The matrix tag has no wiki summary.
1
vote
1answer
68 views
multiply matrix by vector: what to do if need to change y-up to z-up?
I multiply a matrix with a position vector to get a new position, however, now I need to change my matrix from y-up coordinate space to z-up. Changing only the matrix won't work: how to apply the ...
3
votes
1answer
93 views
Moving a rotated model in XNA
This seems like a simple problem with an equally simple solution that is invisible to me.
I have a model that spawns at the origin and looks at my player model wherever it goes.
I would like it to ...
1
vote
1answer
61 views
Rotation going wrong
I'm calculating matrices by hand. Translations are fine:
void Translate (float x, float y, float z, float[4][4] m) {
Identity (m);
m[3][0] = x;
m[3][1] = y;
m[3][2] = z;
}
If ...
2
votes
2answers
58 views
calculate new vertex position given a transform matrix?
How can I get the new position of my vertex given a 4x4 transform matrix or simply 9 floats (positionX, positionY, positionZ, rotationH, rotationP, rotationR, scaleX, scaleY, scaleZ)? Usually I can ...
0
votes
1answer
56 views
Calculate vertex coordinates
Newbie here!
I need to know the effective coordinates of a triangle after applying transformations (rotations & translations) to the current (MODELVIEW) matrix.
That is, given a vertex P, I ...
4
votes
1answer
46 views
Translation from one coordinate system to another having Z-offset issues
I'm using ARToolkit to do an augmented reality application, but my problem is really with the 3D coordinates.
In this application, I use my webcam to generate the scene. I have two markers (printed ...
2
votes
1answer
87 views
Bones Animation - Matrices and calculations
We are 'on final' when it comes to finishing the project, but just before implementing the animation system.
Our Client decided to choose "Bones Animation" - which is that I should export each ...
1
vote
4answers
210 views
Rotating a model AND translating it forward in XNA
I have this enemy class, and I want it to
1) Spawn at a certain place Vector3 pos
2) Rotate to face my player position
3) Move forward
As this code is now, it will appear at it's specified place: ...
3
votes
0answers
113 views
How do I create weapon attachments?
My question is; I am developing a game for XNA and I am trying to create a weapon attachment for my player model. My player model loads the .md3 format and reads tags for attachment points. I am able ...
2
votes
1answer
123 views
Unity3d vector and matrix operations
I have the following three vectors:
posA: (1,2,3)
normal: (0,1,0)
offset: (2,3,1)
I want to get the vector representing the position which is offset in the direction of the normal from posA.
...
2
votes
1answer
91 views
Flip rotation matrix
I'm doing character control with kinect. I need to mirror the joint orientation because the character faces the player. Somehow by Googling through internet I've done it and everything works very ...
0
votes
2answers
120 views
Xna Equivalent of Viewport.Unproject in a draw call as a matrix transformation
I am making a 2D sidescroller and I would like to draw my sprite to world space instead of client space so I do not have to lock it to the center of the screen and when the camera stops the sprite ...
1
vote
2answers
150 views
Matrix rotation of a rectangle to “face” a given point in 2d
Suppose you have a rectangle centered at point (0, 0) and now I want to rotate it such that it is facing the point (100, 100), how would I do this purely with matrix math?
To give some more specifics ...
3
votes
1answer
165 views
C++ problem with assimp 3D model loader
In my game I have model loading functions for Assimp model loading library. I can load the model and render it, but the model displays incorrectly. The models load in as if they were using a seperate ...
2
votes
2answers
97 views
Passing an objects rotation down through its children
In my topdown 2d game you have a player with a sword, like an old Zelda game.
The sword is a seperate entity, and its collision box "rotates" around the player like an orbit, but always follows the ...
