boid | Bird-like behaviours | Game Engine library
kandi X-RAY | boid Summary
kandi X-RAY | boid Summary
Bird-like behaviours
Support
Quality
Security
License
Reuse
Top functions reviewed by kandi - BETA
Currently covering the most popular Java, JavaScript and Python libraries. See a Sample of boid
boid Key Features
boid Examples and Code Snippets
Community Discussions
Trending Discussions on boid
QUESTION
Other questions that I viewed before posting this question:
Debug Assertion Failed: Vector subscript out of range
Debug Assertion Failed Vector Subscript Out of Range C++
I am working on a Boids project, details of which can be found here:
https://www.red3d.com/cwr/boids/
From what I can gather my issue is something to do with an index getting accessed by the function but no data is present in the index. I had this issue yesterday in a different area of my code and fixed it by making one of my getters return a reference rather than a copy of a class object. That approach seems to not be the issue today.
Below is my code:
This code is a snippet from my function that handles simulation events. This is the code that I have narrowed down the issue to.
...ANSWER
Answered 2021-May-15 at 22:42I see nothing in this code that can cause an out of bounds access. However, you should not increment i
on any loop iteration that removes an organism, otherwise you will skip the next organism in the list.
Imagine on the 1st loop iteration, the organism at index 0 needs to be removed. Subsequent organisms move down the list. On the next loop iteration, i
gets incremented to 1, and the organism that had moved into index 0 is skipped.
Try this instead:
QUESTION
So I am trying to make a boids simulation. I am trying to implement the first rule which is that each boid must steer away from nearby boids. I have all boids in a std::vector
called boids. Each boids has a std::vector
called withinSensoryRange
which holds all boids which are within the boids sensory range. The way I went about this is to calculate the closest boid in the withinSensoryRange
vector for each boid and then try to steer away from that boid.
ANSWER
Answered 2021-May-10 at 15:30After a few days of struggle I finally got it working. I got the idea from this paper. Particularly this sentence:
Each boid considers its distance to other flock mates in its neighborhood and applies a repulsive force in the opposite direction, scaled by the inverse of the distance.
The code bellow does exactly what the above sentence says.
QUESTION
Recently I found out about the importance of git and therefor started to experiment with it, however I ran into some problems when trying to implement it in a python project on boids. The project directory looks like this:
...ANSWER
Answered 2021-May-08 at 21:38You really should not include those folders because they are dependent on your system and will most likely not work for other people (e.g., Mac vs Windows). Yes, a .gitignore
(Note the spelling) is the way to go. There are many examples out there. Often when you create a Git Repo you can select to include one. However, it sounds like you already have a full git
configured so it's best to push to an empty GitHub repo. Here's one that I often start with for Python projects: https://github.com/github/gitignore/blob/master/Python.gitignore
QUESTION
I have a Boid class with the following constructor
...ANSWER
Answered 2021-May-08 at 01:44std::unique_ptr
can't be copied, it doesn't have copy-constructor but has move constructor. You can use std::move
to convert boid
to rvalue then the move constructor could be used.
QUESTION
I am trying to make boids simulation. What I am currently doing is checking if boids are in each others range and adding their memoery address to a std::vector
called withinSensoryRange
if they are. Here is the code.
ANSWER
Answered 2021-May-07 at 22:55You can use std::find
to check if an item already exists in a container. Or you could use a container that contains unique keys e.g. std::unordered_set
.
You need to be very careful when storing addresses. If the object moves or goes out of scope the address becomes invalid. This is in fact what can happen in your example because std::vector
will move objects around on resize.
Solutions:
- associate and store some unique identifier instead
- use
std::unique_ptr
(std::vector> boids;
), this will ensure the object doesn't move (it's the smart pointer that moves) - make
boids
vector or set const (initialize it on construction) and make sure the containing object (if any) doesn't move throughout your access via pointers. - use a container that doesn't invalidate iterators on resize e.g.
std::list
I tried doing it the std::unique_ptr way. It does not work when I try to push back the memory address
withinSensoryRange
should be a vector of raw pointers:
QUESTION
I have a boids flocking simulation setup. It originally worked by having every boid loop through every boid so that they all constantly know where each other are at in order to tell if they are close or far away, but then I switched to a quadtree design so that boids only have to loop through boids that are actually nearby. However, it has made virtually no improvement to the simulation's FPS. It's as if I'm still looping through every single boid.
Is there some mistake in my implementation? Repo is here, relevant code is mostly in main.js, quadtree.js, and boid.js. LIve site is here
...ANSWER
Answered 2021-May-02 at 13:02The reason why you are not seeing obvious performance gains from the Quadtree is because of the nature of your simulation. Currently, the default separation causes a large number of boids to "converge" to the same position.
Lots of objects in the same position is going to negate possible speedups due to spatial partitioning. If all the objects are in the same or near position, boids in the area a forced to check against all other boids in the area.
You can demonstrate to yourself that your Quadtree is working by watching or profiling your application with its default settings. Now turn separation up to maximum. You will see visually, or through profiling, that as the boids spread out more evenly, the FPS increases significantly. This is because the Quadtree can now prevent computations thanks to its spatial partitioning.
You can see how performance is increased in the second image. Also note, that the conjecture by another commentor that it is the construction of the Quadtree (insert
) that is taking up all the time is wrong.
While in some applications you may be able to update a Quadtree as things move around, since in this simulation every constituent moves every frame, reconstructing the Quadtree from scratch is less work, then taking every object out and reinserting it into its new position.
The advice to skip square-rooting and just use the distance-squared is good though as this will get you a bit more performance.
QUESTION
I am trying to make boids simulation and for that I need triangles that move and rotate.
I made a Triangle
and a Boid
struct.
ANSWER
Answered 2021-May-01 at 19:15That does not look like a proper rotation to me. A quick search for a 2D rotation matrix yields something more like this:
QUESTION
I'm currently writting a 3D implementation of the boids algorithm in P5.js but I'm having trouble orienting my boids according to their direction (velocity). Rotations are limited to RotateX(), RotateY() and RotateZ(). The simplest solution that I feel should work goes along these lines :
...ANSWER
Answered 2020-Dec-16 at 11:05From your demo, the z component is flipped, and you can test this from only trying one of the rotations at a time. Second, chaining rotations in 3D this way will usually not do what you want, as rotating will change the "up" or "right" vector of the coordinate system attached to a certain object. For example, rotating about the up (-y for p5) vector, or the yaw angle, will rotate the right vector. The second rotation then needs to be about the rotated right vector (now pitch), so you can't just use rotateX/Y/Z as they are still in world space instead of object space. Note that I'm completely ignoring roll in this solution, but if you look at the boids from the front and top angles, it should be aligned with the velocities
QUESTION
I'm very new to Rust and I'm having trouble figuring out how to handle ownership (and lifetime?) in this case. I'm not new to programming and I'm actually re-implementing something that already works in JS (https://sheraff.github.io/boids/).
In this context, Universe
is basically a "simulation" environment containing many Entity
. On each universe.tick()
, each Entity
needs to know which other Entity
it can "see". For that, entity.update()
takes a list of Entity
as an argument.
As a result, I have this piece of script that I can't seem to find a good ownership structure for:
...ANSWER
Answered 2020-Aug-08 at 19:59If each entity needs to know about each entity, then it seems like it's not the entity that's responsible for the update. You should probably refactor from a method on the entity to a function that operates on all entities.
Iterating over the entities in a nested loop is a bit difficult. One solution would be to iterate over one copy of the array and allow the other loop to take a mutable reference.
QUESTION
I was wondering what would be the simplest way to make my group of boids pursue my character in a top down 2d game with a path finding algorithm?
I'm thinking I'd have to first find a path to the player with the path finding, get the desired vector and then subtract that from the velocity to get the steering value.
I found "Pursuit and Evasion steering behaviors" on Craig Reynolds' website but I'm not sure if I'm heading in the right direction.
...ANSWER
Answered 2020-Jul-18 at 17:27Note that there is a little more detail in a 1999 GDC paper. There are also many open source implementations, such as this (in retrospect, surprisingly complicated) one in OpenSteer.
An agent’s seek behavior simply assumes a desired velocity toward a static target, and defines a “steering force” which is the error/difference between that and its current velocity.
So a pursue behavior requires only to estimate a current target location. A rough approximation is usually good enough, since it is discarded after this animation frame / simulation step. Typically steering behaviors use constant velocity predictions, simply multiplying the current velocity by some time interval. A helpful estimate for that interval is the distance to the quarry agent, divided by our current speed.
How this interacts with (a) the pursuers being a flock, and (b) a simulation based on path finding, would depend on specific details of your game. Probably you want to blend a small pursuit “force” with the flocking behavior so it does not interfere with the nature of the flock.
Community Discussions, Code Snippets contain sources that include Stack Exchange Network
Vulnerabilities
No vulnerabilities reported
Install boid
Support
Reuse Trending Solutions
Find, review, and download reusable Libraries, Code Snippets, Cloud APIs from over 650 million Knowledge Items
Find more librariesStay Updated
Subscribe to our newsletter for trending solutions and developer bootcamps
Share this Page