CALC.C

/**************************************************************************** 
                   Microsoft RPC Version 2.0 
           Copyright Microsoft Corp. 1992, 1993, 1994- 1996 
                        mandel Example 
 
    FILE:       calc.c 
 
    PURPOSE:    Server side of the RPC distributed application Mandel 
 
    FUNCTIONS:  MandelCalc() - Do the calculations for the Windows 
                               Mandelbrot Set distributed drawing program. 
 
****************************************************************************/ 
 
#include <stdlib.h> 
#include <stdio.h> 
#include <windows.h> 
 
#ifdef RPC 
#include "mdlrpc.h" 
#endif 
#include "mandel.h" 
 
 
short calcmand(double, double, short); 
 
 
void MandelCalc(PCPOINT    pcptLL, 
                PLONGRECT  prcDraw, 
                double     precision, 
                DWORD      ulThreshold, 
                LINEBUF *  pbBuf) 
{ 
    DWORD   h, height, width; 
    double  dreal, dimag, dimag2; 
    short   maxit = 0; 
    short * pbPtr; 
 
    pbPtr = *pbBuf;   // LINEBUF is an array of shorts 
 
    dreal = pcptLL->real + ((double)prcDraw->xLeft * precision); 
    dimag = pcptLL->imag + ((double)prcDraw->yBottom * precision); 
 
    maxit = (short) ulThreshold; 
 
    height = (prcDraw->yTop - prcDraw->yBottom) + 1; 
    width = (prcDraw->xRight - prcDraw->xLeft) + 1; 
 
    for ( ; width > 0; --width, dreal += precision) { 
        for (dimag2 = dimag, h = height; h > 0; --h, dimag2 += precision) { 
            if ((dreal > 4.0) || (dreal < -4.0) || 
                (dimag2 > 4.0) || (dimag2 < -4.0)) 
                *(pbPtr++) = 0; 
            else 
                *(pbPtr++) = calcmand(dreal, dimag2, maxit); 
        } 
    } 
} 
 
 
/* C version of the assembly language program */ 
short calcmand(double dreal, 
               double dimag, 
               short  maxit) 
{ 
    double x, y, xsq, ysq; 
    short k; 
 
    k = maxit; 
    x = dreal; 
    y = dimag; 
 
    while (1) { 
        xsq = x * x; 
        ysq = y * y; 
        y = 2.0 * x * y + dimag; 
        x = (xsq - ysq) + dreal; 
        if (--k == 0) 
            return((short) (maxit - k)); 
        if ((xsq + ysq) > 4.0) 
            return((short) (maxit - k)); 
    } 
}