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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38 views

Matrix transforms with SpriteBatch overloading - how do you rotate/zoom around a point? [duplicate]

I have a transform matrix which works as intended for game objects I want to be completely controlled by my camera: _transform = Matrix.Identity * Matrix.CreateTranslation(-_position.X, ...
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1answer
58 views

How to modify normal vectors with a tranformation matrix

Transformation is quite simple when it comes to Position or Color of the vertex, for Position just multiply matrix * vector and for color just don't do anything, but my question now is: How to handle ...
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2answers
167 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 ...
3
votes
4answers
256 views

Why not use vectors to represent orientation?

From what I've read, people mostly use either quaternions or 3x3 matrices to represent 3D orientations, while plain vectors are used for angular velocity/momentum. Since we can use vectors to ...
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1answer
101 views

Does a 2D Vector or 2x2 Matrix play any role in 2D Transformations?

I'm having trouble trying to figure out if a vec2 or mat2 class are used at all in transformations for 2D rendering. Vec2, apart from representing UVs, AFAIK, is relatively pointless in regards to ...
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1answer
76 views

Multiplying matrices in HLSL

I have code that calculates a position like this in HLSL: output.ShadowPos = input.VertexPos; output.ShadowPos = mul(output.ShadowPos, gWorld); output.ShadowPos = mul(output.ShadowPos, ...
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2answers
92 views

Encode world matrix as 2 float4s?

On one of the slides of their presentation "Batch, Batch, Batch!" guys from NVidia suggest encoding animation matrices for pallet skinning into two float4s as: • axis/angle • ...
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1answer
40 views

Rotate final image with projection matrix

I'm trying to use space in my shadow (depth) maps in a more efficient way. If I could freely rotate the final image I get with projection matrix I could save a lot of pixels, but I don't know if it is ...
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1answer
81 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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5answers
755 views

How to rotate an object around world aligned axes?

I have a Vector3 which has an euler angle for each axis. Usually, when I want to create a rotation matrix I will use functions such as D3DXMatrixRotationX passing the respective angle from my ...
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0answers
57 views

W2S, worldtoscreen from Projection Matrix and View Matrix

After a couple of days of tremendous trial and error coding, I must give up: I have a simple 3d program that I'm adding a visual layer to. Basically, I want to draw 2d icons and text over 3d objects ...
3
votes
1answer
222 views

How to move an object up and down like a wave?

I am trying to move my object up and down using cos and sin, but I have problem understanding how does the sin and cos work, so I can make my object move up and down like a wave frequently Init Time ...
3
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2answers
570 views

Identity matrix. Confusion. What does it really do

I understand identity matrix is like multiplying to 1. But i can't really understand why would you multiply an a matrix that will only result to the same. Also im messing up with an OpenGL code and ...
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vote
1answer
192 views

Converting 3 axis vectors to a rotation matrix [closed]

I am trying to get a rotation matrix (in 3dsmax) from 3 vectors that form an axis (all 3 vectors are aligned by 90 degrees each other) Somewhere I read that I could build a rotation matrix just by ...
1
vote
3answers
255 views

Orthographic Projection with variable FOV

We are building agame with orthographic view. The problem we face is the fact that with different resolution you can see different area of the game world. E.g. if you have higher resolution you can ...
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1answer
134 views

HLSL What you get when you subtract world position from InvertViewProjection.Translation?

In one of NVIDIA's Vertex shaders (the metal one) I found the following code: // transform object normals, tangents, & binormals to world-space: float4x4 WorldITXf : WorldInverseTranspose < ...
12
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3answers
901 views

Camera for 2.5D Game

I'm hoping someone can explain this to me like I'm 5, because I've been struggling with this for hours and simply cannot understand what I'm doing wrong. I've written a Camera class for my 2.5D game. ...
2
votes
0answers
108 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? ...
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0answers
78 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 ...
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0answers
30 views

Is there a transformation or set of transformations that can approximate a “radial scale”?

Is there a way to, with matrices, scale something as if someone were opening a Japanese fan? I'm at a loss of what to call it, so pointers towards avenues of research would be greatly appreciated. If ...
0
votes
1answer
451 views

View Matrix from Camera in Unity Script

I am looking to get a Camera component's "view" matrix in a script. I see that I can get the projection matrix using Camera.projectionMatrix, but I don't see a Camera.viewMatrix property... I want ...
4
votes
2answers
210 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 ...
1
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1answer
650 views

Need to translate a Rotation Matrix to Rotation y, x, z OpenGL & Jitter for 3D Game

I am using the Jitter Physics engine which gives a rotation matrix: M11 M12 M13 M21 M22 M23 M21 M32 M33 And I need it so OpenGL can use it for rotation GL.Rotate(xr, 1, 0, 0) GL.Rotate(yr, 0, 1, ...
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0answers
114 views

Why my camera sees what is behind it?

I am building a minimal opengl viewer and I am puzzled by what I see : the camera see the (test) object that is behind her. the front and back of the camera looks reverted. I am wondering what could ...
2
votes
2answers
175 views

what is order of implementation of matrix transforms?

What is the meaning of Tr*Sh*Ro*Sc =M ? How is matrix M written to form the graphic transformation : 1st Sc=Scale, 2nd: R=Rotate, 3rd : Sh=Shear 4th: T=Translate ? Is the matrix M above written ...
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1answer
362 views

switching from third person view to first person view

I have done a scene in opengl where I'm using a third person camera (that I can control with the mouse). Then, inside it, it has the camera of the first view (that I called thirdpersonCamera, see the ...
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3answers
1k views

Replace glTranslatef and glRotatef with matrixes

I'm not an opengl expert, and, as a novice, I prefer to practice a little bit with the old opengl just to be sure to understand correctly the basic concept of computer graphics before deal with ...
2
votes
1answer
1k views

Combining rotation,scaling around a pivot with translation into a matrix

In short: I need to combine rotation (in the form of a quaternion), scaling around a pivot point along with translation into a transformation matrix. The long: I am trying to implement a proprietary ...
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2answers
196 views

How to properly translate a point by a matrix?

I wrote a simple Matrix class and it has methods like rotate, translate, etc. They all seem to be working, but whenever I try to translate a rectangle using the matrix, the translation axis seem to be ...
2
votes
1answer
104 views

Minimal Projection Matrix

i hope you can help me. I'm currently stuck at the creation process for projection matrices used by shadow maps. The problem is the following: I got the spot/directional light ...
0
votes
1answer
84 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 ...
1
vote
1answer
164 views

Implementing axonometric bird-view in XNA

I made all kinds of logic (waypath, aso) for my strategical game, based on XNA (monogame). Now I "misused" the Vector2 a little bit: As I'm working from a "top-down" perspective, I'm using the Y-axis ...
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vote
0answers
128 views

Matrix array doesn't seem to get populated

I'm trying to stream an array of matrices to a vertex shader, but it seems that only the first matrix works. What could be the problem? I suspect that I upload the matrices in a wrong way. C# ...
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0answers
24 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 ...
1
vote
0answers
82 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 ...
0
votes
1answer
170 views

Trying to convert as3 Matrix to C++ glm matrix

I am trying to convert a library called DragonBones to C++ Opengl which allows you to use Flash based skeletal animation. I'm almost done but I am running into a problem. I am trying to transform the ...
1
vote
4answers
130 views

Storing tile grid in a matrix: row major vs column major

I'm using a generic matrix container to store the tile grid for my RTS game. This is where I am confused: a matrix is traditionally row major, i.e. matrix(0, 10) means 'at 0th row, 10th column.' A ...
1
vote
1answer
162 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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votes
1answer
180 views

Pinhole matrix problem

I made a program to represent a 3D world. I use the projection matrix we can find on wikipedia. For viewing a scene it's very nice but when I straff in the scene, everything behind the camera go on ...
2
votes
1answer
203 views

XNA matrix order problem

I want a matrix that scales first and then rotates. I tried the code below, but it didn't work. zRotation, yRotation and xRotation are rotations that shouldn't be affected by the origin. allrot should ...
3
votes
1answer
177 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?
1
vote
2answers
319 views

Creating a 2D perspective in 3D game

I'm new to XNA and 3D game development in general. I'm creating a puzzle game kind of similar to tetris, built with blocks. I decided to build the game in 3D since I can do some cool animations and ...
1
vote
1answer
412 views

How to do directional per fragment lighting in world space?

I am attempting to create a GLSL shader for simple, per-fragment directional light. So far, after following many tutorials, I have continually ran into the issue: my light is specified in world ...
4
votes
3answers
259 views

Matrix multiplication - Scene Graphs

I wrote a MatrixStack class in C# to use in a SceneGraph. So, to get the world matrix for an object I am suposed to use: WorldMatrix = ParentWorld * LocalTransform But, in fact, it only works as ...
0
votes
1answer
117 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 ...
1
vote
1answer
106 views

Matrix transforms in XNA

So in my most recent 2D game I draw objects like so. _spriteBatch.Draw(_sprite, Center(), null, Color.White, _rotation, new Vector2(_sprite.Width / 2, _sprite.Height / 2), _scale, ...
0
votes
1answer
535 views

What is the difference between a modelview-projection matrix and world-view-projection matrix?

So basically I wrote a shader a long time ago that uses all World and WVP matrices. Now I am working in an engine that will only give me access to ModelView, MVP, and model to world space matrices. ...
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votes
2answers
228 views

Is this Rotation Matrix correct?

I'm having heavly troubles with setting up a View Matrix and a Projection Matrix. It simply doesnt work. So I think my problem is related to my rotationMatrix function. I'm using this tutorial to ...
2
votes
1answer
124 views

Manual GLU.gluUnproject

Before I used GLU.gluUnproject to calculate my picking ray in my OpenGL game. Recently I switched to my own calculated matrices, and now I can forget the gluUnproject. How can I calculate the picking ...
2
votes
1answer
154 views

Optimising skeletal animation

I am implementing a skeleton system for my latest game. I am using my own linear algebra classes which already have some optimisations, such as separate transformPoint and transformVector functions ...