message.c

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//
//  message.c
//
//  Dissolve in/out messages into the "matrix"
//
//
//
#include <windows.h>
#include "globals.h"
#include "message.h"
#include "matrix.h"
 
//
// this isn't really a random-number generator. It's based on
// a 16bit CRC algorithm. With the right mask (0xb400) it is possible
// to call this function 65536 times and get a unique result every time
// with *NO* repeats. The results look random but they're not - if we
// call this function another 65536 times we get exactly the same results
// in the same order. This is necessary for fading in messages because
// we need to be guaranteed that all cells...it's completely uniform in
// operation but looks random enough to be very effective
//
WORD crc_msgrand(WORD reg)
{
    const WORD mask = 0xb400;
 
    if(reg & 1)
        reg = (reg >> 1) ^ mask;
    else
        reg = (reg >> 1);
 
    return reg;
}
 
//
//  Set a new message based on font and text
//
void SetMatrixMessage(MATRIX_MESSAGE *msg, HFONT hFont, TCHAR *text)
{
    HDC     hdc;
    RECT    rect;
    int     x, y;
 
    HDC     hdcMessage;
    HBITMAP hbmMessage;
 
    HANDLE  hOldFont, hOldBmp;
 
    //
    // Create a monochrome off-screen buffer
    //
    hdc = GetDC(NULL);
 
    hdcMessage = CreateCompatibleDC(hdc);
    hbmMessage = CreateBitmap(MAXMSG_WIDTH, MAXMSG_HEIGHT, 1, 1, 0);
    hOldBmp    = SelectObject(hdcMessage, hbmMessage);
 
    ReleaseDC(NULL, hdc);
 
    //
    // Draw text into bitmap
    //
    SetRect(&rect, 0, 0, msg->width, MAXMSG_HEIGHT);
    FillRect(hdcMessage, &rect, GetStockObject(WHITE_BRUSH));
 
    hOldFont = SelectObject(hdcMessage, g_hFont);
    DrawText(hdcMessage, text, -1, &rect, DT_CENTER|DT_VCENTER|DT_WORDBREAK|DT_CALCRECT);
 
    OffsetRect(&rect, (msg->width-(rect.right-rect.left))/2, (msg->height-(rect.bottom-rect.top))/2);
    DrawText(hdcMessage, text, -1, &rect, DT_CENTER|DT_VCENTER|DT_WORDBREAK);
 
    //
    // Convert bitmap into an array of cells for easy drawing
    //
    for(y = 0; y < msg->height; y++)
    {
        for(x = 0; x < msg->width; x++)
        {
            msg->message[x][y] = GetPixel(hdcMessage, x, y) ? 0 : 1;
        }
    }
 
    //
    //  Cleanup
    //
    SelectObject(hdcMessage, hOldFont);
    SelectObject(hdcMessage, hOldBmp);
 
    DeleteDC(hdcMessage);
    DeleteObject(hbmMessage);
}
 
//
//  Draw any part of the message that is visible. Make the
//  message "shimmer" by using a random glyph each time
//
void DrawMatrixMessage(MATRIX *matrix, MATRIX_MESSAGE *msg, HDC hdc)
{
    int x, y;
 
    for(x = 0; x < msg->width; x++)
        for(y = 0; y < msg->height; y++)
            if((msg->message[x][y] & 0x8000) &&
               (msg->message[x][y] & 0x00FF))
            {
                DrawGlyph(matrix, hdc, x * GLYPH_WIDTH, y * GLYPH_HEIGHT, RandomGlyph(MAX_INTENSITY));
            }
}
 
//
//  Reveal specified amount of message
//
void RevealMatrixMessage(MATRIX_MESSAGE *msg, int amount)
{
    while(amount--)
    {
        int pos;
 
        msg->random_reg1 = crc_msgrand(msg->random_reg1);
        pos = msg->random_reg1 & 0xffff;
 
        msg->message[pos / 256][pos % 256] |= GLYPH_REDRAW;
    }
}
 
//
//  Reset (hide) the message
//
void ClearMatrixMessage(MATRIX_MESSAGE *msg)
{
    int x, y;
 
    for(x = 0; x < msg->width; x++)
        for(y = 0; y < msg->height; y++)
            msg->message[x][y] = 0;
}
 
//
// convert from 50-500 (fast-slow) to slow(50) - fast(500)
//
int MessageSpeed()
{
    return (MSGSPEED_MAX-MSGSPEED_MIN) - (g_nMessageSpeed-MSGSPEED_MIN) + MSGSPEED_MIN;
}
 
//
//  Called once for each iteration of the matrix
//
void DoMatrixMessage(HDC hdc, MATRIX *matrix)
{
    MATRIX_MESSAGE *msg = matrix->message;
 
    int RealSpeed = MessageSpeed();
 
    if(g_nNumMessages > 0)
    {
        // nothing to do yet..
        if(msg->counter++ < 0)
            return;
 
        // has counter reached limit..clear the message
        if(msg->counter++ == RealSpeed / 2 + (RealSpeed/4))
            ClearMatrixMessage(msg);
 
        // reset counter + display a new message
        if(msg->counter >= RealSpeed)
        {
            // mark all message-cells as being "invisible" so the
            // message gets cleared by the matrix decoding naturally
 
            if(g_fRandomizeMessages)
                msg->msgindex = crc_rand() % g_nNumMessages;
            else
                msg->msgindex = (msg->msgindex + 1) % g_nNumMessages;
 
            // make a new message..initially invisible
            SetMatrixMessage(msg, 0, g_szMessages[msg->msgindex]);
 
            msg->counter = -(int)(crc_rand() % MSGSPEED_MAX);
        }
        // reveal the next part of the message
        else if(msg->counter < RealSpeed / 2)
        {
            int w = (g_nMessageSpeed - MSGSPEED_MIN);
            w = (1 << 16) + ((w<<16) / MSGSPEED_MAX);
            w = (w * 3 * g_nMessageSpeed) >> 16;
 
            RevealMatrixMessage(msg, w + 100);
        }
 
        //
        // draw whatever part of the message is visible at this time
        //
        DrawMatrixMessage(matrix, msg, hdc);
    }
}
 
//
//  Set current font used for messages
//
void SetMessageFont(HWND hwnd, TCHAR *szFontName, int nPointSize, BOOL fBold)
{
    int     lfHeight;
    HDC     hdc;
    HFONT   hFont;
 
    hdc = GetDC(hwnd);
 
    lfHeight = -MulDiv(nPointSize, GetDeviceCaps(hdc, LOGPIXELSY), 72);
 
    ReleaseDC(hwnd, hdc);
 
    hFont = CreateFont(lfHeight, 0, 0, 0, fBold ? FW_BOLD: FW_NORMAL, 0, 0, 0,
        ANSI_CHARSET, OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS,
        ANTIALIASED_QUALITY, DEFAULT_PITCH, szFontName);
 
    if(hFont != 0)
    {
        if(g_hFont != 0)
            DeleteObject(g_hFont);
 
        g_hFont = hFont;
    }
}
 
//
//  Create a message!
//
MATRIX_MESSAGE *InitMatrixMessage(HWND hwnd, int width, int height)
{
    MATRIX_MESSAGE *msg;
 
    if((msg = malloc(sizeof(MATRIX_MESSAGE))) == 0)
        return 0;
 
    ClearMatrixMessage(msg);
 
    msg->msgindex = 0;
    msg->width    = min(width, MAXMSG_WIDTH);
    msg->height   = min(height, MAXMSG_HEIGHT);
    msg->counter  = -(int)(crc_rand() % MSGSPEED_MIN + MSGSPEED_MIN);
 
    msg->random_reg1 = (WORD)GetTickCount();
 
    SetMessageFont(hwnd, g_szFontName, g_nFontSize, g_fFontBold);
 
    SetMatrixMessage(msg, 0, g_szMessages[0]);
 
    return msg;
}