GrubStomper29's Project Thread

[raven halo]

case in point

[hushed crescent]

that would not matter at all

unless your resolution algorithm is extremely, extremely fragile

which is a bigger issue

[raven halo]

okay

here it is

if (displacement.x > 0.0f)
{
    fixX = pos.x + hitbox.max.x - tilePos.x;
    return true;
}
else if (displacement.x < 0.0f)
{
    fixX = (pos.x + hitbox.min.x - (tilePos.x + 1.0f));
    return true;
}

[hushed crescent]

https://box2d.org/publications/

you need to combine your resolution and do it via vector math

generally speaking in a physics engine you find the resolution vector between a pair of contacts and apply them, with the vector being the shortest direction + distance required to move them apart

so you need to do some logic to choose the minimum direction and then calculate the distance from there, then apply that vector

[raven halo]

what's sat?

[hushed crescent]

separating axis theorem, you can find tons of info on it if you search, it's pretty much the most popular algorithm/approach for finding intersections between physics objects

the theorem itself just dictates that you can have a specific set of axes upon which you check intersection independently, and two shapes intersect if and only if they intersect when projected onto every axis

and the convenient thing is that the algorithm inherently is set up to give you the framework for finding the minimum axis of penetration, plus it's very simple for AABB vs. AABB like you have

[raven halo]

okay

or...

while (pos.y + hitbox.max.y == std::ceil(pos.y + hitbox.max.y))
{
    pos.y = std::nextafter(pos.y, std::numeric_limits<float>::min());
}```

we are hacking it

[hushed crescent]

don't be the guy that makes a 2d sidescrolling indie game with bad collision

you have the power...

[raven halo]

bad collision code*

you're right

@hushed crescent what about swept, have you heard of that?

it doesn't look too hard

https://noonat.github.io/intersect/

actually the AABB vs AABB (non-swept) section seems to be exactly what you're talking about

[raven halo]

glorious richter was right

[hushed crescent]

swept is for doing continuous collision detection, you basically smudge the AABBs along over time so you can catch if they met somewhere between frames

generally only necessary if you have stuff moving very fast, so fast that they might phase past each other in a single frame

[raven halo]

right

[raven halo]

i think im already seeing some issues like that

not fast enough to phase through but fast enough for the penetration vector to be nonsensical

[raven halo]

🔥 🔥🔥

[keen forge]

nice, you got built in spoodermain capabilities too

[prisma otter]

Getting closer

[raven halo]

yeah i think i just need to write my own slab method and swept functionality

the functions I'm finding on google arent working out too well

[hushed crescent]

you can probably extend it via convex polygon SAT, I don't know anything about CCD resolution

since a swept AABB is a sort of extended hexagon if you look at it

[raven halo]

you can do some fancy minkowski thing to turn it into ray vs aabb

[raven halo]

perhaps my linux needs a minecraft world

[raven halo]

im close to being back at square one

[keen forge]

gp does feel like playing Ludo

[raven halo]

im using swept aabb vs aabb to get a more accurate resolution vector

and that's working, im not really teleporting around anymore

but I still get stuck on floors/walls because the resolution vector fails to full push the player out

i imagine its due to float precision again

[hushed crescent]

are you just altering the position?

[raven halo]

as opposed to

[hushed crescent]

afaik there's a few ways to go about it, but the most common one I know of (sequential impulse) is just to apply a single frame impulse of velocity

so if you know you have a resolution vector r that encodes a certain direction/magnitude, you can apply an impulse of r / dt to resolve the collision

this works out well for a lot of reasons, particularly because you might have multiple objects you're intersecting at once, and in a physics engine you usually have multiple collision resolution sub-steps in a single frame

so usually your frame looks like

integrate_acceleration();

for (int i = 0; i < substepCount; ++i) {
  find_and_resolve_collisions();
  integrate_velocity();
}

it's also more temporally stable so if you're still stuck across frames you'll still have impulses applied proportional to how much you're still stuck

[raven halo]

2.00001383

[hushed crescent]

yeah there's literally always gonna be floating point error

but if you use sequential impulse it should be more manageable

oh yeah, one more thing you can do if you use sequential impulse is apply Baumgarte stabilization

idk the fancy mathematical rigor behind it, but basically you have 2 error factors: an allowable penetration depth and a damping factor on the impulses

so instead of resolving with a pulse of r / dt, you resolve with (r / dt) * 0.999 or something, and allow 0.0001 units of allowable intersection (or whatever you find via tuning that works for both those factors)

but before you add that, just try simple sequential impulse with r / dt

[raven halo]

vel += r / dt? Does that replace all other resolution?

[hushed crescent]

yeah

and of course in intergrate_velocity in the loop above, you just do pos += vel * dt, then reset vel to 0

[raven halo]

im probably misunderstanding something because resetting vel to zero seems like vel will become useless

since no velocity would persist across frames

[raven halo]

wait...i'm goated

[hushed crescent]

you don't have to reset your velocity, you just have to make sure that you calculate a net velocity for each sub-step and make sure it doesn't run away on you

[raven halo]

i think i got it fixed

rn I'm not doing swept and just adding the resolution vector to the player pos

[raven halo]

bruh it rained a little and now theres a layer of ice covering all the snow

[winged ruin]

Dont even start. We had this for week covering the snow and basically everything. The first day when I stepped out of my house I started sliding into incoming traffic

Once I managed to slide my way into tram stop. I saw a guy sliding 100 metre slope downwards with his ass

[mystic kettle]

We have like a 3 cm permanent layer of ice on every road. It's been going for a month probably. I gave up going outside

[raven halo]

https://youtu.be/WQKSyPYF0-Y

primary inspiration for my physics engine

[dry basalt]

I saw this

Absolutely wild shit

[raven halo]

https://tenor.com/view/morgan-jones-uzbek-gif-9108365450976190246

[raven halo]

Metal Gear Solid is a metroidvania

[raven halo]

https://youtu.be/qEYxtbnab4Q

jazz with xylophone and electric fiddle?!

https://tenor.com/view/meowl-british-meowl-british-british-cat-innit-gif-4785724705753395242

[raven halo]

i have achieved phuysics

slopes are still a little janky

[keen forge]

whenever i see the red square jump, i make a :boing.flac: noise

very cool seeing others making progress in their prijects

[raven halo]

sometimes the player gets caught on that little corner when going up a left facing slope

it doesn't happen on right facing slopes so I believe this has to do with the order of collision resolution

which is done left to right, bottom to top

[keen forge]

https://tenor.com/view/caught-me-not-moving-raccoon-standing-up-gif-1385868221932326739

[raven halo]

production of this game must halt momentarily

I have come across a 39 hour youtube video

nvm, its metal gear and i havent yet played 4 so I'm avoiding spoilers

[raven halo]

New Acerola video mentions Cave Story many times 🙂

[raven halo]

been real busy

i believe the next step is to give our guy a gun

ah only after i fix slope physics

[raven halo]

i think theres a lot of value in games that can be played through in one sitting

those vs longer games are like movies vs series, both good for unique reasons

[prisma otter]

Can you give me some examples? I'd be interested in trying them

[worldly acorn]

Squirrel stapler

[raven halo]

ive heard a lot of good stuff about squirrel stapler

ddlc unironically

a long sitting (~5 hr) but still feasible

[worldly acorn]

It's just a bizarre experience that can be had in one or two sittings, it's a perfect example of the kind of thing an indie game can do that a big commercial game can't

There's also that Miziziziz game Wrought Flesh that is similar although it's a bit longer now I think

[prisma otter]

I'm aiming for ASO to be around 10 hours, so like 3-4 sittings

I think that's a good length

I finished Return of the Obra Dinn in around 3 sittings, that was fun

[raven halo]

i hate online classes bro

interpersonality is being replaced and sanity is the tuition

[dry basalt]

The only online class I took ruined my gpa

I got a 68 in statistics, the rest of my classes are like 80+ lol

[raven halo]

they were classes i had to take and the only offerings were online

[dry basalt]

That sucks

Good luck

[raven halo]

just one semester

hopefully when i transfer to umd such a problem will go away

[prisma otter]

I only ever took one online class in my day, & it sucked. I can imagine they are more common now

[raven halo]

thankfully its not online math, that sounds like the ninth circle

[prisma otter]

It's OK nobody actually cares about you GPA

It literally never came up once since I graduated

[raven halo]

yeah maybe im putting too much effort into these classes

[prisma otter]

Nobody is gonna ask you what your GPA was. Try hard people just put it on their resume if it was really high

[raven halo]

doesnt sound worth maintaining straight As

which ive been doing ever since i got a B in an AP class in freshman high school

time to throw in the towel methinks

[worldly acorn]

Yes lol never take an online math class

[raven halo]

well I think I'll have to do online physics over the summer

hopefully itll be using math i already know

somewhat related, I need to write an essay for a college application of which I'm already guaranteed admission

i guess i should still tryhard a little in case the essay is also considered for scholarships

[raven halo]

the best thing about taking a break from this is that main.cpp isnt 1000 lines long

so when i do come back I'll actually understand my own code

[raven halo]

history class is very hard

[worldly acorn]

Good

I've heard unfortunate stories about humanities classes getting easier because people come into college barely knowing how to read and write lol

So I'm glad to hear they are trying to maintain their standards lol

[raven halo]

oh some of the other humanities i took were a joke

technical writing and health

[prisma otter]

What kind of history? Any particular specialization? I love history

[raven halo]

US History of course

i think ancient to civil war

i don't find the surface level post US civil war stuff interesting

[worldly acorn]

ancient to civil war sounds pretty neat to me

[raven halo]

Rhodesian history wasn't offered 😥

[prisma otter]

Don't forget the part where ya'll lose the war of 1812 🇨🇦🔥

[worldly acorn]

Could take anthropology

[prisma otter]

One of my favourite courses back in high school was "History of the world: 1453-Present"

A good film is also "History of the world: Part I"

[raven halo]

iirc we also went on some sidequests during the revolution and invaded Canada (failed)

[raven halo]

by the way, i still have all those reference pictures of the southern leopard frog

I'll dm them to anyone who wants

[raven halo]

i think this is the last remaining slope bug

meaning i can do this

[raven halo]

i guess i can determine this order depending on displacement direction but thats a huge hack

[keen forge]

i like these little clips of progess a lot

[raven halo]

thanks, ill keep spamming them

maybe I record each hit resolution in an array then undo whatever is invalidated by slope physics

[raven halo]

i feel an urge to buy a monitor and gpu despite not playing anything demanding in months

maybe a monitor makes sense since mine is small and 60hz

[worldly acorn]

So is mine lol it doesn't bother me

[raven halo]

ive heard praise and glory for 120hz

[prisma otter]

Don't buy a GPU lol, you will never financially recover

120hz is amazing but you will not be experiencing it unless you are playing older games or have an insane GPU

[raven halo]

tax returns baby, immeaserable wealth and fortune unto me

[keen forge]

a large monitor makes programming on it a sexy time

[raven halo]

i could also convert my pc to sff, but thatd require a new mobo and psu

and likely all new cooling

the worst thing about my current monitor is that it only has 1 hdmi port

[keen forge]

i have a shitty samsung neo g7, its a 43", 4k, 144hz with some pseudo hdr

its shitty because its not oled hehe, but large fonts in 4k look neat in the IDE

or even kmscon on lunix when ze puter is booting

satisfactory looks great on it (probably because you do get some hdrisms, and you usually dont really have dark spots in that game)

check rtings.com and or hardware (or now monitor) unboxed on youtube

before that one i had a 32" 1440p monitor that was a nice upgrade already, i would never go below 32" again, ever .... if you have space

[raven halo]

is oled that good?

I've never tried it

[keen forge]

ive never seen it in person but its supposedly like once you have it you dont want to go back 😄

[dry basalt]

i have a 9060 xt, which is kinda midrange, and i can get 120 fps in most things

like half the time in ff7 rebirth if im not in an area with dense foliage, ez 120fps

[prisma otter]

I assume you are using FSR to do that

[raven halo]

oled is probably out of the budget

[dry basalt]

No the game just has a lot of foliage

Usually get 70-100 fps, dips into 60 sometimes

At 1440p

[raven halo]

maybe i live up to my word and start recursionmaxxing

1. Detect collision
2. Apply resolution
3. Repeat 1&2 until no collision is detected

ofc getting stuck inside a block will crash the game

[raven halo]

or i try resolving collision starting with tiles closest to the center

[raven halo]

I don't understand exactly how, but I think I fixed this

the way I did it at first was accumulate a resolution vector for all regular tiles, but if the player collided with a slope tile, the resolution would immediately apply directly to the position

now its consistent in that slope resolution is added to the accumulation res vector

well I can't complain

if (hit.intersection && (hit.delta.x > 0.0f || hit.delta.y < 0.0f || pos.y < tilePos.y))
{
    delta += hit.delta;
    return false;
}
else if (hit.intersection && relativePos.y < relativePos.x + hitbox.max.x)
{
    if (hit.delta != glm::vec2{ 0.0f, 0.0f })
    {
        float desiredY = std::min(tilePos.y + std::max(relativePos.x + hitbox.max.x, 0.0f), 
        tilePos.y + 1.0f);

        delta.y += desiredY - pos.y;
    }

    return false;
}
else 
{
    return false;
}

this is the resolution code for a left-facing slope tile (i.e., y = x). Read and weep serfs

i should add more comments to my code methinks

[raven halo]

unfortunately its not a magic bullet

aaannnd messing with reaper broke sdl3, so now my crap doesnt compile

easy fixz

so the final remaining physics bug is as follows:

collision resolution from slopes is always vertical so theres no horizontal push to prevent this

[raven halo]

so the reason this is fixed is a serendipitous else in my code

if (thereWasVerticalCol)
{
  vel.y = 0.0f;
}
else if (thereWasHorizcol)
{
  vel.x = 0.0f;
}

since the slope is a vertical col, any subsequent horiz col wont reset the horiz vel

so that buggy collision detection still occurs but doesnt do anything perceivable due to this cursed thing

[raven halo]

so...recursionmaxxing is still on the table

[raven halo]

betteryet, if downwards resolution is applied when theres already upwards, then -displacement.x should be applied to horizontal res

more on this later

[raven halo]

https://tenor.com/view/half-life-half-life-3-half-life-x-hlx-hope-gif-4217642222569936205

[raven halo]

i dont even care about half life. i just see the hope gifs and my day gets a little brighter

[prisma otter]

Hope is a nice thing to have, the gif is very well done

[keen forge]

HL1 > HL2

[keen forge]

i disagree, but ^ this ^ a funny response

[raven halo]

theyre both cool peices of history but not very good games

gaming got much better in 2004 when fun was imvented

[keen forge]

roblox/wow fanboy spotted

[hushed crescent]

roblox would've been 2006/2007 at least

I assume its 2004 because of cave story

[raven halo]

yeah well i take it back, i forgot about mgs2

but cavestory, mgs3, and the NDS in 2004

then all the wii stuff in 2006

[raven halo]

the sun is slowly returning

https://tenor.com/view/old-future-frutiger-aero-nostalgia-gif-5718842770810967140

were gonna make it

[raven halo]

i finished better call saul season 1, the colors were very vibrant

[raven halo]

a few shots gave me that exact vibe lol

this was shot in 2015? i couldve sworn we had lost color tv by that time

[raven halo]

https://youtu.be/9B9C3awB3j4

rediscovery of the century

https://tenor.com/view/gem-alert-gif-14590606955304525995

[raven halo]

well driving in this blizzard tonight i became a sailor

[raven halo]

i have begun the joys of html and css webdev

you react with the bleakekw but i am having fun

[worldly acorn]

I've just heard things

The only web dev I've done was writing HTML by hand which is quite ok and results in positively based looking sites

[raven halo]

well im making myself a website

but I'll keep that on the low for now

[worldly acorn]

Neat

[raven halo]

internet archive?...

[worldly acorn]

Lmao

[raven halo]

i understand this is an edit of the laughing guy but it looks like that fnaf duck

[raven halo]

incoming crunch

big annotated bib for english and huge project for history due within 1.5 weeks

[raven halo]

https://tenor.com/view/green-mile-im-tired-boss-michael-clarke-duncan-gif-2375696290766999196

[raven halo]

mostly my neck

i have a puppy german shepherd i need to watch, so i cant really sit in a small room with my desk

I'm mostly hunched over on a couch with a laptop in my lap

[prisma otter]

~~He's ~~ She's so cute

[worldly acorn]

The ear ratio is out of control

[hushed crescent]

I'm all ears

[raven halo]

great find https://youtu.be/520wYjCrTvs

1. the guitar riff in the verse is great, and so is the harmonization
2. Carlos Santana intro
3. conveys an emotion I've never gotten from a song before

[raven halo]

https://www.instagram.com/reel/DVeHtr7CDPH/?igsh=ZGo3b3VjbDZmaWE4

devhumour.ai

Follow @devhumour.ai for daily corporate and tech memes!
#programmingmemes #techmemes #memes #codinghumor #software

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[raven halo]

i dont like gen ed chemistry class

the stereotypes are true, theres no learning the how or why, just memorizing rules and letters

fortunately there shouldnt be anymore of this or english to complete my degree

i think itll just be compsci, circuitry, physics, and math stuff which should be good fun

[worldly acorn]

That's just how chem is

It's practical

It gets easier

There isn't really any way to derive it from first principles, at some point you're always going to just have to remember the priorities of the periodic table

[raven halo]

yeah I'm good

the crickets are chirping and the stars are visible

https://tenor.com/view/sunshine-bon-giorno-buenos-dias-morning-sunshine-sun-gif-5020455309533021398

[raven halo]

metric system is pretty dope

i like that when you convert between units, "1" is a pretty solid guess

[prisma otter]

He's seen the light

[raven halo]

it blew my mind to learn cm^3 is a mL

[prisma otter]

Guess how much 1L of water weighs

[hushed crescent]

if you guessed 0.157 stone, you are right

[mystic kettle]

Which stone

[raven halo]

that one

[mystic kettle]

I imagine that's how empirical system was made

[worldly acorn]

The only thing I don't use the metric system for is the temperature of the weather and aircraft altitude

Oh and human weights and heights

Just don't have an intuition for the metric versions of those

[raven halo]

i think the school work load will subside a bit so hopefully i can get back to this

i want to do the physics in substeps, maybe 8, so i dont need to rely on my perfect collision res as much

then ill give our little red box a remington 870 or something

[raven halo]

scratch does a lot of really weird stuff but ngl i miss /0 returning infinity

i know its not technically correct but i think it makes a lot more sense in practice than return nan

but i suppose we do want to keep c++ consistent with accepted math

[prisma otter]

I mean also the hardware will generate a NaN so it's best to just what the hardware does

It's not even really a C++ thing

Until c++20 I think the standard allowed floating point math to be entirely implementation defined

But they changed it to follow the IEEE standard

Which in practice is what the hardware does anyway

[raven halo]

added substeps and with only 4 the physics is already smooth as butter 😩

i spoke too soon

i call this the gauntlet

[raven halo]

call my physics theoretical the way it guesses where the player should be

i am once again splitting collision across the axises because any viable combined solution i dabbled in, like sequential impulse, is overkill

who in the world need sequential impulse for a metroidvania? anyways, I now solve the slope collision in the vertical half, which is done before the horizontal half

[raven halo]

but since horizontal movement, which is done later, contributes to where the player is on the slope, there would be issues where he isn't pushed up enough and you end up with this dreaded issue again

the solution? temporarily apply the horizontal displacement for that frame to calculate how high up the slope to go

[raven halo]

pretty much just guessing where the player will be, and it works wonders. The gauntlet is passed flawlessly

the only glaring issue remaining is that slopes can push the player into a block above his head, and im dreaming up a hack to fix it

[hushed crescent]

https://youtu.be/faBrzVHm7ow

reposting, if you want the direct 4ching link just let me know

[raven halo]

developer is listening

and it slaps

[raven halo]

i am a certified genius

heres physics

[raven halo]

@hushed crescent the Cave Story Lyrical Walkthrough has inspired me, i will now be attempting to beat the Sacred Grounds with minimal HP

words cannot express the difficulty of this challenge

[raven halo]

gun

[raven halo]

i have introduced the scene struct

bikeshedding time

[raven halo]

alright guys

struct Scene
{
  Level level = {};
  LevelEditor levelEditor = {};
};```
or
```c++
struct Scene
{
  Level* level = {};
  LevelEditor* levelEditor = {};
};```

well the editor is more of a system so ig that shouldnt be in there

[raven halo]

i think direct ownership will make the most sense

so the question now is what does and doesnt belong in the scene struct

i.e. whats part of the scene and whats not

ig the player is part of the scene, so he can go in it

level is, level editor is not since its a system

(level refers to the tiles)

then there will need to be entities and enemies

pretty easy right

[prisma otter]

Sounds like bikeshed, it doesn't really matter, just pick one and do it

[raven halo]

also sooner than later i should give bullet better collision detection

since they move fast, i should give them longer hitboxes or something

[hushed crescent]

projectiles are usually fine being raycast

or shapecast if they're big enough

[raven halo]

ah yeah raycasting!

[raven halo]

going along nicely

i might want some sort of event system

[worldly acorn]

I forget are you doing this project ECS-style

[raven halo]

nah

there arent too many entities to worry about yet anyways

just the player and his bullets

so my scene update looks like this ```c++
void Scene::update(float deltaTime, std::unordered_map<SDL_Keycode, bool> keyStates,
bool updatePlayer)
{
if (updatePlayer)
{
player.update(deltaTime, keyStates, level, bullets);
}

updateBullets(deltaTime);

camera.pos += (player.pos - camera.pos) / 100.0f;

}

[worldly acorn]

Yeah

Just the most direct way

What are you thinking of making events for

[raven halo]

eventually player update will include stuff like walking thru doors, dying, etc that will necessitate scene change

so at the very least, some way for the player update to send data back to the scene. ig thats more feedback than events

ill probably just return something like vector<Event> from Whatever::update()

anyways heres entities

i gotta give them guns too

[worldly acorn]

I don't think scene changes and stuff necessarily need events

Personally I think I'd just set a flag in the game state that a global game system then reads at the end

[raven halo]

oh yeah flags

maybe i keep those flags in a 64 bit enum and return state changes from a function

sfx? maybe i just let anything anywhere make a sound effect

demon synthesize me some sounds man

[worldly acorn]

I would just fill your struct full of bools

Don't worry about packing them unless you need them to be sent over the network or something

You can find free sfx I can try to help you make some later

[prisma otter]

I shed a tear for each of those 7 of 8 wasted bits...

[raven halo]

sometimes your RAM needs rest, thats what bools are for

anyways i have the little guys physics

@keen forge youll love this one

[raven halo]

im hundreds of attempts in, most of them end like this

[raven halo]

i did not enjoy inception

if you take away the novelty of shared dreams, its just a bad action movie

there were also no moments of silence, there was some royalty free esque orchestra track playing throughout the entire movie

this is the same guy that made inception? wow

[prisma otter]

Rip

[raven halo]

well, "2D Game" has earned the latter part of its title

[raven halo]

clangd broke and all my code has the red underline 🙁

[keen forge]

that usually fixes itself when you restart the ide

i have clangd crash more than once today too for some reason

[raven halo]

Anyone dabbled with sdl's text rendering? Is it any good?

[keen forge]

i have not, or not that i remember

[raven halo]

@prisma otter what do you use?

for text rendering

Happy Easter everyone btw

[prisma otter]

I use an atlas of msdfs

[raven halo]

its always a great pleasure when an NVidia driver update on linux REDUCES the opengl version

[raven halo]

i dont really play demanding games anymore so im considering yeeting my 3050 in favor of some cheap amd card

especially if it will let me use wayland and hdr

[prisma otter]

AMD is pretty good on linux

But I can use wayland on Nvidia it works great

As for HDR...

I wouldn't count on it lol

[raven halo]

darn

[raven halo]

psa

do not update to nvidia driver 595

it, at least on my system, did not include 32 bit drivers

stay on 580

[prisma otter]

What are you using that is 32 bit?

Unless you mean windows

But i thought you were on linux

[raven halo]

steam seems to want a 32 bit driver