I'm working on a 2D game (kind of like a top down space shooter) for the iPhone using an engine very similar to cocos2d (not exactly though) on OpenGL ES. I'm trying to figure out how I'm going to do collision detection.
All the ships for my game are images, and the game will load the image as a texture onto the screen. I've got very very simple detection going already that basically just takes the rectangles of the images and checks to see if those collide and can do that just fine.
But, of course the ship isn't perfectly taking up the entire rectangle so there is whitespace in there. So my question is how am I supposed to account for that whitespace? Do I have to have the matrices of the ships stored? Or is there another way? I've also heard of possibly using the Chipmunk physics engine for collision detection? How would that work?
(1) regarding Chipmunk, the short answer is yes you should immediately download chipmunk, donate something to the bloke, and start learning about it.
Working with that for a day or so will basically answer all the questions you have. If you want to work with physics games you're going to need to get in to it.
(2) you ask about using an approximation ("just" a rectangle) instead of something more accurately shaped like your spaceships. In fact, you'll be perhaps amazed to learn, that is precisely how it is usually done in all your famous big-name games you've played since we were all kids! Indeed sometimes you might use little more than A DOT (!) to detect collisions.
What you'd probably do in production is try a more complicated model, and play with it for a few hours and see, is it actually any better to play with than your simple dot or rectangle model.
If you do want to make a more complicated model -- just make one! Build it up from three or four rectangles using your current system. Try them "all against each other", and have "one big one to check first" to see if it is even anywhere near each other (sort of a simple spatial hashing).
You will find that when you do it with Chipmunk, which as you now know you have to immediately begin after reading this message, you just build it up the same tedious way. It's not a magic bullet. But if you were going to use a "more complicated model" yes it is better to go with something standard, chipmunk, to do the work in - it will get done quicker and better. There is heaps to learn and you should hop to it!
(3) Unity is not just for 3D Finally if you want to do it the smart-ass grown up way, you'd have to use Unity3D which will let you access the very metal, the Nvidia physics on the chipset. Note that unity works perfectly for 2D games also - you just click one button in unity to use a 2D projection (many brand-name ifone 2D games are done exactly like that).
If you use that approach, you can (if you want) have "absolutely exact" physics, with every nook and cranny of your model modelled.
What is the downside to doing this? Ah hah ... well the thing is, you need superb actual 3D models of all the stuff in your game! (Like you see them building in the "how we made the movie" special features that come with your favourite Pixar blu-ray.) To do that you need things like autodesk, maya and the like. you would quite likely buy some models ready-made from a digital prop shop (no need to build "a chair" as it has been done 1000 times already and you can buy one for ten dollars).
(Unity3D is completely free to use for a few months while you see if it can make you money.)
Incidentally on the Chipmunk front --- you can just use Corona which is ridiculously easy to use and has chipmunk-like physics completely built in with zero effort on your part! You could have the whole game done in less time than it took to write this email. You could be selling your game already and thinking up the next one. Or, you could use "Cocos" which indeed has a chipmunk-like physics library built-in .. personally (just me) I do not like and won't touch cocos - but of course many games use it.
(It seems pointless, to me, using cocos which is a "for idiots" product, when you can just go ahead and use Corona, which is a "for idiots" product but stupendously easier to use, 1000x more solid, and probably literally 10x faster to finish your product and start making money.)
Noel Summary:
So in some sense using Unity3D (and hence, the actual nvidia physics on your computer's chips) is the ultimate solution if you want detailed nook-and-cranny collisions. Going down one step, Chipmunk is exactly, precisely what you should be using on the ifone/ipad for 2D physics -- it is precisely what is used in all the famous games we know so well. You have a bit of learning to do so hop to it - it's superfun. Finally go right ahead and just make your current model more complicated if you wish - roll your own by adding more rectangles!
And the fourth point is, be sure to remember that in games, astonishingly, you can often get away with remarkably simple physics (often SIMPLER!! than one rectangle - just a damn point - ie, simply measuring the distance between centers!) Fifthly after going to all the effort of testing more detailed physics, you would play test one against each other, and find out what is the simplest physics you can get away with.
Related
so I've been trying to see if I can make use of Wheel Colliders for the past several months now. As much as I've managed to figure out more and more things about how to set them up properly, there's some things I've been noticing that seem impossible to avoid:
Even if your friction sideways stiffness is lower, there's a chance that your car will continue to "spin" or "rotate" in the direction you were steering if you JUST hold down your input long enough to get the car beyond just rotating. I've noticed this will happen, whether for example the "SteerHelper" or "TractionControl" functions are doing their work or not. This will put a dent in ensuring smooth turn movement. Now, I don't know if maybe this is just due to realistic car physics (I mean, I can picture the car skidding in scenarios where they lost grip of the road for sure), but it just feels kinda glitchy. Sometimes, even when I'm not turning, the car will start to turn a little to the left or right and then gradually seem to "lean" that way in terms of applied torque to the rigidbody. I've seen many suggestions for trying to stop the rigidbody from doing this. Here is one way I'm trying to work against this:
rb.AddTorque(-rb.angularVelocity * 2);
However, it seems that the car will still "spin" more than intended. What would be ideal is to be able to MAYBE allow the car to turn a little extra after the left or right steer buttons were released (maybe more or less depending on the vehicle), and no more than that to ensure there is maximum control to give the engaged and maybe arcadey game play I've been going for for a long while.
It's been difficult to adapt an ideal friction curve value that would give the most ideal feel of a drift turn, especially a more arcadey one. I'm not trying to go for wide turns that slow you down, I'm trying to go for tight (yet controllable) turns that allow you to preserve most of your speed. I find that especially at higher values of stiffness, as I know many people have observed in other posts, that again, the car will turn back an extremely high amount sometimes (you drift left enough, a force is turning your vehicle way to the right). It's sad, because I've wanted to be able to say I've "mastered this beast" and used it for my purposes, but I don't know if that's really a good practical expectation for anyone. I even worked my own alternate friction curve values that would be used in the controller:
But I guess as some people say, you can't polish something that's broken? Moving to the third point...
I've read so many posts that show how to adjust a vehicle's center of mass, or to add more colliders in different spots to correct it, using scripting to add an offset to the center of mass, etc. So many tips that say, "lower the center of mass, you'll find it" and I give that a try. When the center of mass is too low, my car can get pretty shaky on the terrain (not that it hasn't in the past, but it's often been things I could correct, like the weird initialization of the attachedRigidBody of the wheel colliders themselves in the beginning, etc). High enough, and of course, (even when it's lower sometimes???) the car will just start spinning in the air on either multiple axes or specifically the forward z, when you drive off a ledge or bump into something with a high enough speed. It just seems inevitable.
I've been trying to give my benefits of a doubt. I like to think there's a correct way to use this thing, and that I'm just not familiar enough with Unity3D physics concepts. However, it just seems more and more that I'm investing too much time in a broken component - or, maybe I just never got the best grip of physics.
I was about ready to try just convex mesh colliders around my tires, and just abandon the idea of gripping physics altogether, but I'd love to hear suggestions to either address anything I've mentioned above, or just a more ideal package to move onto. I've glanced at packages like Vehicle Physics Pro, but I do want to be sure I'm getting something that makes sense.
Full disclosure: I'm in the middle of trying to make a game that feels incredibly similar to F-Zero, but with wheels.
Thanks in advance for any thoughts or suggestions you can provide.
(Maybe not an answer per se, but hopefully helpful.)
Note Unity also suggests to possibly give the car a constant downward force via script. It might be telling that such workarounds are officially given, one would think proper physics would, well, properly work without them.
There's some assets you might want to give a try generally:
One is the Unity Asset Store asset called Arcade Car Physics, and it's free. I've tried it and it works (but not sure if it works for your needs). It's using Unity's native Wheel Collider plus extra scripts.
Another is the Arcade Car Physics github project. It has nice plane stabilization and more, and works well. It's not using the native Wheel Collider.
Then there's this asset called Vehicle Physics. Instead of native Wheel Colliders, they've create a fully custom wheel system so that it would be more physically workable. The asset is not free, but they offer a free demo executable where you can drive around different vehicles, and that works quite well. (I haven't yet bought this asset myself.) As a downside, some reviews mention there's some complexity in setting this up (and I suppose future support for this custom Wheel Collider hinges on the company continuing to exist).
Good luck!
I plan to take some 3D scans of real people's heads and need to put these new heads onto existing generic avatar bodies (happy to buy these if necessary) for use in some basic VR settings (for research purposes) and would like some advice as to possible (time efficient ways) to do this.
The first part, scanning, cleaning and optimizing the head scans will (I hope) be relatively straightforward but I'm unsure about how I can easily replace the avatar head.
I'm less bothered about perfection of the join (though I don't want it to look like frankenstien's monster) but more on saving time (as I'll need to do this with a lot of scans). In particular what to do about the neck and blending in the join.
I don't need facial expressions (though longer term they might be nice) though I will want to be able to rotate the neck set direction of gaze.
Ideally i'd like to replace the head in code at runtime in Unity rather than hand editing the models but I suspect this might not be possible.
If the process could ultimately be partially automated by scripting that would be even better.
Many thanks,
When you have a rigged character in Unity, you can see the bones in the hierachy. You can put anything on any bone - for example your head on the neck bone. Just make it a child.
This will move and rotate with the bone - for example in animations or motion-capture (VR).
So I am pretty sure what you want to achieve is as simple as adding the Mesh as a child to the bone.
Imagine a large free-roam game in Unity,
The yellow size indicates about the largest you can make a typical Terrain in Unity.
Art dept. will completely build, meter by meter, the entire scene.
Please note, this has absolutely no connection to repeating scenery (as in runners) or procedural scenery (as in say some race games).
Really, what is the correct and good way to do this in Unity?
use say 50 or so terrains, each perhaps 100m x 100m ?
can you even have or use that many terrains?
or what?
For anyone googling here.
The correct solution is indeed
Terrain stitching
that's it.
In practice you must use one of the tools available to do this (eg, TerrainFormer) or, your team will write from scratch a terrain stitcher.
Yes, you just use "many terrains".
The best approach to the exact problem posed,
is in fact to just:
"use lots of Terrains".
It seems to be perfectly viable in Unity to have many (dozens) of Terrain units, basically "sitting next to each other".
In practice, you'll need TerrainFormer
https://assetstore.unity.com/packages/tools/terrain/terrain-former-20052
or one of the similar tools.
(Or, I suppose, from scratch write your own tool to stitch terrains, and allow you manipulate them all at once, join the edge-heights perfectly, etc etc.)
It's not realistically possible to just perfectly sit many Terrains together (by hand), matching all the edges, etc etc. So you're going to need a "stitcher" package for putting many Terrain squares together.
So, this huge area ..
has about 12 Terrain.
So that's the answer, you can indeed have "many, many" Terrain in a Unity project, you do indeed essentially just "sit them next to each other". In practice it's not achievable unless you use one of the editor tools such as TerrainFormer.
The proper way to do this would have been with procedural mesh generation with MeshFilter and Mesh API but you mentioned that this not at all random or generative so that one is eliminated.
It's just simply a very long, thin, hand-made environment
The best way in this case would be a Modular Level Design. You need to create Modular Assets. With this you can have a long road in pieces which can be tileable. A good modeling artist should be able to create and texture modular assets with 3D modeling packages like Blender, Maya or 3ds Max.
All the programmer has to do is make each asset a prefab then use the Instantiate function to instantiate them to create any distance of environment. You can also create a static environment in the scene from the Editor. Almost anything can be made into a modular Asset especially buildings and roads.
After assembling them in Unity, you can do static batch on all the instantiated modular parts with Unity's StaticBatchingUtility.Combine to improve performance of the game since they are not being moved.
Below is an example of a modular road asset that can be used to create almost any amount of road:
You already answered your question
in this case would it be better to not bother with Unity's otherwise excellent Terrain, and the modellers would just outright build the long course/scenery? (Obviously you'd have to chunk it so it all occludes fine)
I think it's the way to go. If the performance is an issue, try putting each chunk in different scenes and then have a master scene to load them async and additively. And of course you want to unload each scene as it becomes invisible in the camera.
I personally go with your own solution which is letting the Unity Occlusion Culling system to take care of the hiding and showing chunks. I only go with the separate scenes approach if I'm not getting enough performance this way.
I recently had the same problem. We build a tilebased infinite runner with road crossings. The camera was positioned behind and over the car looking down on the street and the player car. So the setup is quite comparable.
We used Curvy from the Asset store to create paths for moving the player and also for creating the geometry of the streets and the surroundings among the streets.
https://assetstore.unity.com/packages/tools/level-design/curvy-splines-7038
It is also easy to spawn tiles with curvy paths and combine them at runtime. So you can separate long distances into smaller segments and spawn them randomly.
We also used QuickBrush from ProCore to quickly paint environment detail to the geometry like trees, bushes or stones. I think procore tools are now implemented in the new Unity 2018 version.
Worked quite well.
I want to implement Silhouette Highlight on MouseOver like in this picture:
Built in Unity3d user interface elements have a component called Outline and Shadow, but they only work with the user interface, not with the SpriteRenderer. The first idea was to create a second sprite with highlight at background and enable it to MouseOver, but I think that this method is not good.
As Everts (and me) mentions in a comment,
there's nothing wrong with simply making the "glow sprites" and turning them on and off. That would certainly be done in many large games: it's good.
It's true that you could write a shader that does this, but really that would be "bad engineering" - totally unnecessary for such a simple need. (And to be clear, arguably it's plain better to make custom sprites.)
Now, this brings us to an important point about Unity engineering -
it's critical to use existing assets, in Unity work.
There are a couple of stand-out examples. Like, NatCam and Edy's vehicle system. You just - literally - cannot use the camera in a game unless you use "NatCam"; the only alternative would be to completely pointlessly spend a year building NatCam yourself.
In this case, there are many good "glow shaders" available ...
https://www.assetstore.unity3d.com/en/#!/content/20166
Enjoy!
I have been digging around trying to find a way to show a game board of sorts.
It is basically a square board with a round hole in the middle, I am able to render the scnBox and the scnTube, but I would like the area where the scnTube sits in the box for the box to be transparent and see through the game board, but can't seem to find anywhere that has an example. Any help would be much appreciated. I am hoping that I am just missing something very simple, but this is my first time using scene kit.
Thank you.
Before Unreal Engine 4, (UDK and prior) Epic's modelling space was subtraction - a filled block was your game world and its extents. From inside this block you took chunks out to create space for players to run around in, and shoot each other. All's fair in love and war.
I'm telling you this because it's a good example of how contrived 3D modelling is compared to real world scenarios, and should (hopefully) put you at sufficient unease to digest what follows.
This approach of carving out of a finite block is still in Unreal Engine 4 and popular with older users, but it now defaults to an open, infinite world into which things are added. Most new users gravitate towards building into an infinite space of nothingness rather than carving space out of a solid, finite block.
Everything about 3D modelling is virtual, and virtually impossible to relate to the real world. Instead of thinking in terms of how things could be done if objects were real and literal, you need to think in terms of the limitations (and there are many) of geometry definitions as used in most 3D modelling and game engines.
The programming equivalent of this mental gymnastics is going from the concept of classes and objects to their realities within languages and frameworks. On the one hand the ideas and their ideals are wonderful, and on the other the realities are a bleak reminder that programming languages haven't really progressed very far, at all.
3D modelling is exactly like this. It's not much further along than it was decades ago, and is still using archaic ways to solve many of its original problems.
Cutting a nice, clean, efficient round hole in a cube is one such original problem.
A very simple shape is being intersected and cut by a shape with the potential for infinite complexity. What should happen? Should the simple become complex or the complex become simple? How to make the most graceful transition between the two?
That's the problem you're facing: a cube is a simple geometric shape, easily defined by minimal line segments. A cylinder introduces infinite possibilities for line segmentation around its circumference.
So somewhere along the lines of development, the architects of 3D modelling had to come up with a way to make these contrasting line complexities play well together for lightweight presentation on limited hardware. Their solution, in most cases, is a hybrid and a disaster of user operability, but masterful in its geometric efficiency: Polygon modelling, UVW unwrapping and subdivision!
All of which means that if you want to achieve this in the best way possible, with today's tools, for the purposes of Scene Kit, I suggest polygon modelling this board in Maya for 4 reasons.
It's got a 30 day free trial.
It works on a Mac
It's polygon modelling tools are second only to 3ds Max
It's easier to learn (for a complete newcomer) than MODO, and miles easier to learn than Blender.
MODO is interesting if you're already skilled in Polygon modelling, but it's so utterly discombobulating if you don't have that prior experience that I'd recommend using just about anything else first. Except Blender. Blender is free, but don't be tempted. It will cost you more in learning time than buying a copy of every other professional 3D app.
In MODO's favour, and the reason I mention it, it does export nicely for Scene Kit. I know that for a fact, but am not yet sure how well Maya exports for Scene Kit.
Which is the next problem you're going to come up against. All COLLADA files are not born equal.
New Maya does have Unity and Unreal export presets, so I presume it's possible to calibrate its COLLADA exports to match the demands of Scene Kit perfectly, just haven't yet needed to do it. This will (very likely) involve trial and error to get the settings right. It would be nice if Apple would tell us exactly how to configure export from all major 3D apps for Scene Kit, but instead they're giving us the half baked Model I/O, so we can double the effort of importing artwork.
All context aside (which has largely been to demonstrate that 3D is no simpler nor more refined than using an IDE and frameworks like Xcode and Cocoa), here's the meat and potatoes:
A video on one aspect of what's best to make holes, and starts out as you are, with a cube and a cylinder:
https://www.youtube.com/watch?v=zaEv5rio8bk
But it does presume a certain amount of Maya familiarity, some of which you can gain from this rather slow and ponderous examination of two other ways to make holes in cubes:
https://www.youtube.com/watch?v=lvMfoH5Ikrc
Yes, if you're counting, that's 3 ways to make holes. Actually four, because the first video starts with the boolean operation you might have been expecting to be how this could/should be done. In some parallel future we'll have well working boolean geometry operations. We're not there, yet.
Hopefully that same parallel future will offer us a programming language, frameworks and terminology that's not confusing and maintains metaphors long enough to make teaching easy and usage elegant and simple.
I dont know about that long answer but this can be achieved with Boolean Subtraction. You create a cube and a cylinder. You subtract the cylinder from the cube. In 3ds Max this is under compound objects-modifiers-boolean subtraction. I guess Maya has a similair function somwhere in the menus.