Move in direction using transformed vector and quaternion orientation.

The matrices are defined as:

M11, M12, M13, M14
M21, M22, M23, M24
M31, M23, M33, M34
M41, M42, M43, M44

So direction would equal Rotation.M31, Rotation.M32, Rotation.M33.

However how do I proceed from there as I would need to transform the original move vector by a matrix in order to get the transformed move vector, wouldn't I?

Also, would I have to multiply the new movement vector by the elpased game time to make sure that the camera moved smoothly no matter what, should the frame rate fluctuate?

float elapsedTime = (float)gameTime.ElapsedGameTime.TotalSeconds;

                                              

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>> However how do I proceed from there as I would need to transform the original move vector by a matrix in order to get the transformed move vector, wouldn't I?

If you just want the direction the camera is looking at, then its only the third column, nothing to translate anymore. I saw its XNA, so its:

Vector3 forward = Rotation.Forward();

>> Also, would I have to multiply the new movement vector by the elpased game time to make sure that the camera moved smoothly no matter what, should the frame rate fluctuate?

That depends on, what you mean by smoothly.
However, thats an advanced topic and should be covered in a new question. For starters you can start with a fixed angle-speed, degrees or radians per second.
But then you dont have a smooth start and stop.

Anyhow, that really is a complicated topic and should be handled in a new Question.

Matrix.Forward returns:
-M31, -M32, -M33

If I want to move in the direction the camera is facing I have to use:
-M13, -M23, -M33

This seems a little odd?

I don't understand how this forward vector can then be changed with vectorToAdd to move in direction (Left, Right, Up, Down) in relation to the way the camera is facing.

I've also increased the point value of this question.

>> Matrix.Forward returns:
>> -M31, -M32, -M33
>> If I want to move in the direction the camera is facing I have to use:
>>-M13, -M23, -M33

Not sure what you mean, do you mean the returned vector from the Forward() - Memberfunction is wrong? If yes, please show us your example-data.


>> I don't understand how this forward vector can then be changed with vectorToAdd to move in direction (Left, Right, Up, Down) in relation to the way the camera is facing.

Cant follow you here. You have the camera quaternion and the matrix from the quaternion. What excactly do you want to do now?
If you just want to move the camera in the forward-direction, then just add the forward-vector multiplied by the distance to move to the camera position, thats it.


ike

Here's some differences between Forward() function and Direction:

Direction = {X:0.1155887 Y:0.9297699 Z:-0.3495116}
Rotation Forward = {X:-0.3139897 Y:-0.8827476 Z:-0.3495116}

Direction = {X:-0.982073 Y:-0.06513908 Z:0.1766722}
Rotation Forward = {X:0.9841633 Y:-0.01153504 Z:0.1766722}

As for the forward vector issue.  If I get the direction the camera is facing and I want to go left (-1,0,0) from that or right (1,0,0) from that position how would I transform the left and right vectors based on the orientation of the camera?

As a further clarification it would be the same as doing the following, only in a more efficient manner:

            float moveSpeed = 5.0f;
 
            Matrix Rotation = Matrix.CreateFromQuaternion(orientation);
 
            Vector3 Direction = Vector3.Zero;
            if (vectorToAdd == Vector3.UnitX)
            {
                Direction = new Vector3(-Rotation.M11, -Rotation.M21, -Rotation.M31); 
            }
            if (vectorToAdd == -Vector3.UnitX)
            {
                Direction = new Vector3(Rotation.M11, Rotation.M21, Rotation.M31);
            }
            if (vectorToAdd == Vector3.UnitZ)
            {
                Direction = new Vector3(Rotation.M13, Rotation.M23, Rotation.M33);
            }
            if (vectorToAdd == -Vector3.UnitZ)
            {
                Direction = new Vector3(-Rotation.M13, -Rotation.M23, -Rotation.M33);
            }
             
            position_Current += Direction * moveSpeed * elapsedTime;

                                              

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