OpenGL 3.x Rotation Problem

[Brainer]

I have been trying to include the direction vector in my model matrix, but no success. What can be wrong with this code?
[code=delphi]
function TBrainObject.GetMatrix: TBrainMatrix;
var
M: TBrainMatrix;
V: TBrainVector;
begin
if UpdateNeeded then
begin
M := Mat4CreateRotationEuler(FRotation);
V := Mat4ApplyToVector(M, Vec3(0.0, 0.0, -1.0));
V := Vec3Normalize(V);

CachedMatrix := Mat4Scale(Mat4Translate(M,
Vec3Negate(Vec3Add(FPosition, V))), FScale);

UpdateNeeded := False;
end;
Result := CachedMatrix;
end;
[/code]

What happens is that the camera doesn't include the new direction after rotation and instead moves on the same axes. Here's a video for better explanation: http://www.youtube.com/watch?v=lOL8sqR5fQ0

Do you happen to know what is wrong?

EDIT
Hm, I also thought of using a LookAt function. What do you think?
@User137: Can you post the code of the CreateMatrix function here?

[chronozphere]

Can you elaborate? What does the Direction vector have to do "exactly"?

I think a lookAt function is a must have. Almost everyone uses one.
There are three things you need to know about your camera:
- Position
- LookAt
- UpVector (Denotes the "up" direction)
Simply pass these three to a lookAt function and you should be all good.

http://pyopengl.sourceforge.net/docu...LookAt.3G.html

[Brainer]

The vector specifies what direction the object should move at. By default, the vector is (0,0,-1), but after rotation it should change along with the rotation angles.

[User137]

You can see the whole 3D unit here, didn't paste the 2D math but you can figure if needed functions out i suppose, or ask:
http://pastebin.com/gtLhUvj5

[pascal]// Create a rotation matrix
function CreateMatrix(const x, y, z: TVector): TMatrix;
begin
result[0,0]:=x.x; result[0,1]:=x.y; result[0,2]:=x.z; result[0,3]:=0;
result[1,0]:=y.x; result[1,1]:=y.y; result[1,2]:=y.z; result[1,3]:=0;
result[2,0]:=z.x; result[2,1]:=z.y; result[2,2]:=z.z; result[2,3]:=0;
result[3,0]:=0; result[3,1]:=0; result[3,2]:=0; result[3,3]:=1;
end;

// Rotation matrix written with rows and columns switched
function CreateMatrix2(const x, y, z: TVector): TMatrix;
begin
result[0,0]:=x.x; result[1,0]:=x.y; result[2,0]:=x.z; result[3,0]:=0;
result[0,1]:=y.x; result[1,1]:=y.y; result[2,1]:=y.z; result[3,1]:=0;
result[0,2]:=z.x; result[1,2]:=z.y; result[2,2]:=z.z; result[3,2]:=0;
result[0,3]:=0; result[1,3]:=0; result[2,3]:=0; result[3,3]:=1;
end;

function CreateTranslateMatrix(const p: TVector): TMatrix;
begin
result:=NewMatrix;
result[3,0]:=p.x; result[3,1]:=p.y; result[3,2]:=p.z;
end;[/pascal]

Edit: I changed the code a bit to make everything click. LookAt function has to use CreateMatrix2 that uses opposite row direction while usual operations such as MatrixOnPlane() use CreateMatrix.

[Brainer]

I played with your LookAt yesterday and it seems to work, but there's still a little bug I'm going to track down. Something is calculated wrong, because the object slightly rotates with the camera and when the camera angle is high enough, the triangle disappears.

Clearly, it's a problem with matrices. I suppose the function which returns the direction vector from a matrix is faulty. Here is the code:
[code=delphi]
{ .: Mat4ApplyToVector :. }
function Mat4ApplyToVector(const M: TBrainMatrix; const V: TBrainVector): TBrainVector; inline;
begin
Result.X := V.X * M.M[0, 0] + V.Y * M.M[1, 0] + V.Z * M.M[2, 0] + M.M[3, 0];
Result.Y := V.X * M.M[0, 1] + V.Y * M.M[1, 1] + V.Z * M.M[2, 1] + M.M[3, 1];
Result.Z := V.X * M.M[0, 2] + V.Y * M.M[1, 2] + V.Z * M.M[2, 2] + M.M[3, 2];
end;

{ .: Mat4GetDirectionVector :. }
function Mat4GetDirectionVector(const M: TBrainMatrix): TBrainVector; inline;
var
M1: TBrainMatrix;
E: TBrainEuler;
begin
Result := Vec3(0.0, 0.0, -1.0);

E := Mat4GetRotationEuler(M);
M1 := Mat4CreateRotationEuler(E);
Result := Mat4ApplyToVector(M1, Result);
Result := Vec3Normalize(Result);
end;
[/code]

Or maybe the problem is in the way I use them? I'm not sure. Anyway, if someone can tell me whether these two functions are correct, I'll be glad.

I think I'm very close to solving the problem. Of course once I'm done with that, I'll post a complete source code here.

[User137]

I just doublechecked the camera by looking both directions along all X,Y,Z-axis and their mid-angles and all worked fine. First with up-vector(0,1,0) and then vector(-0.2,0.93,0.2) (normalized).

[Brainer]

Which vector did you normalize?

[User137]

Everything should be normalized unless you absolutely know that it already is. Scaling matrix is exception to that.

I mean, i sometimes test with even vectors like norm(vector(30,50,-70)). Just to vaguely point them somewhere.

[Brainer]

Here's a demo of the framework: http://pateman.net76.net/BrainEngineDemo.rar
Can you tell me whether the camera works correctly in your opinion?
Edit
W,S,A,D - move around
Left key, right key - rotate the camera

[User137]

Looks perfectly normal to me, but oh the colors hurt my eyes