Numeric representation of the location of an entity in the game space. There are multiple forms of coordinate systems to cater to a variety of methods to map position.

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0answers
98 views

Rotate Points with Object in world space

I posted this in the original stack overflow then realized that a game-dev specific one exists. I am working on personal project that requires me to have 4 points surrounding an object (1 at each of ...
-2
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1answer
234 views

Game Editor - When screen is clicked, how do you identify what coordinate you clicked?

This is a follow-up to my earlier question: Game Editor - When screen is clicked, how do you identify which object that is clicked? Something I've noticed is that picking only calculates a ray and ...
2
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2answers
343 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, ...
0
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1answer
222 views

Ways to “invert Z-axis” in shader-based core-profile OpenGL?

In my hobbyist shader-based (non-FFP) GL (3.2+ core) "engine", everything in world-space and model-space is by design "left-handed" (and to stay that way), so X-axis goes from -1 ("left") to 1 ...
5
votes
3answers
2k views

Mapping 3D object coordinates to 2D screen coordinates with perspective projection

Sort of following on from where this person was in their topic: Matrix for 2D perspective What I have at the moment is a transformation matrix that's defined as follows: http://pastebin.com/GM6BhP0R ...
1
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3answers
2k views

What is the Box2D coordinates system?

I know that for Box2d I need to translate pixels to meters which is easy peasy. However my problem is what is the orientation of Box2D coordinates system? Is this the same as screen one (right += x, ...
1
vote
1answer
386 views

In 2d game logic, should I use pixels or world coordinates?

Currently in my game I handle the logic (collisions, movement) using pixels but I find it very limiting espiecially when thinking about variable speed. For example Box2D requires you to use ...
1
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0answers
301 views

Converting motionevent.getx and motionevent.gety to pixel or Object coordinates in the view

I am trying to draw buttons using OpenGL I have added a Gesture Listener for the GLSurface View now i have motionevent when ever the user touches. My question is how can i convert motionevent.getx and ...
3
votes
1answer
144 views

Calibration of a 6 DOF tracking device

Setting: In our facility we have a 3D laboratory with 3 large displays (two edge-to-edge on orthogonal walls, one on the ground, also edge-to-edge). Its primary use-case is exploring 3D virtual ...
1
vote
1answer
182 views

SimpleOpenNI: Check if user hand is in specific area on image

Concerning our Microsoft Kinect project, we need some help. We control a robot with our movements tracked by the Kinect sensor. We display the depth image of the Kinect sensor on our screen, so we ...
1
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1answer
127 views

Blender 2.6: Move Mesh to X Coordinate of Another Mesh

An example: There are two planes A and B with the following median points: ( X | Y | Z ) M_A ( 3 | 2 | 2 ) M_B ( 6 | 1 | 1 ) Now I want to move the plane A on the X-axis to the X coordinate ...
11
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4answers
2k views

Why is Y up in many Games?

I learned at school that the z-axis is up. It is the same in modeling software like Blender. However in many games the y-axis is up. What is reason?
3
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1answer
233 views

Coordinates on the top left corner or center of the tile

I'm setting up a tile system where every tile has x and y coordinates. Right now I assume that the top left corner of the tile is positioned on it's coordinate on the screen, x = tileX * tileWidth and ...
8
votes
4answers
3k views

Staggered Isometric Map: Calculate map coordinates for point on screen

I know there are already a lot of resources about this, but I haven't found one that matches my coordinate system and I'm having massive trouble adjusting any of those solutions to my needs. What I ...
0
votes
1answer
226 views

Curiosity on any Smartphones that Run on Android 2.3.3 with Different Screen Reoslution

I have a question regarding about any smartphones that run only in Android 2.3.3. Is the size of screen or the screen resolution is always HVGA or does it have capable of running this OS (Android ...
2
votes
1answer
195 views

Coordinate spaces and transformation matrices

I'm trying to get an object from object space, into projected space using these intermediate matrices: The first matrix (I) is the one that transforms from object space into inertial space, but since ...
1
vote
1answer
90 views

XNA 3D coordinates seem off

I'm going through a book, and the example it gave me seems like is should work, but when I try and implement it, it falls short. My Camera class takes three vectors in to generate View and Projection ...
1
vote
1answer
262 views

Precise Touch Screen Dragging Issue: Trouble Aligning with the Finger due to Different Screen Resolution

Please, I need your help. I'm trying to make a game that will drag-n-drop a sprite/image while my finger follows precisely with the image without being offset. When I'm trying on a 900x1280 (in X ...
3
votes
1answer
709 views

Spherical to Cartesian Coordinates

Well I'm reading the Frank's Luna DirectX10 book and, while I'm trying to understand the first demo, I found something that's not very clear at least for me. In the updateScene method, when I press A, ...
13
votes
1answer
405 views

Orthographic unit translation mismatch on grid (e.g. 64 pixels translates incorrectly)

I am looking for some insight into a small problem with unit translations on a grid. Update and Solved I solved my own issue. See below for details. Everything in this part of the post turned out to ...
3
votes
1answer
967 views

Convert rotation from Right handed System to left handed

I have Euler angles from a right handed system that I am trying to convert to a left handed system. All the information that I have read online says that to convert it simply multiply the axis and ...
4
votes
2answers
842 views

Get world coordinate under mouse (at a ground plane for Warcraft 3 like movement)

I want to let a unit follow the mouse like in any RTS (Warcraft 3, Starcraft, ...). For that I have a "ground plane" which is defined through 2 vectors, the X and Z axis. Now I need to get the world ...
4
votes
1answer
522 views

Isometric Screen View to World View

I am having trouble working out the math to transform the screen coordinates to the Grid coordinates. The code below is how far I have got but it is totally wrong any help or resources to fix this ...
1
vote
1answer
3k views

Converting world space coordinate to screen space coordinate and getting incorrect range of values

I'm attempting to convert from world space coordinates to screen space coordinates. I have the following code to transform my object position Vector3 screenSpacePoint = ...
0
votes
2answers
244 views

get coordinates of origin of coordinate system in second coordinate system by knowin matrices of one point in bith systems

Situation, two coordinate systems A, B. origins Oa, Ob. I have one point, for which i know modelview matrix (translatoin/orientation) in both systems. And what i need to get is modelview matrix of Ob ...
4
votes
3answers
4k views

OpenGL ES and Screen Coordinates

Is there anyway I can make OpenGL ES 2.0 to accept coordinates (for Vextex for example) in int meaning the pixels instead of the default float system? Also how can I set the point (0,0) to be at the ...
5
votes
2answers
732 views

Draw a 3D object at specific coordinates on the screen

I'm creating an application which allows the user to manipulate 3D models. I would like to draw 3 axis representing the world coordinate system in 3D in order to give the user an idea where he is. ...
4
votes
3answers
482 views

Convert point to its barymetric coordinates

I'm making a 2.5D game engine (in JavaScript) and I'm trying to get it to detect whether a block is under the cursor. This would be a simple task were it restricted to single-level isometric ...
0
votes
2answers
472 views

Screen coordinates to a multilevel isometric world

I have an isometric world that has stuff on multiple levels, i.e. it has an XYZ coordinate system, and tiles can be stacked on each other, accumulating screen Y offset as they go. I currently have an ...
8
votes
4answers
2k views

How do I convert between two different 2D coordinate systems?

I'm trying to convert a coordinate from one coordinate system to another, so that I can draw it on an image. Basically the destination coordinate system is as follows: X range: 0 to 1066 Y range: 0 ...
0
votes
1answer
128 views

How should I position and move objects in my 3D world in relation to terrain

I'm drawing a heightfield as a piece of 3D terrain using the fairly 'dumb' method of drawing triangles, like everyone does when learning this sort of thing. There's no fancy LOD, scenegraphs or other ...
0
votes
1answer
335 views

How to get xy coordinates along a given path

Say i have two points (x,y), (0,0) and (10,10). Now i wan´t to get coordinates along the line by stepping through values of x and y. I thought i solved it with the following functions: fy = startY ...
2
votes
1answer
338 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
3answers
727 views

XNA texture stretching at extreme coordinates

I was toying around with infinitely scrolling 2D textures using the XNA framework and came across a rather strange observation. Using the basic draw code: spriteBatch.Begin(SpriteSortMode.Deferred, ...
2
votes
2answers
266 views

how to transform child elements position into a world position

I'm making a 2d space game in Javascript with canvas. In this game there's a bunch of spaceships, positioned in world space, with turrets, positioned relative to their parent ships. These objects also ...
2
votes
3answers
850 views

Isometric to screen, screen to isometric for irregular projection

I have isometric assets that unfortunately can't change and need to work out the projection for those. Here is how a tile looks like: The tile image width/height ratio is 0.(6) (height/widht = ...
-1
votes
1answer
161 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?
4
votes
1answer
316 views

Translation from one coordinate system to another having Z-offset issues

I'm using ARToolkit to do an augmented reality application, but my problem is really with the 3D coordinates. In this application, I use my webcam to generate the scene. I have two markers (printed ...
6
votes
3answers
3k views

2D isometric: screen to tile coordinates

I'm writing an isometric 2D game and I'm having difficulty figuring precisely on which tile the cursor is. Here's a drawing: where xs and ys are screen coordinates (pixels), xt and yt are tile ...
3
votes
3answers
3k views

Java Slick2d - How to translate mouse coordinates to world coordinates

I am translating in my main class render. How do I get the mouse position where my mouse actually is after I scroll the screen public void render(GameContainer gc, Graphics g) throws SlickException ...
1
vote
1answer
139 views

Map displacement transformation to texture space?

I am trying to displace geometry in object space without giving the appearance of texture warping. My idea is to displace the UV lookup by a relative amount to the geometry displacement. Any ...
0
votes
4answers
3k views

XNA spritebatch drawing to the centre of screen

I have bit of a silly problem. Is is possible to use SpriteBatch.Draw() method to draw to the centre of screen using coords from the beginning of window (So resolution 800x600 would use 400;300) ...
3
votes
3answers
448 views

The ship “shudders” in scrolling Asteroids

In my Asteroids game the user can scroll through space. When scrolling, the ship is drawn in the centre of the window. I use interpolation. I scroll the window uing glOrtho, centering it around the ...
3
votes
1answer
413 views

Does the projection matrix flip winding order in right handed systems?

I am using a right handed coordinate system for my world coordinates (so, positive x goes right, y is up, and z is towards you). However, after projection and the w divide, nomalised device ...
3
votes
2answers
233 views

Real time data retrieval - database vs file system

I'm planning to develop a game in which I want to draw 3d models in real time using some given x,y,z coordinates. The coordinates will be given at an average of 30 coordinates per second. Drawing will ...
2
votes
3answers
3k 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
1answer
368 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
413 views

How to linearly transform vertices for large coordinate systems

Alright, so I'm working on a space game and well, I want it to have a lot of space! So I need a large coordinate system and for my rendering pipeline to not suffer from "vertex jittering" due to ...
2
votes
1answer
446 views

Transformed Pretransformed coordinates?

I am creating a minecraft like terrain engine thing in XNA and C#, and I am trying to create a item/block selector tool. The thing is I would like to have 3D objects on the tool. So I thought for the ...
0
votes
1answer
678 views

Confusion with the texture coordinate system in XNA

I am creating a cow out of primitive shapes, and am using the minecraft cow texture as a placeholder. To create the primitive model I have created a 'model' class and created a sub class 'ModelCow' ...