A mathematical concept that can be used to express position, direction or velocity and which can simplify or outright trivialise spatial problems.
3
votes
2answers
287 views
How do you transform a vector to use another objects orientation?
I want to take a vector that is using world coordinates and position it using the orientation of an object. So, if the direction of the object is the z-axis, and the vector is (0,0,1), then the ...
3
votes
3answers
134 views
Determining a point that reached another point
I have two points, one is moving and one is stationary. I would like to know if the moving point has reached that point or not. I tried to calculate the distance between two vectors and the distance ...
3
votes
4answers
449 views
How to draw a line of a given length towards a given object?
I wanna draw a line between two moving objects
I can't use:
cDrawLine(startPointCG, endPointCG);
because the line must have a length. So I'm trying to measure the angle between those two points ...
3
votes
3answers
291 views
Adding 'swerve' to a direction
I'm not much of a maths expert, so this is probably quite straight forward. I was playing a soccer flash game where you take free kicks. You provide Power, Swerve and Direction. I'm reading up on ...
3
votes
4answers
2k views
Line triangle intersection - last bits
I'm doing line-triangle intersection. I have found the intersection point (vector) on the plane. All I need to do now is work out whether the point is inside the triangle it collided with (not the ...
3
votes
3answers
279 views
When to return a reference and when to return a copy?
I was looking at the d3dx math .h and noticed that a difference between the "+" and "+=" operators:
D3DXVECTOR3& operator += ( CONST D3DXVECTOR3& );
D3DXVECTOR3 operator + ( CONST ...
3
votes
1answer
339 views
Raycasting tutorial / vector math question
I'm checking out this nice raycasting tutorial at http://lodev.org/cgtutor/raycasting.html and have a probably very simple math question.
In the DDA algorithm I'm having trouble understanding the ...
3
votes
2answers
287 views
3D rotation matrices deform object while rotating
I'm writing a small 3D renderer (using an orthographic projection right now).
I've run into some trouble with my 3D rotation matrices. They seem to squeeze my 3D object (a box primitive) at certain ...
3
votes
2answers
84 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 ...
3
votes
2answers
2k views
Is there a good cross-platform C++ vector graphics library out there?
I'm making a game and want to use vector graphics. I started re-coding it using Cairo and the performance is horrific. So, I'm looking for a different library. It needs to be for C++ and ...
3
votes
1answer
97 views
How to make an object stay relative to another object
In the following example there is a guy and a boat. They have both a position, orientation and velocity.
The guy is standing on the shore and would like to board. He changes his position so he is ...
3
votes
2answers
2k views
Vector images (SVG or other formats) support in libgdx or other Android framework?
I'm looking for a website to create games for Android. I'm interested in something that supports vector images. Do you know if libgdx supports them or is there a convenient way to use them in libgdx?
...
3
votes
2answers
135 views
what does AngleVectors method in quake 3 source code does
I just downloaded quake 3 for learning purposes.
I know some of some linear algebra(basic vector math ie: dot,cross product).
However I can't decipher what below method does, I know what is yaw,pitch ...
3
votes
1answer
521 views
Calculating normal vector on a 2d pixelated map
I want to know an efficient way to get the normal of the surface of a 2d map. suppose an object hit the map, i want the object to bounce accordingly. The problem is, the "bounding box" of said object ...
3
votes
1answer
814 views
Points on lines where the two lines are the closest together
I'm trying to find the points on two lines where the two lines are the closest. I've implemented the following method (Points and Vectors are as you'd expect, and a Line consists of a Point on the ...
3
votes
3answers
193 views
Getting correct angles between Vector3s
I'm working on a project where you can draw lines between points. You select one point and drag the mouse onto another point and a line is drawn between them.
The line itself is a 3d object which is ...
3
votes
1answer
205 views
How do I implement a selectable world map?
I want to have a selectable map of the world, preferably zoomable, in a cocos2d project. When I tap on a country, I want that country to be selected so that I can perform some other operations with ...
3
votes
1answer
190 views
Limit rotation heading by cone/angle
What is a fast way of limiting the heading vector to a certain angle so that it turns in greater distance relative to the limit.
A smaller cone/angle should make the object take a far bigger curve to ...
3
votes
1answer
291 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 ...
3
votes
1answer
251 views
Vector fields and game engine
It exist a game developed with a vectorfield game engine?
What I mean is that instead of calculating intersections, one could calculate the vector field generated for example by gravity, and for ...
2
votes
3answers
1k views
Get points on a line between two points
I'm making a simple space game in JavaScript, but now I've hit a wall regarding vectors.
The game view is top-down on a 2d grid. When the user clicks on the grid, the space ship will fly to that ...
2
votes
2answers
236 views
Why does handedness matter at all?
I'm really trying to understand this from a mathematical viewpoint. After all, numbers are numbers, the chirality or handedness depends on how one interprets it.
Say I've three basis vectors x (1, 0, ...
2
votes
3answers
848 views
Check if the vector is behind another or maybe opposite directions?
I'm doing a network game and on the client side, i interpolate the client position with the server sent extrapolated position. The client has its own physics simulation wich is corrected by the server ...
2
votes
6answers
973 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 ...
2
votes
2answers
507 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.
...
2
votes
1answer
163 views
Min/Max of two vectors?
This seems like a simple question, but i'm having trouble searching the internet for it.
In XNA, during a collision detecting method, I would determin the minimum of some vectors.
// Get the minimum ...
2
votes
3answers
516 views
Converting Degrees to X and Y Coordinate change
I am using a float positioning system in my game. IE float x,y,z
now I want to get the location of the mouse, then to fire an arrow to it.
X0 = the players X location
X1 = the mouse X location
Y0 = ...
2
votes
2answers
550 views
Why does my sprite jitter when it arrives at its destination?
I have just started looking into XNA for WP7 - and I am definitely the sort of person who likes to find answers to my questions without begging for help!
I searched here to find an answer but I found ...
2
votes
3answers
308 views
Oriented Bounding Box - How to?
I've been trying to write my own collision code, less because I want to, more because I want to understand its working.
To do this, i've been working off of the popular collision book i'm sure you've ...
2
votes
1answer
792 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 ...
2
votes
1answer
315 views
Confused about order of operation when using a Matrix in XNA, C#
Here are two different pieces of code
This is what I started with
Vector2 hold = Vector2.Transform(pos1, mat1);
Matrix inv = Matrix.Invert(mat2);
Vector2 pos2 = Vector2.Transform(hold, inv);
And ...
2
votes
4answers
1k views
How to detect if object is moving in clockwise- or counterclockwise direction?
I've read this one, but I need more info: rotating an object from sourceAngle to destAngle, both 0-359, clockwise or counter clockwise?
I have a ball. The user is able to drag the ball in any ...
2
votes
2answers
376 views
Swapping axis labels between 2D and 3D coordinates
My game world is 3D.
The map is only 2D, however.
It is natural to think of the map as having an X and Y axis.
And it is natural to think of the world has having an X, Y and Z axis, where Y is ...
2
votes
1answer
3k 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 ...
2
votes
2answers
377 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 ...
2
votes
1answer
264 views
What is wrong with my technique for transmitting server and client game state?
I'm doing a network implementation of a fast-paced game. I have a puck on bot the server and client side of the simulation. I want to update the client puck position only if they are on the same ...
2
votes
2answers
438 views
How to calculate vector that is perpendicular to the direction of moving in Flash?
In flash i have a class that extends movieclip and i am moving it forward, up and down, and rotating it. How can i calculate the vector that is perpendicular to this movieclip?
2
votes
2answers
132 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
234 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
4answers
1k 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 ...
2
votes
1answer
233 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
127 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
428 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
187 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
199 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
160 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
279 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
168 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
193 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
499 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 * ...
