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

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398 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 ...
3
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2answers
5k views

How can I stop transform.position from being modified when adding a child object?

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 ...
2
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2answers
195 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
282 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 ...
5
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1answer
270 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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1answer
200 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
3k views

Unity3D Drag Object with Mouse Gives Invalid Position

I am trying to implement a simple script to drag a GameObject with the mouse in Unity. However, when the position of the object is updated with the following script, I get an error saying: ...
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1answer
80 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
3k 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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2answers
519 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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1answer
299 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 ...
2
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1answer
1k 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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2answers
442 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
89 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: ...
3
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1answer
787 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
115 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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1answer
18k views

Correct way to use a GameObject.Find method in Unity C#

I have been following along with a Lynda.com video course to familiarize with Unity. I am currently attempting to grab a reference to a scene's First Person Controller's transform as follows: ...
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0answers
34 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
267 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
373 views

How do I make my camera follow a Box2D object?

I'm implementing a camera in my game. It worked 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 center of the screen. ...
0
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2answers
114 views

Need transform matrix to translate the center of the view to a custom position within the target texture

My problem is as follows: I want to use a single render target texture for drawing 16 viewports where I want to display the 16 different combinations of the marching squares algorithm with my 3D ...
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1answer
287 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 ...
3
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1answer
370 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
156 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
votes
1answer
303 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
259 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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1answer
656 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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0answers
515 views

Move parent according to child axis in Unity?

Can I ask my parent to move according to the child axis? This means if I turn right, then right again, the parent has to be at 180° from its original position, and not only at 90° (because "Right" ...
3
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2answers
1k 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 ...
0
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1answer
142 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
votes
1answer
412 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 ...
0
votes
2answers
140 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
463 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 ...
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1answer
66 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 ...
2
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1answer
138 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 ...
0
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1answer
1k 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 ...
1
vote
1answer
348 views

Canvas isometric translations to integer coordinates

I'm creating a canvas based game with an isometric playing board. I use the following transformations to get my square tiles to render on the screen: 'applyViewportTransformation' : function() { ...
3
votes
1answer
5k views

Rotate object to always face camera

I'm trying to make a TextMesh appear when ever an enemy prefab is hit. I currently have this functionality working. However, the text doesn't face the direction the players camera is looking. At the ...
3
votes
1answer
8k views

How to extract euler angles from transformation matrix?

I have a simple realisation of entity/component game engine. Transform component have methods to set local position, local rotation, global position and global rotation. If transform is being set new ...
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1answer
199 views

Proper approach to handle transformation matrix and extract its components

Basically I have a Transformation component object with following structure(pseudo): TransformComponent{ Vec3 position; Vec3 rotation; //in euler angles Vec3 scale; Mat4 worldMatrix; ...
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1answer
78 views

How to change Vectors due to change in it's dependent Base Vector?

PLOT : I have been developing a game where the player falls down on Y axis and the camera is a Top-Down view camera. The camera, player (main character in the game) movements etc. have all been ...
3
votes
2answers
387 views

Calculating transform of arrow model pointing at some point in 3D space

I'm working on a 3D flight game and I'd like to implement a simple "navigation arrow" pointing at the next waypoint in world which the player has to fly to. I have position of both airplane (=camera) ...
0
votes
1answer
835 views

Rotation of Rectangle along Y-axis transformed to parallelogram

After the rotation of a rectangular view along the Y-axis, about its center, transformed into parallelogram, how do I get the rotated parallelogram coordinates? By Y-axis, I mean perpendicular to the ...
2
votes
1answer
410 views

How can I create a 2D camera with upscaling and translation?

I've computed a Viewport that is fair in size (a proper aspect ratio to the given device) and then I calculate my ScaleMatrix like so: scaleMatrix = Matrix.CreateScale( (float) ...
3
votes
1answer
859 views

How rotate a 3D cube at its center XNA?

I try to rotate a 3D cube on itself from its center, not the edge. Here is my code used. public rotatemyCube() { ... Matrix newTransform = Matrix.CreateScale(scale) * ...
1
vote
2answers
2k views

Render rotated rectangle inside other rectangle bounds using Libgdx

I have this code to generate a red rectangle inside a grey rectangle: new Rectangle(grey_rectangle_position_x, Game.SCREEN_HEIGHT/2-Rectangle.height/2,0); This code makes the following: Now, I ...
0
votes
2answers
232 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) ...
7
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2answers
2k views

How can you extract orientation from a transformation matrix?

I have a 4x4 transformation matrix M, and I want to find out the shape of a sphere when transformed by M. (Sphere is at the origin and has radius 1.) I know I can find the center by just multiplying ...
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vote
1answer
548 views

2D Matrix Transformation (with a Player and Ground)

I have a simple game that I'm trying to do for learning purposes, but Matrices are a bit hard, especially in DirectX. I currently have a tilesystem that renders tiles at the screen and a character ...
1
vote
1answer
556 views

Pygame's rotation methods have crippling issues, but is it me or Python's pygame?

http://www.youtube.com/watch?v=lNJFxvR6ex8&feature=youtu.be On rotate and rotozoom, can't find fixes on these on the internet, anywhere. Basically, the video is showing 4 things in this order: 1. ...