I am in the extremely early stages of designing a game (so early that I haven't even committed to it yet). The idea is an RPG with a Quick Time Event for attacking and defending that relies on precise mouse movements or timed button presses to reduce damage taken or increase the damage of an attack (similar to Mario and Luigi or Paper Mario). I'm wondering the best way to go about programming a class that can handle this. Ultimately, I'd like to be able to write code such as this when I call the attack function, where all of the functionality of the QTE occurs in a single function call;
//Example code.
int attackPower = 23;
double qteSucessPercent = -1;
//more code
if(e.getSource == player.sword()) //when the player chooses to execute a sword attack.
{
qteSucessPercent = QTE.Jump();
if(qteSucessPercent< 0)
throw BadQTEException;
else if(qteSucessPercent>= .9)
player.attack(enemy[0], attackPower*2);
else if(qteSucessPercent>= .75)
player.attack(enemy[0], attackPower*1.5);
else if(qteSucessRate>= .5)
player.attack(enemy[0], attackPower);
else
System.out.println("Attack Failed");
}
This class needs to do several things.
It needs to be able to draw itself.
The QTE class needs to be able to handle key pressing or mouse motion events. I can handle the code for each type of QTE I wish to implement, but they need to be able to detect, on their own, where the mouse is and what buttons are being pressed.
Whatever it is drawing needs to delete itself once the QTE is over.
There will be multiple types of Quick Time Events. Each one will be drawn differently, have different victory conditions (one may require you to hit a sequence of buttons in the correct order, another may make you press a single button in rapid succession as many times as you can, ect), and modify the attack in various ways. The basic design of all QTEs is that they return a double value between 0 and 1, depending on how well the player did (generally, the higher the number, the better; if the attack returns 0, then the QTE received no input at all). In some situations, the QTE may be pass/fail, but the rest of the program is just watching for a non-0 number to be passed from the function call. For the sword, the attack's power is being modified by how well you do.
I know Swing isn't thread-safe (which, to my knowledge, means components won't update properly if you try to activate parts of their code from a thread other than the one you called them with, meaning I can't have two blocks of code executing at the same time if I want both sets of code to display animations), which is why I've written the code the way I have. The main thread gets to line 6, and executes QTE.Sword(). Until QTE.Sword() returns (which could be as long as five seconds), the rest of the program will freeze and not animate. I plan to use this to my advantage to achieve a bullet time effect, where the only thing animating is the QTE and the players and enemies remain stationary - though if I wanted an animation, like for a Mario and Luigi-like jump QTE, I'd set the player's sprite to be an animated gif that only plays once and only for as long as the QTE goes off.
Note that I am NOT ASKING FOR CODE. I'm asking for either pseudo-code or just a paragraph explanation of how I could program this. I think I can find a dead, open-sourced project on Github or Google Code and figure out the basics of the rest of the engine from there, but this is really the sticking point for me. Also, I am not asking for help handling mouse movements or keyboard presses. I have enough knowledge to code these on my own - I'm just not sure how to implement this in the context of an RPG. I know this isn't really stackoverflow's thing, and this question will probably get deleted, but I figure this is the best place to ask this sort of thing.
Related
I looked up many threads on how to use delta time and I can't figure it out.
I want my guy to move at a constant speed every time I run the game.
So I have:
timer = new Timer(9, this);
timer.start();
then the paint method.
I tried doing start time at the beginning of the paint method and then a current time at the end of it. How would I make it affect the timer's speed or how far the player moves. I've tried multiplying the time delta by the increment to the x. nHeroX = dx*deltaTIme;
I feel like it's very simple I just need someone to tell me straight what to do please.
Traditionally, game programming relies on a continuous loop.
Anyway, all I have realized.
In this loop, you should separate model update and graphic update.
In your snipset, you seem to try mixing the two things.
In this loop :
- In a first time, you let the model to update.For example : guy's move from x to x1.
- In a second time, you must refresh the graphics to allow the guy to have a new position in the screen.
The speed of your guy depends on the guy model (ex: constant in your guy class).
But the speed of another type of guy could be different.
The general speed of your game relies on the FPS set in your main loop.
You can see an example on this post :
Java Main Game Loop
Good luck
Get the system time from the System object.
Get it again during your animation. Delta time is nothing more than subtraction.
Get rid of the JavaScript tag. The languages are completely different.
I've read a few articles about dead reckoning, but it's still a bit confusing to me.
I'm pretty sure I understand the concept of point-and-click movement, but how would I update keystroke movement between the client and server, when the end-point of the movement is unknown?
How would you estimate where the player is going (server-side) if there is no end-point?
Let's start with dead reckoning. Try to think about it on a straight line where there is no left or right movement.
You are at point A and want to get to point B. You know the distance to point B so you can compute how much acceleration and velocity it will take to get there. Dead Reckoning works the other way. You are at point A and will move at a set speed to get near point B.
In the video game world they use this method all the time. So don't think about it as you're moving to point B you're just moving towards point B in increments because in like a FPS your point B will constantly moving. When in fact its really only moving in increments in the direction of point B.
Once you get moving forward then you can start worrying about left/right and up/down which will follow the same principle just in different directions.
As for implementing this you have 2 options.
One way, you could make this calculation on the client side then send the new position to the server. Then update what everyone else sees on screen.
The other way which I think is better you can make all these calculations on the server side and just receive an update where you ended up. X-Box live makes one of the consoles the host so that machine is running all the software and the external users are just firing events. This is why you'll hear people complain about having an unfair host advantage.
Now let's look at some code. This script comes from the Unity Sdk standard install package.
/// This script moves the character controller forward
/// and sideways based on the arrow keys.
/// It also jumps when pressing space.
/// Make sure to attach a character controller to the same game object.
/// It is recommended that you make only one call to Move or SimpleMove per frame.
var speed : float = 6.0;
var jumpSpeed : float = 8.0;
var gravity : float = 20.0;
private var moveDirection : Vector3 = Vector3.zero;
function Update() {
var controller : CharacterController = GetComponent(CharacterController);
if (controller.isGrounded) {
// We are grounded, so recalculate
// move direction directly from axes
moveDirection = Vector3(Input.GetAxis("Horizontal"), 0,
Input.GetAxis("Vertical"));
moveDirection = transform.TransformDirection(moveDirection);
moveDirection *= speed;
if (Input.GetButton ("Jump")) {
moveDirection.y = jumpSpeed;
}
}
// Apply gravity
moveDirection.y -= gravity * Time.deltaTime;
// Move the controller
controller.Move(moveDirection * Time.deltaTime);
}
So in this example we have speed which is set to a constant. So when moving in a direction we will travel in that Vector at a constant rate with no care about where point B is located.
Jump speed is how fast will we move in the y axis in the positive direction and gravity in the negative direction stopping at point 0.
So, How can you use this? You could build a server script that executes a move action and have a client side controller that passes the direction information to the server.
So lets say on the client side action is key press down, you send a call to the server to move you in the direction selection and the server will keep you moving you in that direction until action key press up or a change in direction from another input.
I hope this helped.
Let's see... I understand you know how to code, but not what, am I right?
You can feed the keystrokes directly to the server and let it do all the work. The server has no need to know where you are heading, it has your coordinates and direction and that's all it will need, unless you have server-handled AI. In the later case, you can do something similar to raycasting in Unity, start checking what is straight ahead and see if it is anything of interest, if so you know the potential destination.
It is safe to constantly send back to the client all his data, so it is always up to date. If you believe this will strain your connection you can do that every 50ms or as often as you believe is safe, and for smooth function estimate everything on the client side too. Make sure the server does all the collision detection and all the mechanics not related to the UI, or else the game will be prone to client-side malfunction or malicious tampering.
If you do have to look at where the player might be going, you can use a few approaches, you could either have a number of virtual cubes in the world which keep track of what is inside them, which will simplify finding what's ahead in terms of resources, or you could check everything there is, which is rather heavy on the machine, but this adds some other complexities too. In the first case do not forget to stop looking once you hit an obstacle.
You can also calculate the angle between the player's direction and other items of importance to check what else might be on his mind.
The question about UDP has already been answered, plus I'm sure Wikipedia has a helpful book on UDP and TCP, I have nothing to add.
The explanation of dead reckoning was also quite satisfactory, I hope I added other angles to the concept.
I hope I helped, if you need any clarifications or any other help feel free to contact me, if I was less than unhelpful then feel free to downvote, I study computer engineering and am creating my second game for PC so maybe I have ran into some problem already and can share the knowledge.
I have an applet that I'm running online and I want to make sure people can't use the java Robot class to operate the applet. I know that yahoo does this on several of their game platforms and I was wondering if anyone knew how they accomplished it.
Watch mouse movement, and make sure you're not seeing "jumps" from one place to another, but movement over time instead. Sun/Oracle's J2SE tutorials show how to follow mouse movement events: http://download.oracle.com/javase/tutorial/uiswing/events/mousemotionlistener.html
Keep in mind that this would potentially fail to detect the difference between a robot and a person on something like a touch screen, or tablet input device.
One more thing to watch for is whether the user is clicking the same pixel, or just in the same vicinity. Humans are fairly imprecise, robots generally aren't unless programmed to be.
I would also put in a gesture logger for good measure that compiles this information, and keeps track of the actual movements of your users. If you suspect someone of cheating, you can then look at what their actual mouse movements looked like, and compare that with a known person. That will give you a better idea of what you need to look for than any of us can come up with off the tops of our heads.
keep track of the distribution of mouse positions over time. Humans move the mouse differently than a robot that knows exactly where to position it every single time it is clicked. Of course, a smarter robot can counter this defense.
I've been attempting to develop a means of synthesizing human-like mouse movement in an application of mine for the past few weeks. At the start I used simple techniques like polynomial and spline interpolation, however even with a little noise the result still failed to appear sufficiently human-like.
In an effort to remedy this issue, I've been researching into ways of applying machine learning algorithms on real human mouse movement biometrics in order to synthesize mouse movements by learning from recorded real human ones. Users would be compiling a profile of recorded movements that would trainh= the program for synthesis purposes.
I've been searching for a few weeks and read several articles on application of inverse biometrics in generating mouse dynamics, such as Inverse Biometrics for Mouse Dynamics; they tend to focus, however, on generating realistic time from randomly-generated dynamics, while I was hoping to generate a path from specifically A to B. Plus, I still need to actually need to come up with a path, not just a few dynamics measured from one.
Does anyone have a few pointers to help a noob?
Currently, testing is done by recording movements and having I and several other developers watch the playback. Ideally the movement will be able to trick both an automatic biometric classifier, as well as a real, live, breathing Homo sapien, too.
Fitt's law gives a very good estimation of the time needed to position the mouse pointer. In the derivation section there is a simple explanation I think you could use this as one of the basic building blocks of your app. Start with big movements, put some inacurracy both in the direction and the length of the movement, then do a smaller correction movement and so on...
First, i guess you record human mouse movements from A to B. Because otherwise, trying to synthesize a model for such movement does not seem possible to me.
Second, how about measuring the deviations from the "direct" path, maybe in relation to time. I actually suspect that movements look different for different angles, path lengths etc., but maybe you can try a normalized model first, that you just stretch (in space and time) and rotate like you need it.
Third, the learning. The easiest thing would be to just have a collection of real moves (in the form i discussed above), and sample from that collection. Evaluate how that looks like. If you really want a probabilistic model, then you have to evaluate what kind of models fit. is it enough to blurr the direct path with gaussian noise whose parameters you learn from your training set? Or some (sin-)wavy deviation? Or seperate models for "getting near the button" and "final corrections". Fitts law might be useful for evaluation.
This question reminded me of a website I knew about years ago, so I visited it and found this in-depth discussion on the topic.
The timing is so similar as to make me think this question is related in some way. In fact, someone in the thread linked to the same article you did. If it's not related, well, there's a link to a lot of people discussing exactly what you're thinking about.
I don't think the problem is all that well defined. There is a important notion not mentioned so far, which is context. The mouse movement on my screen when Chrome has focus is massively different that the motion when Vim has focus.
The way a mouse moves varies based on the type of the device, the type of action, the UI elements involved, familiarity with the UI, the speed at which the user is attempting to complete their task, the skill of the user, initial failure of the user (eg miss-clicks), the user's emotional state (as well as many other factors). Do you plan on creating several pathing strategies to correspond to different contexts? Also how well do you know the algorithm you are trying to fool? I assume not extensively or you would simply program directly against that algorithm.
If a human is looking at the pathing, they might be able to identify the state associated with a pathing strategy and may be more inclined to be fooled if they identify it as a human state (eg user is rushing, miss-clicks, quickly closes a resulting popup, tries again slower). UI comes into play with not just size and position. I often quickly point to a toolbar, then slide across the options until I get to my target. Another example is that I typically pause on menu items while I am scanning for my target or hover over text I am reading. Are you attempting to emulate human behavior or just their mouse movements (because I think they are joined at the hip)?
Are you wanting to simulate human-like mouse movement because you are doing real-time online training for your game? If your training sequences are static, just record your mouse movements and play a mouse clicking sound effect whenever you click the mouse button. No mouse movement is going to feel "real enough" to you more than your own.
Personally, I feel experts in software move their mice too quickly in training videos. I prefer an approach taken by screencast video software I've seen that always moves the mouse linearly from point A --> B. The trick was, every mouse move made in the video always took the same amount of time regardless of distance, say 3/4 of a second and then followed by a mouse click sound effect.
I believe they moved the mouse in this way because then the viewer could anticipate the landing area of the mouse by the direction and velocity the mouse moved at the start. In a training situation, I suppose that regular movements like this are gentler on the eye and perhaps easier to retain/recall.
Have you considered adding mouse tracking to your application so you essentially record how the user moves the mouse and then analyze the recordings?
I have not looked into this recently but I believe that a MouseListener in a Swing application get the information you need.
In my little game, I have a background and a player, and obstacles to prevent the player from gaining points. So the player needs to move to avid these obstacles, right? Well my method of taking touch input works and when the user touches the right/left side of the screen to move in the corresponding direction. For some reason my method requires the user to tap the screen once for every single movement (4 pixels) of the player. I want the user to be able to hold their finger down on the direction they wish to go, and not have to continually tap that side of the screen a few hundred times. I'm pretty new to android, so I don't really know how to implement this. I have tried a game loop (it just crashed my game), and I've tried a separate thread to try and repeat the action, but it never gets executed even after I call "game.run()" and with "game.start()" it crashes. Can anyone show me a simple way to make it to where me player will keep moving when holding your finger on the side you wish to move towards? I imagine it's simple and I'm over complicating it, but I am a little clueless. Please provide an example, and not just a "Do it like that" etc. Because again, I am a little clueless in this department. Code pastebin'd below.
My code: http://pastebin.com/3EetUHCx
You want to create a new Runnable object in which to put the code, not to implement Runnable in the main class. That way you will separate the event handling from the main UI.
Even a better option would be to extend SurfaceView instead of View in your Draw class and create a Tread object inside that SurfaceView to handle the actual drawing.
Take a look at the Lunar Lander example from the android dev guide.