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
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1answer
451 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 ...
0
votes
1answer
135 views

Is it safe to cast my 2D points to 3D points for a library which only takes Vector3s?

I need to cast a ray in 2D space for bullet collision detection, but the Ray.Intersects method requires a BoundingBox which uses vector3's not vector2's. My question is should I just ignore the Z ...
0
votes
2answers
960 views

Calculating angle between two vectors to steer towards a target

I have been trying to implement a path following steering behaviour for AI in a 2D racing game. I have two vectors: futurePosition represents the predicted future position given the car's current ...
4
votes
2answers
409 views

What are the properties of “position, velocity, acceleration, rotation” collectively named?

They say naming things is one of the hardest problems in computer programming. They were right. Given the pseudocode below, what is a more appropriate name for this collection of properties? ...
2
votes
2answers
747 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 ...
1
vote
1answer
456 views

Ball bouncing at a certain angle and efficiency computations [closed]

I would like to make a pong game with a small twist (for now). Every time the ball bounces off one of the paddles i want it to be under a certain angle (between a min and a max). I simply can't ...
2
votes
1answer
208 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 ...
1
vote
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 ...
3
votes
6answers
2k views

How to implement object velocity as a vector

I'm working on a Breakout game, and want to change the ball's movement code from how I currently do it, to something based on vectors (as I feel learning and implementing movement based on vectors ...
3
votes
1answer
646 views

How to bounce a 2d point particle off of a circular edge

In a prototype I'm building, a particle can spawn anywhere within a larger, confining circle. Important to note is that the particle will not spawn in the origin of the larger circle, but anywhere ...
3
votes
5answers
2k views

Normalization of Vectors: Return a copy of the result or alter the object itself?

When calculating the normal of a vector, which is considered canon: Returning a copy: Vector2D Vector2D::Normalize() const { double a1 = GetX(); double a2 = GetY(); double a3 = GetZ(); ...
0
votes
3answers
412 views

Parent-Child position mathematics

What is the math theory when a child object moves with the parent transform? I am doing an angle indicator which shows a field of view, which works fantastic when the angle is static. But I cannot ...
0
votes
2answers
579 views

3D Vector “End Point” Calculation for procedural Vector Graphics

Alright, So I need some help with some Vector Math. I've developing some game Engines that have Procedural Fractal Generation for Some Graphics, such as using Lindenmayer Systems for generating Trees ...
3
votes
1answer
446 views

Finding closest object to a location within a specific perpendicular distance to direction vector

I have a location and a direction vector indicating facing, I want to find the closest object to that location that is within some tolerance distance (perpendicular distance) to the ray formed by the ...
2
votes
2answers
202 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) { ...
0
votes
1answer
403 views

C++ and SDL Trouble Creating a STL Vector of a Game Object

I am trying to create a Space Invaders clone using C++ and SDL. The problem I am having is in trying to create Waves of Enemies. I am trying to model this by making my Waves a vector of 8 Enemy ...
2
votes
1answer
379 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 ...
1
vote
0answers
314 views

Calculate initial velocity of a 3d vector-based projectile

Okay, so I got a Projectile with 2 Vectors, position and velocity. I now want to calculate the initial velocity for it in order to reach a specific point on the map. Or actually, how high has the ...
5
votes
3answers
1k views

Split a 2D scene in layers or have a z coordinate

I am in the process of writing a 2D game engine, and a dilemma emerged. Let me explain the situation... I have a Scene class, to which various objects can be added (Drawable, ParticleEmitter, ...
2
votes
1answer
341 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
2answers
517 views

Calc direction vector based on destination vector and distance from enemy in AS3

I'm working on a zombie game in AS3 where I want a character to be able to move away from a zombie depending upon how close the zombie is. The character also has a destination that it's trying to get ...
1
vote
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 ...
1
vote
1answer
500 views

Transform 3d viewport vector to 2d vector

I am playing around with 3d transformations and came along an issue. I have a 3d vector already within the viewport and need to transform it to a 2d vector. (let's say my screen is 10x10) Does that ...
2
votes
2answers
2k views

Smooth vector based jump

I started working on Wolfire's mathematics tutorials. I got the jumping working well using a step by step system, where you press a button and the cube moves to the next point on the jumping curve. ...
0
votes
1answer
477 views

Vector reflect problem

I'm testing some vector reflection and I want to check what happens when a ball collides with a paddle. So if I have: Vector2 velocity = new Vector2(-5, 2); position_ball += velocity; if ...
1
vote
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). ...
8
votes
2answers
2k views

How do I determine if one polygon completely contains another?

I have 2 polygons. I know the vertex coordinates of both polygons. What's the best way to check if one is completely inside the other? For example, the algorithm should only recognize the black ...
0
votes
2answers
764 views

Rotate point by a direction vector

Given a vector, A, which represents a point, and a unit vector, B, which represents the looking direction, how would I rotate A so that B is the axis that's looked down on? Let's say the looking-axis ...
2
votes
1answer
300 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 ...
0
votes
1answer
939 views

Determining and culling non-visible vertices

Ahoy! After posting my previous question on tile maps, i've been tinkering with an implementation i'm rather pleased with so far but would like to gather some more information about submitting ...
-1
votes
1answer
164 views

Find a Rectangle by coordinates - XNA

I have 2 coordinates (X,Y). I have also a 10x10 array. By these coordinates I have to find the rectangle in which is my pointer at the moment. How could I handle it?
3
votes
4answers
3k views

Most effective way to manage a gamestate system that is easy to use?

I just started working on my game, mostly the game management. I plan and using game-states to make the menu's and other stuff easier. My main idea for implementing the game-states is creating a game ...
0
votes
3answers
343 views

How would I successfully split a vector to increase game performance?

Okay so I have a vector for all of the monsters that are spawned in my game. All of these monsters are in a single vector and are "active" according to what zone they are in relative to the player's ...
2
votes
1answer
464 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 ...
3
votes
1answer
2k views

Make objects follow a strict path (Xna)

I am making a defence game. Naturally, this means that there needs to be objects following a path on the screen. I want to make it a strict path from one point to another to another. I could use an ...
7
votes
2answers
5k views

How do I find the angle between two vectors?

I have 3 points on my screen: a = a point which is (c.x, 0) makes a line pointing straight up b = a user input touch, can be anywhere on the screen c = a moving object a _______.________ | ...
2
votes
1answer
878 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 * ...
4
votes
1answer
694 views

How do I determine the position of one vector relative to another?

I'm making a game for Kinect in Unity which tracks hand movements. I have the player's root position and the position of their fist stored as 3-dimensional vectors (Vector3 in Unity), but they're both ...
0
votes
1answer
3k views

The normal vector to a plane ax+by+cz+d=0?

I am calculating the normal vector to a plane ax+by+cz+d=0 According to the book: The normal vector N is often normalized to unit length because in that case the equation d = N ⋅Q + D gives the ...
0
votes
2answers
162 views

How do I make a vector exactly reach a line?

Let's say a vector starts at Point P and points in the direction of v. How do I make sure that this vector exactly reaches the line? Its end should be exactly on the line, and not cross it.
6
votes
3answers
4k views

Implementing Separating Axis Theorem (SAT) and Minimum Translation Vector (MTV)

I was following codezealot's tutorial on SAT and MTV and trying to implement it myself but I've come a cropper when it comes to getting the correct MTV. Here is my example: (Cue pretty pictures...) ...
1
vote
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 ...
-1
votes
2answers
203 views

How to make sure that a Point A moving in the direction V reaches at Point B?

Let say I have, Point A(X1,Y1) moving in the direction V(W, H). I need to make sure that it reaches B(X2,Y2). I think I need to subtract some value in Point A(X1, X2). But not know what? I also sure ...
-1
votes
1answer
392 views

std::vector::size with glDrawElements crashes?

( win32 / OpenGL 3.3 / GLSL 330 ) I decided after a long time of trying to do a graphical user interface using just opengl graphics to go back to a gui toolkit and so in the process have had to port ...
2
votes
1answer
199 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 ...
3
votes
2answers
96 views

Need the co-ordinates of innerPolygon

Let say I have this diagram, Given that i have all the co-ordinates of outer polygon and the distance between inner and outer polygon is d is also given. How to calculate the inner polygon ...
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
3answers
894 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 ...
5
votes
1answer
247 views

Trouble with speed and vectors

I'm working on adding bullets to my game. Right now I can shoot bullets in the direction that I would like from a ship by getting the ship's angle: int speed = 5; int dx = ...
5
votes
1answer
496 views

How can I calculate a vertex normal for a hard edge?

Here is a picture of a lovely polygon: Circled is a vertex, and numbered are its adjacent faces. I have calculated the normals of those faces as such (not yet normalized, 0-indexed): Vertex 1 ...