Logic of why games are built this way?

[Perene]

In the past I remember people used to say that it was due to the low memory that Super NES/PSX/etc. could not store information about something that happened in a game, like a zombie killed and minutes later you return to that spot and it has vanished (instead of the corpse preserved, no matter where you go and what you do).

GTA IV (and countless other games) have the same "issue", if you destroy a specific part of the scenario, say, using the RPG, and comes back later, everything is back to normal (I always thought this was a decision from the creators, either to make an easier game or to make things more convenient for the players).

I want to ask you what is the limitation that prevents a game from remembering something that happened before. Some users said it is technically impossible to accumulate many random "situations" because that would create a very large save file or perhaps it has something to do with the hardware itself.

I don't know anything about this subject, so I hope you can clarify what I am missing.

 

[ImpulsE69]

It's a design decision. Some games do keep that info intact. Some reset on a timer. Many choose to clean up things such as bodies to indeed lower resources.

 

[cmdrdredd]

Memory, think about how much memory and other resources would be required to keep every body, every tree and brick you knocked down, and every car you crashed permanently in the same location. The amount of potential destruction would be impossible to calculate with even a basic physics engine. To have it all there at once it would need to be in some type of memory.

 

[mizzou]

Memory, think about how much memory and other resources would be required to keep every body, every tree and brick you knocked down, and every car you crashed permanently in the same location. The amount of potential destruction would be impossible to calculate with even a basic physics engine. To have it all there at once it would need to be in some type of memory.

I don't think that's right. There were some ancient flight sims that had the ability to play a save game file, watch it on a "recording" from various angles, and then give you the ability to jump in the game at any point during the recording. Wasn't this x-wing vs. tie fighter?

For instance, Minecraft doesn't seem to have any issues recording the specific placement of hundreds of thousands of blocks.

I believe it's more of a design decision then a computing/storage problem. It's akin to letting the player start tearing out several pages of a new book. What the player destroys could potentially wreak havoc on the prepared story.

 

[bystander36]

I don't think that's right. There were some ancient flight sims that had the ability to play a save game file, watch it on a "recording" from various angles, and then give you the ability to jump in the game at any point during the recording. Wasn't this x-wing vs. tie fighter?

For instance, Minecraft doesn't seem to have any issues recording the specific placement of hundreds of thousands of blocks.

I believe it's more of a design decision then a computing/storage problem. It's akin to letting the player start tearing out several pages of a new book. What the player destroys could potentially wreak havoc on the prepared story.

While it is possible to record, that memory does add up, and it has to be stored. Over time it would eat up your hard drive space and they'd have to load that info into RAM when you go back.

Some games may save the info, others don't bother, either because it isn't important enough for them to save and load the state of everything that happens throughout the game, or because they don't want to waste storage on it. If they did, game saves would take a lot more space, most likely.

 

[futurefields]

I want GTA 6 to have a fully destructible city. If I blow up an apartment building I want those NPC's to actually be displaced, and living in a tent city somewhere else on the map.

 

[BoberFett]

I don't think that's right. There were some ancient flight sims that had the ability to play a save game file, watch it on a "recording" from various angles, and then give you the ability to jump in the game at any point during the recording. Wasn't this x-wing vs. tie fighter?

For instance, Minecraft doesn't seem to have any issues recording the specific placement of hundreds of thousands of blocks.

I believe it's more of a design decision then a computing/storage problem. It's akin to letting the player start tearing out several pages of a new book. What the player destroys could potentially wreak havoc on the prepared story.

A flight path is one object's path. That's insanely simple.

Minecraft does'nt have the entire world in memory at all times, it's a 3-dimensional grid system rendering a small portion (1000x1000x255?) of the world at any given time with a single longint able to store what kind of block it is. An open world FPS type game has far more detail about object state to store. You crashed a car? What's the state of every panel and window on the car? Where are the wheels? What are the X, Y, Z and normal of every potential object in the world? Do you know how many objects that is over the course of a game?

I'd love to see more stateful worlds in game someday too, but we're a little ways off.

 

[Kelvrick]

A flight path is one object's path. That's insanely simple.

Minecraft does'nt have the entire world in memory at all times, it's a 3-dimensional grid system rendering a small portion (1000x1000x255?) of the world at any given time with a single longint able to store what kind of block it is. An open world FPS type game has far more detail about object state to store. You crashed a car? What's the state of every panel and window on the car? Where are the wheels? What are the X, Y, Z and normal of every potential object in the world? Do you know how many objects that is over the course of a game?

I'd love to see more stateful worlds in game someday too, but we're a little ways off.

Eventually, as we play virtual reality games, I'm sure it can cheat a bit and pull from our actual memories what happened and reconstruct on the fly. You know, cuzz it KNOWS we didn't remember certain things.

 

[Blitzvogel]

Alot of stuff can be done procedurally now. It's amazing what can be done with a few basic rules, algorithms, and inputs to get pretty awesome results. Something like a car race replay isn't an actual video recording, it's playing back the set of commands that happened to recreate the actual race. Your car however in the replay is shown based on your inputs. Those crazy "fit in 100 Kb demos" work off the same principle.

 

[nightspydk]

It has nothing to do with memory, agreed its design.

Why would a wrecked car take up more memory than a fully functional one. It has just as many windshields or not and so forth.
The broken car example is really just a replacement of textures.
The same would apply to a wall texture etc.

On the other hand a corpse displayed with inventory and stuff. Remnants of a spawned monster ie would require more demand on cpu. Since most games really are individual zones or cells loaded in memory at the required time, it is quite possible and done a number of times. As corpses pile up though the demand on cpu to render the cell would increase.

I remember the old Heroes of WW2. Every single dead enemy stayed on the map inventory etc. If you dropped something on the ground anywhere it would stay there. Many games have done that.

Hope that made sense.

 

[bystander36]

It has nothing to do with memory, agreed its design.

Why would a wrecked car take up more memory than a fully functional one. It has just as many windshields or not and so forth.
The broken car example is really just a replacement of textures.
The same would apply to a wall texture etc.

On the other hand a corpse displayed with inventory and stuff. Remnants of a spawned monster ie would require more demand on cpu. Since most games really are individual zones or cells loaded in memory at the required time, it is quite possible and done a number of times. As corpses pile up though the demand on cpu to render the cell would increase.

I remember the old Heroes of WW2. Every single dead enemy stayed on the map inventory etc. If you dropped something on the ground anywhere it would stay there. Many games have done that.

Hope that made sense.

That does not make sense, as you are forgetting something here. They have to recall the state of every object of the game to keep it persistent. When they do not have to recall what every zone looks like, they do not have to store that information anywhere, because they just load up the default information when they enter an area. If they have to keep track of everything, they have to store it somewhere.

As we learned with DA:I, some of the storage requirements of these things, restrict older consoles, so they omit them for all systems, so everyone is playing the same game.

Even if the visuals of something broken and together are equal, if you only have to recall 1 possible look when you go back to an area, they do not have to save that information in your game saves.

 

[SMOGZINN]

Why would a wrecked car take up more memory than a fully functional one. It has just as many windshields or not and so forth.
The broken car example is really just a replacement of textures.
The same would apply to a wall texture etc.

Something like a car is a predefined thing and when needed is just called up. So that if there are two car_123s sitting at a redlight the memory just points to car_A123 and says draw it in each location needed. But if you break the windshield of one of those car_A123s we now need to create a new instance of car_A123 with every modification to that specific car_A123 stored in memory, now when those two car_A123s are sitting at a redlight we have to have each of them stored in memory instead of just the one with two different location informations.

 

[JamesV]

Something like a car is a predefined thing and when needed is just called up. So that if there are two car_123s sitting at a redlight the memory just points to car_A123 and says draw it in each location needed. But if you break the windshield of one of those car_A123s we now need to create a new instance of car_A123 with every modification to that specific car_A123 stored in memory, now when those two car_A123s are sitting at a redlight we have to have each of them stored in memory instead of just the one with two different location informations.

Each car is a predefined object with properties, like Windshield; if it's true the windshield is drawn, if it's false then it is not.

I've never seen an object instantiated multiple times (ie multiple templates of the same object) from business to game programming; it's simply unacceptable to waste memory like that.

It all comes down to performance. In Dishonored they make bodies disappear, because if you knocked out everyone in a level and threw them all into a small room, some people might crash or have issues, so nobody is allowed to do it (although I think there is a mod for that).

 

[BarkingGhostar]

I have no need, or desire, to walk by my dead self after respawning.

 

[PrincessFrosty]

It's just resources to store the state of the system everywhere.

For instance, Minecraft doesn't seem to have any issues recording the specific placement of hundreds of thousands of blocks.

The Minecraft world is very simple, the map is just a grid of 3D coordinates and then it just needs to store a single number to represent the block type at that part of the grid and maybe an orientation and that's about it.

A more complex system like say GTA IV where you have ragdols and physics enabled objects and potentially thousands of decals (effects pained onto scenery such as explosions marks, bullet impacts, blood splatter etc), keeping track of the states of these systems is a much more memory intensive process, storing them takes up a lot of memory and more importantly for open worlds like GTA IV where content is streamed in/out of memory as you navigate the map (potentially at high speed in cars) this presents a significant bottleneck for populating the area around you.

There's also gameplay and artistic reasons for doing it, there's many instances where debris and bust up cars and things blocking the road for significant periods of time result in unknown conditions for missions and alike, you don't want to start a "follow this bad guy and stay a certain distance" kind of missions only to find they and you both ram into a traffic jam of vehciles you'd previously blown to pieces. Clearing the map allows the game devs to control the experience players have for each mission much more tightly, which is a good thing.

*edit*

I should also add that these kind of systems also allow players to create an unusually large amount of objects/debris/particles all in one area and if it's persistant and the number builds up too high then real time performance will plummet. If you've ever played GTA IV coop and all stood at an intersection and created a massive blockade and fought the police together and left the traffic build up you'll know what kind of performance impact that can have.

 

[DeepPurple]

The game itself would have to be relatively small, as the memory requirements would be huge. Can you image what a save file would look like if it had to remember everything that you did over the course of three weeks of playing mass effect? Not to mention the everything that happens in between re spawns.

 

[clok1966]

Its memory, while most gamers have system that could handle tons of stuff, toady most games are designed console first, then PC. memory in a Console is used much differently then a PC as there is much less. its used for many things (as a pc does too, but again its used more sparingly in a console as there is simply less due to costs). people mention going into a game like Xwing. You have to remember destroyed objects are gone in that (been a long time, that is correct isn't it?) so you just have an ON /off for each object and then a postion, not much memory. Now you take a city, with destructible environments, let alone cars, possible the PC and NPCs. You have to track them all, and while in a NORMAL game that may be easy, what happens if Joe gamer wants to destroy every building just to see if he can, you track destruction states, debris, Do they block people (knock a 10 sotry building down, will it fall on a road an block it? If so how do we make it so this cant stop the game (inaccessible areas) and its not just location, but position, and if you do random, even destruction state, you could destroy that single building 100 times and it would never be the same. For instacne, you hit it in left corner, or right corner, not the same, then it breaks into 100 pieces (just that corner) to 1000? or 10? are they all the same piece of debris? Players would frown on that. SO they are random, how do they lay, all the same? are they on top of each other, what angle, etc.. so while its not huge (probably small) you map all that to memory, then he does the other 4 corners, then 10 more buildings, then 20 more, this starts to add up, say it takes 200K, nothing.. on a PC, but 200 more buildings, tts soon some actual memory that matters. SO do you spend time designing something for console and PC? do you just make a building rebuild? the easy answer is, rebuild as it doesnt effect gameplay, 99% of people will forget or wont care what building was destroyed. Wiht a HD you can write to that and read it on loads, but again, memory, they more it is used (position, placement etc) the less it can be used for math, video swapping, cache, etc..

game designers (some) are brilliant, and i have never programmed anything past simple games, but memory is always a thing to think about.

 

[dave_the_nerd]

That would be cool. I could build a skyscraper in GTA with bodies of cops.

But when a civilian spawned at the edge of my FoV and saw it... they'd scream and run away, right?

Red Faction had destroyable, persistent maps, but I think bodies despawned after a while.

 

[lord_emperor]

Pretty sure with 8+GB of system memory and 2+TB hard drives storing the necessary information isn't a concern. From a gameplay perspective a lot of games would benefit from persistence and a lot would not.

 

[Fallen Kell]

As has been said, it is memory and/or save state/game information that limits this. Some games attempt to remember a lot of this information (think Skyrim), but after a while, the save games become huge with lots of potential for corruption.

There are ways to attempt to optimize the information that is required to be saved. For instance, if a car crashes into a object, you could simply save the point of impact, and the other parameters that are used for generating the damage state (i.e. velocity vector of car, velocity vector of object hit, mass of car, mass of object hit, location of objects at time of impact) and keep a history of those impacts such that a car's final damage state can be simply reapplied to the object when it comes back into frame (after being removed from active memory/cache for performance reasons). But again, the entire game engine would need to be designed from the ground up to support saving that kind of information, and it may not help as much with destructible objects (or simply becomes more complex as the pieces that come apart need to be spawned as new objects with their own damage state history).

 

[Midwayman]

I think a lot of the limits now are artifacts of much older console hardware. The whole idea of checkpoints or save points has console written all over it. As far remembering the world state between saves its a hardware thing again most of the time. If you don't have a limited number of objects in a level they can accumulate (dead bodies) However you run out of GPU to render and memory to store all them eventually. I've seen games handle it different ways. Some have a discrete set of enemies and their state is preserved. Others save them until memory is needed and they get despawned. Other still will allow you to keep adding things until the world performance goes to hell (mostly older titles, PC usually)

But in short is mostly hardware limits. The more stuff you want to store, the higher the minimum requirements on the box.

 

[digitaldurandal]

Why would a wrecked car take up more memory than a fully functional one. It has just as many windshields or not and so forth.
The broken car example is really just a replacement of textures.
The same would apply to a wall texture etc.

Well many of the games that cleanup the wrecked vehicles do NOT hold the non wrecked vehicles in memory. Indeed the normal vehicles spawn in when you enter the zone or approach the street. The game is not actually tracking 1000s of NPCs and vehicles at all times.

You mention a game that tracks when players drop items and this is not nearly as intense as tracking a vehicle with damage. The vehicle has a lot of variables associated with it. Variables for the hood bumper roof each door each tire each window the trunk alternatively there could be different states recorded in a single variable but it would still take more memory to record than the location and orientation of an object.

However there is more than that at play. From a design perspective if you left every wrecked car on a GTA map it would quickly become impossible to commute. Scripts for plot scenes would break because there would be no good path for the NPCs to follow.

 

[nightspydk]

Good point yes, but strictly speaking of the rendering of graphics, I think I made my point. Obviously everytime we are talking about a spawn the requirements of the hardware will increase. If you think of the car as an object yes and you should.
The object in itself do take up the same amount of memory with a broken windshield or not.
As for pathfinding. It should be an algoritm that takes into account all these factors or it will be a lousy one.

That was all I was saying.

look at STALKER lost alpha. It is a prime example of what can be done. It should not require more programming. I mean the sprites etc are there, it just need to be implemented and yes that is where consoles come into play

 

[bystander36]

What do you mean, it doesn't require more programming? Of course it requires more. They have to devise a system to save all that info, and load it when needed.

 

[nightspydk]

mister

try a bit of programming first you will see what i mean. It is all just variables. You put carx on tiley and so on..

I will try to explain again..
as long as you have the skin..textures all you need is the right algoritm to setup the right conditions for something to appear. It might be a car or a plant or a light source anything..
It is basic programming.