In Video Games, The Player Never Moves

In which we explore matrix math and how it's used in video games.

[JoshsHandle]

People keep asking about multiplayer games, so I'll pin a comment here.
In the case of local (split-screen) multiplayer, the world is shifted to one viewpoint while one viewport is being drawn, then shifted to the other player's viewpoint while their viewport is being drawn.
In the case of online multiplayer, the server running the game doesn't have to render graphics so it doesn't have to deal with keeping track of dozens of differently oriented worlds. Each player connected to the game just renders the world shifted to their own personal point of view.

[coalhater]

I hate when high quality channels like this don't get the recognition they deserve.

[addvector]

This was a better summary than my 4th year graphics course. Great job

[TotalJargon]

Went through a 3 year games technology degree and still felt like matrices were a bit of a mystery, in just 20 minutes you've dispelled most of that!

[TheOneCheetah]

I was always told the world doesn’t revolve around me, but here we are, the world revolving around me

[PronteCo]

I heard another interesting reason to fix player at 0 is that otherwise in games with HUGE maps going to the edge (i.e., being far away from 0) would result in significant floating point errors constantly occurring on your coordinates, i.e., laggy and inconsistent movement

[ElTRDG]

The best explanation I've heard about graphic's matrices, I had even understood how they work! Great video, and congrats for the animations, they help a lot.

[AHSEN.]

First time I actually understood matrices. Thank you very much. I hope you gain more subscribers soon! You certainly deserve it. Your raytracing video is one of the best videos I have ever seen on youtube, and this video was extremely helpful.

[curiodyssey]

PLEASE KEEP CREATING CONTENT! You are such a refreshing and highly competent teacher with a natural gift of making things intuitive and easy to understand.
Please, you have the ability to help so many people in ways you could probably hardly imagine. It may be selfish of me to ask, but I crave your content. It is absolutely, insanely well done, while being both high-level yet easy to understand. Your ability borders on genius level with how effortless you make it appear to be.
Please don't make us wait another 8 months. I beg you!
You are utterly incredible. Simply amazing. Positively awe inspiring. Never stop.

[lRyanI]

This is such a relaxing, educational, and well-produced video. Love the music, the sound effects as things appear, and the calmness in your voice. Really glad this popped up in my feed.

[curiodyssey]

This channel is REALLY fucking good and is criminally underrated. Your time will come, believe that. Your content is on-par, if not better, than other YouTuber's in the same category/genre as you.
Absolutely blown away.

[TheLastCrankers]

Good explanation, but the title is just false (and misleding looking at some comments about the multiplayer lmao). Creating a 2d projection of the 3d virtual space cannot be considered moving the world.

[SleepingFumos]

writing something as simple as a rotating cube in modern OpenGL makes you learn a lot about computer graphics, and this is one of the things you'll learn.

highly recommend it to anyone who wants to learn this the practical way

[cmyk]

A form of transformation matrices was used in the SNES’s Mode 7 graphics. Since it was limited to a 2×2 matrix, perspective effects like in F-Zero, Pilotwings, and Super Mario Kart needed to change the scale of the matrix every scanline.

[whiskygrinch]

Damn, I would have needed you... like... 10 years ago when I first fell into VTK and the cursed world of 4x4 Matrizes and later quaternions. WHERE WERE YOU BACK THEN?!

[ctralie]

Wow, really impressive use of sound and pitches here to reinforce the concepts!

[Panda-ekll]

Found you from your quantum computing videos and just watched this! Your content is so underrated!! You need to keep making content man, your animations are descriptive and intuitive and you are amazing at explaining these concepts!! Keep up the great work!

[pavelperina]

Nice one. I don't like how matrices are always explained in a way rotation around x looks like this, translation looks like this. It helped me a lot to multiply matrix by vector by hand and to see the patern. First columns of transformation matrix tells you what happens to unit vector x. 2nd and 3rd columns are for unit vectors y, z. Forth column tells you what happens to unit vector w. You can decompose any vector to sum of perpendicular unit vectors x, y, z, w and scalars. Then you can multiply scalars by matrix columns, they will transform into four new vectors. By adding them together, you get the result of transformation. The last one (w) is perfectly consistent - take unit vector (or zero), in the fourth dimension, because why not. It will transform into three dimensions and add to the result - and that's the translation. From now, put w=0 for vectors and w=1 for points (cause vectors have no origin, they must be immune to translations). That's all that you need to know. From now rotation matrices are not weirdly placed sines and cosines with plus or minus signs, you can just draw a picture of unit vectors x and y rotated by 30 degrees and write them into column of matrix.
And multiplying matrices is not a magic, but transforming base vectors in columns of the matrix on the right by a matrix on the left.
IMPORTANT: all above assumes column vectors.
NOTE: it's hard to explain the part with matrix*columnVector without seeing it. Try yourself with column vector (1 0 0 0) and so on, this one is really affected only by the first column.

[sanador]

Your channel is exactly what I am trying to emulate with my teaching style. I want to write lectures that are in this format that I can move through in class. Adding you to my pile of ideas. Excited to see what else you make

[RevolutionAdvanced]

The introduction of the w vector and particularly fixing its value at 1 to represent eucledean space reminds me a lot of the notion of a "euclidean point" in 3D Projective Geometric Algebra. Have you ever looked into that?