Develop Reference

Collision detection in own game engine

I'm stuck on collision detection:
I've read about different ways of dealing with collisions, and choose to implement it with AABB. Problem appears right in the beginning: I have my test object - wood tower, and I'd like to enclose it with AABB object, I'm iterating through vertices to find min and max values for each axis, which works ok, but takes a lot time, even for single one object (It's quite big object I think ~8000 vertices).
What is proper way of doing it? Should data like this be in object files or I'm just doing it wrong way? Object may be big (I don't know if it is), but it's just one object, I'm afraid about what will happen when I set more of them
I'm writing with c# and OpenTK
Edit:
I know I should use the simplified collision model, I'm trying to find the boundaries over which I will build the AABB box (I had the screen hooked up, but it looks like mods didn't like it). Iterating over each vector seems somehow wrong (although it works, I have a nice box, fitted to the size of the model, but not in the effective processing time)

Yes, you should do that when creating the model resource file. I think your calculation method is fine as is.
And then if this model rotates or scales in your game, make a new AABB from the OBB(which was the AABB loaded from the file before transformation).

Unity2D: move object along path - unevenly distributed waypoints - constant speed needed

I am currently facing a problem I cannot wrap my head around. In my 2D game which in the end should become some kind of virtual model railway, I can create a path, consisting of different railtypes. Each rail has it's own waypoints. Now the issue is as follows:
Straight rails don't need many waypoints, since they only need two to be defined; The start and the end point. Curves on the other hand need a lot more waypoints, so the objects movement on them is not all jaggy and unsmooth. The problem I am facing is, that the waypoints then are so unevenly distributed on the whole railway, it makes the speed which the object moves along the path very uneven.
I also already know the issue: The points are so cramped in the curve sections that the distribution looks like this:
See this picture for an example with red Gizmo.Spheres as waypoints
Now when I move an object along that said path, I do it like this:
wagon.transform.position = Vector2.MoveTowards(wagon.transform.position, wagon.GetNextPosition(), wagon.GetSpeed());
The third parameter of the method Vector2.MoveTowards() is the maxDistanceDelta, so it can only move that amount into the direction of wagon.GetNextPosition(), which is constantly updated.
The twist is, that the densly packed points result in a way shorter distance than the maxDistanceDelta. So in those parts of the railway, the object moves way slower then wagon.GetSpeed() per frame.
I already have a solution to this, which sadly I cannot use: I took every waypoint and distributed them evenly on the path. I don't want that; I want the path to stay as is, but the speed to the eye to be uniform.
Thanks in advance for your help!
PS: I already looked in similar threads, but none of those solutions seems to work for me :( Namely:
This thread
And this one

I would comment this but unfortunately I don't have enough reputation, so here it is:
The best idea I can think of is to create 2 waypoints for your curve (at the start and finish) and use a parabolic function to define the movement between them. So in other words, your train follows a parabola instead of moving towards waypoints directly.
I found a useful answer on a unity forum about parabolic trajectories which you may find useful for your project (It is the first answer beneath the question at the time of writing).

How are you generating those waypoints?
Could you use bezier curves instead?
If yes, there it's typical to run into exactly this issue and solutions have been found. Not solutions with absolute accuracy, but usually sufficient for games (aka visualizations that in the end only need to be as accurate as the pixels you see).
There is this outstanding video about the topic: https://www.youtube.com/watch?v=aVwxzDHniEw

Use c# to animate instead of Animator in Unity

Well I know animator system in Unity is very useful for many things but I find myself having my own state machine in the code and somehow the state machine that the animator provides is not accurate due to blend time maybe I dont know, so I find often my character being in state 2 in the animator state machine and state 0 in my own state machine and its crazy as I cant seem to make it match in limit cases when its about to end the action. So I would like to know if there is a way to just say with code "play this animation from frame A to frame B" and loop it or not loop, that would be much better for me, of course I will lose all the blend features but really I will be better, all I can fin in the docs refer to using the animator so far. Thanks a lot for any help regarding this =)
Edit: Forgot to add that I found Animation.Play but apparently this only play animation saved on separate files like when we use the Animation timeline to record a certain motion, but I have a character with a lot of frames there and I dont think it serves in this case (or in my tests it never finds the specified animation at least, maybe i miss somethnig)

before anything, you can your own state machine with Animator. in fact, you don't need to two different state machine for your purposes. (Watch this video here)
and about your question, I found a good answer here: Link
From what I've seen you can either do AnimationState.normalizedTime
which returns the progress of an animation on a scale of 0 to 1. So if
you have a 30 frame animation and you want frame 15, you can do if
(normalizedTime == 0.5)* Or the better and more reliable option is to
use AnimationEvents that fire on specific frames.
*You won't really be able to do this if we're dealing in floats--You can only get the approximate value or you'll have to check greater
then or equal to 0.4 AND less then or equal to 0.6 because the
animation could go faster than the current frame rate or the
normalized time value could be 0.50000001 because of the nature of
float values.

Truncated Icosahedron Tile Objects

I'm trying to make a truncated icosahedron, though with more subdivision (so more hexagons)
In the game I use it, eacht pentagon and hexagon is a separate object. So after generating the icosahedron, I just use the generated points to place either a pentagon or a hexagon on it (instead of doing the find-middles-of-each-triangle-thing, I do this since I need them to be separate object anyway.) I have some questions about it though, and google doesn't really help, so I'm hoping there are some smart smath-knowing people here :D
Here we go:
Am I assured that the length of each sides is equal?
Since each hexa/petagon is a separate object, I need to rotate them to get them positioned properly, any help with this?
Assuming I have hexa/petagons with a radius of 1 (one), how far for the middle do I have to position them? (Basecly, whats the relationship between the radius of my hexa/pentagons and the radius of my truncated icosahedron.)
Here's my first test, I generated a icosahedron and then on each point put a pentagon model, which I rotate so it's pointing away from the middle. As you can see they still need to be rotated to fit together (question 2) and their distance to the middle has to the tweaked aswell (question 3).
I'll continue on working on this too, though all help will be appreciated! (I'm making this in Unity, using c#, so if you give sample code, it would be really really awesome if you use that.)
Thanks a lot!

Well, not the answer to your questions but maybe worth thinking about:
Wouldn't it be easier to start with a ready made Blender, Maya, ... model of a soccer ball like for example this one on Blend Swap, change it to fit your needs. Or do it on your own as there are a couple of YouTube tutorials. Then you will have far more options like LOD, materials. You can design it in Blender with each pentagon/hexagon as single object and so it will be imported in Unity.

How to effeciently spread objects on a 2D surface in a "natural" way?

i would like to effeciently generate positions for objects on a given surface. As you probably guessed this is for a game. The surface is actually a 3D terrain, but the third dimension does not matter as it is determined by terrain height.
The problem is i would like to do this in the most effecient and easy way, but still get good results. What i mean by "natural" is something like mentoined in this article about Perlin noise. (trees forming forests, large to small groups spread out on the land) The approach is nice, but too complicated. I need to do this quite often and prefferably without any more textures involved, even at the cost of worse performance (so the results won't be as pretty, but still good enough to give a nice natural terrain with vegetation).
The amount of objects placed varies, but generally is around 50. A nice enhancement would be to somehow restrict placement of objects at areas with very high altitude (mountains) but i guess it could be done by placing a bit more objects and deleting those placed above a given altitude.

This might not be the answer you are looking for, but I believe that Perlin Noise is the solution to your problem.
Perlin Noise itself involves no textures; I do believe that you have a misunderstanding about what it is. It's basically, for your purposes, a 2D index of, for each point, a value between 0 and 1. You don't need to generate any textures. See this description of it for more information and an elegant explanation. The basics of Perlin Noise involves making a few random noise maps, starting with one with very few points, and each new one having twice as many points of randomness (and lower amplitude), and adding them together.
Especially, if your map is discretely tiled, you don't even have to generate the noise at a high resolution :)
How "often" are you planning to do this? If you're going to be doing it 10+ times every single frame, then Perlin Noise might not be your answer. However, if you're doing it once every few seconds (or less), then I don't think that you should have any worries about speed impact -- at least, for 2D Perlin Noise.
Establishing that, you could look at this question and my personal answer to it, which is trying to do something very similar to what you are trying to do. The basic steps involve this:
Generate perlin noise; higher turbulence = less clumping and more isolated features.
Set a "threshold" (ie, 0.5) -- anything above this threshold is considered "on" and anything above it is considered "off". Higher threshold = more frequent, lower threshold = less frequent.
Populate "on" tiles with whatever you are making.
Here are some samples of Perlin Noise to generate 50x50 tile based map. Note that the only difference between the nature of the two are the "threshold". Bigger clumps means lower threshold, smaller clumps means a higher one.
A forest, with blue trees and brown undergrowth
A marsh, with deep areas surrounded by shallower areas

Note you'll have to tweak the constants a bit, but you could do something like this
First, pick a random point. (say 24,50).
Next, identify points of interest for this object. If it's a rock, your points might be the two mountains at 15,13 or 50,42. If it was a forest, it would maybe do some metrics to find the "center" of a couple local forests.
Next, calculate the distance vectors between the the point and the points of interest, and scale them by some constant.
Now, add all those vectors to the point.
Next determine if the object is in a legal position. If it is, move to the next object. If it's not, repeat the process.
Adapt as necessary. :-)

One thing: If you want to reject things like trees on mountains you don't add extra tries, you keep trying to place an object until you find a suitable location or you've tried it a bunch of times and you need to bail out because it doesn't look placeable.