Questions tagged [matrix]

The tag has no usage guidance.

19 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
4 votes
0 answers
272 views

View Reference Coordinate System

For a 3D scene in the World Coordinates, its View Reference Point is at c=(0,3,4), and a viewer is looking towards its origin O (0,0,0). Construct a transform matrix which will map World Coordinate ...
3 votes
0 answers
57 views

Bezier curve : Problem deriving control points from matrix form

This is my first post on this website so i have put in a lot of research to get my point across to everyone as clearly as possible. Based on a question i posted on stack overflow i have successfully ...
  • 169
2 votes
0 answers
351 views

Coordinate system transformation in motion capture files

I am trying to align two motion capture files from different sources. The motion capture file consist of a skeleton specified as a hierarchy of joints. Each joint i.e. "shoulder" has three pieces of ...
1 vote
0 answers
146 views

Model View Projection Matrix Multiplcation Order

I'm working on a simple software renderer and have a working implementation so far. I'm curious as to why it's actually working since I would expect the multiplication ordering for my world, view and ...
1 vote
0 answers
319 views

Help with understanding the look-at function (the view matrix)

I've been reading this article about the look-at function. I don't understand the part when they're trying to inverse the matrix N. They say that R is orthogonal because all its row and column ...
1 vote
0 answers
402 views

How to apply scale, translate, rotate with different origin and get new rectangle coordinates

I was reading other questions in this topic but I couldn't apply any viable solution to solve my use case. I have a crop area described with two dimensions (cropWidth, cropHeight) I can easly compute ...
1 vote
0 answers
102 views

Scalar multiplication in vecmath on Matrix4f results in strange values

So I have a matrix: ...
  • 251
0 votes
0 answers
30 views

Previous frame reprojection fails for camera translation

I'm trying to perform forward pixel projection based on previous frame depth. Using UV, I'm reading prevDepth for given pixel and based on that I'm recreating worldPos in camera space (where (0, 0, 0) ...
0 votes
0 answers
55 views

Alternate projections in shader

I have a projection calculation which maps points from 3D space to pixel (image) space, and I want to use it as instead of the standard MVP projections in a vertex shader. In the image below the lower ...
  • 3
0 votes
0 answers
33 views

Calculating texture UVs on world origin shift

I am using procedural tiling terrains for very large worlds, and to avoid floating point errors I'm periodically shifting all parent objects back closer to zero. The Unity terrains textures are ...
0 votes
0 answers
48 views

How to interpolate between two MVP setups?

I am currently writing an AR experience. I have a Camera View Matrix, A Camera Perspective matrix and the Model Matrix of the content I display. The AR content should can be switched to "2D",...
user avatar
0 votes
0 answers
140 views

Matrix transforming with translation/rotation/scale at center of screen

I'm trying to create a camera using matrix transforms, the gist as follows: ...
0 votes
1 answer
464 views

How to calculate position from depth pass of the ZED camera?

I'm using the ZED 2 camera, and although the API provides a means of getting a point cloud position from a specific pixel, for my project I need to be able to perform this calculation myself from the ...
0 votes
0 answers
132 views

Crystal ball rotation - I don't get why the code works

For context: I'm absolutely new to graphics programming and I've always had trouble getting the math. I had the task to write code for a crystal ball interface using OpenGL. There's an object in the ...
user avatar
0 votes
0 answers
62 views

Compose ViewMatrix and ProjectionMatrix

As the title says, you are able to compose the ViewMatrix and the ProjectionMatrix into one instead of multiplying a vector by the individual matrices. Instead of doing this at run time for each item: ...
  • 23
0 votes
0 answers
62 views

How to find matrix that projects 3d points into 2d plane centered in the origin?

I have a list of 3D points defined by Cartesian coordinates, i.e. [(x1,y1,z1), (x2,y2,z2), ..., (xn,yn,zn)]. I want to project them to a 2D plane which has origin in the center (0,0,0) but which is ...
0 votes
0 answers
279 views

Octave matrix to image pixels too small (do not have 1 pixel per integer)

I am working on a project which plots points over a checkerboard (representing seats for people). I would like each pixel in the image to represent each integer matrix entry. After updating my ...
0 votes
0 answers
376 views

Tilting a 3d object to face a camera and have it look like it's spinning on the y axis

I have a scene kit app I'm working on and at a certain point I move the camera under a list of objects and tilt it up to give a star wars type view of them. I then need to pull the objects up one at a ...
  • 101
0 votes
2 answers
68 views

What projection matrix and world transformation do I need to have an isometric projection?

I'm doing my own engine in college to display a wireframe on screen with an isometric projection but I literally can't find any literature about maths behind doing it by hand just for game engines ...
  • 101