I have seen around that there is a b2Manifold. What I want to accomplish is to detect whether or not a collision was on the top part or not of one of the objects that were colliding.
I have already set up a b2ContactListener and it works fine. I would just like to provide more accurate collisions by setting up the manifold to detect if one b2Body is on top of the other b2Body that it collided with.
How would I do this?
Thanks!
http://postimage.org/image/kbfr7c5db/
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I've been looking for a robust method of pathfinding for a platformer based game I'm developing and A* looks like it's the best method available. I noticed there is a demo for the AStar implementation in Godot. However, it is written for a grid/tile based game and I'm having trouble adapting that to a platformer where the Y axis is limited by gravity.
I found a really good answer that describes how A* can be applied to platformers in Unity. My question is... Is it possible to use AStar in Godot to achieve the same thing described in the above answer? Is it possible this could be done better without using the built in AStar framework? What is a really simple example of how it would work (with or without AStar) in GDscript?
Though I have already posted a 100 point bounty (and it has expired), I would still be willing to post another 100 point bounty and award it, pending an answer to this question.
you could repurpose the Navigation2D node for platformer purposes. The picture below shows an example usage. The Navigation2D node makes it possible to navigate the shortest path between two point that lie within the combined navigation polygon (this is the union of all NavigationPolygonInstances).
You can use the get_simple_path method to get a vector2 array that describes the points your agent/character should try to reach (or get close to, by using some predefined margin) in sequence. Place each point in a queue, and move the character towards the different points by moving it horizontally. Whenever your agent's next point in the queue is too high up to reach, then you can make the agent jump.
I hope this makes sense!
The grey/dark-blue rectangles are platforms with collision whereas the green shapes are NavigationPolygonInstance nodes
This approach is by no means perfect. If you were to implement slopes into your game then the agent may jump up the slope instead of ascending it normally. It is also pretty tedious to create all the shapes needed.
A more robust solution would be to have a custom graph system that you could place in the scene and position its vertices. This opens up the possibility to make one-way paths and have certain edges/connections between vertices marked as "jumpable" only. This is a lot more work though if you can not find any such solution online.
I have an iOS app that uploads coordinates to a server. These coordinates can then be viewed in a map, through Google Maps. This is shown as a simple polyline. However, due to the GPS not being very precise, the polyline is often off-road.
I tried using Google's direction service, but it has a limit on how many requests you can send (and there can be a few thousand points on the polyline).
I have no idea how I can solve this problem. Could anybody help me?
I suspect the only way do do this is with manual intervention. The only way I can think of doing it programmatically would involve lots of queries to the directions service (to get "snap to road" functionality), and that probably would still need someone to check that it got it right (or at least need to include some code to look for extra loops to turn around or detours on to side roads that don't make sense).
Whereas if someone gets directions from start to end then drags them to match the track it would be pretty simple to get a version of the track that follows the roads.
The paper discussed in this thread might give you some ideas
What are the parameters/factors that a QR detector need to detect/check before(during) decoding the QR code itself.
From what I know:
1. it need to find/locate three finder patterns
2. need to locate alignment patterns (if there is any)
3. need to check luminance
Is there anything else that need to be determined/checked?
I suppose that there are many ways to detect a QR code, and it's not required to do it one particular way or the other as long as the detection succeeds. There is a reference algorithms in the QR code specification, though in my opinion it is too slow to be practical, though it's quite thorough.
I can tell you how zxing does it. Yes, it first locates the three finder patterns. This is done by looking for 1:1:3:1:1 black/white/black/white/black crossings horizontally and vertically. It figures out which one is which by looking at the vectors between them.
Then it needs a fourth point since four points are needed to correct for perspective distortion. It uses the location of the 3 finder patterns to guess about where it is and scans for it similarly (looking for 1:1:1:1:1). You don't need to find all alignment patterns, though doing so would allow you to correct for warping in the QR code, which is very rare.
Then you can sample the image to get the black/white modules by computing the perspective transform and reversing it. Then the decoding proceeds, the processing of those black/white modules, which is a fair bit of work too but nothing to do with detection or image processing anymore.
Looking at luminance is really a step before all this, so you even have a notion of black and white in the image to begin with. That's different.
I am trying to replicate this game for flash using Box2D http://www.physicsgames.net/game/Tricharge.html . I have everything fine, the only problem i am having is when the group of bubbles burst, How do i apply a uniform increase in speed like it does in the game. I have tried ApplyForce, ApplyImpulse but all i get is what looks like an explosion of balls.
It depends on which framework you are using.
One way to accomplish this is to apply a gravity vector that is specific to these objects in the upward direction.
Another way to accomplish this is to apply an elastic joint so that it's a constant acceleration.
I'm assuming you're using http://www.box2dflash.org/docs/2.0.2/manual#The_Joint_Definition. I believe that you may be able to use the mouse joint.
I'm trying to create a game similar to this (Note:When you click 'play', there are SFX in the game which you can't seem to turn off, so you may want to check volume). In particular, I'm interested in knowing how the 'infinite' landscape is generated. Are there any tutorials/articles describing this? I came across procedural generation, but I'm not quite sure what topics I should be looking for (or if it's even procedural generation).
(I'm using C#, but I don't mind the language as I assume the theory behind it remains the same)
That one seems like it would be pretty easy to duplicate -- I would imagine an algorithm that calculates the next "step" of the landscape (the part that is off the screen). It would need to know the prior height (and maybe even the previous slope) in order to then (randomly) increment or decrement the step. You could then tweak the algorithm to be more fluid (gently sloping), or extreme (whipsawing back and forth) as time passes/levels are completed.
Before I clicked the link though, I thought you might have been talking about voxel landscapes -- which I haven't thought about for over a dozen years, but amazed me when I first saw them. I did some googling, and thought you might be interested in this:
http://www.gamedev.net/reference/articles/article655.asp
(Not sure if the Mars demo still exists, or if anyone has a DOS machine to play it on, but this is a good example that shows what it used to look like: http://www.codermind.com/articles/Voxel-terrain-engine-building-the-terrain.html )