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- /*
- THE COMPUTER CODE CONTAINED HEREIN IS THE SOLE PROPERTY OF PARALLAX
- SOFTWARE CORPORATION ("PARALLAX"). PARALLAX, IN DISTRIBUTING THE CODE TO
- END-USERS, AND SUBJECT TO ALL OF THE TERMS AND CONDITIONS HEREIN, GRANTS A
- ROYALTY-FREE, PERPETUAL LICENSE TO SUCH END-USERS FOR USE BY SUCH END-USERS
- IN USING, DISPLAYING, AND CREATING DERIVATIVE WORKS THEREOF, SO LONG AS
- SUCH USE, DISPLAY OR CREATION IS FOR NON-COMMERCIAL, ROYALTY OR REVENUE
- FREE PURPOSES. IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
- CONTAINED HEREIN FOR REVENUE-BEARING PURPOSES. THE END-USER UNDERSTANDS
- AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.
- COPYRIGHT 1993-1998 PARALLAX SOFTWARE CORPORATION. ALL RIGHTS RESERVED.
- */
- /*
- * $Source: f:/miner/source/2d/rcs/effects.c $
- * $Revision: 1.5 $
- * $Author: john $
- * $Date: 1994/11/18 22:51:04 $
- *
- * special effects stuff
- *
- * $Log: effects.c $
- * Revision 1.5 1994/11/18 22:51:04 john
- * Changed a bunch of shorts to ints in calls.
- *
- * Revision 1.4 1994/04/22 11:16:00 john
- * *** empty log message ***
- *
- * Revision 1.3 1994/02/01 13:18:45 john
- * *** empty log message ***
- *
- * Revision 1.2 1993/10/26 13:18:15 john
- * *** empty log message ***
- *
- * Revision 1.1 1993/10/25 14:56:56 john
- * Initial revision
- *
- *
- */
- #pragma off (unreferenced)
- static char rcsid[] = "$Id: effects.c 1.5 1994/11/18 22:51:04 john Exp $";
- #pragma on (unreferenced)
- #include <stdlib.h>
- #include <stdio.h>
- #include "mem.h"
- #include "gr.h"
- #include "grdef.h"
- #include "effect2d.h"
- int bitwidth(unsigned int n)
- {
- int width = 0;
- while ( n!=0 ) {
- n >>= 1;
- width++;
- }
- return width;
- }
- long randmasks[] = { 0,0,0x03,0x06,0x0c,0x14,0x30,0x60,0xb8,\
- 0x110,0x240,0x500,0xca0,0x1b00,0x3500,0x6000,0xb400,\
- 0x12000,0x204000,0x720000,0x90000,0x140000,0x300000,0x400000,\
- 0xd80000,0x1200000,0x3880000,0x7200000,0x9000000,0x14000000,\
- 0x32800000,0x48000000,0xa3000000 };
- void dissolve_in(grs_bitmap * bitmap )
- {
- int height, width, zz;
- int rwidth, cwidth; /* bit width for rows, for columns */
- int regwidth; /* "width" of sequence generator */
- long mask; /* mask to XOR with to create sequence */
- int rowshift; /* shift distance to get row */
- /* from element */
- int colmask; /* mask to extract column from element */
- unsigned long element; /* one element of random */ /* sequence */
- int row, column; /* row and column for one pixel */
- /* Find the mask to produce all rows and columns. */
- height = bitmap->bm_h;
- width = bitmap->bm_w;
- rwidth = bitwidth (height); /* how many bits needed for height? */
- cwidth = bitwidth (width); /* how many bits needed for width? */
- regwidth = rwidth + cwidth; /* how wide must the register be? */
- mask = randmasks[regwidth]; /* which mask is for that width? */
- /* Find values to extract row and col numbers from each element. */
- rowshift = cwidth; /* find dist to shift to get top bits (row) */
- colmask = (1<<cwidth)-1; /* find mask to extract */
- /* bottom bits (col) */
- /* Now cycle through all sequence elements. */
- element = 1; /* 1st element (could be any nonzero) */
- do {
- for (zz=0; zz < 100; zz++);
- row = element >> rowshift; /* find row number for this pixel */
- column = element & colmask; /* and how many columns across? */
- /* does element fall in the array? */
- /* ...must check row AND column */
- if ((row < height) && (column < width)) {
- // Draw the (r,c)'th pixel
- gr_setcolor(gr_ugpixel( bitmap, column, row ));
- gr_upixel(column, row);
- }
- /* Compute the next sequence element */
- if (element & 1) /* is the low bit set? */
- element = (element >>1)^mask; /* yes: shift value, */
- else
- element = (element >>1); /* no: just shift the value */
- } while (element != 1); /* loop until we return to */
- /* original element */
- gr_setcolor(gr_ugpixel( bitmap, 0, 0 ));
- gr_upixel(0,0);
- }
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