Files
glide/swlibs/texus2/lib/mipmap.c

113 lines
3.2 KiB
C

/*
** Copyright (c) 1995, 3Dfx Interactive, Inc.
** All Rights Reserved.
**
** This is UNPUBLISHED PROPRIETARY SOURCE CODE of 3Dfx Interactive, Inc.;
** the contents of this file may not be disclosed to third parties, copied or
** duplicated in any form, in whole or in part, without the prior written
** permission of 3Dfx Interactive, Inc.
**
** RESTRICTED RIGHTS LEGEND:
** Use, duplication or disclosure by the Government is subject to restrictions
** as set forth in subdivision (c)(1)(ii) of the Rights in Technical Data
** and Computer Software clause at DFARS 252.227-7013, and/or in similar or
** successor clauses in the FAR, DOD or NASA FAR Supplement. Unpublished -
** rights reserved under the Copyright Laws of the United States.
**
** $Revision$
** $Date$
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "texusint.h"
#define B0(x) ((x>>24)&0xFF)
#define B1(x) ((x>>16)&0xFF)
#define B2(x) ((x>>8)&0xFF)
#define B3(x) ((x>>0)&0xFF)
static void
_txImgHalve(int *outdata, int width, int height, int *indata)
{
unsigned int i,j,k;
unsigned int w,h, *p,sum,*q;
if ((outdata == NULL) ||
(width <= 0 ) ||
(height <= 0 ) ||
(width & (width-1)) ||
(height & (height-1)) ||
((width == 1) && (height==1))) return;
w = width>>1;
h = height>>1;
p = (unsigned int *) outdata;
q = (unsigned int *) indata;
if ((w == 0) || (h == 0)) {
// Input and output are a single span each (row or column)
for (j=0; j<w; j++) {
sum = B0(q[0]) + B0(q[1]); sum = (sum + 1) >> 1; k = sum;
sum = B1(q[0]) + B1(q[1]); sum = (sum + 1) >> 1; k = (k << 8) + sum;
sum = B2(q[0]) + B2(q[1]); sum = (sum + 1) >> 1; k = (k << 8) + sum;
sum = B3(q[0]) + B3(q[1]); sum = (sum + 1) >> 1; k = (k << 8) + sum;
*p++ = k;
q += 2;
}
return;
}
for (i=0; i<h; i++) {
for (j=0; j<w; j++) {
sum = B0(q[0]) + B0(q[1]) + B0(q[width]) + B0(q[width+1]);
sum = (sum + 2) >> 2; // add 2 to round, then divide by 4
k = sum;
sum = B1(q[0]) + B1(q[1]) + B1(q[width]) + B1(q[width+1]);
sum = (sum + 2) >> 2; // add 2 to round, then divide by 4
k = (k<<8) + sum;
sum = B2(q[0]) + B2(q[1]) + B2(q[width]) + B2(q[width+1]);
sum = (sum + 2) >> 2; // add 2 to round, then divide by 4
k = (k<<8) + sum;
sum = B3(q[0]) + B3(q[1]) + B3(q[width]) + B3(q[width+1]);
sum = (sum + 2) >> 2; // add 2 to round, then divide by 4
k = (k<<8) + sum;
*p++ = k;
q += 2;
}
q += width;
}
}
void
txMipMipmap(TxMip *txMip)
{
int i, w, h;
w = txMip->width;
h = txMip->height;
if( txVerbose )
{
printf("Mipmapping: .."); fflush(stdout);
printf(" %dx%d", w, h);
}
for (i=1; i< txMip->depth; i++) {
_txImgHalve (txMip->data[i], w, h, txMip->data[i-1]);
if (w > 1) w >>= 1;
if (h > 1) h >>= 1;
if( txVerbose )
{
printf(" %dx%d", w, h); fflush(stdout);
}
}
if( txVerbose )
{
printf(".\n");
}
}