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Questions tagged [floating-point]

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43
votes
8answers
7k views

How can I perform a deterministic physics simulation?

I'm creating a physics game involving rigid bodies in which players move pieces and parts to solve a puzzle/map. A hugely important aspect of the game is that when players start a simulation, it runs ...
0
votes
1answer
46 views

How can I avoid the precision loss when recentering objects on open terrain?

For a better context this question is related to this one: What's the largest "relative" level I can make using float? When the player is moving too far away from the center, all the ...
1
vote
1answer
136 views

How much slower is it to draw on “half pixels”?

I've noticed that games like Diep.io are using floating decimal points for thin stroke lines on the grid. I have even tried this myself, by adding 0.5 to all of the ...
0
votes
1answer
349 views

HLSL float bitfield

In HLSL I want to store a bitfield for each color in a texture. Specifically spanning 3 floats (RGB, not alpha). Since each float has to be between 0 and 1 I can only use the significand/mantissa of ...
5
votes
1answer
1k views

Why loss of floating point precision makes rendered objects vibrate?

I'm working on an open-world game. I noticed glitches when I move far away from the origin. The objects seem to be shaking or wiggle. Especially the z-fighting seems to wiggle. And the objects that ...
1
vote
1answer
130 views

Saving total play time could be fine?

I'm making a game that needs to save total played time into file (using JSON) for comparing & resolving data conflicts between local and cloud. I will override outdated one. Currently, I'm just ...
4
votes
2answers
429 views

Prevent tile layout gaps

I'm making a map viewer where you can specify where tiles go in a map and then see it on the screen, translate it, and zoom in and out. Here's a picture showing the tiles used to make my example map ...
2
votes
2answers
576 views

Setting a uniform float in a fragment shader results in strange values, is this a type conversion? How can it be fixed?

First, some details: I'm learning OpenGL from the tutorials on https://open.gl My computer is running Linux Mint 18.1 Xfce 64-bit My graphics card is a GeForce GTX 960M OpenGL Version: 4.5.0 NVIDIA ...
4
votes
0answers
138 views

How can I render geometry represented in a 64-bit floating point environment?

In this video about Star Citizen, right at the 12:30 mark on the timeline you can see the player zooming in on a space station who's location is clearly out of the limit of 32-bit floating point ...
5
votes
5answers
3k views

Are very long floating point numbers a problem?

Very simple question, but important: I was using a floating point number ('float') in C++ to handle movement speed, and it suddenly ran crazy. It turns out the speed increased very fast to ...
0
votes
2answers
175 views

Float inaccuracy. libgdx only? java only? also why?

Hey all I have just come to notice that floats are not accurate even when they are explicitly set and unchanged. For example i have some basic code running and it is: ...
1
vote
0answers
27 views

Fallback for R32F alpha blending

I'm rendering an aggregation of value into an R32F format texture, using alpha blending to accomplish the sum operation. R32F alpha blending is not supported on all hardware. What kind of fallback ...
21
votes
3answers
3k views

Non-integer speed values - is there a cleaner way to do this?

Often I will want to use a speed value such as 2.5 for moving my character in a pixel-based game. Collision detection will generally be more difficult if I do that, though. So I end up doing something ...
1
vote
1answer
2k views

Why aren't there game and physics engines with double precision?

Choice of game design and other human psychological factors aside is the present hardware not capable of working with double precision floating point calculations with reasonable performance? It can ...
0
votes
2answers
123 views

Unity, positioning with ints instead of floats

I round my transform.position to the nearest integer at the end of every frame so it's never a decimal number. I would like to know if there's a way to make unity store the position in ints instead of ...
1
vote
0answers
242 views

Precision problems with realistically scaled planets/terrains [duplicate]

Recently I've been working on a realistically scaled planet engine. I found several interesting links about how to do it, what problems will come up after, and how to solve them. The approach I took ...
17
votes
1answer
3k views

In Unreal, what are the differences between C++'s float and FFloat32?

I have been trying to learn some deeper aspects of UE4 and while reading many examples codes and also the source base of the engine, I noticed that sometimes people (and the very source code) use the ...
2
votes
1answer
239 views

Simulating elastic ball collisions quickly escalates to disaster

I'm trying to learn HTML canvas and was working on a basic physical simulation, where a number of balls are drawn and set in motion, and the program simulates them colliding and bouncing off the walls ...
1
vote
0answers
294 views

Handle floating point precision errors in collision detection and resolution

I am experimenting with a continuous collision detection and response of points on a tile map. This are my results for now: I did this by shooting a ray (red line) from the current position (red ...
1
vote
1answer
197 views

Floating point determinism with respect to procedural generation, clustering and GPU offloading

I've been designing a distributed procedural generation system for a while now in my spare time and one of the problem's I've been thinking about recently, with respect to the broader architecture, is ...
6
votes
1answer
953 views

How do I avoid floating point indeterminism when implementing lockstep?

I am working on a multiplayer RTS game in Java. It uses lockstep for networking, which requires that both computers can deterministically. These are the 2 closest/more viable approaches I could come ...
6
votes
1answer
548 views

Why don't objects far away from the camera experience floating point issues?

In Kerbal Space Program, a space exploration game made with Unity, Floating origin technique is used to overcome the floating point precision issues. While in map view, the world (a scaled space with ...
1
vote
1answer
717 views

WebGL half float equivelant?

I'm trying to find a half float for the purposes of doing math in a fragment shader, not trying to have a half float texture. Is there an equivalent of the ...
2
votes
1answer
447 views

How can I deal with vertex precision errors between terrain chunks?

I am using OpenGL to render the following scene, using vertex data from one of the map files of a popular MMORPG. The data is chunked and the pictured scene is made up of 256 (16x16) chunks. However ...
2
votes
2answers
839 views

Getting around limitations posed by float in space game

I'm working on a procedurally generated game set in outer space. As in the real world, the game universe will be pretty much 99% empty, with planets/stars/solar systems etc... being very far apart. ...
4
votes
1answer
512 views

How do I deal with floating-point error given a far-away camera?

Whenever a camera is "far" away (its location is some "large" vector), trouble arises when rendering objects close to it: It is the classic precision loss from subtracting 2 floating point numbers. I ...
12
votes
5answers
6k views

How do I generalise Bresenham's line algorithm to floating-point endpoints?

I'm trying to combine two things. I'm writing a game and I need to determine the grid squares lying on a line with the floating-point endpoints. Moreover I need it to include all the grid squares it ...
2
votes
1answer
163 views

how did coordinate-handling in old flightsimulators work?

Im currently working on a combat flight simulator pure for own fun. Using a floating-origin i thought the float inprecision was history, however this was the case untill i tried adding multiplayer to ...
2
votes
2answers
1k views

How can I simplify this code to compute the shortest rotation between two angles?

The following code will find the shortest rotation (in radians) (from pi to -pi) that I need to apply to from to leave me with to...
13
votes
3answers
1k views

What's the largest “relative” level I can make using float?

Just like it was demonstrated with games like dungeon siege and KSP, a large enough level will start to have glitches because of how floating point works. You can't add 1e-20 to 1e20 without losing ...
4
votes
4answers
4k views

How to reset the world in an infinite runner game to prevent an overflowing float?

Im following Mike Geig's 2D infinite runner tutorial. However, I'm seeing a potential problem of overflowing the float How can I reset all objects and camera back again to the origin? The approach I'...
0
votes
1answer
584 views

Point rotation around point, accuracy question

I study OpenGL ES 2.0. But I think it's more a C++ question rather then an OpenGL one. I am stuck with the following rotation question: It is known, that rotation transformation can be applied using ...
4
votes
1answer
833 views

Deterministic calculation in JavaScript [closed]

I want to create a multiplayer game with HTML/JavaScript and only send user input between players. I read some articles for C++, saying that I could not expect floating point to get the same results ...
0
votes
2answers
136 views

Algorithmic error in tile engine? [closed]

I'm toying with creating a tile-based 2D java game engine. I can render the "local" area without issues(I.E. deciding which local tiles to render). The problem came when I introduced floating point ...
0
votes
1answer
220 views

XNA Float values don't work as parameter

With the Microsoft XNA Framework I can change the color of a tinted texture by changing it's integer values like so: ...
3
votes
1answer
413 views

Continuous world and very large levels: going around the FPU limitations with Ogre3D

I'm currently using Ogre3D, and I'm wondering is it's possible to have a very large level (hundreds of kilometers) using the right scenemanager. Storing or having the level is not a problem, since I ...
0
votes
1answer
417 views

Issues calculating frame independent movement

I'm developing a Breakout style game in C++ using SDL. The problem so far is that the ball slows down and speeds up for no particular reason. The slowdowns usually last a few seconds. EDIT : When ...
14
votes
3answers
2k views

What caused “falling out of the world” and what fixed it?

A lot of early 3D games had the problem where you'd be trundling merrily along and suddenly everything was black, with an island of what looked like the hollow facade shell of the scene you'd been ...
3
votes
1answer
851 views

Vertices shaking with large camera position values

Basicly when i set the position of my camera (my character in game) to a high value, the geometries seems to be shaking, the higher the position value, the more they shake. On low position values you ...
1
vote
1answer
3k views

Unity3d Transform.position float range

I thought floating point has a very large range, for example up to 3.4*10^38. However today I tried to set my player's Transform.position.x to 1000000 in the GUI and it gave me a warning: "Due to ...
-1
votes
2answers
492 views

JavaScript “Floats”, or ThreeJS wrong positioning? [closed]

I want to learn how to use Vectors with 3D. Here is a strange Error I have encountered today. Instead of stopping exactly on the other Cube, I get this: When I change the IF to (cube.position.y <...
5
votes
1answer
3k views

Should I use float, double, or decimal for stats, position, etc?

The problem with float and double is that they are not exact. If you are to do something like store replays, the values would have to be exact. The problems with decimal is that they are ...
10
votes
1answer
3k views

Floating Point Precision (fp:precise vs. fp:fast)

In C or C++, does the compiler option of floating point precision really make a difference in real world (small/indie) games? From my observations, setting fp:fast is many times faster than fp:...
1
vote
2answers
597 views

Deterministic Multiplayer RTS game questions?

I am working on a cross-platform multiplayer RTS game where the different clients and a server(flash and C#), all need to stay deterministically synchronised. To deal with Floatpoint inconsistencies, ...
3
votes
4answers
2k views

How can I view an R32G32B32 texture?

I have a texture with R32G32B32 floats. I create this texture in-program on D3D11, using DXGI_FORMAT_R32G32B32_FLOAT. Now I ...
4
votes
3answers
5k views

Python float 32bit to half float 16bit

I'm trying to write a 3D model exporter addon for Blender in Python and need some help. The spec of the 3D format uses some compression on the vertices, there is a vertex buffer that contains ...
-1
votes
2answers
397 views

Could a large number, such as 255.000255 be converted to it's RGB channels in a Shader language?

If I had a Vertex Shader constant holding one float value, like: 255.000255 Where: The first 3 numbers are actually red (255), next three are green (000), then ...
4
votes
4answers
7k views

Conversion of a number from Single precision floating point representation to a Half precision floating point

Hope it is relevant here. I have a code where I have to work on Half precision floating point representation numbers. To achieve that I have created my own C++ class fp16 with all operators(...
52
votes
9answers
15k views

How are deterministic games possible in the face of floating-point non-determinism?

To make a game like an RTS networked, I've seen a number of answers here suggest to make the game completely deterministic; then you only have to transfer the users' actions to each other, and lag ...