Good evening guys!
I'm currently designing a desktop interface with various features using Firemonkey/FMX. One of these features is the ability to show information inside a "panel". This "panel" consists of a title and context (both tlabel), and an image (timage). One panel is created for each "application" that wishes to interact with my application. Each panel is named when it's created using a variable assigned when calling the procedure to create it, which is designed to allow other developers to access their panel with ease, but there's a risk this could be exploited so i may switch to bindingname.
I've already written the code to create one of these panels based upon variables, as well as the code to typecast down to the label and image levels based on a nested iterative .children and FindComponent loop, and i can freely change the text of the labels or the image (with .loadfromfile) using this method (i.e. the code works). However, as i'm wanting to open this feature to other applications and developers to actually display information inside one of these "panels", i need to work with Shared Memory.
The problem is that i truly can't understand it. Everything i've read implies that using SharedMem is easy, but i just can't understand it at all. Even the simple example in XE2's included samples confuses me. I unfortunately don't understand IPC at all, despite trying numerous times to get a grasp on it. I could use inifiles, but i don't feel they have flexibility required. I considered GlobalAtomTable, but as with SharedMem, i don't understand that either, not to mention that it reportedly leaks in Delphi.
Essentially, i'm looking for a function/procedure where i first create the area of shared memory. I'm then really looking for a function to read a string from that sharedmemory and output the result for me to access via other procedures or functions. As i'd like to make my other projects compatible with this one, i'd also be looking to get a procedure/function to write values to the shared memory from a seperate application.
As i said, i don't understand IPC or SharedMem, and i really need a basic start point from which i can work and teach myself, up to the more advanced levels. A step-by-step Walkthrough on exactly what i'm hoping to learn would be much appreciated. I am wanting to learn this rather than just get a lump of code as it's pretty much a given that i should be working with IPC by now.
Look at Cromis IMC or IPC components.
The IMC is for inter machine communication using tcp (indy) and the IPC is for inter process communication using windows named pipes.
Both uses the same client/server message system(packet based), so you don't have to dwell over the windows documentation to implement your application.
Just follow the examples found on the links above and you would have your application running in no time. Btw, the author Iztok Kacin is a SO member.
Related
I have an existing application which is quite large, uses a SQL Server database and LINQ to SQL built in MVC. It does what it needs to do very well, but the CMS is sadly lacking (it's difficult, complicated to use and prone to errors).
I like the look of Composite C1 to migrate this application to so that my users can get a good CMS experience.
I don't really want to center my development around C1, so I've been looking at creating an MVC application:
http://docs.composite.net/Functions/MVC
I've created a sample controller, view and then returned some static data to the view and finally posted some data to the controller. All works as a "normal" MVC application would do.
Has anyone used this concept for a real world application? The idea is that if a user want's to display one of my controls on a page they just add the control via the Composite editor. I'll also add basic pages on installation.
It's a bit of a vague question, but I'm really looking for feedback on the following:
1) How "involved" do you need to be with Composite C1 stuff? I want to just create my controllers and other classes to do my work
2) How is the performance with this approach?
3) Is there many gotcha's that you've experienced?
I have built a larger application within/on top of a Composite C1 environment, so I can say its definitely possible and the compatibility with .NET application development is actually one of the main reasons why we chose Composite in the first place.
1) How "involved" do you need to be with Composite C1 stuff? I want to just create my controllers and other classes to do my work
You won't be able to completely ignore everything Composite related when developing a full fledged application however, simply because your controls/views/controllers will run on and be rendered by Composite C1. So necessarily some of the work is done at least in part by the C1 foundation you build on, e.g. Routing, Exception Handling or Rendering.
However you can usually work with or around those features without too much trouble. It may however take some understanding of how Composite works.
2) How is the performance with this approach?
So far I cannot say that Composite would slow down the application in any significant way. It may in fact support you in tasks like Output Caching.
3) Is there many gotcha's that you've experienced?
This is a very broad question, but you generally will always have to make sure you know whether something belongs in one of your controls or would be better fit into a Composite component (page, reusable html block). If you put things into the wrong place, the easiest things will become complicated (like creating a page link) due to information being not present in the current context. But as I said, you can solve this through clever design.
Another thing to look out for is that correct source versioning is a bit harder to set up in the first place with a Composite application, because you have to figure out what is content and what is application.
So far I have made good experiences with C1 and will be using it in the future. It may take a little more time to get into it in the first place compared to a vanilla ASP.NET application, but the work that is done for you regarding CMS parts is well worth it.
I wonder what sort of things you look for when you start working on an existing, but new to you, system? Let's say that the system is quite big (whatever it means to you).
Some of the things that were identified are:
Where is a particular subroutine or procedure invoked?
What are the arguments, results and predicates of a particular function?
How does the flow of control reach a particular location?
Where is a particular variable set, used or queried?
Where is a particular variable declared?
Where is a particular data object accessed, i.e. created, read, updated or deleted?
What are the inputs and outputs of a particular module?
But if you look for something more specific or any of the above questions is particularly important to you please share it with us :)
I'm particularly interested in something that could be extracted in dynamic analysis/execution.
I like to use a "use case" approach:
First, I ask myself "what's this software's purpose?": I try to identify how users are going to interact with the application;
Once I have some "use case", I try to understand what are the objects that are more involved and how they interact with other objects.
Once I did this, I draw a UML-type diagram that describe what I've just learned for further reference. What happens after depends on the task I've been assigned, i.e. modify the code, document the code etc.
There is the question of what motivation do I have for learning the new system:
Bug fix/minor enhancement - In this case, I may focus solely on that portion of the system that performs a specific function that needs to be altered. This is a way to break down a huge system but also is a way to identify if the issue is something I can fix or if it is something that I have to hand to the off-the-shelf company whose software we are using,e.g. a CRM, CMS, or ERP system can be a customized off-the-shelf system so there are many pieces to it.
Project work - This would be the other case and is where I'd probably try to build myself a view from 30,000 feet or so to know what are the high-level components and which areas of the system does the project impact. An example of this is where I'd join a company and work off of an existing code base but I don't have the luxury of having the small focus like in the previous case. Part of that view is to look for any patterns in the code in terms of naming conventions, project structure, etc. as this may be useful once I start changing some code in the system. I'd probably do some tracing through the system and try to see where are the uglier parts of the code. By uglier I mean those parts that are kludge-like and may have some spaghetti code as this was rushed when first written and is now being reworked heavily.
To my mind another way to view this is the question of whether I'm going to be spending days or weeks wrapping my head around a system like in the second case or should this be a case where it hopefully takes only a few hours, optimistically that is, to get my footing to make the necessary changes.
I've been using Delphi for a little over a month, but I still do not know the proper way of doing things.
If I have methods which I can use on a lot of projects should I put them on a Unit, Form or DataModule?
I have not used a unit (in itself), New-> Unit. Should I put my utility methods there? If so, is there an example I can look at, a tutorial or whatever.
I've used DataModules in the past, though it gives me the impression that it should only be used when I'm dealing with databases and such.
Another thing, I'm customizing some forms (for instance a form with some TEdits that do specific things).
To use this, first I add this to the uses in the .dpr
CustomizedForm in '\CForm\CustomizedForm.pas' ;
then I add CustomizedForm to the uses in my mainform (where I'll be using it).
Is this the correct way to do it? I'm was just guessing, it seems to work though I'm not particularly confident that it's the proper way.
I put all mine in a unit called utils.pas. It works for me.
If you have different segmentations of utilities that some programs use but not others, you may want to create separate units for them.
Look at: Anatomy of a Delphi Unit
It is part of the excellent Beginner's Guide to Delphi Programming by Zarko Gajic that is very worthwhile to go through.
For the best "visual" introduction, see Nick Hodges' Thirty Camtasia Demos in Thirty Days. It is for Turbo Delphi which no longer is offered, but is still very similar to full Delphi and lets you visually get a feel for how to do things in Delphi.
Where you put things depends on what they do. The unit associated with a form should really only contain code that's directly related to the user interface that the form presents. Putting business logic directly into a form unit is considered bad practice for a number of reasons. If your utility methods aren't part of a specific form, it's best to put them in a Unit.
As for Data Modules, they're containers for holding non-visual controls. As the name implies, they were created for database access, but they can hold all sorts of other things. For example, at work we have a handful of data modules that contain TImageList controls, which hold lists of icons that are used in various places throughout the app. If you have any non-visual controls that you need to share with several different forms, a Data Module is the logical place to put them.
And yeah, it looks like you're doing the customized form right. If you have a second form that the first form needs access to, (to make it show up when you hit a button or menu item, for example,) then the first form's unit will need the second form's unit in its uses clause. (There are ways around this involving class registration techniques, but that's an advanced topic.)
You might want to avoid using the global form variable that Delphi likes to set up in a form unit, though. It makes your program start up more slowly, and using globals is another thing that's considered a bad practice. A form is an object like any other Delphi object, and you can create it with its constructor, call Show or ShowModal to make it appear, and then call Release or Free on it (read up on TForm.Release in the helpfile to know when you need to use it) when you're done with it.
For starters, create a few different units based on categories - StringUtils.pas, MathUtils.pas, DateTimeUtils.pas, etc - put your functions into those units according to category and be sure to include all the prototypes in your interface section so they'll be visible to other units (but don't get too caught up in how to categorize things...) and keep all your util units in a separate, dedicated directory. Then, point your Delphi or Project library paths to that directory and you'll be able to use the functions in all your utility units. Eventually, you may want to make the units into classes with class functions or persistent structures etc. I myself generally create a project group that includes a package called MyProjectUtils.bpl and I put all my utility units and classes into that package. I never actually deploy it as a package, but since they are wrapped up together I can always check that they all compile properly and they are all available immediately for browsing in the IDE, etc.
I am working on a game in C++. I've been told, though, that I should also use an embeddable scripting language like Lua or Angelscript, but to be honest, I have no idea how or why. What advantages would this bring me, over storing all of my data in some sort of text file? How do I get started? I tried to read some Lua examples, but I don't see how it works, or how exactly I am supposed to use it.
First the "why" question:
If you've made reasonable progress so far, you have game scenery where the action happens, and then a kind of GUI with your visible game controls: Maps, compass, hotkeys, chat box, whatever.
If you make the GUI (positions, sizes, settings, defaults, etc) configurable through a configuration file, that's OK for starters. But if you make it controllable by code then you can do many very cool things. Example: Minimize the map when entering a city. Show other player's portraits when in group. Update the map. Display different hot keys in combat. That kinda thing.
Now you can do your code-controlling of your GUI in C/C++ code, but one problem is that whenever you want to change the behavior, even if only a little, you need to recompile the whole dang game client. If you have a billion players, you have to ship them all a new game client. That's a turn-off. Another problem is that there's no way on earth that a player can customize the GUI.
A simple embedded language solves both problem. You can put that kind of code in separate files that get loaded at runtime and can be fiddled with to anyone's heart's content. If you want to update the GUI in some minor way, you can deliver updates of the GUI code separately from the game proper.
As for the how:
The simplest thing to do is to call a (e.g.) Lua "main" routine once for every frame, perhaps passing a bunch of parameters with the latest updatable information, and let that main routine call other functions to do whatever's needed. The thing to be aware of is that your embedded code only gets control for a short time, namely the time between two screen refreshes; so it does a little updating and painting, then it exits again and returns control to your C/C++ main program loop.
Technically, embedding a Lua interpreter in your program is pretty easy. The Lua interpreter has C source code, or there's pre-compiled libraries (DLLs) for Windows. Just link them into your program, initialize once, call the entry point on every iteration of the main frame loop, done.
Scripts are more powerful than storing all of your data in text files. You can assign arbitrary behavior, construct data from other data (e.g., orc captains are orcs with a bit more), and so on.
Scripts allow for faster development and easier maintenance than C++. No compile / edit / link cycle, you can even tweak the scripts while the game is running, and they're easier to update on end users' machines.
As far as the how, one suggestion would be to see how other games do it. For example, TOME, a Roguelike RPG written in C, uses Lua extensively.
For some inspiration, check out the Alternate Hard and Soft Layers pattern described on the C2 wiki.
As for my two cents, why embed a scripting language? Some reasons that I've experienced include,
REPL
easy string manipulation tools
leverage the power of loops, macros, and recursion within your data set
create dynamically generated content
wrappers to fetch content from the web
logic to provide default values if data is missing
unit tests written at the data set level
I am trying to write a statistics tool for a game by extracting values from game's process memory (as there is no other way). The biggest challenge is to find out required addresses that store data I am interested. What makes it even more harder is dynamic memory allocation - I need to find not only addresses that store data but also pointers to those memory blocks, because addresses are changing every time game restarts.
For now I am just manually searching game memory using memory editor (ArtMoney), and looking for addresses that change their values as data changes (or don't change). After address is found I am looking for a pointer that points to this memory block in a similar way.
I wonder what techniques/tools exist for such tasks? Maybe there are some articles I can read? Is mastering disassembler the only way to go? For example game trainers are solving similar tasks, but they make them in days and I am struggling already for weeks.
Thanks.
PS. It's all under windows.
Is mastering disassembler the only way to go?
Yes; go download WinDbg from http://www.microsoft.com/whdc/devtools/debugging/default.mspx, or if you've got some money to blow, IDA Pro is probably the best tool for doing this
If you know how to code in C, it is easy to search for memory values. If you don't know C, this page might point you to your solution if you can code in C#. It will not be hard to port the C# they have to Java.
You might take a look at DynInst (Dynamic Instrumentation). In particular, look at the Dynamic Probe Class Library (DPCL). These tools will let you attach to running processes via the debugger interface and insert your own instrumentation (via special probe classes) into them while they're running. You could probably use this to instrument the routines that access your data structures and trace when the values you're interested in are created or modified.
You might have an easier time doing it this way than doing everything manually. There are a bunch of papers on those pages you can look at to see how other people built similar tools, too.
I believe the Windows support is maintained, but I have not used it myself.