I have player,as shown in the image on a bridge.I want his movement to be restricted to the bridge.(at present he can run outside the bridge in air).How should i achive this.?
1 method i have thought of is to use use continous collision detection between the bridge and the player,to check if he stays within the area.is this the right way to approach?and are there any other alternate ways
Continuous Collision Detection isn't strictly necessary unless it's moving really fast.
I see to way:
Use 3 collider: one for the player the other 2 for limit the sides of the bridge. This way the player can't compenetrate colliders and won't fall dawn.
Manually check inside input handling function that the limits of player movements (since the bridge has a simple shape, it shouldn't be difficult)
Related
I am working on a 2D game with colleagues that is basically a fighting game on a vertical map with platforms. Right now I am spawning items on the map for player to gather, but I was wondering how could I do that while checking that I'm not in one of the platform's collider to avoid spawning the item in?
You should take a look at the overlap functions from Physics2D (for example here). Just generate a drop position and pass it to this function, if it returns null then the position is free. If you get unexpected results make sure to set the layer mask to the same as the platforms or whatever objects you don't want to intersect with.
I just started (yesterday) using unreal engine and I need to simulate a drunk character using BPs.
I'm using two camera shakes (one for standing still and one for walking) but I want to add some "displacement" on charater when he's walking.
Basically I want to define a random float to be added to X axis location in order to make character wobble smoothly.
It will be acceptable even if there's a way to make the character move along with the camera when it's shaking.
What I tried until now is using AddActorLocalOffset and a timeline to lerp between actor's location and actor's location+offset, but both are very choppy to me.
Maybe it's a noob question but as I told I'm very new to this and need it for a quick work.
Any suggestion?
Thanks
If you are targetting physically correct model, you should use AddForce (UE Docs). But this approach would require implementation of a "drunk animation" where your character will modify it's movement animation to "compensate" this force by stepping aside etc.
Another (much more simple) approach is by using AddMovementInput. This example can be seen here: UE Aswers. In this case, you are basically simulate player's input by adding small amount of side force here and there.
I'm new to using xna and I want to make my player collide with with multipe walls from the same class. So I looked around and I understood that the best way for doing that is to create a list of variables containing the walls id's and make a loop that circles them all and then returns the variable of the objects that collide.
My question is if there is a faster more efficient way for doing that? I mean if I have like 10000 objects that loop can cause a lot of memory use.
Thx in advance
Option 1) If these 10000 object are walls of a level, then you should probably use some sort of grid (like this very old example: https://en.wikipedia.org/wiki/The_Legend_of_Zelda#mediaviewer/File:Legend_of_Zelda_NES.PNG)
With a grid you only have to check collision with adjacent objects, or only with objects that are nearby.
Option 2) If these 10000 objects are enemies or bullets that move more freely, then you could also calculate the distance first and only check for collision if the objects are nearby.
But may I ask why you are using XNA? I used to work with XNA 4.x but in my understanding it is pretty much dead (http://www.computerandvideogames.com/389018/microsoft-email-confirms-plan-to-cease-xna-support). If you're new to XNA, I would advice to use other software to make games (like Unity3D). In Unity3D the hard part of collision detection is done for you (is has standard functions for collision detection) and Unity3D also works with C# (like XNA)
You always want to do the least amount of processing to get the job done. For a tiled 2D game you usually have a 2 dimensional grid. When the player want to walk on a certain tile you can check that tile if it is allowed to walk there. In this case you just have to check a single tile. If you have a lot of NPC's you could divide your map into sections and keep track of in what sections the NPC's are. Now you just have to do collision detection on the enemies within your section.
When you need expensive collision, pixel perfect or polygon collision you should first check if an object is even close with a simple radius float or BoundingSphere only then you go on with more expensive collision detection.
Same goes for pretty much anything, if you have a 100x100 tilemap but only need to draw 20x10 for the screen then you should just render that portion by calculations. In unreal, mappers create invisible boxes, when inside these boxes it only draws a certain part of the map and only checks collision within these boxes. GameDev is all about tricks to make things work smoothly.
xcode 5 iOS7 sprite kit.
My wish is to make a sprite that has its own gravity.
Like a planet. If another sprite comes within a certain range of it, it will slowly pull the other sprite closer.
I have two sprites. One moving and one stationary. When the moving sprite gets in a given distance of the stationary sprite the stationary sprite gravity should slowly pull the other sprite towards it. This way the moving sprite would change its path in a soft curve.
My idea would be to calculate the distance from the stationary object to any other object and if close enough start pulling and if the moving object gets out of range ageing, then stop pulling.
Would probably need to research some vector calculation.
Thats my immediate thoughts.
Is this possible and how? Does it already exist?
A friend of mine did this for his physics dissertation. multibody gravity simulation. So yeah you can but you need to be willing to learn some maths. Apparently there is a clever optimisation to make it run decently nlog(n) rather than n^2). you probably want to ask this on the physics version of stack overflow to get a good answer. I have the code at home ... will post it later but you will want an explanation - i used it in an xna app. Its badass once you get it working - although if you want naturally orbiting objects then you will want to code them using parametric equations for easy and cool orbits. Simply because its hard to solve and with time even using double will result in some errors (the good implementations also work out the error and adjust - again will post later). But the real problem is solving for stable orbits. You then use the algorithm for free moving bodies such and player objects / npcs. Although solving accurate movement for npc in a changing field is v hard.
you want to look at this question: Jon Purdys answer is the one you want
multi body physics - gravity
and this one (which is linked from above) ...
https://gamedev.stackexchange.com/a/19404
There is not a dead-simple way of doing that in any platform as far as I know maybe except for some game engines/platforms that export for different platforms (cocos2d, construct 2 etc).
What you need is a physics engine whether you write one (which is a complicated but fun thing to do) or use an available one.
Luckily I've found a link describing the usage of the famous 2D physics engine "Box2D" on iOS.
This one explains how you can include Box2D in an openGL application (but you can apply this to other environments (sprite kit) I think altough I'm not an iOS guy);
http://www.iforce2d.net/b2dtut/setup-ios
Anyways, you now know what to look for...
For iOS 8.0+ : you have SKFieldNode : radialGravityField()
For iOS 8.0- : one solution could be : 3 to 9
add your sprite ( planet ) with its physics
add an invisible SKNode ( the gravity zone ) with its own physics, as a child of your sprite, but with a radius much more than your sprite's one
you have a little explanation about invisible node here : https://developer.apple.com/documentation/spritekit/skphysicsworld
both, your sprite and the invisible node are centered in a zero gravity world
we look for contact and not collision ( set correctly your bit masks )
when any object get in contact with the invisible node ( gravity zone ), first you remove any moving action or impulse from it and then we add to this object an SKAction to move it toward the center of your sprite ( planet )
at second contact between this object and your sprite ( planet ), you remove all actions again from the object with a velocity = zero
I have a sphere build from multiple objects. What I want to do is when I touch/click an object, that object should find all adjunctive objects. But because none off them are moving, no collision detection can be used.
I can't find a way to detect these adjunctive objects even when the colliders do collide with each other, as I can see that in the scene. I tried all the possibilities, but none off them are working, because no objects are moving.
Is there a way to check for manual collision detection, or is there some sort of way to let Unity3d do the collision detection automatically?
You could keep a list of all those objects, then when your event happens you can send messages to all them to do what you want them to do.
Lets assume you want your sphere to break into little pieces. You send a Force message to the sphere. Then you use Newton's Laws of motion and find out how much velocity each piece gets. Remember velocity is a vector thus it has direction.
This is how I would do it and still keep the right amount of control over what happens in my game/simulation. Remember F = ma.
you could use RaycastHit (http://docs.unity3d.com/Documentation/ScriptReference/RaycastHit.html) for your collision, this also works on non-moving objects but it needs more performance
You can add rigidbody to every objects; when you touch one of them, give a force onto it, then it is going to move and trigger event of the adjacent objects.
for the reason you do not want to move the object you touch, you can cancel movement in the OnCollider or OnTrigger event handler function.
I managed to work around this by checking the distance from the selected object and all other objects that are part of the sphere. If the distance is below a certain value, then it is an adjunctive object.
Although this is certaintly not fool proof, it works without problems so far.
I am sorry I was not clear enough. Thanks for all the advice what so ever.