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Build your own old-school 3D shooter in a weekend

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Re: Build your own old-school 3D shooter in a weekend

#51

Post by robterrell »

Tempest1981 wrote: post #13

I'd kill for a dozen comments, esp. if a goal is to educate students. 498 lines would still be impressive.

It's a neat trick of projection, and really easy to hack on and extend yourself once you know the trick. Using your map of the space, cast a ray from the camera position through every column of the display rectangle; using the distance the ray travelled before intersecting the wall, you can calculate the apparent height of the wall seen in that column of the display; so, in that column, draw the wall that high. You can get fancier with textures for the walls, varying the floor height, walls that can appear and disappear (i.e. "doors"), and so on.

Better than my 10-second explanation: https://lodev.org/cgtutor/raycasting.html

Re: Build your own old-school 3D shooter in a weekend

#52

Post by AnIdiotOnTheNet »

dragontamer wrote: post #28
cabaalis wrote: post #26

I'm way out of practice with C++. (It's been since like 2006.) Framebuffer clear function appears to allocate a new vector. Does std::vector automatically handle the memory releases? This is called every frame, so I wanted to check here to see if I'm crazy or not.

> Does std::vector automatically handle the memory releases? Yes. What is going on here is that "img" is being assigned. The "old vector" will have its destructor called, which will call the destructor of all of its elements by default. ------- I assume you're talking about this code: https://github.com/ssloy/tinyraycaster/blob/master/framebuff... void FrameBuffer::clear(const uint32_t color) { img = std::vector (w*h…

Note for readers looking to hack on a raycaster: If you were to clear the first and second half of the buffer to different colors, you've got a ceiling and floor.

Re: Build your own old-school 3D shooter in a weekend

#54

Post by dang »

throwaway2016a wrote: post #6

I think leaving the "old-school" out of the title doesn't do this justice. My first thought was, with modern engines, or even raw OpenGL that isn't that hard... I did it in a weekend for my "Advanced Computer Graphics" elective in college using OpenGL and that was 2008. But this is kind of cool... it's more of a tiny ray tracer and... well to borrow the title... old-school arcade game.

Ok, let's put the old school back in there.

Re: Build your own old-school 3D shooter in a weekend

#55

Post by cobbzilla »

AnIdiotOnTheNet wrote: post #46
halfnibble wrote: post #42

People are saying this is a "quite dated" method for creating a 3D game. Does anyone have a tutorial on creating a 3D game in one weekend (or even 1 day?) using modern tooling? It'd be cool to make a token 3D game with the kids. I'm curious myself.

This kind of engine is great as a starting place for programmers, I think, but Unity is probably what you want for the kind of thing you're doing. There's also Godot if you want to stay in Open Source land, but it probably isn't as good and certainly doesn't have the same level of coverage in tutorials and documentation. Or there's the time-tested path to gamedev: modding existing games.

Disclaimer: I've never used Unity but have played around with Godot quite a bit.

Godot's 3D capabilities, while almost certainly not as full-featured as Unity, are plenty enough to make an old-school FPS, and a lot more.

The Godot online docs are quite good; well organized, clean layout, easy to find stuff. But for tutorials and howtos, I've had more success with YouTube screencast videos vs the Godot docs.

Re: Build your own old-school 3D shooter in a weekend

#56

Post by AnIdiotOnTheNet »

robterrell wrote: post #51
Tempest1981 wrote: post #13

I'd kill for a dozen comments, esp. if a goal is to educate students. 498 lines would still be impressive.

It's a neat trick of projection, and really easy to hack on and extend yourself once you know the trick. Using your map of the space, cast a ray from the camera position through every column of the display rectangle; using the distance the ray travelled before intersecting the wall, you can calculate the apparent height of the wall seen in that column of the display; so, in that column, draw the wall that high. You c…

Note that the site has several more entries with extensions to that base raycaster, which you can find in the index.

Interesting note about this technique: you get perspective correct texturing for free. "Real" 3D rendering usually had to cope with affine texturing due to performance costs until dedicated hardware for it came along.

Re: Build your own old-school 3D shooter in a weekend

#57

Post by doctorpangloss »

AnIdiotOnTheNet wrote: post #46
halfnibble wrote: post #42

People are saying this is a "quite dated" method for creating a 3D game. Does anyone have a tutorial on creating a 3D game in one weekend (or even 1 day?) using modern tooling? It'd be cool to make a token 3D game with the kids. I'm curious myself.

This kind of engine is great as a starting place for programmers, I think, but Unity is probably what you want for the kind of thing you're doing. There's also Godot if you want to stay in Open Source land, but it probably isn't as good and certainly doesn't have the same level of coverage in tutorials and documentation. Or there's the time-tested path to gamedev: modding existing games.

> Or there's the time-tested path to gamedev: modding existing games.

Definitely for kids, modding an existing game is the right way to go. It will be way more fun, and it'll be a lot more motivating to share things with friends than to do stuff because dad said so.

I think you're also right that Unity is better but it's still pretty challenging. Programming is really crazy hard, especially for young kids.

That's despite great things like Code.org and Scratch. Those activities are substantiated by good observational (qualitative) evidence measuring creativity, not programming ability.

The only hard quantitative data people have is engagement time--that kids spend more time in apps than equivalent regular instruction when learning idiosyncratic turtle graphics in apps. Pretty unsurprising in my opinion.

As far as I know, there is no evidence that these pre-high school programming experiences retain acceptably-performing students in high school programming like AP Computer Science better than forcing them to take the class. Scratch's educational mission, which I am most familiar with, has for now not made such test-based outcomes an investigative priority.

Honestly an old-school 3D shooter is just about the worst thing you can coerce a disinterested kid into doing. If they're pre-puberty and still care what dad thinks, this sort of activity is exactly what kids drop when they get older. If they're in high school and don't care what dad thinks: it's not a multiplayer game, it doesn't inhabit some social space/it isn't a "third place," it's not taking advantage of the greatest power of the classroom in high school, peer pressure.

This is based on my experience making a game that kids 12+ regularly mod, being the only kid in high school that programmed regularly before 18, and interacting with (but not conducting research with) the wonderful people at Scratch, who really do know how to make algorithmic thinking and creativity work for kids 12 and younger.

Maybe at Stuyvesant parents are making the kids learn C++, but you gotta understand that coercion is the placebo, not the treatment. If you're going to coerce your kids into doing something incredibly boring, it might as well be whatever narrow testing regime is hot these days and not what we fantasize vicariously they should be interested in doing.

Re: Build your own old-school 3D shooter in a weekend

#58

Post by soup10 »

AnIdiotOnTheNet wrote: post #46
halfnibble wrote: post #42

People are saying this is a "quite dated" method for creating a 3D game. Does anyone have a tutorial on creating a 3D game in one weekend (or even 1 day?) using modern tooling? It'd be cool to make a token 3D game with the kids. I'm curious myself.

This kind of engine is great as a starting place for programmers, I think, but Unity is probably what you want for the kind of thing you're doing. There's also Godot if you want to stay in Open Source land, but it probably isn't as good and certainly doesn't have the same level of coverage in tutorials and documentation. Or there's the time-tested path to gamedev: modding existing games.

i wanted to like unity but not having low level access to the rendering and physics internals is intolerable.

Re: Build your own old-school 3D shooter in a weekend

#59

Post by dejv »

halfnibble wrote: post #42

People are saying this is a "quite dated" method for creating a 3D game. Does anyone have a tutorial on creating a 3D game in one weekend (or even 1 day?) using modern tooling? It'd be cool to make a token 3D game with the kids. I'm curious myself.

Checkout this Minecraft clone: https://github.com/fogleman/Craft

It is not tutorial, but the code is very clean and readable and it use modern techniques (compared to Wold3D/Doom style raycasters). The codebase could be extended easily.

Re: Build your own old-school 3D shooter in a weekend

#60

Post by laputan_machine »

tezza wrote: post #11

Unity give away a complete 6DOF FPS with multiplayer. All source and assets included https://unity.com/fps-sample

game engine != game.

learning how to raycast, the maths involved, how to make your own game engine, none of those things are covered in that repo. It's a different thing. This kind of negativity is damaging.

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