C Board - Windows Programming

AlphaBlend and BlendFunction - dynamic opacity

ulillillia — Thu, 19 Nov 2009 11:45:55 GMT

I've got the formula working and the debugger is showing that I have the correct values each time. Trouble is, the transparency is not working.

What I'm trying to do is get a color fade dependent on the current and maximum HP. At 50% remaining HP, the text is yellow. At 0% remaining HP, the text is red. For values between these, the text fades from red to yellow as HP increases (it's white above 50%). To accomplish this, I have it so that the red text is drawn first. The yellow text is drawn on top and it's the yellow text that has varying opacity. Both versions of the text uses a 32-bit TGA image and a custom-made font of my own (which leaves out TrueType fonts). I'm using AlphaBlend to do the drawing in all cases. This means I need the "BlendFunction" struct, of which I have filled out. The red text is drawn normally at full opacity. The problem comes from the yellow text. If I directly set the "SourceConstantAlpha" to 153 (to simulate 30% HP remaining), the text is still drawn as if it still was at 255.

My question is, how do I get this fade effect without creating extra versions of the font for more colors? A simulation screenshot I made earlier shows what the effect should be like (note the bottom right corner).

Edit: never mind, I found the problem - it was a copy/paste mistake causing the text to yellow in both cases instead of a separate yellow and red one. It's now working as I expected it.

A way to automatically detect the base address of a PCI card

binaryboy — Tue, 17 Nov 2009 11:49:55 GMT

Hi guys,

I have a program that interfaces with a PCI card and it works fine, except that the needed PCI base address either has to be hard-coded or entered by the user. Ideally I would prefer for the app to automatically detect the base address of the PCI card.

Is there a way to do this?

Loading images that aren't BMP...

yaya — Sun, 15 Nov 2009 22:35:22 GMT

I'm looking for a way to load other image formats such as PNG, JPEG, DDS, etc, and use them like you can with BMP files (ie use with Win32 functions). For example, how could I load a PNG file into a HBITMAP structure?

I have looked at libpng.org: top level, but that seems to only do PNG files and I'm not sure if it can turn it into a HBITMAP. Anyone know anything about this?

Thanks.

WINAPI thread problem

samguddy — Fri, 13 Nov 2009 16:23:16 GMT

Hey there,
I've been working on this project for a long time now and can't seem to find how this is done.

c++ language under windows.

I created 4 threads. Inside one of the threads I want to call another thread funtion. How is this done?? Cause it does not seem to work like other threads.

Thanks so much in advance.

Code:

DWORD WINAPI R1 (LPVOID)

{

      while(TestAndSet(&lock))

          while(lock==true);



        readcount++;

        cout << "R1 in CS." << endl;

        cout << readcount << "Readers in CS." << endl;

        cout << writecount << "Wrtiers in CS." << endl;        

        

           //want to call a thread here. example R#2.

                

               readcount--;

          lock=false;

                        

                return (DWORD) 0;        

        

                        }

Simple File Write

like_no_other — Thu, 12 Nov 2009 17:47:11 GMT

The Following code is used to keep a log about my process' activity. The problem is that it the debug output file gets the wrong name (unreadable characters). I can't figure out where my pointers go wild. Sorry for such a silly problem :D.

Code:

#include "includes.h"

#include "externs.h"





HANDLE hDebug;

HANDLE mDebug;





void AddLog(char *buffer)

{

        #ifdef DEBUG

        DWORD dwBytesWritten=0;

        DWORD dwBytesToWrite=0;

        dwBytesToWrite =(DWORD) strlen(buffer);

        if( hDebug == INVALID_HANDLE_VALUE || hDebug == NULL )

        return;

        WaitForSingleObject(mDebug, INFINITE);

        

        while(dwBytesWritten < dwBytesToWrite)

        {

                                        

                WriteFile(hDebug, buffer+dwBytesWritten, dwBytesToWrite - dwBytesWritten, &dwBytesWritten,NULL);

                

        }        

        

        ReleaseMutex(mDebug);

        #endif

}



void StartDebug()

{



        wchar_t FileDebug[]={'d','e','b','u','g','.','e','t','h'};

        mDebug = CreateMutex(NULL, false, NULL);

        hDebug = CreateFile( (LPWSTR) FileDebug,

                                                GENERIC_WRITE,

                                                0,

                                                NULL,

                                                CREATE_ALWAYS,

                                                FILE_ATTRIBUTE_NORMAL,

                                                NULL

                                                );

                        

                                                

        

                                                

                                                                



}

Win32 API and sockets question.

Joelito — Wed, 11 Nov 2009 14:39:21 GMT

Hi all!

I'm trying to get two values for my app:

1) ISPN
2) DNS server from my ISP

is it possible with sockets? I already have the hostname and the IP:

Code:

char hostname[128];

HOSTENT *lpHost;

 IN_ADDR inaddr;

 // hostname

gethostname (hostname, sizeof hostname);

SetDlgItemText(hwndDlg, IDC_EDIT1, hostname);

// ip

lpHost = gethostbyname(hostname);

memcpy(&inaddr, lpHost->h_addr_list[0], 4);

SetDlgItemText(hwndDlg, IDC_EDIT2, inet_ntoa(inaddr));

Thanks for the tips.

Task Scheduling every two days but..

simpatico_qa — Sat, 07 Nov 2009 11:41:35 GMT

Hello,

I�d like to schedule a task (through a script) such that it executes an application every two days. However I cannot guarantee that the computer will be on every two days at a specific time.
Can I not somehow specify that it should run every 2 days as soon as possible, and not at a specific time?

export table

MrNoobah — Fri, 06 Nov 2009 12:50:14 GMT

hey i m confused little bit abt export table's in dll's like what i don't get i read that everything relys on kernel32.dll every dll so that means that every dll doesn't got export's only kernel32.dll got exports? for exampe i m calling printf which is in msvrt.dll i noticed that my import there are also calling to kernel32.dll but why would my function also call msvrt.dll if only kernel32.dll has export table ?

How to create and manipulate Terabyte size Arrays with Win32API

KrishnaPG — Thu, 05 Nov 2009 06:05:38 GMT

If you are like me, working on serious scientifc projects, then the chances are you are required to deal with huge data, data that does not fit into your tiny 2 or 4Gb RAM. If you are looking for a way of creating and accessing very large arrays, arrays that can handle content in the order of Tera Bytes, then probably you might find a technique I have developed sometime back, described at Creating very large arrays (Terabyte size arrays) with Win32 File mapping, useful.

Its a simple Win32 File mapping concept, but very powerful when used in the right way with C++ templates. File mapping is the association of a file's contents with a portion of the virtual address space of a process. It allows the process to work efficiently with a large data files without having to map the whole file into memory. Processes read from and write to the file view using pointers, just as they would with dynamically allocated memory. This improves efficiency because the file resides on disk, but the file view resides in memory, the page-in and page-out happening seamlessly behind the scenes.

In a typical Win32 environment, applications have 4 gigabyte (GB) of virtual address space available. The virtual address space is divided so that 2 GB is available to the application and the other 2 GB is available only to the system. The size of a file mapping object that is backed by a named file is limited by disk space. The size of a file view is limited to the largest available contiguous block of unreserved virtual memory. This is at most 2 GB minus the virtual memory already reserved by the process.

To create a huge array, create multiple temporary files, each of _MaxFileSize, _MaxFileSize being any convenient maximum file size limit such as 2GB, and access their content by mapping and unmapping portions of them to the main memory as required. Creating the temporary files and mapping/unmapping them can be taken care by the CreateFile, CreateFileMapping, MapViewOfFile, and UnmapViewOfFile API. A simple implementation of this and sample code can be found at: Creating very large arrays (Terabyte size arrays) with Win32 File mapping

Gopalakrishna Palem,
Creator of CFugue, the world's first and only high level Music Note Programming Library for C/C++
Palem Gopalakrishna's Homepage

Signal in windows

kalamram — Wed, 04 Nov 2009 12:38:28 GMT

Hi,
i a writing one socket program and in my program I am creating child processes and executing different applications.

If any process killed, i need to send signal to parent process like unix.

Is it possible in windows.

If possible give some examples.

Also, in windows we can use createProcess() like fork() in unix.

but, is it correct to send info to parent process like unix.

thanks.

Help with F#

ingenting — Tue, 03 Nov 2009 03:06:16 GMT

Hello,

Im just starting a class about F# in school and was wondering if i can use microsoft express to start, like a F# project or file? I have seen on the www that you can do it with visual studio pro edition but that i dont have.

The express programs i have is C#, C++ and Visual Web.

Me teacher couldnt answer this question because he only run linux....

Thanks!

Graphics under Windows in C.

yugal0007 — Mon, 02 Nov 2009 13:57:09 GMT

Here's a simple program which shows how to animate, or create an animation in C.

A file has been attached.Attachment 9422

Attached Files

A_CAR.C (1.1 KB)

How to play an audio file in c program?

yugal0007 — Mon, 02 Nov 2009 13:46:42 GMT

Please can any one tell me how to open an audio file in C Program?
I came across a function "fopen", but i think its for opening text file. If i m wrong with that, can anyone tell me how to open audio file using "fopen".

OutText - absolutelly newbie...

stefan63 — Thu, 29 Oct 2009 22:54:47 GMT

Please, help me with some directions and advises!
I'm working with small microcontrollers and WinAPI is very , very unknown.
(Un)fortunately, i need program , which:
- is talking with small device via RS232,
- receives strings, analises these strings , reformats them and outputs on
WindowsApp window.
- keyboard input must be redirected to serial port.
In other words - goal is to make PC based terminal for this small device (which has 240x64 pixels display and some keypad).
In this moment i want to learn faster
1) how to output text in graphic mode, how to control font parameters,
2) how to control stretching of window - i assume to work in window 240x64 or 480x128 , but what happens , when one resizes window?

Last few days i have played with WinBGI ( library, wrapper , which gives to me graphic control in known for me TurboPascal style). Problem here is size - i have about 2MB exe even on start, with 3 strings , drawed in window. Additionally , i'm not sure how stable is this library.
On serial side i experimented with one simple library, but found problems - characters are lost, even on low speed. (Serial Communication for WIN32 (Event-driven)). Maybe i'm wrong, but library does not specify any buffers, when comport is initialised with CreateFile.( Does Window have long buffers by default?) So i'm planning to try other library - from Welcome to Ramon's homepage. But this is other story...
I have Dev-Cpp installed and i want to learn.
Any advice and comment, link to library/ wrapper will be useful for me.
Thanks.
Stefan

Empty child window...

yaya — Thu, 29 Oct 2009 17:53:30 GMT

I'm trying to implement a child window so I can put buttons and such in it, though things aren't going to plan. This is what I've got:

Code:

hChild = CreateWindowEx( NULL, "", NULL, WS_CHILD | WS_VISIBLE, 0, 0, 0, 0, hMainWindow, (HMENU)ID_CHILD, GetInstance(), NULL );

The problem is, hChild is always 0 (because it failed). I'm guessing the problem is that I don't have a WNDCLASSEX in there, but I want it to be empty. So what's wrong? Or am I going about this the complete wrong way?

Cheers.

EDIT: Sorry, I should've explained the situation more. What I'm trying to do is implement pages in my Tab Controls. I've got the tabs appearing and running fine, but I'm thinking I will add a child window for each page. When the user clicks on a tab, I'll use ShowWindow() to hide the old child window and display the new one. I've figured this would be a pretty good way of doing it (or is it?). So, more or less, how do you implement a child window into a tab, so that I can put in my other controls on the page?