Coding Train Live 177: 2D Ray Casting and Ray Marching

Today we will explore 2D Ray Casting and Ray Marching

Timestamps:
0:00 Live Stream Starts
5:52 Introduction
12:31 Community Contributions
23:35 Setting Up
25:48 Code! Ray Casting Coding Challenge
2:50:26 Small Break
2:55:40 Returning From Break
3:01:50 Code! Ray Marching
4:04:14 Conclusions and Goodbyes

[thebirdhasbeencharged]

If you think I'm going to sit here and watch a 4 hour hour video I have something to tell you...






You're right. Thanks.

[yourteacher]

Just one more video before I go to bed...

[fazalali]

I tuned into the live stream when it started, then got busy with work all day. Just got home and the stream ended 5 minutes ago. Daniel does not have a setting for tired. <3 Thanks professor!

[bwatspro]

Dude, you and your channel are another reasons to be happy.

[UPD]

I love the way that he was really patient with all people's work, a good trait of the great mentor

[metadaat]

Hey, about the wolfenstein-like "3d view" of your raycasting experiment: Your walls appear curved because the rays in your field of vision are separated by steps of equal degree angles. That way you get a sort of "fish eye lens" type of thing. If you want to fix that, you need to do it like this:



The Particle (player) is in a certain position, looking in a certain direction. A little bit in front of the player, imagine a short line segment perpendicular to the viewing direction. The player is looking straight at the centre of this line segment. Consider this line segment as your virtual screen, or "scene". You loop over points on the line segment with equal steps, and you cast rays from the player to these points. So the points on the virtual screen are steps of equal distance, instead of the rays being cast with steps of equal angle. (this line segment is actually your "near plane" in 2D, if you're familiar with that term)

For short line segments (small field of vision) this may seem like a very subtle difference from the top-down (left) view, but in the 3d (right) view it is noticeable because the lines of straight walls aren't curved anymore.

Oh there is one more thing you need to fix: Currently you're mapping the height of a vertical strip to the distance reversed like height = (max_dist - distance)/something, but to get a proper perspective view the height must be proportional to the reciprocal of the distance, so like: height = someconstant / distance.

[ArtyomGalstyan]

1:28:54 add ray gradient transparency according to inverse square law."physical quantity or intensity is inversely proportional to the square of the distance from the source of that physical quantity"

[DroidTsuenik]

Coding Challenge: Cellular Automata on a "torus" shape or a sphere. You get the idea :)

[lonec]

Ive been waiting years for this.... but totally worth it

[pullingrabbitsouttaahat]

Good God Your Energy is Awesome ! 4 Hrs at a stretch !

[DogwafflDan]

Thanks for talking about all this. For a lot of years, it's been hard to get good information.

[skippythemagnificent]

Frame 25:55 Slippy floor dancing ... Wonderful :)

[CalculusPhysics]

At around 2:30:00 when you were working on the perspective thing, I think you needed to do

Height = map(1/scene[i], 1, 1/sceneW, sceneH, 0)

That way you're mapping the inverse of the distance, which goes between 1 and 1/sceneW, to between 0 and sceneH.

you also might need to multiply it by some scaling factor if its not quite right. But that's how you would do a map for an inverse relationship. And it would be a similar thing for the inverse square for distance, you would just do

Brightness = map(1/(scene[i]**2), 1, 1/(sceneW**2), 255, 0)

[anonymoussloth]

I love your videos! You explain the most complex topics like you were explaining them to Michael Scott from the office😂❤️

[codeforest]

He STARTED typing at 35:05 (in the non-stream but stream part)

[mabadi]

Two lines intersection is simply solution for 2 simultaneuous equations for lines

[PhilBoswell]

Something odd starts happening at about 3:40:30 when someone mentions "clicking", then it goes into slideshow mode from 3:41:00 to 3:42:00 when the chat notifies you: I think you say it's not recording to disk :-(

[TharxGamma]

Starts at 29:00 because we need his giggles

[heroiuraresjustinian]

36:33 while you were typing the text editor was telling you wich value was what(x1, y1...etc)...Where do you gett this addon from and what is its name?

[kernelpanic]

Could you please do TETRIS? I tried it in Processing but failed.