gimp/plug-ins/file-dds/mipmap.c

1133 lines
28 KiB
C

/*
* DDS GIMP plugin
*
* Copyright (C) 2004-2012 Shawn Kirst <skirst@gmail.com>,
* with parts (C) 2003 Arne Reuter <homepage@arnereuter.de> where specified.
*
* 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; see the file COPYING. If not, write to
* the Free Software Foundation, 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301, USA.
*/
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <float.h>
#include <gtk/gtk.h>
#ifdef _OPENMP
#include <omp.h>
#endif
#include "dds.h"
#include "mipmap.h"
#include "imath.h"
#include "color.h"
typedef float (*filterfunc_t)(float);
typedef int (*wrapfunc_t)(int, int);
typedef void (*mipmapfunc_t)(unsigned char *, int, int, unsigned char *, int, int, int, filterfunc_t, float, wrapfunc_t, int, float);
typedef void (*volmipmapfunc_t)(unsigned char *, int, int, int, unsigned char *, int, int, int, int, filterfunc_t, float, wrapfunc_t, int, float);
/******************************************************************************
* size functions *
******************************************************************************/
int
get_num_mipmaps (int width,
int height)
{
int w = width << 1;
int h = height << 1;
int n = 0;
while (w != 1 || h != 1)
{
if (w > 1) w >>= 1;
if (h > 1) h >>= 1;
++n;
}
return n;
}
unsigned int
get_mipmapped_size (int width,
int height,
int bpp,
int level,
int num,
int format)
{
int w, h, n = 0;
unsigned int size = 0;
w = width >> level;
h = height >> level;
w = MAX(1, w);
h = MAX(1, h);
w <<= 1;
h <<= 1;
while (n < num && (w != 1 || h != 1))
{
if (w > 1) w >>= 1;
if (h > 1) h >>= 1;
if (format == DDS_COMPRESS_NONE)
size += (w * h);
else
size += ((w + 3) >> 2) * ((h + 3) >> 2);
++n;
}
if (format == DDS_COMPRESS_NONE)
{
size *= bpp;
}
else
{
if (format == DDS_COMPRESS_BC1 || format == DDS_COMPRESS_BC4)
size *= 8;
else
size *= 16;
}
return size;
}
unsigned int
get_volume_mipmapped_size (int width,
int height,
int depth,
int bpp,
int level,
int num,
int format)
{
int w, h, d, n = 0;
unsigned int size = 0;
w = width >> level;
h = height >> level;
d = depth >> level;
w = MAX(1, w);
h = MAX(1, h);
d = MAX(1, d);
w <<= 1;
h <<= 1;
d <<= 1;
while (n < num && (w != 1 || h != 1))
{
if (w > 1) w >>= 1;
if (h > 1) h >>= 1;
if (d > 1) d >>= 1;
if (format == DDS_COMPRESS_NONE)
size += (w * h * d);
else
size += (((w + 3) >> 2) * ((h + 3) >> 2) * d);
++n;
}
if (format == DDS_COMPRESS_NONE)
{
size *= bpp;
}
else
{
if (format == DDS_COMPRESS_BC1 || format == DDS_COMPRESS_BC4)
size *= 8;
else
size *= 16;
}
return size;
}
int
get_next_mipmap_dimensions (int *next_w,
int *next_h,
int curr_w,
int curr_h)
{
if (curr_w == 1 || curr_h == 1)
return 0;
if (next_w) *next_w = curr_w >> 1;
if (next_h) *next_h = curr_h >> 1;
return 1;
}
/******************************************************************************
* wrap modes *
******************************************************************************/
static int
wrap_mirror (int x,
int max)
{
if (max == 1) x = 0;
x = abs(x);
while (x >= max)
x = abs(max + max - x - 2);
return x;
}
static int
wrap_repeat (int x,
int max)
{
if (x >= 0)
return x % max;
return (x + 1) % max + max - 1;
}
static int
wrap_clamp (int x,
int max)
{
return MAX(0, MIN(max - 1, x));
}
/******************************************************************************
* gamma-correction *
******************************************************************************/
static int
linear_to_gamma (int gc,
int v,
float gamma)
{
if (gc == 1)
{
v = (int)(powf((float)v / 255.0f, gamma) * 255);
if (v > 255) v = 255;
}
else if (gc == 2)
{
v = linear_to_sRGB(v);
}
return v;
}
static int
gamma_to_linear (int gc,
int v,
float gamma)
{
if (gc == 1)
{
v = (int)(powf((float)v / 255.0f, 1.0f / gamma) * 255);
if(v > 255) v = 255;
}
else if (gc == 2)
{
v = sRGB_to_linear(v);
}
return v;
}
/******************************************************************************
* filters *
******************************************************************************/
static float
box_filter (float t)
{
if ((t >= -0.5f) && (t < 0.5f))
return 1.0f;
return 0.0f;
}
static float
triangle_filter (float t)
{
if (t < 0.0f) t = -t;
if (t < 1.0f) return 1.0f - t;
return 0.0f;
}
static float
quadratic_filter (float t)
{
if (t < 0.0f) t = -t;
if (t < 0.5f) return 0.75f - t * t;
if (t < 1.5f)
{
t -= 1.5f;
return 0.5f * t * t;
}
return 0.0f;
}
static float
bspline_filter (float t)
{
float tt;
if (t < 0.0f)
t = -t;
if (t < 1.0f)
{
tt = t * t;
return ((0.5f * tt * t) - tt + (2.0f / 3.0f));
}
else if (t < 2.0f)
{
t = 2.0f - t;
return (1.0f / 6.0f) * (t * t * t);
}
return 0.0f;
}
static float
mitchell (float t,
const float B,
const float C)
{
float tt;
tt = t * t;
if (t < 0.0f)
t = -t;
if (t < 1.0f)
{
t = (((12.0f - 9.0f * B - 6.0f * C) * (t * tt)) +
((-18.0f + 12.0f * B + 6.0f * C) * tt) +
(6.0f - 2.0f * B));
return t / 6.0f;
}
else if (t < 2.0f)
{
t = (((-1.0f * B - 6.0f * C) * (t * tt)) +
((6.0f * B + 30.0f * C) * tt) +
((-12.0f * B - 48.0f * C) * t) +
(8.0f * B + 24.0f * C));
return t / 6.0f;
}
return 0.0f;
}
static float
mitchell_filter (float t)
{
return mitchell(t, 1.0f / 3.0f, 1.0f / 3.0f);
}
static float
sinc (float x)
{
x = (x * M_PI);
if (fabsf(x) < 1e-04f)
return 1.0f + x * x * (-1.0f / 6.0f + x * x * 1.0f / 120.0f);
return sinf(x) / x;
}
static float
lanczos_filter (float t)
{
if (t < 0.0f) t = -t;
if (t < 3.0f) return sinc(t) * sinc(t / 3.0f);
return 0.0f;
}
static float
bessel0 (float x)
{
const float EPSILON = 1e-6f;
float xh, sum, pow, ds;
int k;
xh = 0.5f * x;
sum = 1.0f;
pow = 1.0f;
k = 0;
ds = 1.0f;
while (ds > sum * EPSILON)
{
++k;
pow = pow * (xh / k);
ds = pow * pow;
sum += ds;
}
return sum;
}
static float
kaiser_filter (float t)
{
if (t < 0.0f) t = -t;
if (t < 3.0f)
{
const float alpha = 4.0f;
const float rb04 = 0.0884805322f; // 1.0f / bessel0(4.0f);
const float ratio = t / 3.0f;
if ((1.0f - ratio * ratio) >= 0)
return sinc(t) * bessel0(alpha * sqrtf(1.0f - ratio * ratio)) * rb04;
}
return 0.0f;
}
/******************************************************************************
* 2D image scaling *
******************************************************************************/
static void
scale_image_nearest (unsigned char *dst,
int dw,
int dh,
unsigned char *src,
int sw,
int sh,
int bpp,
filterfunc_t filter,
float support,
wrapfunc_t wrap,
int gc,
float gamma)
{
int n, x, y;
int ix, iy;
int srowbytes = sw * bpp;
int drowbytes = dw * bpp;
for (y = 0; y < dh; ++y)
{
iy = (y * sh + sh / 2) / dh;
for (x = 0; x < dw; ++x)
{
ix = (x * sw + sw / 2) / dw;
for (n = 0; n < bpp; ++n)
{
dst[y * drowbytes + (x * bpp) + n] =
src[iy * srowbytes + (ix * bpp) + n];
}
}
}
}
static void
scale_image (unsigned char *dst,
int dw,
int dh,
unsigned char *src,
int sw,
int sh,
int bpp,
filterfunc_t filter,
float support,
wrapfunc_t wrap,
int gc,
float gamma)
{
const float blur = 1.0f;
const float xfactor = (float)dw / (float)sw;
const float yfactor = (float)dh / (float)sh;
int x, y, start, stop, nmax, n, i;
int sstride = sw * bpp;
float center, contrib, density, s, r, t;
unsigned char *d, *row, *col;
float xscale = MIN(xfactor, 1.0f) / blur;
float yscale = MIN(yfactor, 1.0f) / blur;
float xsupport = support / xscale;
float ysupport = support / yscale;
unsigned char *tmp;
if (xsupport <= 0.5f)
{
xsupport = 0.5f + 1e-10f;
xscale = 1.0f;
}
if (ysupport <= 0.5f)
{
ysupport = 0.5f + 1e-10f;
yscale = 1.0f;
}
#ifdef _OPENMP
tmp = g_malloc(sw * bpp * omp_get_max_threads());
#else
tmp = g_malloc(sw * bpp);
#endif
#ifdef _OPENMP
#pragma omp parallel for schedule(dynamic) \
private(x, y, d, row, col, center, start, stop, nmax, s, i, n, density, r, t, contrib)
#endif
for (y = 0; y < dh; ++y)
{
/* resample in Y direction to temp buffer */
d = tmp;
#ifdef _OPENMP
d += (sw * bpp * omp_get_thread_num());
#endif
center = ((float)y + 0.5f) / yfactor;
start = (int)(center - ysupport + 0.5f);
stop = (int)(center + ysupport + 0.5f);
nmax = stop - start;
s = (float)start - center + 0.5f;
for (x = 0; x < sw; ++x)
{
col = src + (x * bpp);
for (i = 0; i < bpp; ++i)
{
density = 0.0f;
r = 0.0f;
for (n = 0; n < nmax; ++n)
{
contrib = filter((s + n) * yscale);
density += contrib;
if (i == 3)
t = col[(wrap(start + n, sh) * sstride) + i];
else
t = linear_to_gamma(gc, col[(wrap(start + n, sh) * sstride) + i], gamma);
r += t * contrib;
}
if (density != 0.0f && density != 1.0f)
r /= density;
r = MIN(255, MAX(0, r));
if (i != 3)
r = gamma_to_linear(gc, r, gamma);
d[(x * bpp) + i] = (unsigned char)r;
}
}
/* resample in X direction using temp buffer */
row = d;
d = dst;
for (x = 0; x < dw; ++x)
{
center = ((float)x + 0.5f) / xfactor;
start = (int)(center - xsupport + 0.5f);
stop = (int)(center + xsupport + 0.5f);
nmax = stop - start;
s = (float)start - center + 0.5f;
for (i = 0; i < bpp; ++i)
{
density = 0.0f;
r = 0.0f;
for (n = 0; n < nmax; ++n)
{
contrib = filter((s + n) * xscale);
density += contrib;
if (i == 3)
t = row[(wrap(start + n, sw) * bpp) + i];
else
t = linear_to_gamma(gc, row[(wrap(start + n, sw) * bpp) + i], gamma);
r += t * contrib;
}
if (density != 0.0f && density != 1.0f)
r /= density;
r = MIN(255, MAX(0, r));
if (i != 3)
r = gamma_to_linear(gc, r, gamma);
d[(y * (dw * bpp)) + (x * bpp) + i] = (unsigned char)r;
}
}
}
g_free (tmp);
}
/******************************************************************************
* 3D image scaling *
******************************************************************************/
static void
scale_volume_image_nearest (unsigned char *dst,
int dw,
int dh,
int dd,
unsigned char *src,
int sw,
int sh,
int sd,
int bpp,
filterfunc_t filter,
float support,
wrapfunc_t wrap,
int gc,
float gamma)
{
int n, x, y, z;
int ix, iy, iz;
for (z = 0; z < dd; ++z)
{
iz = (z * sd + sd / 2) / dd;
for (y = 0; y < dh; ++y)
{
iy = (y * sh + sh / 2) / dh;
for (x = 0; x < dw; ++x)
{
ix = (x * sw + sw / 2) / dw;
for (n = 0; n < bpp; ++n)
{
dst[(z * (dw * dh)) + (y * dw) + (x * bpp) + n] =
src[(iz * (sw * sh)) + (iy * sw) + (ix * bpp) + n];
}
}
}
}
}
static void
scale_volume_image (unsigned char *dst,
int dw,
int dh,
int dd,
unsigned char *src,
int sw,
int sh,
int sd,
int bpp,
filterfunc_t filter,
float support,
wrapfunc_t wrap,
int gc,
float gamma)
{
const float blur = 1.0f;
const float xfactor = (float)dw / (float)sw;
const float yfactor = (float)dh / (float)sh;
const float zfactor = (float)dd / (float)sd;
int x, y, z, start, stop, nmax, n, i;
int sstride = sw * bpp;
int zstride = sh * sw * bpp;
float center, contrib, density, s, r, t;
unsigned char *d, *row, *col, *slice;
float xscale = MIN(xfactor, 1.0f) / blur;
float yscale = MIN(yfactor, 1.0f) / blur;
float zscale = MIN(zfactor, 1.0f) / blur;
float xsupport = support / xscale;
float ysupport = support / yscale;
float zsupport = support / zscale;
unsigned char *tmp1, *tmp2;
/* down to a 2D image, use the faster 2D image resampler */
if (dd == 1 && sd == 1)
{
scale_image(dst, dw, dh, src, sw, sh, bpp, filter, support, wrap, gc, gamma);
return;
}
if (xsupport <= 0.5f)
{
xsupport = 0.5f + 1e-10f;
xscale = 1.0f;
}
if (ysupport <= 0.5f)
{
ysupport = 0.5f + 1e-10f;
yscale = 1.0f;
}
if (zsupport <= 0.5f)
{
zsupport = 0.5f + 1e-10f;
zscale = 1.0f;
}
tmp1 = g_malloc(sh * sw * bpp);
tmp2 = g_malloc(dh * sw * bpp);
for (z = 0; z < dd; ++z)
{
/* resample in Z direction */
d = tmp1;
center = ((float)z + 0.5f) / zfactor;
start = (int)(center - zsupport + 0.5f);
stop = (int)(center + zsupport + 0.5f);
nmax = stop - start;
s = (float)start - center + 0.5f;
#ifdef _OPENMP
#pragma omp parallel for schedule(dynamic) \
private(x, y, slice, i, n, density, r, t, contrib)
#endif
for (y = 0; y < sh; ++y)
{
for (x = 0; x < sw; ++x)
{
slice = src + (y * (sw * bpp)) + (x * bpp);
for (i = 0; i < bpp; ++i)
{
density = 0.0f;
r = 0.0f;
for (n = 0; n < nmax; ++n)
{
contrib = filter((s + n) * zscale);
density += contrib;
if (i == 3)
t = slice[(wrap(start + n, sd) * zstride) + i];
else
t = linear_to_gamma(gc, slice[(wrap(start + n, sd) * zstride) + i], gamma);
r += t * contrib;
}
if (density != 0.0f && density != 1.0f)
r /= density;
r = MIN(255, MAX(0, r));
if (i != 3)
r = gamma_to_linear(gc, r, gamma);
d[((y * sw) + x) * bpp + i] = (unsigned char)r;
}
}
}
/* resample in Y direction */
d = tmp2;
#ifdef _OPENMP
#pragma omp parallel for schedule(dynamic) \
private(x, y, col, center, start, stop, nmax, s, i, n, density, r, t, contrib)
#endif
for (y = 0; y < dh; ++y)
{
center = ((float)y + 0.5f) / yfactor;
start = (int)(center - ysupport + 0.5f);
stop = (int)(center + ysupport + 0.5f);
nmax = stop - start;
s = (float)start - center + 0.5f;
for (x = 0; x < sw; ++x)
{
col = tmp1 + (x * bpp);
for (i = 0; i < bpp; ++i)
{
density = 0.0f;
r = 0.0f;
for (n = 0; n < nmax; ++n)
{
contrib = filter((s + n) * yscale);
density += contrib;
if (i == 3)
t = col[(wrap(start + n, sh) * sstride) + i];
else
t = linear_to_gamma(gc, col[(wrap(start + n, sh) * sstride) + i], gamma);
r += t * contrib;
}
if (density != 0.0f && density != 1.0f)
r /= density;
r = MIN(255, MAX(0, r));
if (i != 3)
r = gamma_to_linear(gc, r, gamma);
d[((y * sw) + x) * bpp + i] = (unsigned char)r;
}
}
}
/* resample in X direction */
d = dst;
#ifdef _OPENMP
#pragma omp parallel for schedule(dynamic) \
private(x, y, row, center, start, stop, nmax, s, i, n, density, r, t, contrib)
#endif
for (y = 0; y < dh; ++y)
{
row = tmp2 + (y * sstride);
for (x = 0; x < dw; ++x)
{
center = ((float)x + 0.5f) / xfactor;
start = (int)(center - xsupport + 0.5f);
stop = (int)(center + xsupport + 0.5f);
nmax = stop - start;
s = (float)start - center + 0.5f;
for (i = 0; i < bpp; ++i)
{
density = 0.0f;
r = 0.0f;
for (n = 0; n < nmax; ++n)
{
contrib = filter((s + n) * xscale);
density += contrib;
if (i == 3)
t = row[(wrap(start + n, sw) * bpp) + i];
else
t = linear_to_gamma(gc, row[(wrap(start + n, sw) * bpp) + i], gamma);
r += t * contrib;
}
if (density != 0.0f && density != 1.0f)
r /= density;
r = MIN(255, MAX(0, r));
if (i != 3)
r = gamma_to_linear(gc, r, gamma);
d[((z * dh * dw) + (y * dw) + x) * bpp + i] = (unsigned char)r;
}
}
}
}
g_free (tmp1);
g_free (tmp2);
}
/******************************************************************************
* filter lookup table *
******************************************************************************/
static struct
{
int filter;
filterfunc_t func;
float support;
} filters[] =
{
{ DDS_MIPMAP_FILTER_BOX, box_filter, 0.5f },
{ DDS_MIPMAP_FILTER_TRIANGLE, triangle_filter, 1.0f },
{ DDS_MIPMAP_FILTER_QUADRATIC, quadratic_filter, 1.5f },
{ DDS_MIPMAP_FILTER_BSPLINE, bspline_filter, 2.0f },
{ DDS_MIPMAP_FILTER_MITCHELL, mitchell_filter, 2.0f },
{ DDS_MIPMAP_FILTER_LANCZOS, lanczos_filter, 3.0f },
{ DDS_MIPMAP_FILTER_KAISER, kaiser_filter, 3.0f },
{ DDS_MIPMAP_FILTER_MAX, NULL, 0.0f }
};
/*
* Alpha test coverage - portion of visible texels after alpha test:
* if (texel_alpha < alpha_test_threshold)
* discard;
*/
static float
calc_alpha_test_coverage (unsigned char *src,
unsigned int width,
unsigned int height,
int bpp,
float alpha_test_threshold,
float alpha_scale)
{
unsigned int x, y;
int rowbytes = width * bpp;
int coverage = 0;
const int alpha_channel_idx = 3;
if (bpp <= alpha_channel_idx)
{
/* No alpha channel */
return 1.f;
}
for (y = 0; y < height; ++y)
{
for (x = 0; x < width; ++x)
{
const float alpha = src[y * rowbytes + (x * bpp) + alpha_channel_idx];
if ((alpha * alpha_scale) >= (alpha_test_threshold * 255))
{
++coverage;
}
}
}
return (float)coverage / (width * height);
}
static void
scale_alpha_to_coverage (unsigned char *img,
unsigned int width,
unsigned int height,
int bpp,
float desired_coverage,
float alpha_test_threshold)
{
int i;
unsigned int x, y;
const int rowbytes = width * bpp;
const int alpha_channel_idx = 3;
float min_alpha_scale = 0.0f;
float max_alpha_scale = 4.0f;
float alpha_scale = 1.0f;
if (bpp <= alpha_channel_idx)
{
/* No alpha channel */
return;
}
/* Binary search */
for (i = 0; i < 10; i++)
{
float cur_coverage = calc_alpha_test_coverage(img, width, height, bpp, alpha_test_threshold, alpha_scale);
if (cur_coverage < desired_coverage)
{
min_alpha_scale = alpha_scale;
}
else if (cur_coverage > desired_coverage)
{
max_alpha_scale = alpha_scale;
}
else
{
break;
}
alpha_scale = (min_alpha_scale + max_alpha_scale) / 2;
}
/* Scale alpha channel */
for (y = 0; y < height; ++y)
{
for (x = 0; x < width; ++x)
{
float new_alpha = img[y * rowbytes + (x * bpp) + alpha_channel_idx] * alpha_scale;
if (new_alpha > 255.0f)
{
new_alpha = 255.0f;
}
img[y * rowbytes + (x * bpp) + alpha_channel_idx] = (unsigned char)new_alpha;
}
}
}
/******************************************************************************
* mipmap generation *
******************************************************************************/
int
generate_mipmaps (unsigned char *dst,
unsigned char *src,
unsigned int width,
unsigned int height,
int bpp,
int indexed,
int mipmaps,
int filter,
int wrap,
int gc,
float gamma,
int preserve_alpha_coverage,
float alpha_test_threshold)
{
int i;
unsigned int sw, sh, dw, dh;
unsigned char *s, *d;
mipmapfunc_t mipmap_func = NULL;
filterfunc_t filter_func = NULL;
wrapfunc_t wrap_func = NULL;
float support = 0.0f;
const int has_alpha = (bpp >= 3);
float alpha_test_coverage = 1;
if (indexed || filter == DDS_MIPMAP_FILTER_NEAREST)
{
mipmap_func = scale_image_nearest;
}
else
{
if ((filter <= DDS_MIPMAP_FILTER_DEFAULT) ||
(filter >= DDS_MIPMAP_FILTER_MAX))
filter = DDS_MIPMAP_FILTER_BOX;
mipmap_func = scale_image;
for (i = 0; filters[i].filter != DDS_MIPMAP_FILTER_MAX; ++i)
{
if (filter == filters[i].filter)
{
filter_func = filters[i].func;
support = filters[i].support;
break;
}
}
}
switch (wrap)
{
case DDS_MIPMAP_WRAP_MIRROR: wrap_func = wrap_mirror; break;
case DDS_MIPMAP_WRAP_REPEAT: wrap_func = wrap_repeat; break;
case DDS_MIPMAP_WRAP_CLAMP: wrap_func = wrap_clamp; break;
default: wrap_func = wrap_clamp; break;
}
if (has_alpha && preserve_alpha_coverage)
{
alpha_test_coverage = calc_alpha_test_coverage(src, width, height, bpp,
alpha_test_threshold,
1.0f);
}
memcpy (dst, src, width * height * bpp);
s = dst;
d = dst + (width * height * bpp);
sw = width;
sh = height;
for (i = 1; i < mipmaps; ++i)
{
dw = MAX(1, sw >> 1);
dh = MAX(1, sh >> 1);
mipmap_func(d, dw, dh, s, sw, sh, bpp, filter_func, support, wrap_func, gc, gamma);
if (has_alpha && preserve_alpha_coverage)
{
scale_alpha_to_coverage(d, dw, dh, bpp, alpha_test_coverage, alpha_test_threshold);
}
s = d;
sw = dw;
sh = dh;
d += (dw * dh * bpp);
}
return 1;
}
int
generate_volume_mipmaps (unsigned char *dst,
unsigned char *src,
unsigned int width,
unsigned int height,
unsigned int depth,
int bpp,
int indexed,
int mipmaps,
int filter,
int wrap,
int gc,
float gamma)
{
int i;
unsigned int sw, sh, sd;
unsigned int dw, dh, dd;
unsigned char *s, *d;
volmipmapfunc_t mipmap_func = NULL;
filterfunc_t filter_func = NULL;
wrapfunc_t wrap_func = NULL;
float support = 0.0f;
if (indexed || filter == DDS_MIPMAP_FILTER_NEAREST)
{
mipmap_func = scale_volume_image_nearest;
}
else
{
if ((filter <= DDS_MIPMAP_FILTER_DEFAULT) ||
(filter >= DDS_MIPMAP_FILTER_MAX))
filter = DDS_MIPMAP_FILTER_BOX;
mipmap_func = scale_volume_image;
for (i = 0; filters[i].filter != DDS_MIPMAP_FILTER_MAX; ++i)
{
if (filter == filters[i].filter)
{
filter_func = filters[i].func;
support = filters[i].support;
break;
}
}
}
switch (wrap)
{
case DDS_MIPMAP_WRAP_MIRROR: wrap_func = wrap_mirror; break;
case DDS_MIPMAP_WRAP_REPEAT: wrap_func = wrap_repeat; break;
case DDS_MIPMAP_WRAP_CLAMP: wrap_func = wrap_clamp; break;
default: wrap_func = wrap_clamp; break;
}
memcpy (dst, src, width * height * depth * bpp);
s = dst;
d = dst + (width * height * depth * bpp);
sw = width;
sh = height;
sd = depth;
for (i = 1; i < mipmaps; ++i)
{
dw = MAX(1, sw >> 1);
dh = MAX(1, sh >> 1);
dd = MAX(1, sd >> 1);
mipmap_func (d, dw, dh, dd, s, sw, sh, sd, bpp, filter_func, support, wrap_func, gc, gamma);
s = d;
sw = dw;
sh = dh;
sd = dd;
d += (dw * dh * dd * bpp);
}
return 1;
}