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

learn more… | top users | synonyms

3
votes
1answer
3k views

Orthographic Camera and Raycasting in Three.js

I'm working on a test project porting a simple game from iOS to Javascript. I've got the orthographic camera working and it can view the objects in the scene and move up and down the tower of meshes ...
3
votes
2answers
911 views

How to find point on a circle that's opposite another point?

How do I find the coordinate of point and angle value on circle sprite which placed on opposite side of sprite from a touch point and the center point of the sprite? I know A position, B position and ...
0
votes
2answers
601 views

How to add a constant horizontal force just like gravity?

I want to add a constant horizontal force, just like gravity to a projectile or a sphere moving in 3d space, which will make the projectile or ball or sphere or whatever be influenced by this force so ...
0
votes
2answers
213 views

Collision detection: Swinging bat/racket and ball

I am programming a side-view tennis game, inspired by an old arcade game, using Javscript and HTML5 canvas elements. The player can move left and right and holds a racket at arms length which can be ...
1
vote
0answers
352 views

Closest distance from 3D point to vector line

First let's have a look at my little drawing: I have an origin point p1 defined by x, y and z co-ordinates, and a vector v given by x, y and z magnitude. I also have an arbitrary point, p2, given ...
1
vote
2answers
107 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 ...
1
vote
1answer
548 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 ...
1
vote
1answer
2k 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 ...
1
vote
1answer
92 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 ...
0
votes
1answer
512 views

How do I find a unit vector of another in Java?

I'm writing a Java formula based on this tutorial: 2-D elastic collisions without Trigonometry. I am in the section "Elastic Collisions in 2 Dimensions". Part of step 1 says: Next, find the unit ...
0
votes
1answer
201 views

What is wrong with my specular phong shading

I'm sorry if this should be placed on stackoverflow instead however seeing as this is graphics related I was hoping you guys could help me: I'm attempting to write a phong shader and currently working ...
1
vote
1answer
212 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 ...
0
votes
1answer
454 views

Sorting for 2D Drawing

I am drawing a game in 2D (isometric) My objects have their own arrays. (i.e. Tiles[], Objects[], Particles[], etc) I want to have a draw[] array to hold anything that will be drawn. Because it is ...
4
votes
2answers
1k views

Why isn't this physics code scaling velocities separately?

I'm working my way through this book and I'm trying to work this code out: var squaredVelocity = this.velocity.x*this.velocity.x + this.velocity.z*this.velocity.z; if ...
1
vote
1answer
727 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 ...
0
votes
0answers
244 views

How do I find the camera direction vector for 3D sound purposes? (C++, DirectX)

Question I'm trying to make a sound class for playing 3D sound effects with DirectSound and DirectX, without using DirectSound's 3D libraries. The plan is to have every game object constantly play ...
3
votes
1answer
349 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 ...
11
votes
2answers
832 views

Dynamic thruster balancing of space ship

The space ships in my game a meant to be player-built with an arbitrary amount of thrusters attached anywhere with any rotation. I currently have some dirty code to rotate the ship to a given angle ...
0
votes
1answer
63 views

How to set LinearVelocity exactly in onSceneTouchEvent?

I'm beginner in Android programming. And i use AndEngine GLS2 with Body and AnimatedSprite. I have a object ball and i want to move it to follow my hand. This is description for my idea: And my ...
1
vote
1answer
62 views

How to rotate vector A around another vector B?

Lets say I know what is directly above a turret. I also know where the turrets gun is currently pointing. I would like to know where will the turret's gun will point if I rotate it. I suppose I could ...
0
votes
1answer
248 views

How to tell right from left: Finding the vector pointing towards the right side of a character?

We have two vectors: Pointing from the floor to a 3d character's head. Pointing from the character towards where it's facing. How do I find the vector point from the character towards the right? ...
0
votes
0answers
58 views

How to find optimal perpendicular axis of rotation vector to draw arrows?

I am drawing lines on the screen. Each line has a point (x,y,z) and a direction (u,v,w). I want to draw arrow heads on these lines, like two lines that start from (x,y,z) and leave at a 15 degree ...
0
votes
1answer
176 views

Projecting a light onto a quad

I need to project the light onto the quad and use its value for translating the vertices. I'm currently having 6 vertices, two quads, The points are A X C B Y D Point X, Y are coming from two ...
0
votes
0answers
256 views

How to rotate a line in 3d space?

I am trying to figure out direction vectors of the arrowheads of an arrow. Basically I'm given a normalized direction vector (u,v,w) and I need the normalized direction vectors of the its two arrow ...
2
votes
2answers
978 views

Intelligently move aircraft using curves

I am trying to code a script to move an aircraft entity from point A to point B and at some point in the middle of moving have the aircraft forward vector face Point C (to fire a missile at an enemy ...
0
votes
1answer
252 views

Separating axis Theorem rotation issue

I made a post yesterday to see if anyone could understand my problem. However I did not receive much guidance, probably because my question was not clear. I have worked on it a little more and ...
-2
votes
1answer
131 views

How to remove line between two Points XNA 4.0?

I'm new to XNA and wondering if it is possible to remove a line (that lies between two vectors) when the mouse clicks on that line. I've searched everywhere but I can't seem to find anything. My ...
3
votes
1answer
674 views

What is Vector Projection and what is it's use in games?

Couldn't find a clear enough answer on Google. I know what vectors are. But what does it mean to project a vector onto another, and what is it used for in games?
0
votes
2answers
851 views

Using a vector to store multiple instances of a class

To warm up with SMFL, I am creating a simple Block Breaker game. For the blocks and balls, I would like to store them as "instances" in a vector so that they can be added/removed with ease. However, ...
0
votes
3answers
270 views

How can I calculate force and acceleration?

I have problem of calculating the movement of the object. At the moment, I have a vectors calculated from the center of the screen minus the position of the object. direction vector = centerScreen ...
0
votes
1answer
197 views

Relative Position/Rotation calculation

I have 2 objects each with a 3x3 Matrix (Orientation) and a Vector3 (Translation). Both are relative to world coordinates. How do I calculate the position and orientation of object B in relation to ...
2
votes
2answers
48 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 ...
0
votes
1answer
56 views

Getting the position of a directional light w.r.t. a moving object.

I have a forward vector of my object, which is a bike, and its position, and I have a directional light direction. I would like to know where the light is with regards to the bike ...
1
vote
2answers
323 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
2answers
363 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 ...
0
votes
1answer
202 views

Tangent plane vectors smoothing with vertex normals [closed]

I'm trying to find a way to smooth out normals obtained from cross product of tangent and bitangent vectors calculated per face basis. I've already asked a similar question on SO, however with no ...
-2
votes
1answer
383 views

How to know the relative facing angles between two players? [closed]

I want a grappling system similar to Tekken, in which different grapples animations are performed depending on which side of the opponent the player performing the grapple is facing. For example, ...
1
vote
2answers
522 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 ...
2
votes
2answers
3k 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 ...
2
votes
1answer
87 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
2answers
2k views

Convert atan2 value to standard 360-degree-system value [duplicate]

Lets say I'm using atan2 to get the angle between two vectors. atan2 gives a value in radians. I convert it to degrees using a built in function in Java. This gives me a value between 0 and 180 ...
-1
votes
2answers
1k views

How does atan2 work when getting angle of a vector?

I know that atan2 gives me the absolute angle of any vector. But it doesn't give a value from 0 to 360 degrees. Instead, it gives a value (if I'm not mistaken), between 0 and 180, or between 0 and ...
1
vote
1answer
4k 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: ...
1
vote
1answer
165 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 ...
1
vote
3answers
3k views

How to move an object along a vector

Let's say I got an object A and object B in a 2D game. I create a vector leading from A to B. It's name is AB. How can I make A move along the vector AB and reach B? One way I was thinking of doing ...
5
votes
2answers
5k views

How do I use the dot product to get an angle between two vectors?

I am learning to use normalized vectors in my games. I've learned that in order to know the angle between two vectors, I can use the dot product. This gives me a value between -1 and 1, where 1 ...
-1
votes
3answers
3k views

Move player to mouse click

Im hopelessly not good at algebra and such. But im trying to learn. I want to learn and understand how to use it in game programming rather than modifying snippets or using classes that do it for me. ...
3
votes
4answers
7k views

How can I implement a directional melee attack?

I am attempting to make a top down game similar to the SNES Zelda games, in Unity 4.3, in 2D. When my character swings their sword, every enemy within a radius takes damage. I want to make sure that ...
0
votes
1answer
48 views

What does it mean to cross a scalar with a vector in a 2D plane?

At the moment, I'm following this page to create a physics engine. As per that page, I need to cross angular velocity by a distance vector to get relative torque and such, but I'm not sure how (in a ...
2
votes
1answer
262 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 ...