Transformation in game development is usually refers to linear algebra operations on points, vectors and matrices.

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Coordinates estimation

Hi im using artoolkit to extract the coordinates of the marker im detecting with the camera. I need to know the values returned when arGetTransMat is the coordinates (x,y,z) which is returned ...
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66 views

Transformed Vertices have wrong Z Axis

For quite some time I've been working on my open 3D game engine, to learn how this stuff works. You can see the full codebase relating to my problem here on GitHub. I'm using an OpenGL 3.3 Core ...
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281 views

Does vector transformation order matter?

Theoretical question - imagine a car object. There are two (or more) 'forces' acting on this car, these forces will affect where the car will steer. But the forces are calculated using car's location ...
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1answer
59 views

Proper normal vector transformations in normal mapping

Hello! This question is about transforming normal vectors from normal maps properly. I have tried methods from over five sources, still can't get it to work, and I'm really desperate. Included are ...
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35 views

In Java swing, while handling a 2D top down game, how should I handle scaling for quality transformations (mainly screen rotation)

For my top down game, I plan to have screen rotation where entities don't rotate, but everything else does. I am using a raster array to store my image so I don't have to render things stacked on each ...
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56 views

OpenGL model transforms wrong on AMD GPU

I've been writing a program that uses OpenGL to display some simple 3D models (rays, cuboids, spheres and simple meshes). I am targeting the programmable pipeline in OpenGL 3.2. So far I have been ...
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1answer
50 views

How to force a translation to go through an exact point?

I have a camera object with a script that will whether translate it with a set speed, or stop it. I also have 7 "checkpoints", where there are 7 different quads, who will stop the camera whenever the ...
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1answer
26 views

Rendering curved text in AndEngine

I'm trying to implement a small game using AndEngine and I have a question about the Text. More specifically, I'm wondering if it is possible to deform the text so that you can have a "curved" text or ...
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57 views

Java Slick2D rotating a Shape using transform(Transform.createRotateTransform())

I have spent most of the day trying to debug this tiny piece of code, and I can't for the life of me figure it out. I'm making a pong game for the Mini Ludum Dare currently going on. I am programming ...
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1answer
44 views

How can I rotate a Transform over a specified time in a single line of code? [duplicate]

How can I rotate a Transform over a specified time in a single line of code? I have had a lot of trouble with this in the past. I wrote a script which rotates a Transform by a specified rotation ...
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2answers
101 views

Making a cube slowly rotate 180 degress one time on a mouseclick

I am new to C# and new to Unity. I made a script that can turn a cube slowly one time after a mouse click but I feel like its probably wrong for using FixedUpdate. Is this OK or is there a better way? ...
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1answer
36 views

Flipped model has wrong triangle order

I have list of models and transform matrix for each of them. Some of models are flipped along X or Y or Z axis. This meshes will be rendered wrong, back face is rendered instead of front. I tried to ...
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51 views

parented/constrained object transform lags when moving character in unity3D

Hi I have a simple raycast-base gun that emits particles along it's path to fake bullets. Whenever I move the camera/character- the particles are misaligned, as well as anything else I try to modify ...
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1answer
34 views

Inline-Building a World (SRT) Matrix

Currently, to construct a world matrix, I have the following code: return FromScale(scale) * rotation.RotMatrix * FromTranslation(translation); However, this is constructing three matrices, and ...
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1answer
87 views

Problem with 2D matrix transform og shapes

I have set myself onto the task of creating a class BaseObject, which represents a graphics object with an associated shape as the member variable shape, which is a pointer an object Polygon. I'll ...
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0answers
17 views

How can I increase the horizontal speed of something every N seconds in Unity and make it STAY increased? [duplicate]

I have these particles that only move horizontally and to make the game harder I would like to increase the speed of these particles every 5 or so seconds. I am not sure how to do this I am still ...
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1answer
66 views

Organizing a Transform class to internally use quaternions

So, I'm interested in building a Transform class similar to the one used in Unity Engine, but in C++. My intent is for it to be user-friendly to change the position, rotation, and scale of a variable ...
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1answer
77 views

Why does the projection matrix transform object points into a unit cube in computer graphics?

This semester I both took a computer vision and a computer graphics seminar. But only now before the exams I realize that there seems to be a fundamental difference between projection in both topics. ...
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2answers
111 views

Translating an object in the rotation direction

I am creating a graphical scene with OpenGL and SDL, and I'm running into a problem in regards to translating an object in its rotation direction. Each of the graphical objects in the scene has a ...
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2answers
79 views

Cube goes through objects

I have Unity Pro 4.6.1 and I am trying to make a cube move with the arrow keys. Here are the barriers before I move the cube: And here's when I move the cube (the problem): I don't want the ...
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0answers
55 views

How do I create a view matrix directly from a quaternion and a position vector?

Given a quaternionic camera such that: typedef struct { vector3 upReference; vector3 rightReference; vector3 forwardReference; vector3 position; quaternion orientation; ...
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1answer
51 views

How to compute the forward, up and right vectors from a single quaternion?

Given a quaternion float x, y, z, w; How does one the forward, up and right vector from a single quaternion? vec3 up; vec3 forward; vec3 right; quat_get_all_axis(&quat, &up, &forward, ...
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Transformation order for augmented reality game using OpenCV and OpenGL

I'm trying to create a simple AR application where I'm augmenting the camera image of a Kinect with virtual objects that are tracked using an optical tracking system. The following picture ...
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231 views

OpenGL - Arcball camera rotation

I'm implementing arcball camera rotation, whereby a camera is looking at a coordinate and rotates around it in the x-axis or the y-axis such that the camera is circulating around it; the y-axis will ...
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1answer
196 views

Is it more efficient to transform vertices on the CPU or the GPU?

Working on optimizing the rendering core of my game engine and I have a couple of questions. Is it more efficient to transform vertices to world space on the CPU before you send then stream to the ...
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1answer
345 views

Libgdx, how do i get the translation and rotation of a node from a model instance?

I have a model instance of a character, and a model instance of a sword weapon. THe character has a node on his right hand so he can "carry" the sword. Right now I use this code so the sword's ...
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1answer
105 views

what is the very last element of a 4x4 transformation matrix for? [duplicate]

while its a similar value to its neighbour - Z translation (and I wont say if thats above or to the left for fear of sparking a religious war!) and it only seems to change when the Z translation value ...
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2answers
50 views

Translating Objects in Worldspace

Given the worldspace coordinates of a collection of arbitrarily positioned objects, how do I translate them while preserving their relative placement? For instance, I have a table and a few bowls that ...
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0answers
28 views

Connecting a model's joint to the joint of another model

I am trying to figure out the math behind orientating and translating a model so that a specified point on the model will connect with a specified point on another model. For example, given the ...
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3answers
109 views

Hero made of parts 2d rotation

I have a problem with rotation of my hero in 2D space. The hero is made of body parts such as: head, arms etc. Every part is a separate sprite. When I want to rotate the hero, I have to rotate all ...
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1answer
89 views

Transformations and basis vectors

I've been reading this very nice tutorial on OpenGL, and I encountered a statement which I can't wrap my head around. In Chapter 6, it states: Transformation from one space to another ultimately ...
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1answer
236 views

How to compute matrix transform local/world on OpenGL

I'm developing an OpenGL program where each object / entity contains m_WorldPosition, m_WorldOrientation, m_WorldScale and m_WorldTransform (Vector3, Quaternion, Vector3 and Matrix4f). The problem is ...
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1answer
155 views

How to constrain axis-angle rotation?

I have a problem where I'm performing an axis-angle rotation and am trying to constrain my rotations. Specifically I have a skeleton (model/mesh with rig, transforms are hierarchy parented to pelvis ...
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51 views

Translate click on screen to point on plane in 3D space

I am creating a 2.5D game with the camera at a slight angle, like so: The grid is the "playing field," and the positive x, y, and z directions are labelled. I already know all the details about ...
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58 views

Instantiating and deleting objects with triggers problem

I'm trying to create some kind of dust field, by now I'm just creating small balls for testing, between the bounds of a BoxCollider which I use as my dust field. When the box collider goes outside the ...
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0answers
229 views

In libgdx, how do I get the intersection of a ray with a model instance?

I am using LibGDX trying to use raypicking to pick a point on a Mesh. I have two methods for this that don't seem to work quite right: /** * @param ray * @param intersection The vector to store ...
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0answers
58 views

Relative Transformations for Bones

I'm using Blender to export my armatures in relative coordinates, and I'm trying to get to absolute coordinates in my engine. For the above example, the childBone's tip is an offset of [-1,0,0], ...
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1answer
126 views

OpenGL not rendering full scene, it is a mystery [closed]

I am trying to draw a scene in the sort of style of mock vector graphics. I've helped on a 2D game before with GLSL, but I tried to keep a simple approach to this project since I'm working by myself, ...
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0answers
74 views

How to translate vertex buffer coordinates in 2D

I am trying to (using a 2D Directx9 engine library) rotate/translate a set of points in a vertex buffer. I understand how this would be done in a 3D system - i.e using the vertex shader stage of ...
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1answer
29 views

Can't figure out projection transform

I'm trying to fugure out all the spaces transformations, and currently have some inconsistency I can't understand. I'm working on a 2D game (so we assuming Z is always 0 for now), on a device with ...
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1answer
70 views

Distort a quad with a World Matrix

Is it possible to distort a quad multiplying its vertices by a specific world matrix? See the picture to understand what kind of distortion I need: Please note, that the quad is in 3d space and I ...
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1answer
419 views

How do I rotate and flip 2D sprites stored in a 1D array of pixels?

I am using a 1D array of pixels for rendering in 2D in java. I am interested in rotation (in radians) and mirroring across the x and y axes. The desired result looks something like this: Public void ...
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1answer
48 views

Camera world matrix to view matrix

I've been working on a game engine and I model every object in my scene graph as an "entity" this includes my camera. My camera therefore has a position and rotation in world space and at the moment ...
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2answers
121 views

Why does my ship look like it's going backwards instead of fowards? [closed]

I'm making an Asteroids-clone based on this tutorial. I'm stuck on the 5th part of the tutorial. For some reason my ship is going backwards instead of forward or it looks like its going forward, but ...
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1answer
1k views

Simultaneously translating and rotating sprite in Unity

I have a 2D object (a PNG file I dragged onto the screen) which is a circle I would like to move left and right when the correct side of the screen is touched and have it rotate in the respective ...
0
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1answer
179 views

How do I get a SphereCollider's global origin in Unity?

I've been following this tutorial: Understanding Steering Behaviors: Collision Avoidance but I'm having trouble implementing one of the functions correctly in Unity, here's the code: private ...
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1answer
61 views

If object is bellow another object… do something [closed]

I have 2 objects in scene. When pillar is bellow target, pillar object needs to animate. I get this error: "NullReferenceException: Object reference not set to an instance of an object". var pillar : ...
4
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1answer
109 views

How do I deal with floating-point error given a far-away camera?

Whenever a camera is "far" away (its location is some "large" vector), trouble arises when rendering objects close to it: It is the classic precision loss from subtracting 2 floating point numbers. I ...
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1answer
42 views

transformation before the perspective divide but after projecting perspectively

My problem is that I would like to confine a scene render to a (possibly rotated) rectangle without using glViewport(). I don't want to use it to save, if possible, some cycles that would otherwise be ...
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1answer
96 views

When and how to apply affine translations to vertices of a mesh with LWJGL

So, I have a rigid body class, containing a list of vertices and a 4x4 transformation matrix. At the moment, I'm applying the transformation matrix to each vertex individually, and am unable to revert ...