# Tagged Questions

223 views

### Unity falling body pendulum behaviour

I wonder if someone could provide some guidance. Im attempting to create a pendulum like behaviour in 2D space in Unity without using a hinge joint. Essentially I want to affect a falling body to ...
127 views

### How to correctly handle multiple movement key presses resulting in double the speed?

I am trying to implement acceleration and drag into my top-down 2D game. The player can move using the WASD keys. Acceleration works fine, but the way I handle the directional velocity causes the ...
150 views

### Calculating/Predicting a way

I'm just starting with physics, so I'm not always sure about what I'm doing. It's a 2D project but I'm using 3D physical objects like SphereCollider etc.. What I have: Objects floating in space and ...
89 views

### Player glitches through floor? [closed]

I'm making a 2D platformer in Unity, and everything is going pretty smooth, accept I can't figure out why my player is glitching through the floor, the player will collide for a few seconds while ...
244 views

### Why do my velocity estimates have such a large margin of error

I am writing a script in unity that applies a force to the object to advance it a set distance in an environment without friction or drag, producing a cosine force curve. However, as the target ...
76 views

### Farseer - Difference between Position, GetLocalVector, and GetWorldVector

I have used Box2D extensively, and am used to just calling body.GetPosition(). But Farseer does not have this. Instead it has a property Position, as well as methods GetLocalVector and GetWorldVector. ...
318 views

### Increasing efficiency of N-Body gravity simulation

I'm making a space exploration type game, it will have many planets and other objects that will all have realistic gravity. I currently have a system in place that works, but if the number of planets ...
1k views

I'm building a space exploration game and I've currently started working on gravity ( In C# with XNA). The gravity still needs tweaking, but before I can do that, I need to address some performance ...
354 views

### Move a player in the opposite direction they are looking

I'm looking to move the player in the opposite direction they are facing with a specified force. Rather than try to explain that better I created an image showing what I mean, I've tried reversing ...
243 views

### Game physics presentation by Richard Lord, some questions

I been implementing (in XNA) the examples in this physics presentation by Richard Lord where he discusses various integration techniques. Bearing in mind that I am a newcomer to game physics (and ...
134 views

### Farseer: Shooting a ball in a certain angle?

How can I shoot a ball in a certain angle? When I press the Space key, the ball should be shot in a 45 degree angle. How can I do that?
182 views

### Farseer: Difficulties with implementation of DebugView

I added the project "Farseer Physics Engine 3.3.1 HelloWorld XNA\DebugView XNA\DebugView XNA.csproj" to my solution explorer in Visual Studio. In addition, I added a reference to my project and the ...
61 views

### Farseer: RemoveBody is not working [closed]

I want to remove bodies after they touched the character(playerrect). But the bodies get not removed. I set a breakpoint in the following line but it doesn't get yellow: ...
125 views

### Farseer: How can I remove a body?

I have many sensors(coins) in each level and I want to remove the sensors(coins) when the player rectangle(Mario) touches them. I check in OnCollision if Mario touches a coin, if he touches it, it ...
644 views

### “Car” movement in 2D dimension [closed]

I am searching for a simple tutorial how to add arcade car physics for my game. Exactly same user units behaviour i found in next games: Tank Hero: Laser Wars Death Worm: Video: ...
51 views

### Farseer: Difficulties with ContactListener

How can I register the ContactListener in XNA? In the box2d manual is written: 9.4 Contact Listener ... At run-time you can create an instance of the listener and register it with ...
190 views

### How do I make a tile passable in one direction only?

I want that my character can jump through some of the tiles, like Mario does in this video: http://www.youtube.com/watch?v=zIPYzbNrNhc In this video, Mario jumps up through orange platforms, but ...
237 views

### Farseer: are you missing a using directive or an assembly reference?

I want to create a polygon in Farseer. I found an example in the documentation but it's not working because I get this error message: The type or namespace name 'Vertices' could not be found (are you ...
100 views

### Farseer: Ball is not getting slower

The ball is not getting slower when it rolls over a straight platform. I added friction but that changed nothing, the ball still gets not slower. I want that the ball gets slower and slower and stops ...
178 views

### Farseer: Ball is not bouncing realistically

I created a ball that is rolling over platforms. When it falls from one platform to another, it should bounce just like in real life, but the ball keeps bouncing constantly and I don't know how to ...
30 views

### Farseer physics engine: The name 'ConvertUnits' does not exist in the current context [duplicate]

http://digitalerr0r.wordpress.com/2012/03/11/farseer-physics-in-xna-4-0-for-windows-phone-1/ I tried this Farseer tutorial but I always get that error message in the following lines: ...
132 views

### How to use a physics engine for collision detection? [closed]

I want to use Box2D.XNA or Farseer for collision detection in my 2D game, but I don't know how to start. I added Box2D.XNA to my solution, but I don't know how to create rectangles, circles or ...
182 views

### Creating physics in xna

I am creating a racing game using visual studio 2010 and xna 4.0. I'm trying to create some simple physics so my car sticks to the heightmap I have created within my game world and the model adjusts ...
885 views

### How should I calculate the new angle/direction of my ball hitting a wall? [duplicate]

I'm building a Pong game and I am stuck at how the ball should bounce when hitting a horizontal wall. I tried a few methods but none seems to work. So far I have an update method, which is called ...
481 views

### Ball bouncing infinitely and constantly

Alright, so I've got hold of some simple physics mechanics, and am currently trying to implement bouncing. Based on the first answer of this question, I've developed the following algorithm: ...
865 views

### How to make a smooth movement in XNA?

I'm trying to make a nice controls for my game, but I can't achieve enough SMOOTHNESS. if (kbState.GetPressedKeys().Length != 0 && _direction != Vector2.Zero) { ...
320 views

### XNA (BEPU) Physics Performance

Im using XNA 4.0 with the BEPU physics engine v1.2 and I have encountered some performance problems on Xbox. Im not sure if the my mesurements are an expected result of the Xbox (with alot of dynamic ...
2k views

### Get collision details from Rectangle.Intersects()

I have a Breakout game in which, at some point, I detect the collision between the ball and the paddle with something like this: // Ball class rectangle.Intersects(paddle.Rectangle); Is there any ...
8k 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" ...
200 views

### Scaling Sound Effects and Physics with Framerate

(I'm using XNA and C#) Currently, my game (a shooter) runs flawlessly with 60 FPS (which I developed around). However, if the framerate is changed, there are two major problems: Gunshot sound ...
208 views

### What is going on in this SAT/vector projection code?

I'm looking at the example XNA SAT collision code presented here: http://www.xnadevelopment.com/tutorials/rotatedrectanglecollisions/rotatedrectanglecollisions.shtml See the following code: private ...
839 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, ...
182 views

### 2D Physics Engine to Handle Shapes Composed of Multiple Densities XNA

The game I'm working on involves shapes that might be composed of multiple materials in a variety of ways. Let's just take for example a wooden rod with and sizable tip of iron or say a block composed ...
553 views

### Breakout… Getting the ball reflection X angle when htitting paddle / bricks [duplicate]

Im currently creating a breakout clone for my first ever C# / XNA game. Currently Ive had little trouble creating the paddle object, ball object, and all the bricks. The issue im currently having is ...
1k views

### Platformer Starter Kit - Collision Issues

I'm having trouble with my game that is based off the XNA Platformer starter kit. My game uses smaller tiles (16x16) then the original (32x40) which I'm thinking may be having an effect on collision ...
197 views

### How can I stop my Jitter physics meshes being offset? [closed]

I'm developing a C# game engine and have hit a snag trying to add physics. I'm using XNA for graphics and Jitter for physics. I am trying to split the XNA model into it's meshes, then create a ...
3k 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 ...
979 views

### Getting started using C# and Physics (Resources, Tutorials, Samples, etc.) [closed]

As an application developer, I plan on now getting started in game development so I have come along to this site. I am a proficient C# developer so I guess it makes sense to start game development in ...
259 views

### Free physics library?

What are some good recommendations? I have a vertex buffer and indices and I want to be able to detect collision between it and a bounding box or another object.
1k views

### How to make a ball fall faster on a ramp?

So, I'm making a ball game. Where you pick up the ball, drop it on a ramp, and it flies off in to blocks. The only problem right now is it falls at a normal speed, then lightly falls off, not nearly ...
533 views

### Getting a sphere to roll down a .FBX object Unity3D/C#

I'm working on a little ramp and ball game in Unity, I modeled the ramp outside Unity and exported it to a .FBX file, then I imported the ramp in to Unity. I set up the ball and ramp, both have ...
517 views

### Making particle bounce off a line with friction

So I'm making a game and I need a particle to bounce off a line. I've got this so far: public static Vector2f Reflect(this Vector2f vec, Vector2f axis) //vec is velocity { Vector2f result ...
546 views

### Calculating torque required to turn an object to a target rotation, depending on timestep

The function below works fine, when the timesteps of the physicsengine are short enough for the function to update often. It determinates when the ship(the object) needs to start decelerating to reach ...
642 views

### IndexOutOfRangeException on World.Step after enabling/disabling a Farseer physics body?

Earlier, I posted a question asking how to swap fixtures on the fly in a 2D side-scroller using Farseer Physics Engine. The ultimate goal being that the player's physical body changes when the player ...
1k views

### Jumping Vs. Gravity

Hi i'm working on my first XNA 2D game and I have a little problem. If I jump, my sprite jumps but does not fall down. And I also have another problem, the user can hold spacebar to jump as high as he ...
709 views

### RK4 Bouncing a Ball

I am trying to wrap my head around RK4. I decided to do the most basic 'ball with gravity that bounces' simulation. I have implemented the following integrator given Glenn Fiedler's tutorial: /// ...
179 views

### Is it possible (from the vertex shader) to always draw at specific pixels?

I am wondering if I can (if possible) make a vertex shader that will always make the pixel shader draw everything in 1 pixel, at position 0,0. I know this sounds crazy, but it's needed in the ...
2k views

### 2D Platformer Collision/Physics Problems

I'm making a 2D platformer similar to Terraria, although I'm having some problems with some collision detection code. I'm using the code from the AppHub Platformer sample, but tweaked so it fits with ...