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-rw-r--r--plug-ins/file-dds/mipmap.c1132
1 files changed, 1132 insertions, 0 deletions
diff --git a/plug-ins/file-dds/mipmap.c b/plug-ins/file-dds/mipmap.c
new file mode 100644
index 0000000..a1ad0c1
--- /dev/null
+++ b/plug-ins/file-dds/mipmap.c
@@ -0,0 +1,1132 @@
+/*
+ * 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;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-10 05:07:50 +0000