An array of numbers, symbols or expressions, arranged in row and columns. The numbers, symbols or expressions themselves are called elements or entries.

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2answers
748 views

Matrix rotation wrong orientation LibGDX

I'm having a problem with matrix rotation in libgdx. I rotate it using the method matrix.rotate(Vector3 axis, float angle) but the rotation happens in the model orientation and I need it happens in ...
5
votes
1answer
205 views

How can I convert OBJ data into CSS3D transformations?

I want to convert the data in a 3D .obj file (vertices, normals, faces) to CSS3D (width, height, rotateX,Y,Z and/or similar transforms). I found a bunch of formulae and what-not, but 3D isn't my ...
1
vote
1answer
230 views

What is the correct multiplication order for a 2D matrix?

I'm currently trying to create a camera and entity/model matrix for my 2D game similar to that of Unity3D. I've already tried to find answers to this question on stackoverflow/gamedev but i couldn't ...
1
vote
1answer
235 views

Camera lookAt target changes when rotating parent node

have the following issue.I have a camera with lookAt method which works fine.I have a parent node to which I parent the camera.If I rotate the parent node while keeping the camera lookAt the target , ...
1
vote
1answer
651 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 ...
0
votes
1answer
49 views

Java OpenGL Perspective matrix not working

I'm trying to render a simple triangle with OpenGL in Java using LWJGL3. Everything is working great, but the projection matrix (perspective) is not working. In C++ I just used to apply the ...
0
votes
1answer
44 views

Rotate heading relative to agent's local space

I'm having a little trouble translating a point in my game's world space to an object's local space. I have a cannon in my game with a normalized heading vector that's always supposed to point in the ...
0
votes
1answer
108 views

libgdx - Box2d debug draw not correct

I have a problem where the bodies in my debug draw does not draw correctly, take a look: As you can see, there is some space between the dynamic body and the ground. I have checked the contact ...
0
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1answer
58 views

Problematic cameraposition (Eye = (0,0,0), at=(0,-2,0) and up = (0,1,0))?

I am taking a course in computergraphics and we talk a lot about OpenGL and the math you need to do everything OpenGL does "by hand". A Question which was asked in an old exam (I am preparing at the ...
0
votes
1answer
102 views

Directional lights (not) rotating with camera (opposite problem)

I am trying to implement a shader for directional lights correctly, but I am bit confused as to why it works when it shouldn't and vice versa. People usually encounter problem with lights changing ...
0
votes
1answer
156 views

Relative Position/Rotation calculation

I have 2 objects each with a 3x3 Matrix (Orientation) and a Vector3 (Translation). Both are relative to world coordinates. How do I calculate the position and orientation of object B in relation to ...
0
votes
1answer
101 views

How do I ADD gravitation to a rotation matrix?

I have ported the Matlab script from https://instruct1.cit.cornell.edu/courses/bionb441/LSystem/ to POV-Ray and everything works fine (although I'm not quite sure why). To navigate a "turtle" through ...
2
votes
0answers
145 views

Unproject considering parallax depth

How can I take screen coordinates (or alternatively world coordinates on the 'primary' parallax plane) and find out what world coordinates they translate into when taking parallax depth into account? ...
1
vote
0answers
43 views

Confused About My Code Suggesting The Normal Matrix Is Equivalent To The ModelView Matrix

I'm learning environment mapping in OpenGL by following this page. In his vertex shader, the author calculates the vertex normal in eye space with the following code: nEye = vec3(viewMatrix * ...
1
vote
0answers
190 views

How should matrix-based Parallax Scrolling work?

The question is at the end, as it requires a bit of context. I'm not sure if my understanding, my code, or LibGDX's ParallaxCamera is wrong. LibGDX's ParallaxCamera uses Matrix4s to achieve a ...
1
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0answers
52 views

How can I approximate an “opening fan”-transformation?

Is there a way to—with matrices—transform something as if opening the image on a Japanese folding fan? Image from Wikimedia Commons. I'm at a loss of what to call it, so pointers towards avenues of ...
1
vote
0answers
118 views

Rotate view matrix based on touch coordinates

I'm working on an Android game where I need to rotate the camera around the origin based on the user dragging their finger. My view matrix has initial position of sitting on the negative z and facing ...
1
vote
0answers
114 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 ...
1
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0answers
489 views

Stacking Drawing Matrix for SpriteBatch in XNA

I'm trying to make a 2D engine for XNA with SpriteBatch. My object unit is Entity, which can include other Entities as its children. However, when drawing them, the rotation and scaling stacking do ...
1
vote
0answers
188 views

How do I implement a physics gun?

I'm currently trying to implement a physics gun for my game. What I want is for the entity to stay in the same position on the screen no matter how I wiggle the camera about, what is the correct way ...
1
vote
0answers
335 views

Drawing two orthogonal strings in 3d space in Android Canvas?

I want to draw two strings in canvas. The first string must be rotated around the Y axis, for example 45 degrees. The second string must start at the end of the first string and also it must be ...
1
vote
0answers
312 views

Matrix.CreateBillboard centre rotation problem

I'm having an issue with Matrix.CreateBillboard and a textured Quad where the center axis seems to be positioned incorrectly to the quad object which is rotating around a center point: Using: ...
1
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0answers
244 views

How do I convert my matrix from OpenGL to Marmalade?

I am using a third party rendering API, Marmalade, on top of OpenGL code and I cannot get my matrices correct. One of the API's authors states this: We're right handed by default, and we treat y ...
1
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0answers
272 views

Getting and Setting Rotation in XNA around the Center of my Model with XNA

Alright, so I'm currently debating how I want to do this. Basically this is what I'm trying to accomplish. I've created a system to allow me to make my environment a little bit easier. I'm ...
1
vote
0answers
179 views

reflection plane 3d

Hey there I'm trying to create a plane that can have a texture on it and reflect the 3d elements around it. for example a plane with a laminate floor texture and above it a cube rotating. I want the ...
0
votes
0answers
13 views

Adding a 2D transformation matrix to GLSL

I'm having trouble understanding the matrices I need to render an object in OpenGL. I've been using a matrix to make up for the translation and scaling from the camera in my game but I didn't have a ...
0
votes
0answers
19 views

Determine local “roll” from matrix

I'm allowing my player to maneuver freely in three dimensions. The world is very cubical, so it is useful to know internally (to help hint controls) which ground plane they're closest to paralleling. ...
0
votes
0answers
32 views

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 ...
0
votes
0answers
29 views

OpenGL - Cubemap “Rotating” Proportional To Camera Movement

I'm doing a simple planet rendering project and am running into an issue with accessing cubemap textures correctly. The planet terrain is generated using the diamond square algorithm done 6 times and ...
0
votes
0answers
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 ...
0
votes
0answers
21 views

2D viewport matrix World to Local coordinates

I would like to use a Matrix but it causes (or I think it does) problems with accuracy. Clearly classic float matrix causes jaggy movement/accuracy issues. The reason is that my objects have real ...
0
votes
0answers
24 views

change position/orientation of a bone using assimp

I have been using assimp to import rigged models and animations. I followed this tutorial for skeletal animation and I have got it done properly. The part that I am trying to do now is to orient a ...
0
votes
0answers
38 views

Coordinate system in OGLdev tutorials

Working with OGLdev tutorials http://ogldev.atspace.co.uk/ I found that this code uses coordinate system, which doesn't look like in most other samples. Positive x-axis direction is left, and not ...
0
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0answers
61 views

Pre- or post-multiplication for rotation between coordinate frames

I have three 3D coordinate frames: O, A and B, as shown below. I want to know the rotation matrix RAB between A and B, that is the rotation that is required, with respect to the frame A, to move ...
0
votes
0answers
25 views

Use Android 4x5 ColorMatrix in OpenGL ES 2 Shader

I am trying to use Android Color Matrix in OpenGL ES 2. I have been able to use a 4x4 Matrix using the following code in the Shader (this adds also an intensity parameter): varying vec2 ...
0
votes
0answers
38 views

GLSL billboarding

I want to make billboarding using GLSL. For what I've got so far it works, but not exactly the way I want. My vertex shader looks like this: #version 120 uniform float partSize; varying vec2 ...
0
votes
0answers
67 views

Matrix, vector multiplications in OpenTK

I developed a 3d model viewer in c++ with OpenGL, and in c# in OpenTK. Both are using the same shader, but the output from OpenTK is not correct. I read that OpenTK is row major order, and OpenGL is ...
0
votes
0answers
27 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 ...
0
votes
0answers
622 views

Implement Camera (former: CCCamera) v2 in cocos2d-x v3.3

we want to port camera code from cocos2d-x version 2 to version 3.3 with the goal to imitate the behaviour of a CCCamera in cocos2d-x version 2 exactly. You can assume that values for "eye" and "up" ...
0
votes
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], ...
0
votes
0answers
25 views

Transform screenquad around object's view space boundaries (GLSL)

Im not sure how to ask this, but essentially I am looking for a way to optimize rendering screen quad lights per object. I have a deferred renderer that draws directional lights onto a screen quad. ...
0
votes
0answers
76 views

XNA C# - Get original rotation from parent bone transform

I have a 3DS Max made model, exported into FBX and imported into XNA project. The parts I am working with have NOT been rotated in Max (specifically, collision mesh is made of Axiz-Aligned boxes). ...
0
votes
0answers
59 views

3d Rotation problem

I was given an interesting (but tough) problem to solve: In a game, you want to change the heading of an enemy by +30°. Construct a Rotation Matrix, Euler Angles and a Quaternion that would do this. ...
0
votes
0answers
85 views

Apply android.graphics.Matrix transformation to an Open GL ES shader

I am currently using a 4x4 matrix to convert from "pixel" coordinates to OpenGL ones, my scene is full screen so my screen matrix looks like this: 2f / width, 0f, 0f, 0f, 0f, -2f / height, 0f, 0f, ...
0
votes
0answers
38 views

XNA - Link between Create Rotations matrices

A friend of mine have been coding some rotations on my XNA project, but the order of the matrices rotation are not good. Some are of form : Matrix.CreateRotationZ(1.21f) * ...
0
votes
0answers
79 views

Matrix Translate Camera has some sort of spiky movement

public class Camera2D { private Vector2 _position; protected float _viewportHeight; protected float _viewportWidth; public Vector2 ScreenCenter; protected Being _unit; // the sprite camera is ...
0
votes
0answers
63 views

“Blinking” graphical bug when rotating shadow matrix

So, we have implemented Krypton shadows into our code for our 2D game, and it's working beautifully. Only issue is that we're running into a bizarre graphical bug when rotating the shadows with the ...
0
votes
0answers
31 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 ...
0
votes
0answers
69 views

Transform a Screen Delta

I have a delta in screen coordinates that I want to transform to a 3d delta in world space. The delta is in this case a movement across the (x,y) coordinates in screen space on the near projection ...
0
votes
0answers
522 views

Calculating the correct roll from a bone transform matrix

Read this forum topic for more info: http://blenderartists.org/forum/showthread.php?260602-transform-matrix-to-bone-%28head-tail-roll%29-bug I'm trying to get my Blender3d modeller importer to create ...