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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1answer
950 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 ...
2
votes
1answer
325 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 ...
2
votes
1answer
240 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
479 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
515 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
233 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
451 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
339 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
798 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
222 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
617 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
1answer
168 views

Libgdx : point that scrolls on the edge of a circle

I'm not very familiar with libgdx vectors. I want to create my own joystick-controller and I want to know how can I find the coordinates of B by using Vectors. I can calculate the radius and I have ...
2
votes
2answers
45 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
83 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
845 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
571 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
298 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
639 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
214 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
1k 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
4k 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
83 views

How to calculate if a point is contained in rectangular camera viewport with rotation?

I am working with my camera, and am trying to improve it so that I can calculate if a world point is on screen, taking rotation into account. Currently, my camera rectangle is calculated as so: ...
2
votes
1answer
51 views

Unable to achieve two finger panning

I'm looking to achieve a two finger smooth pan system in my project. However, the code below does not work, any interaction with the screen doesn't change to position of the camera. I am unsure where ...
2
votes
1answer
69 views

How to prevent bullets from passing right through entities?

(sorry for bad english) I'm making 2D arcade game. I write all of physics stuff myself. The problem involves bullet behaviour. Imagine bullet flying towards some entity. If the bullet's velocity is ...
2
votes
1answer
355 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
2answers
1k 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
284 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
524 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
610 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
1answer
68 views

Ball's velocity vector, reflect against a point

I need to calculate the new velocity vector when the ball collides with one of the paddle's corners. Let d be the velocity vector of the ball, r the target velocity vector and n the surface normal ...
2
votes
1answer
41 views

Find your value between four values in a grid based on distance, Unity

Please note: Originally posted in stack overflow, redirected due to nature of problem. I am making a procedural mesh game. I am trying to calculate the temperature for the player's current chunk by ...
2
votes
0answers
27 views

Weird warping with per-vertex normals

I've had this little problem for a while now, where for some reason my calculations for per-vertex normals results in a weird distortion or warping, skewing my lighting, shading, and reflection ...
2
votes
1answer
206 views

Problems with Raycasting Requirements

Im working on a script which kinda works like an Enemy AI. Its kinda like a detection system with requirements that are required to be met. This is a recent question i asked using my code Raycast ...
2
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0answers
464 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
291 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
2answers
2k views

How can I find the perpendicular to a 2D vector?

I'm making a top down game where the player moves forwards towards the position of the mouse cursor. As part of the player's movement code, I need to determine a vector that is perpendicular to the ...
1
vote
1answer
3k 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
3answers
6k views

Scale a normalized 2D vector always to the same length

For any normalized 2D vector, except for ( 0, 0 ), how would I scale the vector to always be the same length? For example: int length = 10; vector v = vector( 0.1, 0.5 ); vector v2 = vector( 0.3, ...
1
vote
1answer
1k 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
4answers
3k 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 ...
1
vote
3answers
703 views

Create random polygon shapes

I want to make a random shape made out of points. I want the points to create a polygon shape. Is there a clever way to create a random shape like this? Im thinking going throug X points and giving ...
1
vote
2answers
4k 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
3answers
647 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|| – ...
1
vote
1answer
59 views

How do I convert two vectors into a bounding box with 8 vertices?

I created two vectors named bboxmin and bboxmax using the functions vector3 applymin_xyz() and vector3 applymax_xyz(). How do I convert them to 8 vertices,so I can test cull with them?
1
vote
1answer
564 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 ...
1
vote
1answer
509 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
258 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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2answers
615 views

Asteroids Movement

I have been making an asteroids clone, in C#. However, the ship's movement is... not quite right. My plan is this: there is a speed, and two directions, namely the direction the ship is facing ...
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vote
2answers
87 views

Malformed/Pixelated Vertex Normals

I am trying to generate vertex normals for a given triangles/vertices list with the following code: **BASE METHOD:** private void CalculateNormals() { for (Int32 i = 0; i < m_Meshes.Count; ...
1
vote
1answer
300 views

Estimate the time it takes for an object to travel from point A to point B

I have an object with vec2 position, velocity, and destination with 2 variables maxspeed and acceleration. In each step, its position is calculated as follows: vec2 desiredVel = destination - ...