# Tagged Questions

16 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 ...
104 views

### What are the performance and size tradeoffs of Eigen::Transform versus Eigen::Matrix4f?

We finished migrating from DirectXMath to the Eigen math libraries for our 3D-Game Engine last week for portability reasons. After implementing transformations with matrices as we know them, we found ...
83 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 ...
162 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 ...
230 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 ...
76 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 ...
77 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: ...
271 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. ...
291 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() { ...
4k 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 ...
74 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 ...
1k 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 ...
236 views

### Rotate/Translate object in local space

I am just trying to create a movementcontroller class for game entities. These class should transform the entity affected by the mouse and keyboard input. I am able to calculate the changed rotation ...
330 views

### Inverting matrix then decomposing gives different quaternion than decomposing then inverting the quat

I'm getting different signs when I convert a matrix to quaternion and invert that, versus when I invert a matrix and then get the quaternion from it: Quaternion a = Quaternion.Invert(getRotation(m)); ...
405 views

### Optimizing hierarchical transform

I'm transforming objects in 3D space by transforming each vector with the object's 4x4 transform matrix. In order to achieve hierarchical transform, I transform the child by its own matrix, and then ...