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

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OpenGL camera Rotation Matrix & view Transformations [on hold]

Recently i implemented a simple Opengl program that composes of a scene of objects, i've applied most of the transformation & projection matrices, in such away that i am able to rotate transform ...
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1answer
55 views

How to rotate vertices of 2D shape using a transform matrix?

I am making a top-down 2D game and am currently working on implementing improved collision using SAT. I programmed a Shape class with a Vector2 center that is its position in world space. On top of ...
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1answer
207 views

Transforms in Box2D

I'm attempting to implement a camera in my game. I had it working for regular objects, but I began using Box2D and obviously things changed a bit. I have a Body object that I want to draw at the ...
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1answer
49 views

How can I make an attached gameobject behave correctly on character flip?

I have a character that on start-up is equipped with another gameobject/prefab as a weapon, attaching it to a hand. void Start() { handFront = transform.Find ...
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2answers
117 views

How can I determine the pixels covered by a transformed triangle (without drawing it)?

I have three points that form a triangle in a 3D scene. I want to apply an arbitrary rotation/translation transformation to this polygon and later check in which pixels of an image they would be ...
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1answer
500 views

importing animations in Blender, weird rotations/locations

This is for the Blender 2.6 API. There are two problems: 1. When I import a single animation frame from my animation file to Blender, all bones look fine. But when I import multiple (all of the ...
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1answer
98 views

How can I translate a game object towards a position?

I am instantiating my game objects (spheres) through scripts. I want my spheres to move from one location to another. but I don't know how to do this. Update is called once per frame. Is that what I ...
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1answer
205 views

Are there multiple valid definitions for what translate, rotate and scale do?

Are there multiple valid definitions for what translate, rotate and scale do to the 4x4 matrix? I bring up this question, because I have a simple webgl program that draws a square and does a few ...
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57 views

Rasterizing euclidean planes

I'd like to visualize a BSP tree. To do this, I need to project an arbitrary euclidean plane onto a projection plane. I was thinking about calculating the intersections of the plane with the viewing ...
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2answers
300 views

How do I make a background fill the whole screen in Libgdx?

I'm using this code to set a 800x420 image to be full screen: public void show() { float w = Gdx.graphics.getWidth(); float h = Gdx.graphics.getHeight(); camera = new ...
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1answer
84 views

Build unity like Transform class [closed]

I am building a Unity-like Transform class. This is my header file: #include "Common.h" struct Transform { public: Transform(); void Translate(float x, float y, float z); ...
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1answer
42 views

How can I GL_SELECT from a gluPerspective-transformed scene?

I'm using JOGL to access OpenGL-methods on an old OpenGL version, because of school. I have written a method which is called before any objects are drawn. This method shows which object is picked. ...
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2answers
120 views

DirectX11: Drawing multiple objects

How can I draw many different objects on screen at once, with multiple vertex buffers, using DrawIndexed()? (Drawing the same object is simple, and I'm not looking to instance) ...but I am looking ...
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0answers
55 views

How to convert bones skeleton into joints skeleton?

I'm exploring skeletal animation and taking Half-Life SMD format as example. It has skeleton rigged as hierarchy of joints. Each joint has a parent and offset + rotation to it. Now I'm importing ...
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3answers
107 views

How can I properly rotate a 2D vector in the “flipped” XNA client space?

In my 2d XNA game, because SpriteBatch treats world space as client space and has positive Y axis down and negative up, I've built my game's world space with that coordinate system too. However, I've ...
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1answer
178 views

How to stop transform.position from being modified when adding child object in Unity

I suspect there is a well-known and easy to explain reason for the behavior I'm seeing, but I am having difficulty explaining it. (And likely not able to Google for the answer.) When adding a child ...
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2answers
181 views

Why translation uses multiplication and not addition? [closed]

To translate an object from (x, y, z) to (a + x, b + y, c + z) it's done using: OK, that's cool, but why would we multiply in the first place when we can add the two matrices directly as: ...
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2answers
130 views

Keep Mini map static after rotating / zooming with camera

Hi I am making a 2D game, where the Camera is able to rotate / zoom in or out on the camera focus (the player usually). However my game also contains a mini-map, and so far whenever I have to rotate ...
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1answer
69 views

How to make child transforms honor parent origin

I'm working on a 2D transform system that has the following requirements: Transforms can have children Transforms have anchor points/origins that offset them Children should honor the parent's ...
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1answer
230 views

World to Pixel Transformation

My objects have a location in world coordinates (basically 1.0f is a meter). If I simply draw my objects using their world coordinates, each meter will correspond to a pixel. Obviously that's not what ...
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2answers
473 views

getting bone base and tip positions from a transform matrix?

I need this for a Blender3d script, but you don't really need to know Blender to answer this. I need to get bone head and tip positions from a transform matrix read from a file. The position of base ...
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2answers
177 views

Precision loss when transforming from cartesian to isometric

My goal is to display a tile map in isometric projection. This tile map has 25 tiles across and 25 tiles down. Each tile is 32x32. See below for how I'm accomplishing this. World Space World Space ...
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2answers
292 views

Split up a screen into regions

My task: I want to split up a screen into 3 regions for buffs-bar (with picked items), score-info and a game-map. It doesn't matter are regions intersect with each other or not. For example: I have ...
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1answer
372 views

The View-Matrix and Alternative Calculations

I'm working on a radiosity processor in DirectX 9. The process requires that the camera be placed at the center of a mesh face and a 'screenshot' be taken facing 5 different ...
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1answer
143 views

OpenGL camera translate and rotate on cameras local axis

How can I make rotation and translation on a local camera axis in OpenGL? I want to make camera like "aeroplane" camera with a pitch yaw and roll. I want to have good explanation on everything! Can ...
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1answer
73 views

Displaying normals of a geometry

I have a rectangle which is created by 2 triangles and it is in x-z plane, and i have object on it. Now, the normals of two triangles (face normals) are y axis i.e. (0,1,0). I want to display normals ...
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1answer
528 views

rotating 3D object around the center

I have object moving from A to B on x-axis and there is no translation of object apart from it. Now, while moving, i want to rotate it around y-axis and the motion should change accordingly, i mean if ...
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1answer
286 views

Android OpenGLES 2 ray picking, resulting coordinate jumpy in certain spots?

I am trying to implement object picking based on touch coordinates via an intersecting ray test. I am having trouble finding information on converting the touch coordinates to the coordinate system ...
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1answer
64 views

Picking problem with rotated view matrix

I have picking code that works, if my view matrix has no rotation (only translation). Now If I rotate my camera, picking goes to hell. I cant find whats wrong My code: ...
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1answer
286 views

Rotate 2D Isometric World

Games like RollerCoaster Tycoon allow you to rotate the view at 90 degree intervals. I'm wondering how I could apply this to a game I'm making. I'm using MonoGame... but I'm wondering more if anyone ...
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1answer
81 views

Last Matrix operation ignored?

I have 2 methods, one to rotate my Quad and one to flip it (using scaleM), they are as follows: (Note, all values in these methods have been properly defined). If I call just one, they work as ...
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0answers
16 views

Constrain parent node transform to child bounds

If I have some node rendering tree set up, where a node basically has a draw method to render things, and a transform, represented as a 3x3 matrix, with scale and translation. Now, I would like to ...
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1answer
148 views

How can shears/reflections/enlargements be represented by 4x4 matrices? [closed]

I understand that 4x4 matrices can represent transformations on a 3d point (represented as x, y, z, w) Eg, a translation is [1 0 0 0] [0 1 0 0] [0 0 1 0] [x y z 1] where x, y and z are the amount ...
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1answer
143 views

Shear transformation in the projection matrix?

I am trying to understand what the shear transformation (l+r/r-l & b+t/t-b) is actually doing in the projection matrix? The only thing I got till now is headache :) Can you please help?
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1answer
109 views

Common way to store model transformations

I ask myself what's the best way to store the transformations in a model class. What I came up with is to store the translation and scaling in a Vector3 and the rotation in a Matrix4. On each update ...
3
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1answer
165 views

Sfml: Sprite scale transformation animation

Is there any way to animate a transformation on sf::Sprite like setScale or setPosition? ie: sprite.setScale(0.5f,0.5f);. I want the transition between normal and half scale be smooth. Thanks!
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1answer
137 views

How to calculate the Screen Position of a bounding sphere/box?

Synopsis: What I have is an object rendered on the screen. I need to calculate the top-left / bottom-right of it's location on the screen in Screen Coordinates. Explanation: The object is ...
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2answers
409 views

Realtime fisheye to cubic or spherical panorama transformations with OpenGL or pixelshaders

I'd like to transform a sequence of circular fisheye-images to cubic or spherical panorama images to be used in a panorama-viewer based on OpenGL. The viewer-part is nemas problemas but the transform ...
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9answers
12k views

Why do we move the world instead of the camera?

I heard that in an OpenGL game what we do to let the player move is not to move the camera but to move the whole world around. For example here is an extract of this tutorial: OpenGL View matrix ...
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2answers
212 views

OpenGL: Transformations

I'm not sure if I correctly understand 3D transformations in OpenGL. Let's assume I'm using the typical matrix stack. It seems like you move the world X units over, drop in a bag of verts (a mesh) ...
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1answer
117 views

XNA Camera Positioning All Wrong

I've been working in 3DSMax for years now and decided to give XNA 4.0 a try. I've got the majority of it working, however the camera is being a pain to me and I can't discern what's gone wrong. I ...
2
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1answer
137 views

Translating Viewmatrix is inverted, why?

So I've defined a Projectionmatrix, Viewmatrix and a Modelmatrix using OpenGL (LWJGL). But when I translate my Viewmatrix to +X it moves my object to the right (hence my camera is moving to the ...
2
votes
1answer
418 views

Scaling along an arbitrary axis (Dealing with non-uniform scale)

I'm trying to build my own little engine to get more familiar with the concepts of 3D programming. I have a transform class that on each frame it creates a Scaling Matrix (S), a Rotation Matrix from ...
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2answers
97 views

Transform translation relative to world space

What is common algorithm for translating a transform matrix relative to world space axis? E.g. Matrix M is representing some local space. When I want to translate M relative to it's own local axis, I ...
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1answer
124 views

Transformations are not correct using GLM and OpenGL

The aim of my program is to render a simple colored triangle in rotation. The rotations are correct if all Z values of my vertices are equals to 0.0f. If one of these values are different of 0.0f the ...
4
votes
2answers
838 views

How is the gimbal locked problem solved using accumulative matrix transformations

I am reading the online "Learning Modern 3D Graphics Programming" book by Jason L. McKesson As of now, I am up to the gimbal lock problem and how to solve it using quaternions. However right here, ...
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1answer
61 views

changing coordinate system

I'm currently trying to transform a system by scaling it on x and y axis and have some uncertainty. I have the general concept that scaling works as such: My original box has corners at (0, 0) and ...
0
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1answer
599 views

Interpolating a player between two 2D points?

I would like a player to be able to move in a direction smoothly, whilst sticking to a fixed grid. Much like in Pokemon, how the player can move, but when the key is pressed and released quickly, they ...
2
votes
1answer
113 views

transformations of matrices

I'm in the process of reading up on 3d matrices and trying to following this powerpoint and had a few questions as to how to exactly determine the type of transformation from a matrix. If I have a ...
3
votes
1answer
135 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 ...