Relating to the motion of objects through space and time. Including concepts such as acceleration (thrust and gravity), mass, collision response, friction and more.
120
votes
8answers
23k views
Fixed time step vs Variable time step
What is better for games when developing game loops, fixed time steps or variable time steps? What type of games are better with one or the other?
Variable time steps:
With variable time step, I ...
16
votes
2answers
3k views
How to make a character jump?
I am currently making a game in C# using Direct X 9.0. The game remake is Donkey Kong NES. I have nearly everything completed, but I am having problems with the physics of Mario's jump. I have ...
49
votes
5answers
14k views
Good 2D Platformer Physics
I have a basic character controller set up for a 2D platformer with Box2D, and I'm starting to tweak it to try to make it feel good. Physics engines have a lot of knobs to tweak, and it's not clear to ...
10
votes
3answers
4k views
Is there an algorithm for a pool game?
I am looking for algorithm to calculate direction and speed of balls in a pool game. I am sure there has to be some type of open source code for this since pool games are some of the oldest computer ...
4
votes
3answers
2k views
Why is my velocity decaying?
Programming in Java. Tinkering around with physics. My entities all have position and velocity. In the main loop, all I'm doing is applying gravity and bouncing off the edges, like so:
// add ...
11
votes
5answers
5k views
How can I implement gravity?
How can I implement gravity? Not for a particular language, just pseudocode...
43
votes
7answers
3k views
2D Platformer AABB collision problems
I have a problem with AABB collision resolution.
I resolve AABB intersection by resolving the X axis first, then the Y axis.
This is done to prevent this bug: http://i.stack.imgur.com/NLg4j.png
...
14
votes
2answers
3k views
How are physics or graphics components typically built in a component-oriented system?
I have spent the last 48 hours reading up on Object Component systems, and feel I am ready enough to start implementing it. I got the base Object and Component classes created, but now that I need to ...
6
votes
1answer
237 views
How do I detect ledges?
In my game, I'd like my character to be able to grab and hold onto ledges, and to be able to pull themselves up if there's room to do so.
How do I detect if there's a ledge, and if the character has ...
4
votes
3answers
1k views
Determine Resulting Angle of Wall Collision
So I have an object moving in a direction towards a fixed horizontal or vertical wall. How do I compute the angle that the object should bounce off at? The object can approach the wall at an arbitrary ...
13
votes
5answers
4k views
Lag compensation with networked 2D games
I want to make a 2D game that is basically a physics driven sandbox / activity game. There is something I really do not understand though. From research, it seems like updates from the server should ...
10
votes
7answers
10k views
How do you calculate where a ball should go when it bounces off the bar?
I'm trying to wrap my head around this very Hello World-y problem in game development. I've created a TicTacToe game in XNA so I guess the next step would be a breakout clone.
Keep in mind that I ...
10
votes
3answers
482 views
Animated examples of different interpolations formulas: any link?
I remember having spotted a link to a huge page with different equations to non linear interpolation curves, for example if you want to stop a car smoothly, etc.
Those can sometime be useful to ...
5
votes
3answers
1k views
Resources to learn programming rigid body simulation
Where I can start learning about simulating rigid bodys 2d and 3d ?
10
votes
4answers
2k views
Physics engine recommendation which can simulate pool game correctly?
I'm making pool game like game. This game requires correct (or very accurate) reflective bounces.
I tried Box2D and Bullet Physics, but they have this problem.
If there is a wall on top of this ...
10
votes
5answers
834 views
How could you parallelise a 2D boids simulation
How could you program a 2D boids simulation in such a way that it could use processing power from different sources (clusters, gpu).
In the above example, the non-coloured particles move around ...
10
votes
2answers
346 views
Implementing a homing missile [duplicate]
I'm having some trouble implementing a homing missile that satisfies what I'm looking for. I have already tried the Seeking and Arrival behaviours described in this link, but none of them were what I ...
10
votes
2answers
572 views
Resources of realistic water simulation?
I want to study water simulation, with a a demo with source code which using physically-based methods(Eulerian approaches or Lagrangian approaches).
How can I get some examples?
9
votes
1answer
1k views
Angle of Reflection
I have this "Breakeout style" game.
I have a cannon at the center, blocks around the cannon and pads around the blocks. This is how the game looks like:
I've managed to get the collision per ...
7
votes
5answers
3k views
2D rectangular object collision - Detect direction
Coming form this question, I'm needing some more help.
I need some ideas to find out from which side the collision came, and react accordingly.
Use this image as reference:
The blue lines are the ...
1
vote
4answers
899 views
Which Side Was Hit?
I am working on an Android game and I have two objects A and B (both rectangles) and when they collide I simply want to know which side of B was hit. I have detected the collision fine, but I am ...
7
votes
3answers
276 views
Impulsioned jumping
There's one thing that has been puzzling me, and that is how to implement a 'faux-impulsed' jump in a platformer. If you don't know what I'm talking about, then think of the jumps of Mario, Kirby, and ...
5
votes
2answers
321 views
“Super meatboy”-ish replay
I'm making a platformer built from mini-levels - and I want to create a sort of a replay of all the player tries that the player did for the level.
My question is - what is the best way to record the ...
4
votes
1answer
742 views
Character bouncing off ground due to gravity
Implementing gravity in the game, the character keeps bouncing up and down slightly when he hits the ground, upon debugging the character is essentially bouncing on and off the ground. Not quite sure ...
3
votes
1answer
1k views
New Vector Calculation for Elastic Collision of Circle and Fixed Rectangle
I am writing a fairly simple breakout-style game for Android phones. I have successfully detected the collisions between the ball(s) and bricks. The problem that I am having is in calculating the new ...
1
vote
1answer
343 views
Farseer Physics for Xna missing ConvertUnits class
Im using Farseer Physics with Xna 4.0. Im following a starter guide. It said that to draw, I need to convert the meters to pixels with the ConvertUnits namespace. I looked through all of the engine, ...
1
vote
4answers
750 views
Solving for velocity in the x/y/z axes?
In a 3D environment I have an object with a displacement x that I know I need to traverse in a given time interval. I have the object's heading and elevation and I want to figure out the distance the ...
-5
votes
2answers
371 views
two balls stick together in a pool game? [closed]
when multiple collisions occur between balls..sometimes they stick together..mostly in cases of either of the balls having high velocity..can somebody explain pls
25
votes
3answers
3k views
2D water with dynamic waves
New Super Mario Bros has really cool 2D water that I'd like to learn how to create.
Here's a video showing it. When something hits the water, it creates a wave. There are also constant "background" ...
27
votes
2answers
2k views
Water/Ocean simulation and physics
I'm looking for some references about water simulation, and how to model it's interaction with bodies (like boats, ships, submarines).
I've found a lot of references on the visual aspects of water ...
18
votes
3answers
5k views
Is there a 2d physics engine that can model fluids and gases?
At this point the platform and programming language don't matter I would just like to know if something out there exists for this. Any help is appreciated.
21
votes
6answers
2k views
Implementing a wrapping wire (like the Worms Ninja Rope) in a 2D physics engine
I've been trying out some rope-physics recently, and I've found that the "standard" solution - making a rope from a series of objects strung together with springs or joints - is unsatisfying. ...
13
votes
3answers
2k views
What is a good book on physics for game development?
I'm looking for a good beginners' book on the subject of physics in game development. Something that focuses on 2D games would be preferable.
29
votes
6answers
3k views
Analysis of Mario game Physics [closed]
I know there's a breakdown of Sonic the Hedgehog physics found here, and I was wondering, does there exist a breakdown of any of the Mario games? Something similar to this but for Mario is what I'm ...
22
votes
7answers
4k views
About floating point precision and why do we still use it
Floating point was always troublesome for precision on large worlds.
This article explains behind-the-scenes and offers the obvious alternative - fixed point numbers. Some facts are really ...
9
votes
4answers
3k views
Vehicle physics with skid
How would I go about creating vehicle physics for a car that can loose traction? I want it to seem like the driver has a flat foot, so when you press the gas, they cars driving (rear) wheels loose ...
18
votes
6answers
1k views
Data structures for interpolation and threading?
I've been dealing with some frame-rate jittering issues with my game lately, and it seems that the best solution would be the one suggested by Glenn Fiedler (Gaffer on Games) in the classic Fix Your ...
11
votes
2answers
2k views
In a 2D platform game, how to ensure the player moves smoothly over sloping ground?
I'm developing a physics engine for a 2D platform game. I'm using the separating axis theorem for collision detection. The ground surface is constructed from oriented bounding boxes, with the player ...
9
votes
2answers
1k views
Continuous Physics Engine's Collision Detection Techniques
I'm working on a purely continuous physics engine, and I need to choose algorithms for broad and narrow phase collision detection. "Purely continuous" means I never do intersection tests, but instead ...
9
votes
6answers
2k views
Ball Physics : Smoothing the final bounces as the ball comes to rest
I've come against another issue in my little bouncing ball game.
My ball is bouncing around fine except for the last moments when it is about to come to rest. The movement of the ball is smooth for ...
9
votes
1answer
1k views
Separating physics and game logic from UI code
I'm working on a simple block-based puzzle game.
The game play consists pretty much of moving blocks around in the game area, so it's a trivial physics simulation. My implementation, however, is in ...
8
votes
3answers
2k views
How do you do AI path following within a 2d physics engine like farseer/box2d?
I'm in the process of moving a 2d top down game I've been working on into a proper rigid body physics engine like Farseer. Up until now, I had just hacked together my own physics code where needed.
...
7
votes
4answers
647 views
Not sure how to handle “deceleration”
I say "deceleration" because I'm not using acceleration at the moment (it is being calculated, it's just set to 0 0); what I mean is moving the velocity back towards zero, eventually stopping.
I'm ...
6
votes
2answers
657 views
How to implement friction in a physics engine based on “Advanced Character Physics”
I have implemented a physics engine based on the concepts in the classic text Advanced Character Physics by Thomas Jakobsen. Friction is only discussed very briefly in the article and Jakobsen himself ...
2
votes
3answers
646 views
Coarse Collision Detection in highly dynamic environment
I'm currently working a 3D space game with A LOT of dynamic objects that are all moving (there is pretty much no static environment). I have the collision detection and resolution working just fine, ...
10
votes
1answer
520 views
How does pixeljunk shooter simulate its liquids?
I am really impressed by the liquids in pixeljunk shooter. I would love to know how they do it.
9
votes
1answer
954 views
Adding air drag to a golf ball trajectory equation
I'm developing a 2D golf game in VB.NET 2005, but I am stuck on how to implement air or wind drag that should affect the ball.
Already I have these equations for projectile:
Vo ...
8
votes
6answers
572 views
Ragdoll on alive creatures: has somebody already implemented it?
I find that a dead creature falling realistically is boring.
I wonder, has any game implemented an animation system where the model moves depending of the muscle forces and the velocity of the limbs, ...
8
votes
3answers
695 views
Forces on a wire in a 2D environment? (Physics)
Assume I have a physics primitive I am going to call a "wire" wrapped around a 2D environment (as described in this question).
Here's an illustration of what that might look like:
In the example ...
0
votes
5answers
426 views
Collision detection logic
Edit 2
In the following picture sprite1 (the red square) is hitting the platform from the left, so:
sprite1_rightEdge>platformSprite leftEdge
would be true, so I can simply reposition ...
