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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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 ...
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0answers
297 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) * ...
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1answer
277 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 ...
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1answer
629 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 ...
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1answer
2k 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 ...
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2answers
2k 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 ...
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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 ...
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3answers
897 views

What Java class should I use to represent a Vector?

Does Java have a built-in Vector class suitable for handling collision detection / response? It should have methods like subtract(Vector v), normalize(), dotProduct(Vector v), ... It seems logical to ...
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3answers
571 views

How does this circle collision detection math work?

I'm going through the wildbunny blog to learn about collision detection. I'm confused about how the vectors he's talking about come into play. Here's the part that confuses me: p = ||A-B|| – ...
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1answer
354 views

Beginner: How do I calculate a vector?

I am trying to wrap my head around some concepts in a side project I'm working on. I'm struggling with how I can calculate a vector based on my character movement logic. Here are the relevant details ...
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1answer
306 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 ...
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1answer
199 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 ...
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3answers
66 views

How do I interpret the dot product of non-normalized vectors?

I know that if you take the dot-product of two normalized vectors, you get the cosine of the angle between them. But if I take the dot-product of two non-normalized vectors (or one normalized, one ...
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2answers
165 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 ...
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1answer
119 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 ...
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2answers
565 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 ...
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2answers
970 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 ...
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1answer
897 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 ...
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2answers
126 views

How can I pass a std::vector<Vector3f> to my shader?

I have a Vector3f type which has x, y, and z properties. I have a std::vector of these vertices which describe my terrain. I would like to pass these values to a vertex shader through a uniform ...
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1answer
84 views

Rotate an arrow on a plane?

I'm creating a display for a GPS-based embedded system and would like to have an arrow indicating the current bearing. I'd love the arrow to have a 3d appearance by rotating it on a plane tilted up ...
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1answer
71 views

Reflection velocity

I'm trying to get a moving circular object to bounce (elastically) off of an immovable circular object. Am I doing this right? (The results look right, but I hate to trust that alone, and I can't ...
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1answer
87 views

Eculidean space and vector magnitude

Below we have distances from the origin calculated in two different ways, giving the Euclidean distance, the Manhattan distance and the Chebyshev distance. Euclidean distance is what we use to ...
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2answers
244 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 ...
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1answer
181 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, ...
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1answer
1k 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 ...
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1answer
1k 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). ...
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4answers
191 views

Vectors and corners of squares

I am having some problems with some vector math. Imagine a square and coming from each corner of the square is an invisible vector, which starts at the square's centre and ends at the edge of the ...
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1answer
2k views

how to create a Quaternion from an Orientation Vector in xna

i have a Vector3 represents an Orientation in 3D , how to convert it to the corresponding Quaternion ? is there any quick way ? EDIT : i want to add an angular velocity vector to the Orientation ...
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3answers
516 views

Get intersection of vector in the middle of the screen

My screen resolution is 640x480 and I have two Vector2 objects located at (10,10) and (600, 320). How can I connect these two objects and extend the line to encompass the whole screens width, how can ...
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1answer
127 views

Opentk LookAt() and 'eye' argument rotating

I'm trying to create rotating camera, which looks down by 45 deegre like this: However my code for rotating eye vector is not working properly and I achieve vertical rotation, when it should be ...
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2answers
75 views

How to get the normal that points *out* of a polygon

In 2D, each vector (x, y) has two normals: (-y, x) and (y, -x), pointing in opposite directions. Say I have a polygon and for each of it's edges I need to get the normal pointing outwards. In the ...
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2answers
205 views

Adding an angle variance to a 3d vector

I am converting a particle emitter from 2d to 3d. In the 2d system the original coder used a random angle variance and added it to the angle. So it would be something like: thisAngle = emitterAngle ...
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1answer
956 views

Using atan2 to calculate angle between two vectors

I understand that: atan2(vector.y, vector.x) = the angle between the vector and the X axis. But I wanted to know how to get the angle between two vectors using atan2. So I came across this solution: ...
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1answer
108 views

3D vector graphics - maintaining correct Z 'length'

So I'm trying to build myself a 3D display 'engine', or whatever it ought to be called. I've been experimenting with PyGame, as it's familiar to me. In a way this has almost been more an excuse to ...
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2answers
141 views

Twitchy sprite movement

I'm having an issue with sprite movement, and I'm not sure how to deal with it. When I set a destination for my player sprite (by clicking the screen), it sets the player moving in that direction. ...
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1answer
315 views

How to simulate acceleration and then deceleration?

Currently I am only using deceleration. Here is how I do it I need to cover Vector(x,y) unit distance to reach B from A. I simply do - rendering loop-> position = A + Vector(x,y).scale(factor); ...
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1answer
394 views

How do I get the axes for SAT collision detection

In SAT collision detection how do I calculate the axes for projection?
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1answer
660 views

how can i get rotation vector from matrix4x4 in xna?

i want to get rotation vector from matrix to realize some parent-children system for models. Matrix bonePos = link.Bone.Transform * World; Matrix m = Matrix.CreateTranslation(link.Offset) * ...
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1answer
261 views

Viewport.Unproject - Checking if a model intersects a large sprite

Let's say I have a sprite, drawn like this: spriteBatch.Draw(levelCannons[i].texture, levelCannons[i].position, null, alpha, levelCannons[i].rotation, Vector2.Zero, scale, SpriteEffects.None, 0); ...
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1answer
2k views

Vector movement in space type game (Mouse rotation)

I'm having an issue with my movement in my 'game' prototype. It's basically not working and admittedly my knowledge with vectors is lacking. The issue I'm running into is that the ship won't move in ...
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1answer
555 views

Trouble with SAT style vector projection in C#/XNA

Simply put I'm having a hard time working out how to work with XNA's Vector2 types while maintaining spatial considerations. I'm working with separating axis theorem and trying to project vectors onto ...
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1answer
167 views

Moving in an arc using Vector3

I'm trying to get this object to move right across the screen until it gets close to the center and arc down smoothly into a straight downward movement. Here's what I've tried: if (position.X < ...
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1answer
285 views

XNA - Incorrect Mouse Ray?

I have the following code: Vector3 nearSource = new Vector3(mState.X, mState.Y, 0.0f); Vector3 farSource = new Vector3(mState.X, mState.Y, 3.0f); Vector3 nearPoint = ...
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1answer
125 views

How should I update vectors, et cetera, in a time-based fashion?

I'm trying to write something I believe is straightforward but wanted to check that I'm doing it right. All I want is to update the position of a 2D sprite based an acceleration and velocity. I'm ...
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1answer
238 views

What can I use to generate 2d vector graphics as a list of coordinates?

I am working on a game that uses simple 2d vector graphics. I want a tool that will let me visually draw things like arbitrary polygons by placing points. A perfect tool would present a grid that I ...
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1answer
79 views

Smooth anmiation with LibGDX

I want to move a enemy from its current position toward the mouse position in LibGDX. x, y - enemy position saveX, saveY - position where my enemy need to go(or mouse position saved at specific ...
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1answer
228 views

Unity: Rolling a ball around a spherical planet with forces

I'm trying to make a game in Unity where the player character is a ball (a sphere), and the game world is a planet (a very large sphere) that the ball can roll around on. The ball can be rolled in any ...
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1answer
564 views

How to move Vector2 along angle?

These are my Vector2's that I am using for this function. public Vector2 position = new Vector2(); public Vector2 velocity = new Vector2(); public Vector2 movement = new Vector2(); public Vector2 ...
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1answer
133 views

How do I make a sprite move to another position using vectors

Ok, so far I have made the sprite move to a mouse position. But I got a question, does anyone know how to make a sprite move by itself without the use of a mouseclick from Point a to point b using ...
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1answer
167 views

Spaceship acceleration for following waypoints

I'm creating a turn based space ship strategy game with simultaneous turn resolution similar to Steam Birds. After all the orders are given, the ships run through a real time simulation where they ...