/*
* Texture Filtering
* Version: 1.0
*
* Copyright (C) 2007 Hiroshi Morii All Rights Reserved.
* Email koolsmoky(at)users.sourceforge.net
* Web http://www.3dfxzone.it/koolsmoky
*
* this 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, or (at your option)
* any later version.
*
* this 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 GNU Make; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "TxReSample.h"
#include "TxDbg.h"
#include <stdlib.h>
#include <memory.h>
#define _USE_MATH_DEFINES
#include <math.h>
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif
int
TxReSample::nextPow2(int num)
{
num = num - 1;
num = num | (num >> 1);
num = num | (num >> 2);
num = num | (num >> 4);
num = num | (num >> 8);
num = num | (num >> 16);
/*num = num | (num >> 32);*//* for 64bit architecture */
num = num + 1;
return num;
}
boolean
TxReSample::nextPow2(uint8** image, int* width, int* height, int bpp, boolean use_3dfx = 0)
{
/* NOTE: bpp must be one of the follwing: 8, 16, 24, 32 bits per pixel */
if (!*image || !*width || !*height || !bpp)
return 0;
int row_bytes = ((*width * bpp) >> 3);
int o_row_bytes = row_bytes;
int o_width = *width;
int n_width = *width;
int o_height = *height;
int n_height = *height;
/* HACKALERT: I have explicitly subtracted (n) from width/height to
* adjust textures that have (n) pixel larger width/height than
* power of 2 size. This is a dirty hack for textures that have
* munged aspect ratio by (n) pixel to the original.
*/
if (n_width > 64) n_width -= 4;
else if (n_width > 16) n_width -= 2;
else if (n_width > 4) n_width -= 1;
if (n_height > 64) n_height -= 4;
else if (n_height > 16) n_height -= 2;
else if (n_height > 4) n_height -= 1;
n_width = nextPow2(n_width);
n_height = nextPow2(n_height);
row_bytes = (n_width * bpp) >> 3;
/* 3dfx Glide3 format, W:H aspect ratio range (8:1 - 1:8) */
if (use_3dfx) {
if (n_width > n_height) {
if (n_width > (n_height << 3))
n_height = n_width >> 3;
} else {
if (n_height > (n_width << 3)) {
n_width = n_height >> 3;
row_bytes = (n_width * bpp) >> 3;
}
}
DBG_INFO(80, L"using 3dfx W:H aspect ratio range (8:1 - 1:8).\n");
}
/* do we really need to do this ? */
if (o_width == n_width && o_height == n_height)
return 1; /* nope */
DBG_INFO(80, L"expand image to next power of 2 dimensions. %d x %d -> %d x %d\n",
o_width, o_height, n_width, n_height);
if (o_width > n_width)
o_width = n_width;
if (o_height > n_height)
o_height = n_height;
/* allocate memory to read in image */
uint8 *pow2image = (uint8*)malloc(row_bytes * n_height);
/* read in image */
if (pow2image) {
int i, j;
uint8 *tmpimage = *image, *tmppow2image = pow2image;
for (i = 0; i < o_height; i++) {
/* copy row */
memcpy(tmppow2image, tmpimage, ((o_width * bpp) >> 3));
/* expand to pow2 size by replication */
for(j = ((o_width * bpp) >> 3); j < row_bytes; j++)
tmppow2image[j] = tmppow2image[j - (bpp >> 3)];
tmppow2image += row_bytes;
tmpimage += o_row_bytes;
}
/* expand to pow2 size by replication */
for (i = o_height; i < n_height; i++)
memcpy(&pow2image[row_bytes * i], &pow2image[row_bytes * (i - 1)], row_bytes);
free(*image);
*image = pow2image;
*height = n_height;
*width = n_width;
return 1;
}
return 0;
}
/* Ken Turkowski
* Filters for Common Resampling Tasks
* Apple Computer 1990
*/
double
TxReSample::tent(double x)
{
if (x < 0.0) x = -x;
if (x < 1.0) return (1.0 - x);
return 0.0;
}
double
TxReSample::gaussian(double x)
{
if (x < 0) x = -x;
if (x < 2.0) return pow(2.0, -2.0 * x * x);
return 0.0;
}
double
TxReSample::sinc(double x)
{
if (x == 0) return 1.0;
x *= M_PI;
return (sin(x) / x);
}
double
TxReSample::lanczos3(double x)
{
if (x < 0) x = -x;
if (x < 3.0) return (sinc(x) * sinc(x/3.0));
return 0.0;
}
/* Don P. Mitchell and Arun N. Netravali
* Reconstruction Filters in Computer Graphics
* SIGGRAPH '88
* Proceedings of the 15th annual conference on Computer
* graphics and interactive techniques, pp221-228, 1988
*/
double
TxReSample::mitchell(double x)
{
if (x < 0) x = -x;
if (x < 2.0) {
const double B = 1.0 / 3.0;
const double C = 1.0 / 3.0;
if (x < 1.0) {
x = (((12.0 - 9.0 * B - 6.0 * C) * (x * x * x))
+ ((-18.0 + 12.0 * B + 6.0 * C) * (x * x))
+ (6.0 - 2.0 * B));
} else {
x = (((-1.0 * B - 6.0 * C) * (x * x * x))
+ ((6.0 * B + 30.0 * C) * (x * x))
+ ((-12.0 * B - 48.0 * C) * x)
+ (8.0 * B + 24.0 * C));
}
return (x / 6.0);
}
return 0.0;
}
/* J. F. Kaiser and W. A. Reed
* Data smoothing using low-pass digital filters
* Rev. Sci. instrum. 48 (11), pp1447-1457, 1977
*/
double
TxReSample::besselI0(double x)
{
/* zero-order modified bessel function of the first kind */
const double eps_coeff = 1E-16; /* small enough */
double xh, sum, pow, ds;
xh = 0.5 * x;
sum = 1.0;
pow = 1.0;
ds = 1.0;
int k = 0;
while (ds > sum * eps_coeff) {
k++;
pow *= (xh / k);
ds = pow * pow;
sum = sum + ds;
}
return sum;
}
double
TxReSample::kaiser(double x)
{
const double alpha = 4.0;
const double half_window = 5.0;
const double ratio = x / half_window;
return sinc(x) * besselI0(alpha * sqrt(1 - ratio * ratio)) / besselI0(alpha);
}
boolean
TxReSample::minify(uint8 **src, int *width, int *height, int ratio)
{
/* NOTE: src must be ARGB8888, ratio is the inverse representation */
#if 0
if (!*src || ratio < 2) return 0;
/* Box filtering.
* It would be nice to do Kaiser filtering.
* N64 uses narrow strip textures which makes it hard to filter effectively.
*/
int x, y, x2, y2, offset, numtexel;
uint32 A, R, G, B, texel;
int tmpwidth = *width / ratio;
int tmpheight = *height / ratio;
uint8 *tmptex = (uint8*)malloc((tmpwidth * tmpheight) << 2);
if (tmptex) {
numtexel = ratio * ratio;
for (y = 0; y < tmpheight; y++) {
offset = ratio * y * *width;
for (x = 0; x < tmpwidth; x++) {
A = R = G = B = 0;
for (y2 = 0; y2 < ratio; y2++) {
for (x2 = 0; x2 < ratio; x2++) {
texel = ((uint32*)*src)[offset + *width * y2 + x2];
A += (texel >> 24);
R += ((texel >> 16) & 0x000000ff);
G += ((texel >> 8) & 0x000000ff);
B += (texel & 0x000000ff);
}
}
A = (A + ratio) / numtexel;
R = (R + ratio) / numtexel;
G = (G + ratio) / numtexel;
B = (B + ratio) / numtexel;
((uint32*)tmptex)[y * tmpwidth + x] = ((A << 24) | (R << 16) | (G << 8) | B);
offset += ratio;
}
}
free(*src);
*src = tmptex;
*width = tmpwidth;
*height = tmpheight;
DBG_INFO(80, L"minification ratio:%d -> %d x %d\n", ratio, *width, *height);
return 1;
}
DBG_INFO(80, L"Error: failed minification!\n");
return 0;
#else
if (!*src || ratio < 2) return 0;
/* Image Resampling */
/* half width of filter window.
* NOTE: must be 1.0 or larger.
*
* kaiser-bessel 5, lanczos3 3, mitchell 2, gaussian 1.5, tent 1
*/
double half_window = 5.0;
int x, y, x2, y2, z;
double A, R, G, B;
uint32 texel;
int tmpwidth = *width / ratio;
int tmpheight = *height / ratio;
/* resampled destination */
uint8 *tmptex = (uint8*)malloc((tmpwidth * tmpheight) << 2);
if (!tmptex) return 0;
/* work buffer. single row */
uint8 *workbuf = (uint8*)malloc(*width << 2);
if (!workbuf) {
free(tmptex);
return 0;
}
/* prepare filter lookup table. only half width required for symetric filters. */
double *weight = (double*)malloc((int)((half_window * ratio) * sizeof(double)));
if (!weight) {
free(tmptex);
free(workbuf);
return 0;
}
for (x = 0; x < half_window * ratio; x++) {
//weight[x] = tent((double)x / ratio) / ratio;
//weight[x] = gaussian((double)x / ratio) / ratio;
//weight[x] = lanczos3((double)x / ratio) / ratio;
//weight[x] = mitchell((double)x / ratio) / ratio;
weight[x] = kaiser((double)x / ratio) / ratio;
}
/* linear convolution */
for (y = 0; y < tmpheight; y++) {
for (x = 0; x < *width; x++) {
texel = ((uint32*)*src)[y * ratio * *width + x];
A = (double)(texel >> 24) * weight[0];
R = (double)((texel >> 16) & 0xff) * weight[0];
G = (double)((texel >> 8) & 0xff) * weight[0];
B = (double)((texel ) & 0xff) * weight[0];
for (y2 = 1; y2 < half_window * ratio; y2++) {
z = y * ratio + y2;
if (z >= *height) z = *height - 1;
texel = ((uint32*)*src)[z * *width + x];
A += (double)(texel >> 24) * weight[y2];
R += (double)((texel >> 16) & 0xff) * weight[y2];
G += (double)((texel >> 8) & 0xff) * weight[y2];
B += (double)((texel ) & 0xff) * weight[y2];
z = y * ratio - y2;
if (z < 0) z = 0;
texel = ((uint32*)*src)[z * *width + x];
A += (double)(texel >> 24) * weight[y2];
R += (double)((texel >> 16) & 0xff) * weight[y2];
G += (double)((texel >> 8) & 0xff) * weight[y2];
B += (double)((texel ) & 0xff) * weight[y2];
}
if (A < 0) A = 0; else if (A > 255) A = 255;
if (R < 0) R = 0; else if (R > 255) R = 255;
if (G < 0) G = 0; else if (G > 255) G = 255;
if (B < 0) B = 0; else if (B > 255) B = 255;
((uint32*)workbuf)[x] = (((uint32)A << 24) | ((uint32)R << 16) | ((uint32)G << 8) | (uint32)B);
}
for (x = 0; x < tmpwidth; x++) {
texel = ((uint32*)workbuf)[x * ratio];
A = (double)(texel >> 24) * weight[0];
R = (double)((texel >> 16) & 0xff) * weight[0];
G = (double)((texel >> 8) & 0xff) * weight[0];
B = (double)((texel ) & 0xff) * weight[0];
for (x2 = 1; x2 < half_window * ratio; x2++) {
z = x * ratio + x2;
if (z >= *width) z = *width - 1;
texel = ((uint32*)workbuf)[z];
A += (double)(texel >> 24) * weight[x2];
R += (double)((texel >> 16) & 0xff) * weight[x2];
G += (double)((texel >> 8) & 0xff) * weight[x2];
B += (double)((texel ) & 0xff) * weight[x2];
z = x * ratio - x2;
if (z < 0) z = 0;
texel = ((uint32*)workbuf)[z];
A += (double)(texel >> 24) * weight[x2];
R += (double)((texel >> 16) & 0xff) * weight[x2];
G += (double)((texel >> 8) & 0xff) * weight[x2];
B += (double)((texel ) & 0xff) * weight[x2];
}
if (A < 0) A = 0; else if (A > 255) A = 255;
if (R < 0) R = 0; else if (R > 255) R = 255;
if (G < 0) G = 0; else if (G > 255) G = 255;
if (B < 0) B = 0; else if (B > 255) B = 255;
((uint32*)tmptex)[y * tmpwidth + x] = (((uint32)A << 24) | ((uint32)R << 16) | ((uint32)G << 8) | (uint32)B);
}
}
free(*src);
*src = tmptex;
free(weight);
free(workbuf);
*width = tmpwidth;
*height = tmpheight;
DBG_INFO(80, L"minification ratio:%d -> %d x %d\n", ratio, *width, *height);
return 1;
#endif
}