Rolling a dice, with a dice :) - android

I currently need some advice about a "simple" issue.
I'm building a game helper, where users may roll dices (6 faced dice, 20 faced dice, etc). Actually, I displaying only the number to the user.
But, to make that much better to use, i want to display THE dice on the screen (on an alert dialog with custom layout for example).
My problem is here, and I don't really know how achieve that. I can't believe that the only way is to create each face of the dice to display it.
For your information, I need theses dices : 6 faced, 8 faced, 12, 20 and special 6 faced. :) That will be a very long task if I have to create all dices :(
The best i can dream, is to have the dice animation, but i guess is a bit too complex for me at this time.
Anyone as some advice about it ?

Best Quality / Highest Effort:
If you want to show a 3-D tumbling die, you probably want to look into the free 3D modeling/rendering/simulation packages. Blender is the first that comes to mind, although there are probably easier free alternatives. They take some time to learn, but you can model a photo-realistic 3D solid and then animate them in real physical simulations.
Going that route, you'd render short (GIF?) animations for each. Then you just have to look up how to display an animated GIF in a dialog (there's plenty of examples available).
Lower Quality / Less Effort
You could just display a single, 2D face of the die being rolled on your dialog, with a number (or pattern of dots) in the center. Depending upon the type of die, the 2D outline of the face could be a square, triangle, pentagon, etc.
The drawing logic for this would be fairly trivial (again, many examples available online). You could even do a crude animation, by having it cycle through several values before stopping on one. Have the cycling rapid at the start and slow at the end, and add a little 'click' sound for each, and you'd have something users would probably like.

Related

How to design a algorithm for bigger Tic Tac Toe game boards?

I have created a tactactoe game in Android and it is great. But this game has 3*3 game play. In 3*3 game we can implement our manual AI(Filling corner position first) or we can use Minimax algorithm to get best move. This is great for 3*3 board. But when I tried the same algorithm for 4*4 and 5*5 the algorithm is taking a huge time to determine the best move.
Hence I can not use minimax algorithm.
So what can I do now? I want to implement different level with different goal like below
Here it is 6*6 board and the goal(Consecutive symbol to win) is 5. So I want to design an ai for this dynamic board with dynamic goal.Goal can be 3,4,5 etc. How can I do that?
Thanks in advance.
ohh boy.. I'd rather use strategies instead of actual AI paradigms on this type of game. Make a hardcore strategy, and then for lower levels of difficulty make it dumb with random moves with a p probability.
Basically your strategy is what any 5 year old would do: if the opponent is 1 or 2 steps* away from making a full line, block him. else, work on expanding one of your longest lines.
1 step, if his line is closed on the other end, 2 steps if his line is open on both ends.
Of course, you might trick this strategy if you're given the opportunity to make a cross, or develop 2 lines simultaneously. But you can make a program to watch out for that too.
But if you really want to go the AI route, why not try a genetic algorithm that saves and cumulates its results (best individuals) after each game? if calibrated correctly it will run pretty fast and then all you have to do is train it like a dog a couple of rounds.

Plotting 3D Math Functions in Android

as part of my project, I need to plot 2D and 3D functions in android using android studio. I know how to plot 2D functions but I'm struggling with 3D functions.
What is the best way to plot 3D functions? What do I need and where do I start?
I'm not looking for code or external libraries that do all the work, I just need to know what I need to learn to be able to do it myself.
Thanks in advance.
I know how to plot 2D functions but I'm struggling with 3D functions.
What is the best way to plot 3D functions? What do I need and where do I start?
I'm not looking for code or external libraries that do all the work, I just need to know what I need to learn to be able to do it myself.
Since you already understand 2D and want to advance to 3D there's a simple and non-optimal method:
Decide on how much z depth you desire:
EG: Currently your limits for x and y in your drawing functions are 1920 and 1080 (or even 4096x4096), if you want to save memory and have things a bit low resolution use a size of 1920x1080x1000 - that's going to use 1000x more memory and has the potential to increase the drawing time of some calls by 1000 times - but that's the cost of 3D.
A more practical limit is matrices of 8192,8192,16384 but be aware that video games at that resolution need 4-6GB graphic cards to work half decently (more being a bit better) - so you'll be chewing up some main memory starting at that size.
It's easy enough to implement a smaller drawing space and simply increase your allocation and limit variables later, not only does that test that future increases will go smoothly but it allows everything to run faster while you're ironing the bugs out.
Add a 3rd dimension to the functions:
EG: Instead of a function that is simply line_draw(x,y) change it to line_draw(x,y,z), use the global variable z_limit (or whatever you decide to name it) to test that z doesn't exceed the limit.
You'll need to decide if objects at the maximum distance are a dot or not visible. While testing having all z's past the limit changed to the limit value (thus making them a visible dot) is useful. For the finished product once it goes past the limit that you are implementing it's best that it isn't visible.
Start by allocating the drawing buffer and implementing a single function first, there's no point (and possibly great frustration) changing everything and hoping it's just going to work - it should but if it doesn't you'll have a lot on your plate if there's a common fault in every function.
Once you have this 3D buffer filled with an image (start with just a few 3D lines, such as a full screen sized "X" and "+") you draw to your 2D screen X,Y by starting at the largest value of Z first (EG: z=1000). Once you finish that layer decrement z and continue, drawing each layer until you reach zero, the objects closest to you.
That's the simplest (and slowest) way to make certain that closest objects obscure the furthest objects.
Now does it look OK? You don't want distant objects the same size (or larger) than the closest objects, you want to make certain that you scale them.
The reason to choose numbers such as 8192 is because after writing your functions in C (or whichever language you choose) you'll want to optimize them with several versions each, written in assembly language, optimized for specific CPUs and GPU architectures. Without specifically optimized versions everything will be extremely slow.
I understand that you don't want to use a library but looking at several should give you an idea of the work involved and how you might implement your own. No need to copy, improve instead.
There are similar questions and answers that might fill in the blanks:
Reddit - "I want to create a 3D engine from scratch. Where do I start?"
Davrous - "Tutorial series: learning how to write a 3D soft engine from scratch in C#, TypeScript or JavaScript"
GameDev.StackExchange - "How to write my own 3-D graphics library for Windows? [closed]"

as3: better way to render many objects with png-sequences?

so I'm working on a game for mobile using AirForAndroid as3. In the game I need to have a lot of enemies at once on the screen (up to 15 would do I assume). These enemies are atm movieclips and contain various movieclips within, such as shapes that work as hitareas which are vital to the games functionality. The enemy-movieclip also contains a png sequence (a walk loop). Right now this seems to be veeeery unefficient for mobile devices, since 4 or 5 enemies at once already makes the game extremely slow on my galaxyS3.
So the question is, is there a diffrent approach to "render" the enemies, to make the display process less "expensive" ... I can't really get around the png sequence itself, which will span to maybe 200 pics combined, walk, run, fight animations and so on. If anybody has an idea or knows a trick or can put me towards a better solution, that would be awesome.
thanks for reading,
ANB_Seth
The MovieClip is very expensive (memory consumption and CPU/GPU performance) object. Especially on mobile devices. I recommend you to give up using MovieClips at all.
There is standard game-dev technique to make animation: Spritesheet animation.
Some links: Tutorial, Performance comparison: MovieClip vs Spritesheet, Descriptions of the main idea and implementation

Simple particle system on Android using OpenGL ES 1.0

I'm trying to put a particle system together in Android, using OpenGL. I want a few thousand particles, most of which will probably be offscreen at any given time. They're fairly simple particles visually, and my world is 2D, but they will be moving, changing colour (not size - they're 2x2), and I need to be able to add and remove then.
I currently have an array which I iterate through, handling velocity changes, managing lifecyling (killing old ones, adding new ones), and plotting them, using glDrawArrays. What OpenGl is pointing at, though, for this call, is a single vertex; I glTranslatex it to the relevant co-ords for each particle I want to plot, one at a time, set the colour with glColor4x then glDrawArrays it. It works, but it's a bit slow and only works for a few hundred particles. I'm handling the clipping myself.
I've written a system to support static particles which I have loaded into a vertex/colourarray and plot using glDrawArrays, but this approach only seems suitable for particles which will never change relative location (ie I move all of them using glTranslate), colour and where I don't need to add/remove particles. A few tests on my phone (HTC Desire) suggest that trying to alter the contents of those arrays (which are ByteBuffers, pointed to by OpenGL) is extremely slow.
Perhaps there's some way of manually writing the screen myself with the CPU. If I'm just plotting 1x1/2x2 dots on the screen, and I'm purely interested in writing and not doing any blending/antialiasing, is this an option? Would it be quicker than whatever OpenGl is doing?
(200 or so particles on a 1ghz machine with megs of ram. This is way slower than I was getting 20 years ago on a 7mhz machine with <500k of ram! I appreciate I'm using Java here, but surely there must be a better solution. Do I have to use the NDK to get the power of C++, or is what I'm after possible)
I've been hoping somebody might answer this definitively, as I'll be needing particles on Android myself. (I'm working in C++, though -- Currently using glDrawArrays(), but haven't pushed particles to the limit yet.)
I found this thread on gamedev.stackexchange.com (not Android-specific), and nobody can agree on the best approach there, but you might want to try a few things out and see for yourself.
I was going to suggest glDrawArrays(GL_POINTS, ...) with glPointSize(), but the guy asking the question there seemed unhappy with it.
Let us know if you find a good solution!

Android drawBitmap Performance For Lots of Bitmaps?

I'm in the process of writing an Android game and I seem to be having performance issues with drawing to the Canvas. My game has multiple levels, and each has (obviously) a different number of objects in it.
The strange thing is that in one level, which contains 45 images, runs flawlessly (almost 60 fps). However, another level, which contains 81 images, barely runs at all (11 fps); it is pretty much unplayable. Does this seem odd to anybody besides me?
All of the images that I use are .png's and the only difference between the aforementioned levels is the number of images.
What's going on here? Can the Canvas simply not draw this many images each game loop? How would you guys recommend that I improve this performance?
Thanks in advance.
Seems strange to me as well. I am also developing a game, lots of levels, I can easily have a 100 game objects on screen, have not seen a similar problem.
Used properly, drawbitmap should be very fast indeed; it is little more than a copy command. I don't even draw circles natively; I have Bitmaps of pre-rendered circles.
However, the performance of Bitmaps in Android is very sensitive to how you do it. Creating Bitmaps can be very expensive, as Android can by default auto-scale the pngs which is CPU intensive. All this stuff needs to be done exactly once, outside of your rendering loop.
I suspect that you are looking in the wrong place. If you create and use the same sorts of images in the same sorts of ways, then doubling the number of screen images should not reduce performance by a a factor of over 4. At most it should be linear (a factor of 2).
My first suspicion would be that most of your CPU time is spent in collision detection. Unlike drawing bitmaps, this usually goes up as the square of the number of interacting objects, because every object has to be tested for collision against every other object. You doubled the number of game objects but your performance went down to a quarter, ie according to the square of the number of objects. If this is the case, don't despair; there are ways of doing collision detection which do not grow as the square of the number of objects.
In the mean time, I would do basic testing. What happens if you don't actually draw half the objects? Does the game run much faster? If not, its nothing to do with drawing.
I think this lecture will help you. Go to the 45 minute . There is a graph comparing the Canvas method and the OpenGl method. I think it is the answer.
I encountered a similar problem with performance - ie, level 1 ran great and level 2 didn't
Turned it wasn't the rendering that was a fault (at least not specifically). It was something else specific to the level logic that was causing a bottleneck.
Point is ... Traceview is your best friend.
The method profiling showed where the CPU was spending its time and why the glitch in the framerate was happening. (incidentally, the rendering cost was also higher in Level 2 but wasn't the bottleneck)

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