A mathematical concept that can be used to express position, direction or velocity and which can simplify or outright trivialise spatial problems.

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2
votes
3answers
689 views

How to find the entity I'm looking at?

I am currently making a mod for Minecraft but I have come to a stop because I am lacking in some knowledge. I need to get data for the entity I am looking at, which I believe requires the use vectors, ...
2
votes
2answers
581 views

android 2d bullet-spawn (shooting)

This will be a quick question since Im pretty sure I'm overlooking something small that I for some reason cant see. My sprite is moved using a joystick, and I want my sprite to be able to shoot. I've ...
2
votes
1answer
275 views

What is wrong with my technique for transmitting server and client game state?

I'm doing a network implementation of a fast-paced game. I have a puck on bot the server and client side of the simulation. I want to update the client puck position only if they are on the same ...
2
votes
2answers
676 views

How to calculate vector that is perpendicular to the direction of moving in Flash?

In flash i have a class that extends movieclip and i am moving it forward, up and down, and rotating it. How can i calculate the vector that is perpendicular to this movieclip?
2
votes
1answer
91 views

How do I compute the point of a triangle-ray intersection?

I have a line (the direction vector of the player) and a triangle representing the face of a model (so composed of 3 points). I can't find the mathematical operation to check if that vector is ...
2
votes
1answer
139 views

Rotate Camera as an Object Manoeuvres

There are loads of questions (all of which I have looked at) on here about cameras following objects. Using them, I have successfully got my camera to follow my car when driving, but I am unable to ...
2
votes
4answers
187 views

How do I rotate a camera around the Y axis of the object it's looking at? [duplicate]

I'm making a camera that can currently rotate freely from the back to the front of a target object by giving it an angle and a distance. I do the above with the following code directionVector = ...
2
votes
2answers
171 views

How can I move a polygon edge 1 unit away from the center?

Let's say I have a polygon class that is represented by a list of vector classes as vertices, like so: var Vector = function(x, y) { this.x = x; this.y = y; }, Polygon = function(vectors) { ...
2
votes
1answer
317 views

Detect if square in grid is within a diamond shape

So I have a game in which basically everything is a square inside a big grid. It's easy to check if a square is inside a box whose center is another square: *** x *o* --> x is not in o's ...
2
votes
1answer
336 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 ...
2
votes
1answer
175 views

Calculate the direction, From Outer Polygon Point to Inner Polygon inside Point

I was able to find the co-ordinates of inner Polygon using this trick. Need the co-ordinates of innerPolygon But, I have some problem in getting the direction from Outer Polygon Point to Inner ...
2
votes
1answer
474 views

Calculate the initial velocity of a 3D trajectory

I've got a 2D projectile code sample working, but would like to extend it to 3D. How would I calculate the initial velocity of the Z-axis? At the moment, I've got: initVel.X = (float)Math.Cos(45.0); ...
2
votes
2answers
25 views

Derive direction in which a spot light emites its light from a projection matrix

First of all, sorry if my question sounds too basic or even makes no sense. I'm new with game development I'm working with HPL1Engine, specifically, the lights parts. I need to know the direction in ...
2
votes
1answer
55 views

Get a random vector

I'm trying to make a small pariticle-like simulation, and I'm trying to make each parrticle go a random direction from one point (mouse pos). The problem is I don't know how to get the random vector ...
2
votes
1answer
445 views

2D Top down acceleration vector

I have been wanting to solve the issue of movement once and for all... with all that I have learnt and read through, should be a piece of cake one would have thought... , seems it isn't. Having ...
2
votes
1answer
330 views

Shooting Bullets Around a Sphere

I currently have a ship that can orbit around a sphere freely controlled by a joystick. There is a separate joystick that controls the gun and starts shooting when it is touched. Right now the ...
2
votes
1answer
237 views

Turning to face mouse

Given three points on the same Y plane; A ship A point along the ships heading A mouse cursor How can I find which direction and angle the mouse cursor is from the ships heading? I have a limited ...
2
votes
1answer
360 views

android game-logic for shooter

Im creating a 2d game for android. I'll just get right to it. I have a sprite controlled by a joystick that needs to shoot, sofar Ive managed to get direction and movement on my bullet, but then I ...
2
votes
1answer
199 views

XNA Framework sprite vectors and also scaling

I'm working on making my first Pong game with XNA Framework 4.0. Right now i've put 2 pong paddles and a ball (they have separate classes). In the "Paddle" class i've made a function that returns a ...
2
votes
1answer
254 views

Moving Unit Parallel to Mouse in TBS Game

I'm writing a basic Turn-Based Strategy game using Unity3D. It's not grid-based. I've come to the point where I'm coding unit movement, and I'm having trouble figuring out how far to move the units ...
2
votes
1answer
696 views

Rotating a vector by a quaternion

I am trying to rotate a direction vector (0,0,1,0) by a rotation quaternion in DirectX. From what understanding, to rotate the vector you must do NewVector = rotQuaternion * Vector * ...
2
votes
1answer
3k views

2d tank movement and turret solution

I'm making a simple top-down tank game on the ipad where the user controls the movement of the tank with the left "joystick" and the rotation of the turret with the right one. I've spent several hours ...
2
votes
1answer
217 views

How to correctly represent a bone system?

I'm currently representing my bone system as follows, in pseudocode: root = {} root.rot = v3(0,0,0) root.pos = v3(0,0,0) function create_child(parent,rot,length): child_bone = {} ...
2
votes
1answer
137 views

front and back face detection

I am trying to implement a dynamic shadow system for a 2d game using this tutorial : ...
2
votes
2answers
407 views

Relative cam movement and momentum on arbitrary surface

I have been working on a game for quite long, think sonic classic physics in 3D or tony hawk psx, with unity3D. However I'm stuck at the most fundamental aspect of movement. The requirement is that I ...
2
votes
1answer
209 views

How to shift a vector based on the rotation of another vector?

I’m learning 2D programming, so excuse my approximations, and please, don’t hesitate to correct me. I am just trying to fire a bullet from a player. I’m using HTML canvas (top left origin). Here is a ...
2
votes
1answer
293 views

Transform 3D vectors between coordinate systems

I've got 6 points in 3D space: A,B,C,D,E,F, that represent 4 vectors. AB is perpendicular to AC and DE is perpendicular to DF. I need to find a transformation matrix M, that transforms AB to DE and ...
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 ...
2
votes
1answer
445 views

Calculating camera zoom value (top-down)

I need some help in 'camera maths'. I have a birds eye view of two characters. One character is static and the other can move. I would like the camera to always show both characters in full and, in ...
2
votes
2answers
2k views

Weird rotation problem

I'm creating a simple tank game. No matter what I do, the turret keeps facing the target with it's side. I just can't figure out how to turn it 90 degrees in Y once so it faces it correctly. I've ...
2
votes
0answers
135 views

Quaternion to direction vector - flipping

I've kinda solved this myself by adapting the Camera::setDirection code from OGRE to work for my need: Now I have the following code: Vector3 boneDir = getBoneWorldOrientation(mEntity, mHips) * ...
1
vote
1answer
269 views

Determining relative velocities on impact?

I'm trying to figure out a way to determine the relative velocity of a body colliding with another in a 2D environment. For example if one body is moving at (1,0) and another traveling behind it ...
1
vote
1answer
374 views

How to get a point to the left/right of a vector

I have a position vector of a point in space and a quaternion for it's rotation. What i'm trying to calculate is a point too the left and a point to the right. I have the position and ...
1
vote
1answer
1k views

Understanding math used to determine if vector is clockwise / counterclockwise from your vector

I'm reading Programming Game AI by Example by Mat Buckland. In the Math & Physics primer chapter there's a listing of the declaration of a class used to represent 2D vectors. This class contains ...
1
vote
2answers
511 views

convert orientation vec3 to a rotation matrix

I've got a normalized vec3 that represents an orientation. Each frame of animation, an object's orientation changes slightly, so I add a delta vector to the orientation vector and then normalize to ...
1
vote
2answers
1k views

Line Intersection from parametric equation

I'm sure this question has been asked before. However, I'm trying to connect the dots by translating an equation on paper into an actual function. I thought It would be interesting to ask here instead ...
1
vote
4answers
1k views

How to smoothly rotate a vector in a direction?

I'm looking for an easy way to achieve the following: Object A, B { Vector2D position; Vector2D orientation; } update(elapsed) { //rotate A's orientation in B's direction by x * elapsed ...
1
vote
2answers
2k views

Calculating the 2D edge normals of a triangle

What's a reliable way to calculate a 2D normal vector for each edge of a triangle, so that each normal is pointing outwards from the triangle? To clarify, given any triangle - for each edge (e.g ...
1
vote
1answer
214 views

Calculating projectile velocity from moving object

I'm working on a top down space shooter and am having trouble with calculating/understanding the physics for projectiles launched from the space ship. The ships have a velocity vector and a turret ...
1
vote
1answer
173 views

When to use an Array vs When to use a Vector, when dealing with GameObjects?

I understand that from other answers, Arrays and Vectors are the best choices. Many on SE claim that Linked Lists and Maps are bad for video game programming. I understand that for the most part, I ...
1
vote
2answers
80 views

matrix to rotate a vector to a known arbitrary axis

Let's say I have a vector V (v.x,v.y,v.z) which is normalized and points somewhere in 3d space. And that I have another vector Z of (0,0,1). Knowing only these two things I'm looking for a ...
1
vote
1answer
87 views

Does a 2D Vector or 2x2 Matrix play any role in 2D Transformations?

I'm having trouble trying to figure out if a vec2 or mat2 class are used at all in transformations for 2D rendering. Vec2, apart from representing UVs, AFAIK, is relatively pointless in regards to ...
1
vote
2answers
263 views

What is the camera direction vector for an isometric view?

What values correspond to a 3D vector for screen-normal from within an isometric game? It needs to be in game coordinates. It is a standard isometric where tiles are rotated 45 degrees and half ...
1
vote
2answers
463 views

Libgdx: Am I abusing Vector2? Is there a better way to do my position updates and rendering?

I'm simulating hair in a game. Currently I have a HairField object, which has a position defined by a Vector2. Each HairField has multiple Hair objects in a list, each with a position defined by a ...
1
vote
2answers
582 views

Determining if something is on the right or left side of an object?

I have a character in a 3D world which is facing an arbitrary direction on a flat plane, the player can click on the left or right side of the character and based on which side is clicked on a ...
1
vote
1answer
593 views

Rotate triangle so that its tip points in the direction of the point on the screen that we last touched

OpenGL ES - Android. Hello all, I am unable to rotate the triangle accordingly in such a way that its tip always points to my finger. What i did : Constructed a triangle in by GL.GL_TRIANGLES. Added ...
1
vote
2answers
152 views

How can I project a vector on another vector?

I have a generic not normalized Vector3 v1 and I want to calculate its component along another Vector3 v2. I used to normalize the vector I want to be the direction and then multiplying the other ...
1
vote
1answer
150 views

Confusing with an articles wording on Clamping a Vector2

I have been reading an article on Collision Detection and how to resolve it. http://www.wildbunny.co.uk/blog/2011/04/20/collision-detection-for-dummies/ In the section describing an AABB vs Circle, ...
1
vote
1answer
904 views

Unity: parallel vectors and cross product, how to compare vectors

I read this post explaining a method to understand if the angle between 2 given vectors and the normal to the plane described by them, is clockwise or anticlockwise: public static AngleDir ...
1
vote
1answer
843 views

Interpolation between two 3D points?

I'm working with some splines which define a path a character follows (you can see a gameplay video here to get a better understanding of what's going on: http://www.youtube.com/watch?v=BndobjOiZ6g). ...