An array of numbers, symbols or expressions, arranged in row and columns. The numbers, symbols or expressions themselves are called elements or entries.

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5
votes
2answers
245 views

Randomly generated track

I would like to create randomly generated track from one point to another with specified length of that track (it can be 2 more or less as a result of that function) in matrix. I have function called ...
8
votes
1answer
5k views

Transform Matrix multiplication order

I am experiencing difficulties trying to figure out the correct multiplication order for a final transform matrix. I always get either strange movement or distorted geometry. My current model is ...
0
votes
2answers
4k views

Scaling Model in XNA, keep position

I am trying to create a little fun 3D game in XNA, but I am having some problems with scaling my models. I use models from random sites, so my battleship is for an example 10 times larger than my ...
2
votes
2answers
1k views

XNA Camera 2D confusion

I have followed the tutorial at http://www.david-amador.com/2009/10/xna-camera-2d-with-zoom-and-rotation/ to implement my 2D camera and everything works just fine. However this leaves me confused. ...
1
vote
4answers
2k 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: ...
2
votes
1answer
335 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 ...
4
votes
1answer
2k 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 ...
2
votes
1answer
166 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
2k 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
143 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
300 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 ...
4
votes
1answer
2k 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 ...
3
votes
1answer
3k 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. ...
1
vote
4answers
4k views

Transform coordinates from 3d to 2d without matrix or built in methods

Not to long ago i started to create a small 3D engine in javascript to combine this with an html5 canvas. One of the issues I run into is how can you transform 3d to 2d coords. Since I cannot use ...
2
votes
1answer
1k 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 ...
1
vote
2answers
717 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
2answers
527 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 ...
10
votes
1answer
2k views

Screen space to world space

I am writing a 2D game where my game world has x axis running left to right, y axis running top to bottom, and z axis out of the screen: Whilst my game world is top-down, the game is rendered on a ...
1
vote
1answer
326 views

How to prevent 2D camera rotation if it would violate the bounds of the camera?

I'm working on a Camera class and I have a rectangle field named Bounds that determines the bounds of the camera. I have it working for zooming and moving the camera so that the camera cannot exit its ...
2
votes
2answers
412 views

3D Translation using only distance and angles

So I'm starting to foray into 3D game programming, but I've hit something of a snag. I have an object I want to move around. It should always move either forward or backward relative to its local Z ...
3
votes
2answers
513 views

Trying to understand 2D vector -> projection space conversion

I'm trying to understand how I can transform 2D vectors (x, y) to projection space. Something hasn't quite clicked for me yet. As per my previous question, here's the effect I'm trying to achieve: ...
6
votes
2answers
1k views

Matrix for 2D perspective

I'm trying to determine whether what I'm attempting to achieve is even possible mathematically. I'm obviously not a seasoned game developer so I'm having trouble even coming up with the terminology to ...
3
votes
1answer
949 views

How do I know if a perspective matrix is right or left handed coordinate system?

For example, if I define my perspective matrix as the following: m[0] = 1.f / ( aspect * focalLength ); m[5] = 1.f / focalLength; m[10] = -zFar / (zFar - zNear); m[11] = -1; m[14] = ...
1
vote
2answers
764 views

Transformation order when dealing with Meshes

I have created a player model out of primitive types. To do this I have created a Model class and Component (mesh) class. Each model consists of one or more components my problems start when you have ...
1
vote
1answer
791 views

Translating local to global coordinates in ARToolkit / OpenGL

Ok, so I've tried reading over the other questions and something's just not clicking for me. I am working on an augmented reality application using ARToolkit, however it should just be straight ...
13
votes
5answers
605 views

Is there a common word that encompasses handling of position, rotation, and scale together?

I'm looking for a name for my class that manipulates 4x4 matrices that handle position, rotation, and scale. Is there a common word that encompasses all three? (I'm splitting the matrix math into its ...
2
votes
2answers
799 views

What is the difference between Vector2.Transform and this method?

I've been working on some steering behaviors and ran into trouble with my logic for converting points in world space into points in local space. I had this (it's not optimized for multiple points yet, ...
3
votes
1answer
1k views

Can a 4x4 matrix describe a camera's perspective?

I'm working with a closed-source 3D engine, and it only allows you to set the view projection via a 4x4 matrix. Can this matrix describe the camera's translation, rotation & perspective? I turned ...
1
vote
0answers
293 views

How can I draw a model perpendicular to a sloped surface? [duplicate]

Possible Duplicate: How do I find rotation in 3D based on a vector/normal? My models are axis-aligned. I know the normal of the surface I want to draw them on. How do I compute the ...
2
votes
1answer
340 views

How do you extract a Vector3 positions only from a world matrix in an array of positions (from Kinect)

've just started building a physical camera class for the depth data you get from a Kinect. I have a Vector3 array of [imageWidth, imageHeight] describing the LOCAL positions I get in from the kinect ...
3
votes
1answer
373 views

Confused about order of operation when using a Matrix in XNA, C#

Here are two different pieces of code This is what I started with Vector2 hold = Vector2.Transform(pos1, mat1); Matrix inv = Matrix.Invert(mat2); Vector2 pos2 = Vector2.Transform(hold, inv); And ...
2
votes
1answer
396 views

How to linearly transform vertices for large coordinate systems

Alright, so I'm working on a space game and well, I want it to have a lot of space! So I need a large coordinate system and for my rendering pipeline to not suffer from "vertex jittering" due to ...
2
votes
1answer
1k views

How can I use a 3x3 matrix within a 4x4 matrix representation?

In XNA there is only one Matrix class which is actually 4x4 matrix. How to use it to represent a 3x3 matrix? I am trying to represent the inertia tensor of a body which is a 3x3 matrix, so I have ...
2
votes
1answer
437 views

Transformed Pretransformed coordinates?

I am creating a minecraft like terrain engine thing in XNA and C#, and I am trying to create a item/block selector tool. The thing is I would like to have 3D objects on the tool. So I thought for the ...
4
votes
3answers
4k views

How to get translation from view matrix

How can I retrieve the camera's world-space position from its view matrix? The only answers I've seen to this question suggest the translation is in the last row/col but this wouldn't work since the ...
4
votes
1answer
332 views

Getting the Bounds of a 2D Cameras View with Zoom

I am using a 2D camera, which does rotations and zoom. Currently, I am using the following to get my MinX, MinY, MaxX and MaxY... public float MinX { get { return ...
2
votes
1answer
645 views

How to create projection/view matrix for hole in the monitor effect

Lets say I have my XNA app window that is sized at 640 x 480 pixels. Now lets say I have a cube model with its poly's facing in to make a room. This cube is sized 640 units wide by 480 units high by ...
0
votes
1answer
2k views

matrix 4x4 position data

I understand that a 4x4 matrix holds rotation and position data. The rotation data is held in the 3x3 sub-matrix at the top left of the matrix. The position data is held in the last column of the ...
2
votes
1answer
203 views

Translating an object along its heading

Solved! I was not applying the transformations in the proper order. I am working on a simulation that requires me to have several objects moving around in 3D space (text output of their current ...
2
votes
1answer
309 views

How do I build a matrix to translate one set of points to another?

I've got 3 points in space that define a triangle. I've also got a vertex buffer made up of three vertices, that also represent a triangle that I will refer to as a "model". How can I can I find the ...
6
votes
3answers
737 views

Why is my model's scale changing after rotating it?

I have just started a simple flight simulator and have implemented Roll and pitch. In the beginning, testing went very well; however, after about 15-20 seconds of constantly moving the thumbsticks in ...
3
votes
1answer
447 views

Better data structure for a game like Bubble Witch

I'm implementing a bubble-witch-like game (http://www.king.com/games/puzzle-games/bubble-witch/), and I was thinking on what's the better way to store the "bubbles" and to work with. I thought of ...
4
votes
1answer
358 views

UVW: better explanation, and how to implement with GLES texture2D()

UVW texture coordinates, as opposed to UV texture coordinates, do not get very adequate explanation on the web. Many people offer the simple exlanation, "UV is for 2-dimensional textures and UVW are ...
9
votes
2answers
4k views

How can I rotate about an arbitrary point in 3D (instead of the origin)?

I have some models that I want to rotate using quaternions in the normal manner, except instead of rotation about the origin, I want it to be offset slightly. I know that you don't say, in 3d space, ...
4
votes
2answers
746 views

Ara matrices calculated on the GPU or on the CPU? Would built-in matrix functions be faster than my custom ones?

If I add a math library (for example containing a Matrix class) and use it in my program drawing with OpenGL, will my be work slower than if I used standard OpenGL functions for matrix calculations? ...
6
votes
2answers
1k views

Vector games (Wireframe, Elite-like) theory and implementations?

I'm interesting in knowing more about how vector games like Elite and Star Wars Atari were built from grounds up. The question is not how to implement vector graphics with modern 3D APIs like OpenGL ...
7
votes
3answers
1k views

Should I use a world matrix?

Image reference for the question: (image from the CG tutorial) The D3D9 API got us used to world matrices. However, if you use world matrices, then you have to do an extra matrix multiply in the ...
1
vote
1answer
1k views

Converting to and from local and world 3D coordinate spaces?

I've been following a guide I found here (http://knol.google.com/k/matrices-for-3d-applications-view-transformation) on constructing a matrix that will allow me to 3D coordinates to an object's local ...
2
votes
1answer
168 views

Integration of homogenous wave

I have a 2D matrix; each of its elements describes a homogenous coordinate in 3D wave (the values of wave coordinates are changed in time). The wave rendering is done with texture. I need to make an ...
2
votes
1answer
491 views

COLLADA: Inverse bind pose in the wrong space?

(Crosspost from StackOverflow) I'm working on writing my own COLLADA importer. I've gotten pretty far, loading meshes and materials and such. But I've hit a snag on animation, specifically: joint ...