Afisare text ca in Matrix folosind C & WinAPI

#include <Windows.h>
#include <stdlib.h>
#include <time.h>

typedef struct Context
{
	const char* availableChars;
	size_t availableCharsLen;
	CHAR_INFO* buffer;
	HANDLE consoleHandle;
	int iteration;
	int millisecondsToWait;
	int maxIterations;
	int newColumnEveryIterations;
	int textStyle;
	int width;
	int height;
} Context;

const char* TODISPLAY = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";

void ClearScreen(const Context* context, char withChar)
{
	COORD start = {0, 0};
	DWORD charsWritten;

	FillConsoleOutputCharacterA(context->consoleHandle, withChar, 
		context->width * context->height, start, &charsWritten);
}

void ClearBuffer(const Context* context, char withChar)
{
	int i;
	for (i = 0; i < context->width * context->height; i++)
	{
		context->buffer[i].Char.AsciiChar = withChar;
		context->buffer[i].Attributes = FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE;
	}
}

BOOL IsEmpty(char value)
{
	return ' ' == value;
}

void SetCharacter(Context* context, int row, int column, char value)
{
	CHAR_INFO* info = &(context->buffer[row * context->width + column]);
	info->Attributes = context->textStyle;
	info->Char.AsciiChar = value;
}

void ExpandColumn(Context* context, int column, char value)
{
	CHAR_INFO *current, *below;
	int j;
	for (j = context->height - 1; j > 0; j--)
	{		
		current = &(context->buffer[j * context->width + column]);
		below = &(context->buffer[(j - 1) * context->width + column]);
		if ( ! IsEmpty(below->Char.AsciiChar))
		{
			current->Char.AsciiChar = below->Char.AsciiChar;
			current->Attributes = below->Attributes;
		}
	}
	SetCharacter(context, 0, column, value);
}

void UpdateBuffer(Context* context)
{
	int* emptyColumns = NULL;
	int currentEmptyColumns = 0;
	int i;

	if (context->iteration % context->newColumnEveryIterations == 0)
	{
		//a new column will be added
		//first, search empty columns
		emptyColumns = (int*)malloc(context->width * sizeof(int));
		for (i = 0; i < context->width; i++)
		{
			if (IsEmpty(context->buffer[i].Char.AsciiChar))
			{
				emptyColumns[currentEmptyColumns++] = i;
			}
		}
	}

	for (i = 0; i < context->width; i++)
	{
		if ( ! IsEmpty(context->buffer[i].Char.AsciiChar))
		{
			//move all items on the column 1 step below
			//and add a new character at the first position
			ExpandColumn(context, i, context->availableChars[rand() % context->availableCharsLen]);
		}
	}

	if (currentEmptyColumns > 0)
	{
		//empty columns are available to add
		//pick a random empty one and add a character
		i = emptyColumns[rand() % currentEmptyColumns];
		SetCharacter(context, 0, i, context->availableChars[rand() % context->availableCharsLen]);
	}

	if (NULL != emptyColumns) {
		free(emptyColumns);
	}
}

void DisplayAnimation(Context* context)
{
	COORD bufferSize, bufferStart;
	SMALL_RECT writeRegion;

	bufferSize.X = context->width;
	bufferSize.Y = context->height;
	bufferStart.X = bufferStart.Y = 0;
	writeRegion.Left = writeRegion.Top = 0;
	writeRegion.Right = context->width;
	writeRegion.Bottom = context->height;
	context->iteration = -1;		 

	ClearBuffer(context, ' ');
	ClearScreen(context, ' ');

	while (context->iteration++ < context->maxIterations)
	{
		UpdateBuffer(context);
		WriteConsoleOutputA(context->consoleHandle, context->buffer, bufferSize, bufferStart, &writeRegion);
		Sleep(context->millisecondsToWait);
	}
}

void InitContext(Context* context)
{
	CONSOLE_SCREEN_BUFFER_INFO bufferInfo;
	CONSOLE_CURSOR_INFO cursorInfo;

	context->availableChars = TODISPLAY;
	context->availableCharsLen = strlen(context->availableChars);
	context->millisecondsToWait = 50;
	context->maxIterations = 1000;
	context->newColumnEveryIterations = 3;
	context->textStyle = FOREGROUND_GREEN | FOREGROUND_INTENSITY;
	context->consoleHandle = GetStdHandle(STD_OUTPUT_HANDLE);

	GetConsoleScreenBufferInfo(context->consoleHandle, &bufferInfo);

	context->width = bufferInfo.srwindow.Right - bufferInfo.srwindow.Left + 1;
	context->height = bufferInfo.srwindow.Bottom - bufferInfo.srwindow.Top + 1;
	context->buffer = (CHAR_INFO*)malloc(context->width * context->height * sizeof(CHAR_INFO));

	cursorInfo.dwSize = 1;
	cursorInfo.bVisible = FALSE;
	SetConsoleCursorInfo(context->consoleHandle, &cursorInfo);
}

void ClearContext(Context* context)
{
	free(context->buffer);
}

void InitRandomEngine()
{
	srand((unsigned int)time(0));
}

int main(void)
{
	Context context;

	InitContext(&context);
	InitRandomEngine();

	DisplayAnimation(&context);

	ClearContext(&context);

	return 0;
}

Edited by dani.user, 14 March 2015 - 18:36.

Edited by dani.user, 14 March 2015 - 18:38.

 dani.user, on 13 martie 2015 - 18:17, said:

void InitContext(Context* context)
{
CONSOLE_SCREEN_BUFFER_INFO bufferInfo;
...
context->width = bufferInfo.srwindow.Right - bufferInfo.srwindow.Left + 1;
context->height = bufferInfo.srwindow.Bottom - bufferInfo.srwindow.Top + 1;

 EnachescuAlin, on 14 martie 2015 - 18:21, said:

 OriginalCopy, on 14 martie 2015 - 18:47, said: