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gimp/plug-ins/flame/rect.c

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/*
flame - cosmic recursive fractal flames
Copyright (C) 1992 Scott Draves <spot@cs.cmu.edu>
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 3 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, see <https://www.gnu.org/licenses/>.
*/
#include "rect.h"
#include <string.h>
/* for batch
* interpolate
* compute colormap
* for subbatch
* compute samples
* buckets += cmap[samples]
* accum += time_filter[batch] * log(buckets)
* image = filter(accum)
*/
typedef short bucket[4];
/* if you use longs instead of shorts, you
get higher quality, and spend more memory */
#if 1
typedef short accum_t;
#define MAXBUCKET (1<<14)
#define SUB_BATCH_SIZE 10000
#else
typedef long accum_t;
#define MAXBUCKET (1<<30)
#define SUB_BATCH_SIZE 10000
#endif
typedef accum_t abucket[4];
/* allow this many iterations for settling into attractor */
#define FUSE 15
/* clamp spatial filter to zero at this std dev (2.5 ~= 0.0125) */
#define FILTER_CUTOFF 2.5
/* should be MAXBUCKET / (OVERSAMPLE^2) */
#define PREFILTER_WHITE (MAXBUCKET>>4)
#define bump_no_overflow(dest, delta, type) { \
type tt_ = dest + delta; \
if (tt_ > dest) dest = tt_; \
}
/* sum of entries of vector to 1 */
static void
normalize_vector(double *v,
int n)
{
double t = 0.0;
int i;
for (i = 0; i < n; i++)
t += v[i];
t = 1.0 / t;
for (i = 0; i < n; i++)
v[i] *= t;
}
void
render_rectangle (frame_spec *spec,
unsigned char *out,
int out_width,
int field,
int nchan,
int progress(double))
{
int i, j, k, nsamples, nbuckets, batch_size, batch_num, sub_batch;
bucket *buckets;
abucket *accumulate;
point *points;
double *filter, *temporal_filter, *temporal_deltas;
double bounds[4], size[2], ppux, ppuy;
int image_width, image_height; /* size of the image to produce */
int width, height; /* size of histogram */
int filter_width;
int oversample = spec->cps[0].spatial_oversample;
int nbatches = spec->cps[0].nbatches;
bucket cmap[CMAP_SIZE];
int gutter_width;
int sbc;
image_width = spec->cps[0].width;
if (field)
{
image_height = spec->cps[0].height / 2;
if (field == field_odd)
out += nchan * out_width;
out_width *= 2;
}
else
image_height = spec->cps[0].height;
if (1)
{
filter_width = (2.0 * FILTER_CUTOFF * oversample *
spec->cps[0].spatial_filter_radius);
/* make sure it has same parity as oversample */
if ((filter_width ^ oversample) & 1)
filter_width++;
filter = malloc (sizeof (double) * filter_width * filter_width);
/* fill in the coefs */
for (i = 0; i < filter_width; i++)
for (j = 0; j < filter_width; j++)
{
double ii = ((2.0 * i + 1.0) / filter_width - 1.0) * FILTER_CUTOFF;
double jj = ((2.0 * j + 1.0) / filter_width - 1.0) * FILTER_CUTOFF;
if (field)
jj *= 2.0;
filter[i + j * filter_width] = exp(-2.0 * (ii * ii + jj * jj));
}
normalize_vector(filter, filter_width * filter_width);
}
temporal_filter = malloc (sizeof (double) * nbatches);
temporal_deltas = malloc (sizeof (double) * nbatches);
if (nbatches > 1)
{
double t;
/* fill in the coefs */
for (i = 0; i < nbatches; i++)
{
t = temporal_deltas[i] = (2.0 * ((double) i / (nbatches - 1)) - 1.0)
* spec->temporal_filter_radius;
temporal_filter[i] = exp(-2.0 * t * t);
}
normalize_vector(temporal_filter, nbatches);
}
else
{
temporal_filter[0] = 1.0;
temporal_deltas[0] = 0.0;
}
/* the number of additional rows of buckets we put at the edge so
that the filter doesn't go off the edge */
gutter_width = (filter_width - oversample) / 2;
height = oversample * image_height + 2 * gutter_width;
width = oversample * image_width + 2 * gutter_width;
nbuckets = width * height;
if (1)
{
static char *last_block = NULL;
static int last_block_size = 0;
int memory_rqd = (sizeof (bucket) * nbuckets +
sizeof (abucket) * nbuckets +
sizeof (point) * SUB_BATCH_SIZE);
if (memory_rqd > last_block_size)
{
if (last_block != NULL)
free (last_block);
last_block = malloc (memory_rqd);
if (last_block == NULL)
{
fprintf (stderr, "render_rectangle: cannot malloc %d bytes.\n",
memory_rqd);
exit (1);
}
last_block_size = memory_rqd;
}
buckets = (bucket *) last_block;
accumulate = (abucket *) (last_block + sizeof (bucket) * nbuckets);
points = (point *) (last_block + (sizeof (bucket) + sizeof (abucket)) * nbuckets);
}
memset ((char *) accumulate, 0, sizeof (abucket) * nbuckets);
for (batch_num = 0; batch_num < nbatches; batch_num++)
{
double batch_time;
double sample_density;
control_point cp;
memset ((char *) buckets, 0, sizeof (bucket) * nbuckets);
batch_time = spec->time + temporal_deltas[batch_num];
/* interpolate and get a control point */
interpolate (spec->cps, spec->ncps, batch_time, &cp);
/* compute the colormap entries. the input colormap is 256 long with
entries from 0 to 1.0 */
for (j = 0; j < CMAP_SIZE; j++)
{
for (k = 0; k < 3; k++)
{
#if 1
cmap[j][k] = (int) (cp.cmap[(j * 256) / CMAP_SIZE][k] *
cp.white_level);
#else
/* monochrome if you don't have any cmaps */
cmap[j][k] = cp.white_level;
#endif
}
cmap[j][3] = cp.white_level;
}
/* compute camera */
if (1)
{
double t0, t1, shift = 0.0, corner0, corner1;
double scale;
scale = pow (2.0, cp.zoom);
sample_density = cp.sample_density * scale * scale;
ppux = cp.pixels_per_unit * scale;
ppuy = field ? (ppux / 2.0) : ppux;
switch (field)
{
case field_both:
shift = 0.0;
break;
case field_even:
shift = -0.5;
break;
case field_odd:
shift = 0.5;
break;
}
shift = shift / ppux;
t0 = (double) gutter_width / (oversample * ppux);
t1 = (double) gutter_width / (oversample * ppuy);
corner0 = cp.center[0] - image_width / ppux / 2.0;
corner1 = cp.center[1] - image_height / ppuy / 2.0;
bounds[0] = corner0 - t0;
bounds[1] = corner1 - t1 + shift;
bounds[2] = corner0 + image_width / ppux + t0;
bounds[3] = corner1 + image_height / ppuy + t1 + shift;
size[0] = 1.0 / (bounds[2] - bounds[0]);
size[1] = 1.0 / (bounds[3] - bounds[1]);
}
nsamples = (int) (sample_density * nbuckets /
(oversample * oversample));
batch_size = nsamples / cp.nbatches;
sbc = 0;
for (sub_batch = 0;
sub_batch < batch_size;
sub_batch += SUB_BATCH_SIZE)
{
if (progress && (sbc++ % 32) == 0)
(*progress)(0.5 * sub_batch / (double) batch_size);
/* generate a sub_batch_size worth of samples */
points[0][0] = random_uniform11 ();
points[0][1] = random_uniform11 ();
points[0][2] = random_uniform01 ();
iterate (&cp, SUB_BATCH_SIZE, FUSE, points);
/* merge them into buckets, looking up colors */
for (j = 0; j < SUB_BATCH_SIZE; j++)
{
int k, color_index;
double *p = points[j];
bucket *b;
/* Note that we must test if p[0] and p[1] is "within"
* the valid bounds rather than "not outside", because
* p[0] and p[1] might be NaN.
*/
if (p[0] >= bounds[0] &&
p[1] >= bounds[1] &&
p[0] <= bounds[2] &&
p[1] <= bounds[3])
{
color_index = (int) (p[2] * CMAP_SIZE);
if (color_index < 0)
color_index = 0;
else if (color_index > CMAP_SIZE - 1)
color_index = CMAP_SIZE - 1;
b = buckets +
(int) (width * (p[0] - bounds[0]) * size[0]) +
width * (int) (height * (p[1] - bounds[1]) * size[1]);
for (k = 0; k < 4; k++)
bump_no_overflow(b[0][k], cmap[color_index][k], short);
}
}
}
if (1)
{
double k1 = (cp.contrast * cp.brightness *
PREFILTER_WHITE * 268.0 *
temporal_filter[batch_num]) / 256;
double area = image_width * image_height / (ppux * ppuy);
double k2 = (oversample * oversample * nbatches) /
(cp.contrast * area * cp.white_level * sample_density);
/* log intensity in hsv space */
for (j = 0; j < height; j++)
for (i = 0; i < width; i++)
{
abucket *a = accumulate + i + j * width;
bucket *b = buckets + i + j * width;
double c[4], ls;
c[0] = (double) b[0][0];
c[1] = (double) b[0][1];
c[2] = (double) b[0][2];
c[3] = (double) b[0][3];
if (0.0 == c[3])
continue;
ls = (k1 * log(1.0 + c[3] * k2))/c[3];
c[0] *= ls;
c[1] *= ls;
c[2] *= ls;
c[3] *= ls;
bump_no_overflow(a[0][0], c[0] + 0.5, accum_t);
bump_no_overflow(a[0][1], c[1] + 0.5, accum_t);
bump_no_overflow(a[0][2], c[2] + 0.5, accum_t);
bump_no_overflow(a[0][3], c[3] + 0.5, accum_t);
}
}
}
/*
* filter the accumulation buffer down into the image
*/
if (1)
{
int x, y;
double t[4];
double g = 1.0 / spec->cps[0].gamma;
y = 0;
for (j = 0; j < image_height; j++)
{
if (progress && (j % 32) == 0)
(*progress)(0.5 + 0.5 * j / (double)image_height);
x = 0;
for (i = 0; i < image_width; i++)
{
int ii, jj, a;
unsigned char *p;
t[0] = t[1] = t[2] = t[3] = 0.0;
for (ii = 0; ii < filter_width; ii++)
for (jj = 0; jj < filter_width; jj++)
{
double k = filter[ii + jj * filter_width];
abucket *a = accumulate + x + ii + (y + jj) * width;
t[0] += k * a[0][0];
t[1] += k * a[0][1];
t[2] += k * a[0][2];
t[3] += k * a[0][3];
}
/* FIXME: we should probably use glib facilities to make
* this code readable
*/
p = out + nchan * (i + j * out_width);
a = 256.0 * pow((double) t[0] / PREFILTER_WHITE, g) + 0.5;
if (a < 0) a = 0; else if (a > 255) a = 255;
p[0] = a;
a = 256.0 * pow((double) t[1] / PREFILTER_WHITE, g) + 0.5;
if (a < 0) a = 0; else if (a > 255) a = 255;
p[1] = a;
a = 256.0 * pow((double) t[2] / PREFILTER_WHITE, g) + 0.5;
if (a < 0) a = 0; else if (a > 255) a = 255;
p[2] = a;
if (nchan > 3)
{
a = 256.0 * pow((double) t[3] / PREFILTER_WHITE, g) + 0.5;
if (a < 0) a = 0; else if (a > 255) a = 255;
p[3] = a;
}
x += oversample;
}
y += oversample;
}
}
free (filter);
free (temporal_filter);
free (temporal_deltas);
}
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