kandi X-RAY | pymunk Summary
kandi X-RAY | pymunk Summary
Pymunk is a easy-to-use pythonic 2d physics library that can be used whenever you need 2d rigid body physics from Python
Top functions reviewed by kandi - BETA
- Fill a space
- Adds objects to the constraints
- Sleep the body
- Add a body to the space
- Draws a wheel
- Return the vertices of the polygon
- Generates an ellipse from a circle
- Generate a list of points from a polygon
- Creates a bar chart
- Perform a segment query
- Generate a convex hull of a list of points
- Query the coordinates of a point in the space
- Step a space
- Perform a point query
- Creates a polyline set of points
- Creates a polyline set for a given point
- Updates the event loop
- Draw a polygon
- Setup the player level
- Create a collision handler
- Creates a collision handler
- Apply a function to each arbiter
- Parse examples
- Draw a circle
- Draw the frame
- Generate geometry for a surface
- Get the vertices of the current mesh
pymunk Key Features
pymunk Examples and Code Snippets
Trending Discussions on pymunk
I follow a youtube video 'https://www.youtube.com/watch?v=cCiXqK9c18g' and in the video he make a class that represent a ball and he used pymunk to make a body and added it to the space and after that he created a method inside the ball class that will use pygame to draw the ball and I did almost like him...
ANSWERAnswered 2022-Jan-18 at 01:28
You error is both a typo and using the wrong variable.
Inside your particles draw function...
I have read that advancing the pymunk space by several steps per screen update can lead to a smoother simulation and help prevent objects tunneling through each other, e.g. How to prevent fast moving objects passing through statics when calculating pi with colliding blocks. The example suggests this:...
ANSWERAnswered 2021-Dec-30 at 19:52
The big downside is performance. It is much more expensive to call step 10000 times than 1 time for a given period of time.
I imagine that sooner or later there will be other effects as well, for example around the floating point precision when the dt becomes very small. E.g if an object has a very low velocity it will move a tiny distance, and if that number is very small it might not be possible to accurately store it as a floating point number (64 bit double in the case of pymunk), so that errors accumulate and the end result is a worse simulation than calling step only once.
I've been investigating Pymunk as a possible platform for a spatial chemistry simulation. I naively thought that when two shapes collide there would be a single contact point. In fact that can be up to two contact points. I also find that each contact point has two points, point_a and point_b. The documentation says
point_a and point_b are the contact position on the surface of each shape
I wonder if someone less naive than I am could explain:
- Why can the ContactPointSet contain one or two contact points only and not three or more?
- Why are point_a and point_b for a given ContactPoint not necessarily the same point, since they are the point at which contact occurs between two shapes?
- Is the shape that point_a is on guaranteed to be arbiter.shapes and the shape that point_b is on guaranteed to be arbiter.shapes, or do I need to check that?
ANSWERAnswered 2021-Dec-05 at 19:42
Im dont know enough of the collision algo to answer from the mathematical background, but I can give some help on the way:
This is from the collision algorithm used. For easy (e.g. Circle to circle) collisions only one point is found, as you can see here: https://github.com/slembcke/Chipmunk2D/blob/master/src/cpCollision.c#L526 In more advanced cases, e.g. Poly to Poly, then the GJK & EPA algorithms are used, https://github.com/slembcke/Chipmunk2D/blob/master/src/cpCollision.c#L607 and this can produce one or two points.
I think the reasoning is shown in the below picture. The points are located on each shape, and since they can be overlapping it becomes natural with one for each.
- I suspect so, but am not 100% sure.
If you are intersted about the GJK & EPA implementation, there's a intro blog post from when it was first introduced into Chipmunk here: http://howlingmoonsoftware.com/wordpress/enhanced-collision-algorithms-for-chipmunk-6-2/
I am trying to make a game, which includes polygons in pymunk, and to be able to do that in pymunk I decided to use many segments and draw it as a solid polygon. When I implement the code im getting an error
ANSWERAnswered 2021-Nov-07 at 08:15
pymunk.Bodys. These bodies must also be added to the space.
Reed the error message:
The shape's body must be added to the space before (or at the same time) as the shape.
Why do bodies in pymunk keep colliding without actually touching each other even after the position and body shape is correctly set?
You will see from my code below that the bird keeps colliding with the ball without actually touching the ball....
ANSWERAnswered 2021-Nov-02 at 21:16
The 2nd argument of
pymunk.Circle is the radius, but not the diameter:
shape = pymunk.Circle(body, 60)
My question is pretty straightforward I just wanna know a way to make a static body, which is a rectangle using pymunk. I tried reading the docs and found out about Segments, but couldn't really understand it. So any kind of help is very much appriciated !...
ANSWERAnswered 2021-Sep-07 at 08:54
Either you can use the static body already attached to the Space, or you make a new one. To create a rectangle, either you provide the corners to the Poly constructor (as shown below), or you use the shorthand Poly.create_box method.
ANSWERAnswered 2021-Aug-23 at 19:22
The problem is that both Poly shapes that are created with the shorthand
create_box method are created with their center at the position of the body they are attached to. So the two boxes are positioned on top of each other.
To fix this you need to use the more generic
Poly constructor. In this way you can pick the positions as you want.
If I just take your picture and write up the coordinates times 10, it would be something like this:
I am interested in simulating a sort of rod-pendulum system:...
ANSWERAnswered 2021-Aug-11 at 06:29
The torque is reset every step, as written here: http://www.pymunk.org/en/latest/pymunk.html#pymunk.Body.torque Given this I think the expectation is that it should slow down over time. I should also add that usually its a bit tricky to set these kinds of values manually, better would be to use a SimpleMotor constraint.
Yes, the center of gravity seems to be the issue here just as you write. The center of gravity will be at 0,0 of the Segment (and similar at 0,0 in case you create a Poly shape). So
c1has the center of gravity in the middle, while
c2has it at one end. You can either just change the definition of
(b2, (0,-20), (0,20)...)and modify the position of the body to compensate, or use the body center_of_gravity property to adjust its location. http://www.pymunk.org/en/latest/pymunk.html#pymunk.Body.center_of_gravity
I think the issue is that the moment you use for the two segment bodies are very extreme. The moment can be calculated with the built in method moment_for_segment, e.g.:
pymunk.moment_for_segment(1000, (0, -40), (0, 40), 6)The calculated moment is 717000, which is quite different from the value in your code. You can also let Pymunk calculate the mass and moment for a body from the Shapes attached, http://www.pymunk.org/en/latest/pymunk.html#pymunk.Body.__init__
Pymunk uses the C library Chipmunk for the actual simulations. The focus of this library was mainly gaming or other realtime uses, and the same for Pymunk. However, I know that Pymunk has been used for many different purposes, as shown in the list of uses here: http://www.pymunk.org/en/latest/showcase.html page. If the algorithms inside Pymunk are accurate and comprehensive enough for your use case I do not know.
A final note is that its probably a good idea to use as small dt in the
space.step function as possible since that will produce better simulations.
I'm fairly new to pymunk and I wanted to make physics engine for my future games, there's just a small problem, My code won't draw the circle that pygame is trying to visualize. Here's my code....
ANSWERAnswered 2021-May-26 at 09:25
You have to draw the objects before updating the display
I was following this tutorial https://www.youtube.com/watch?v=nNjRz31-7s0&t=181s because I wanted to learn pymunk, but then the problem that is described in the title occured. I´ve already tried restarting IDLE and searching for a solution online, but its difficult to find something because I´m not getting an error message . Can you tell were the mistake is?...
ANSWERAnswered 2021-May-24 at 09:36
I am getting an error message:
No vulnerabilities reported
You can use pymunk like any standard Python library. You will need to make sure that you have a development environment consisting of a Python distribution including header files, a compiler, pip, and git installed. Make sure that your pip, setuptools, and wheel are up to date. When using pip it is generally recommended to install packages in a virtual environment to avoid changes to the system.
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