An array of numbers, symbols or expressions, arranged in row and columns. The numbers, symbols or expressions themselves are called elements or entries.
1
vote
0answers
21 views
Rotating and Translating a Node in Horde3D with Matrices and Quaternions
I have been trying to learn how to use the Horde3D rendering engine for the past couple of days,
and so far I have managed to learn a decent amount and integrate Bullet Physics with it as well.
My ...
0
votes
1answer
47 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 ...
3
votes
2answers
109 views
What kind of projection is ScreenX=X/Z, ScreenY=Y/Z?
I have an existing class which transforms 3D vectors and projects them on a 2D plane (Camera). The code is all written in C without help from an external library.
To project a single vector (X,Y,Z) ...
2
votes
1answer
96 views
Negative scale in Matrix 4x4
After some rotations and to from quaternion conversions I get negative scale from Matrix 4x4, is it possible? I need that scale to draw sprite on screen so I get sprite flipped,
how to deal with this ...
2
votes
2answers
94 views
Java Tetris - Matrix Rotations
I'm building Tetris in Java and am trying to use linear algebra to rotate a piece composed of 4 tiles.
My friend was explaining the way to do it is:
He said:
"To clarify, you do need to rotate ...
3
votes
3answers
196 views
Tetris - Rotations using Linear Algebra (Rotation Matrices)
I'm making Tetris in Java and am at the point of rotations... Originally I was hardcoding each rotation:
if (direction.equals("right")) {
if (shape.equals("Bar")) {
if ...
2
votes
1answer
55 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
45 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 ...
1
vote
0answers
75 views
Box2D, OpenGL, resolution and matrix setup
Okay, my internal units are going to be meters, ranging between 0.1 and 10 meters for size.
First of all, my mind is all wrapped up in a knot trying to understand how to handle my game with multiple ...
2
votes
1answer
83 views
Camera not strafing (GLSL)
I use this code in my GLSL vertex shader, where v_position is the vertex position:
gl_Position = v_position * u_camera;
and set u_camera as follows:
meshShader.setUniformMatrix("u_camera",
...
2
votes
1answer
85 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
votes
1answer
47 views
Box2D OpenGL debug renderer convert box2d coordinates to world space
I made an OpenGL 3.x renderer for Box2D's debug draw (b2Draw base class). Unfortunately I've tried for a while now to convert the box2D units, which are meters to my internal units which are pixels. I ...
-1
votes
3answers
102 views
Directional light and matrix issues
I'm trying to implement basic directional lightning in OpenGL 3.3 by emulating the logic shown in this guide: http://www.arcsynthesis.org/gltut/Illumination/Tutorial%2009.html
I do not understand ...
1
vote
0answers
53 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 ...
2
votes
2answers
135 views
World space and model space the dummies version [closed]
I'm by no means a 3d programmer but have recently taken it upon myself to build a Voxel based game and I'm having a little trouble understanding some of the concepts around matrices (what with my ...
5
votes
1answer
90 views
Rotating plane to be parallel to given normal via change of basis
I have two planes and their respective normals. I would like to rotate the second plane, planeB, so that it is parallel to the first, planeA.
To do this, I am using a change of basis to rotate each ...
1
vote
2answers
103 views
Accumulating rotations for camera
It seems there are three ways to store a camera's rotation: in angles, view matrix or quaternion. I was using euler angles since when I used a matrix it had a tendency to accumulate rounding errors ...
1
vote
1answer
86 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; ...
0
votes
1answer
61 views
Ways to “invert Z-axis” in shader-based core-profile OpenGL?
In my hobbyist shader-based (non-FFP) GL (3.2+ core) "engine", everything in world-space and model-space is by design "left-handed" (and to stay that way), so X-axis goes from -1 ("left") to 1 ...
0
votes
0answers
42 views
Proper matrix rotation and storing rotation values
I have GameObject's transform component(position+rotation) and shape mesh(array of vertices).
On each game tick I update coordinates of vertices relatively to game object's rotation.
And my current ...
2
votes
1answer
292 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) ...
1
vote
2answers
213 views
What matrix operations do I perform to translate then rotate then translate then rotate?
In an android game I want to draw a running leg. To output the thigh I do something like:
// legCX,legCY is the location on screen about which the leg rotates.
Matrix m = new Matrix();
...
4
votes
3answers
435 views
Mapping 3D object coordinates to 2D screen coordinates with perspective projection
Sort of following on from where this person was in their topic:
Matrix for 2D perspective
What I have at the moment is a transformation matrix that's defined as follows:
http://pastebin.com/GM6BhP0R
...
6
votes
2answers
299 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 ...
0
votes
1answer
53 views
Assigning bone transform in every draw a good idea?
In my Draw method, I am doing the following:
thisMesh.CopyAbsoluteBoneTransformsTo(transforms);
Is this a good idea? Or should I do this once at the constructor level?
1
vote
1answer
158 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 ...
0
votes
1answer
158 views
All of my matrix functions not working? OpenGL ES 2.0
I am trying to make a projection matrix scaling the screen and making a coordination system. For some reason I don't think any of my matrix calling is working... the 3 function I am using are
...
3
votes
1answer
194 views
Rotating 3d plane to XY plane
I have a triangle in 3d space and would like to create a grid over the triangle, such as in the image below.
The purpose of this is to store information about each block of the grid. In order to ...
0
votes
0answers
118 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 ...
2
votes
1answer
104 views
Handling Origin/Anchor Points in a Scene Graph
I'm trying to implement a simple scene graph on iOS using GLKit but handling origin/anchor points is giving me fits. The requirements are pretty straightforward:
There is a graph of nodes each with ...
1
vote
0answers
149 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
1answer
120 views
Is my idea of how to use matrices to layer 2D on top of 3D correct?
I'm new to using matrices, so I'd like some input on whether I've understood the use of them in the context described in the title.
Right now I have a small Direct3D 11-based game engine which ...
0
votes
0answers
226 views
Transformation Matrix in Android Canvas?
This question is following up my previous question that I asked it in stackoverflow: Hide a face of a 3D shape behind another,Android canvas?
I have a canvas and I have to get the normal vector of a ...
0
votes
0answers
39 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 ...
1
vote
2answers
223 views
Matrix Rotation with three Angles
I want to rotate a form with three given angles fo each of the three axis. But the GLM rotation function takes only one angle and a vector as arguments.
How can I convert between both formats?
2
votes
1answer
141 views
How attach a model with another model on a specific bone?
I meet a difficulty attached to a model to another model on a "bone" accurate.
I searched several forums but no result. I saw that many people have asked the same question but no real result see no ...
2
votes
1answer
152 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 ...
0
votes
0answers
85 views
Camera Projection back Into 3D world, offset error
I'm using XNA to simulate a robot in a 3D world and then do image analysis on what the camera sees.
I have my camera looking down in front of the direction that the robot is going, and I have the ...
1
vote
2answers
174 views
convert orientation vec3 to a rotation matrix
I've got a normalized vec3 that represents an orientation.
Each frame of animation, an object's orientation changes slightly, so I add a delta vector to the orientation vector and then normalize to ...
8
votes
4answers
972 views
Staggered Isometric Map: Calculate map coordinates for point on screen
I know there are already a lot of resources about this, but I haven't found one that matches my coordinate system and I'm having massive trouble adjusting any of those solutions to my needs.
What I ...
0
votes
1answer
110 views
Y Axis inverted on vertex output
I've got my project running and somehow it seems my vertex y components are inverted. 10 in the positive on Y goes down and 10 negative on the Y axis goes up.
I can't find anything with the ...
1
vote
1answer
260 views
How to do geometric projection shadows?
I have decided that since my game world is mostly flat I don't need better shadows than geometric projections - at least for now.
The only problem is I don't even know how to do those properly - that ...
6
votes
1answer
232 views
How can I attach a model to the bone of another model?
I am trying to attach one animated model to one of the bones of another animated model in an XNA game.
I've found a few questions/forum posts/articles online which explain how to attach a weapon ...
4
votes
1answer
116 views
How to transform mesh components?
I am attempting to transform the components of a mesh directly using a 4x4 matrix. This is working for the vertex positions, but it is not working for the normals (and probably not the tangents ...
1
vote
0answers
163 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 ...
2
votes
2answers
213 views
How should I organize my matrices in a 3D game engine?
I'm working with a group of people from around the world to create a game engine (and hopefully a game with it) within the next upcoming years. My first task is to write a camera class for the engine ...
6
votes
4answers
333 views
How can I generate a view or projection matrix for OpenGL 3.+
I'm transitioning from OpenGL 2 to OpenGL 3.+ and to GLSL 1.5. I'm trying to avoid using the deprecated features.
My question how do we now generate the view or projection matrix. I was using the ...
0
votes
1answer
150 views
Stage3D: Camera pans the whole screen
I am trying to create a 2D Stage3D game where you can move the camera around the level in an RTS style. I thought about using Orthographic Matrix3D functions for this but when I try to scroll the ...
1
vote
0answers
137 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:
...
2
votes
2answers
300 views
The purpose of using invert and transpose
In openGl ES and the World of 3D - why use the invers matrix?
The thing is that I dont have any intuition to, why it is used, therefore please correct me:
As fare as I understand, it is used in ...
