# Tagged Questions

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

31 views

### Movement for Box2D Bodies

I'm having trouble wrapping my head around something that should be relatively simple. I'm making a breakout clone using LibGDX and Box2D. I'm also using the Ashley ECS. For movement with bodies, I ...
579 views

### calculating torque from angular momentum considering inertia moment

so I am trying to determine exactly how much torque to apply to a 3d model to make it rotate at a particular rate. I apply force from the location of each engine on the craft so if one breaks the ...
253 views

### How to apply friction vector to acceleration in top-down 2D game?

I'm making a top-down view 2D RPG game, meaning the player can move in any direction on a 2D plane, and I'm trying to implement a somewhat realistic non-orthogonal acceleration/friction physics model ...
57 views

### find Vector2 libgdx

I need to get coorinates of red point. Coordinates are just for example, it would be better to see the common formula. Found code like this, but it gains wrong result.() Vector2 o = new Vector2(6f,2f)...
79 views

### How to convert velocity (Vector) to m/s (Scalar)

I have a variable called velocity which I get from a dynamic body in Box2D. It is the velocity of a pirate ship and when I add torque to the ship I want that to be proportional to the speed (m/s - ...
5k views

### How do I calculate collision response between a sphere and a plane?

I'm trying to create a simple 3D game and need to constrain the player within the limits of the game world. When the player hits the sides of the world I want the player's ship to bounce off slightly. ...
78 views

### Should I store local forward/right/up vector or calculate when necessary?

I'm working on an object picking and translation/rotation/scale gizmos system in my engine where you select objects and perform transformations on them in a 3d editor-like fashion (e.g. Blender) In ...
58 views

### how to set in vector float x y coordinates [closed]

i am use eclipse java android i am try to projectile trajectory in my game like angry birds example here http://blog.gemserk.com/2012/07/03/drawing-a-projectile-trajectory-like-angry-birds-using-...
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 ...
98 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 ...
70 views

### How to get the angle an object is travelling at

I'm trying to figure out how to get the angle an object is moving at, but have ran into a few problems. My player object is moved by rotating the entity left and right by using the left and right ...
44 views

### Vector out of range (Batch rendering & opengl)

So ive (tried to) implement a batch rendering system, and at the for loop the error pops up and I'm not shure what ive done wrong. Any suggestions to improve the system would be much appreciated. (It'...
102 views

### How to calculate a vector for multi-axis rotations from sphere coordinates?

I'm working on a SceneKit project in iOS, trying to rotate a sphere (representing a planet) so that a point at a given longitude/latitude coordinate is facing "forward" (i.e. that point moves to the {...
208 views

### Movement with Vector Math

After reading This SO post on Vectors, I'm still pretty confused on how to use vectors to move my entities at any angle. The SO post assumes only 90 degree angles: if up pressed: direction = ...
86 views

### How to make an enemy projectile head to the player's position with constant speed

How can I dynamically set the movement speed of the X and Y of the projectile so that it moves at a constant speed when the projectile heads at the player's position? I know this has something to do ...
137 views

### Intersection of a Line and a Rectangle

I have to calculate the intersection of a line segment (represented by 2 points) with a rectangle. For example: Axis aligned rectangle corners: (0, 0) (100, 100) Point 1: (50, 50) Point 2: (50, ...
140 views

### Path following with Asteroids-like movement. Time to complete path

I'm currently learning about how to do this, but it's best to post the problem beforehand. (posting on Physics and GameDev, as you guys know your math) It's quite difficult to explain. This specific ...
49 views

### Space of Tangent and Bitangent Vectors

I have a really simple question I cannot be sure about the answer. What is the space of tangent (T), and bitangent (B) vectors when we calculate them using vertex positions, and texture coordinates?
62 views

### Moving vector shooting at other moving vector

The following code creates an accurate shot to be made at a moving target from a stationary position. (ie a tower or non-moving vector). It works GREAT, but I need it to consider the movement of the ...
9k views

### Do I need the 'w' component in my Vector class?

Assume you're writing matrix code that handles rotation, translation etc for 3d space. Now the transformation matrices have to be 4x4 to fit the translation component in. However, you don't actually ...
91 views

### Calculating the vector to catch a falling object

I have two objects in a three dimensional world. One is a ballistic projectile: that is, it is free-falling with some known gravitational acceleration. The other is a catcher that travels with ...
2k views

### How do I restrict the movement of a point to within a radius of another?

I have a situation where a sprite's center point needs to be constrained within a certain boundary in 2D space. The boundary is circular, so the sprite is constrained within a radius. This radius is ...
33 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 passes....
68 views

### How do I create a rocket projectile that is “dropped”, then accelerates toward the enemy?

I'm making an Asteroids-like game. I've successfully implemented linear bullets. Now I want to add some rocket-styled bullets, with a certain flight path: The rockets should be "dropped" back first, ...
53 views

### How to find if an object is facing another object given position and direction as separate vectors

I found a very helpful post about exactly what I need here. It uses dot products to which is what I'm specifically looking for. It talks about players facing monsters basically. They give a helpful ...
53 views

### In unity, how do I rotate a vector in relation to the player?

I am making a radar script in a unity FPS game project I am making for class. I already have a working example of a radar script that works in relation to the player's position. However the rotation ...
267 views

### Unity3d - Transform rotation(angle) help

Im trying to rotate an object 90 degrees to the left but instead of rotating straight left it rotates 270 degrees to the right. Here's the part of the code which controls the rotation: ...
78 views

### Clamp view direction vector to nearest axis

In JMonkeyEngine, given any view direction Vector3f instance, I'd like to get a new vector facing the nearest x or z axis (positive or negative), with y set to 0. For example [-0.99915564, -0....
45 views

### Camera will not move between given points, stuck at first given point

[EDIT: Working code added] [Original question] I'm putting together a "raid cam" or "overview cam" for a given map in my shooter for an observing player to use to fly down a given preset path (to ...
53 views

### Direct3D - Get screen coordinates for printing multiple text elements

I have a function that I use to print text PrintText(char* text) that stores the text to a vector, which is then displayed if the vector is not empty. I'm trying to figure out how can I correctly ...
283 views

### How to check distance between two different vectors?

So I have a very basic racing game, where I would like the car to stop once it hits the finish line. Respectively when the distance between the car and the finish line hits or goes under 0 the car ...
224 views

### 2D Rendering Based On Y Coordinates

I'm trying to build an RPG worldbuilder. I have seperate classes for images. Like this. Object1::Object1(int x, int y, CSDL_Setup *sdl_set, int *p_CamX, int *p_CamY) { X_pos = x; Y_pos = y; ...
70 views

### scrolling ruining bullet physics

the code below is the bullet class for my shooter game in pygame. as you can see if you run the full game (https://github.com/hailfire006/economy_game/blob/master/shooter_game.py) the code works ...
166 views

### Unity 3D - Rotate towards object with random offsets

Title is a little confusing, but let me explain: I want to make the enemies look at the player, and shoot at him, with random precision, meaning that one time the enemy will shoot a little bit to the ...
870 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 ...
222 views

### Unity 3D - Confine a gun rotation within certain degrees

I am having troubles making my gun rotate up and down, and have limits, for example, I want the down limit to be 0 degrees, and the up limit to be 90 degrees. Currently I can't figure out how to ...
166 views

### Unity - Check if object is facing Vector3 coordinates

I am having a hard time figuring this out, I want to have objects that move around randomly, and when they get new coordinates to move towards, face them, and then move. Here's explained: Target ...
168 views

### Raycast Flashing problem

Can anyone tell me what is wrong with me code? If you can see, whenever the player is in range of the raycast, the enemy turns red. But for some reason, even when the player has meet the requirement ...
40 views

### Finding vectors to create an inner border for a mesh

I'm looking to create an inner border for generated polygons, which function as provinces in my game. As an example: I have the outer black vectors, that I use to generate the mesh for the province,...
102 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: ...
66 views

### libgdx Vector.cpy question

Why do people use this: public void set(Vector2 v) { this.vector2 = v.cpy(); } insted of just using: public void set(Vector2 v) { this.vector2 = v; } What I don't know that I should know?...
2k views

### Unity3D Get object size in order to be used in Vector3 coordinates

I have a plane in Unity in 3D project, and I want to get its boundaries so I can use them in random function for getting Vector3 coordinates. Currently I am trying like this GameObject ground; void ...
73 views

### How to get a pleasant path accelerating to a point

I am having trouble moving an object to a target position with a maximum acceleration limit. If i just accelerate towards the target the object will fly in a doughnut a few times before hitting the ...
58 views

Hello i have two points (Vector3) A and B. And have a radius r How can i find a coords of point P in a circle by angle?
35 views

### Making a node map with PNG alpha channels

I currently creating a 2d game that requires the usage of boats that travel from one country to another. The countries are individual objects with there own png. Nehow I've got the original map of the ...
4k views

### Adding 2D vector movement with rotation applied

I am trying to apply a slight sine wave movement to objects that float around the screen to make them a little more interesting. I would like to apply this to the objects so that they oscillate from ...
2k views

### What is a direction vector and why should it be normalized?

I've been trying to get the hang of vectors and I read Wolfire's blog about linear algebra and I seem to understand most stuff except when it comes to storing a direction as a vector and using it by ...
131 views

### In XNA, how do I make a sprite move towards another?

I am making a shoot-em-up with a player-controlled sprite with a gun: I have most of the game working, but I have gotten to the point where I need to load in the enemy characters and make them move ...