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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
/** Antialiasing code **/
#include "sci/include/gfx_system.h"
#include "sci/include/gfx_tools.h"
static void
antialiase_simple(gfx_pixmap_t *pixmap, int mask[], int shift_const, gfx_mode_t *mode) {
int x, y, c;
int bytespp = mode->bytespp;
int line_size = bytespp * pixmap->xl;
char *lastline[2];
char *lastline_p = NULL;
char *data_p = (char *) pixmap->data;
lastline[0] = (char*)sci_malloc(line_size);
lastline[1] = (char*)sci_malloc(line_size);
for (y = 0; y < pixmap->yl; y++) {
int visimode = (y > 0 && y + 1 < pixmap->yl) ? 1 : 0;
unsigned long last_pixel = 0;
memcpy(lastline[y & 1], data_p, line_size);
lastline_p = lastline[(y & 1)^1];
for (x = 0; x < pixmap->xl; x++) {
unsigned long result = 0;
if (x == 1)
visimode++;
else if (x + 1 == pixmap->xl)
visimode--;
for (c = 0; c < 3; c++) {
unsigned long accum = 0;
unsigned long reader = 0;
int y_mode;
/* Yes, bad compilers will read three times as often as neccessary.
** This optimization is straightforward to detect (common subexpression
** elemination), so I prefer to write the stuff semi-legibly...
*/
for (y_mode = 0; y_mode < 2; y_mode++)
if ((y_mode == 0 && y > 0)
|| (y_mode == 1 && y + 1 < pixmap->yl)) {
char *src = (y_mode) ? data_p + line_size : lastline_p;
if (x > 0) {
memcpy(&reader, src - bytespp, bytespp);
accum += ((reader >> shift_const) & mask[c]) << 0;
}
memcpy(&reader, src, bytespp);
accum += ((reader >> shift_const) & mask[c]) << 1;
if (x + 1 < pixmap->xl) {
memcpy(&reader, src + bytespp, bytespp);
accum += ((reader >> shift_const) & mask[c]) << 0;
}
}
if (x > 0)
accum += ((last_pixel >> shift_const) & mask[c]) << 1;
memcpy(&reader, data_p, bytespp);
if (c == 2)
last_pixel = reader;
accum += ((reader >> shift_const) & mask[c]) << 2;
if (x + 1 < pixmap->xl) {
memcpy(&reader, data_p + bytespp, bytespp);
accum += ((reader >> shift_const) & mask[c]) << 1;
}
switch (visimode) {
case 0:
accum /= 9; /* Only happens twelve times */
break;
case 1:
accum = (accum >> 6) + (accum >> 4); /* 15/16 intensity */
break;
case 2:
accum >>= 4;
break;
default:
accum = (c == 0) ? 0xffffffff : 0; /* Error: mark as red */
}
result |= (accum & mask[c]);
}
result <<= shift_const;
memcpy(data_p, &result, bytespp);
data_p += bytespp;
lastline_p += bytespp;
}
}
free(lastline[0]);
free(lastline[1]);
}
void
gfxr_antialiase(gfx_pixmap_t *pixmap, gfx_mode_t *mode, gfxr_antialiasing_t type) {
int masks[3];
int shift_const = 0;
#ifdef WORDS_BIGENDIAN
shift_const = (sizeof(unsigned long) - mode->bytespp) << 3;
#endif /* WORDS_BIGENDIAN */
masks[0] = mode->red_mask;
masks[1] = mode->green_mask;
masks[2] = mode->blue_mask;
if (mode->palette)
return;
switch (type) {
case GFXR_ANTIALIASING_NONE:
break;
case GFXR_ANTIALIASING_SIMPLE:
antialiase_simple(pixmap, masks, shift_const, mode);
break;
default:
GFXERROR("Invalid antialiasing mode %d (internal error)\n", type);
}
return;
}
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