT) {

		CVector vecPointOffset = m_recordData.v_playerSyncData[0].vecPosition - vecPoint;
		CVector Initial = m_recordData.v_playerSyncData[0].vecPosition - vecPointOffset;

		float s, c;

		s = sin(zoff * M_PI / 180);
		c = cos(zoff * M_PI / 180);

		btQuaternion deltaRot;
		btQuaternion currentRot;

		deltaRot.setW(fQuaternion[0]);
		deltaRot.setX(fQuaternion[1]);
		deltaRot.setY(fQuaternion[2]);
		deltaRot.setZ(fQuaternion[3]);

		currentRot += deltaRot;

		for (int i = 0; i < iSize; i++) {

			if (zoff < 0.0 || zoff > 0.0)
			{
				m_recordData.v_playerSyncData[i].byteHealth = 255;
				m_recordData.v_playerSyncData[i].byteArmour = 255;

				// Perform position calculations
				float xNew, yNew;

				xNew = (m_recordData.v_playerSyncData[i].vecPosition.fX * c - m_recordData.v_playerSyncData[i].vecPosition.fY * s);
				yNew = (m_recordData.v_playerSyncData[i].vecPosition.fX * s + m_recordData.v_playerSyncData[i].vecPosition.fY * c);

				m_recordData.v_playerSyncData[i].vecPosition.fX = xNew + Initial.fX;
				m_recordData.v_playerSyncData[i].vecPosition.fY = yNew + Initial.fY;
				m_recordData.v_playerSyncData[i].vecPosition.fZ -= vecPointOffset.fZ;


				// Perform rotation calculations
				currentRot.setW(m_recordData.v_playerSyncData[i].fQuaternion[0]);
				currentRot.setX(m_recordData.v_playerSyncData[i].fQuaternion[1]);
				currentRot.setY(m_recordData.v_playerSyncData[i].fQuaternion[2]);
				currentRot.setZ(m_recordData.v_playerSyncData[i].fQuaternion[3]);

				if (fQuaternion) {
					currentRot *= deltaRot;
					m_recordData.v_playerSyncData[i].fQuaternion[0] = currentRot.getW();
					m_recordData.v_playerSyncData[i].fQuaternion[1] = currentRot.getX();
					m_recordData.v_playerSyncData[i].fQuaternion[2] = currentRot.getY();
					m_recordData.v_playerSyncData[i].fQuaternion[3] = currentRot.getZ();
				}

				// Perform velocity calculations

				btQuaternion currentVelocity;

				currentVelocity.setW(0.0);
				currentVelocity.setX(m_recordData.v_playerSyncData[i].vecVelocity.fX);
				currentVelocity.setY(m_recordData.v_playerSyncData[i].vecVelocity.fY);
				currentVelocity.setZ(m_recordData.v_playerSyncData[i].vecVelocity.fZ);

				btQuaternion rotateVelocity;
				rotateVelocity.setW(1 / zoff);
				rotateVelocity.setX(0.0);
				rotateVelocity.setY(0.0);
				rotateVelocity.setZ(0.0);

				currentVelocity *= rotateVelocity;

				m_recordData.v_playerSyncData[i].vecVelocity.fX = currentVelocity.getX();
				m_recordData.v_playerSyncData[i].vecVelocity.fY = currentVelocity.getY();
				m_recordData.v_playerSyncData[i].vecVelocity.fZ = currentVelocity.getZ();

			}
			else
				m_recordData.v_playerSyncData[i].vecPosition -= vecPointOffset;
		}
	}
}


m_dwStartTime = GetTickCount();
return true;

}`