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/*
* Copyright (c) 2019 Paul B Mahol
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Sierpinski carpet fractal renderer
*/
#include "avfilter.h"
#include "video.h"
#include "internal.h"
#include "libavutil/imgutils.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/opt.h"
#include "libavutil/lfg.h"
#include "libavutil/random_seed.h"
#include <float.h>
#include <math.h>
typedef struct SierpinskiContext {
const AVClass *class;
int w, h;
int type;
AVRational frame_rate;
uint64_t pts;
int64_t seed;
int jump;
int pos_x, pos_y;
int dest_x, dest_y;
AVLFG lfg;
int (*draw_slice)(AVFilterContext *ctx, void *arg, int job, int nb_jobs);
} SierpinskiContext;
#define OFFSET(x) offsetof(SierpinskiContext, x)
#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
static const AVOption sierpinski_options[] = {
{"size", "set frame size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="640x480"}, 0, 0, FLAGS },
{"s", "set frame size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="640x480"}, 0, 0, FLAGS },
{"rate", "set frame rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"}, 0, INT_MAX, FLAGS },
{"r", "set frame rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"}, 0, INT_MAX, FLAGS },
{"seed", "set the seed", OFFSET(seed), AV_OPT_TYPE_INT64, {.i64=-1}, -1, UINT32_MAX, FLAGS },
{"jump", "set the jump", OFFSET(jump), AV_OPT_TYPE_INT, {.i64=100}, 1, 10000, FLAGS },
{"type","set fractal type",OFFSET(type), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS, .unit = "type" },
{"carpet", "sierpinski carpet", 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, .unit = "type" },
{"triangle", "sierpinski triangle", 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, .unit = "type" },
{NULL},
};
AVFILTER_DEFINE_CLASS(sierpinski);
static int fill_sierpinski(SierpinskiContext *s, int x, int y)
{
int pos_x = x + s->pos_x;
int pos_y = y + s->pos_y;
while (pos_x != 0 && pos_y != 0) {
if (FFABS(pos_x % 3) == 1 && FFABS(pos_y % 3) == 1)
return 1;
pos_x /= 3;
pos_y /= 3;
}
return 0;
}
static int draw_triangle_slice(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
{
SierpinskiContext *s = ctx->priv;
AVFrame *frame = arg;
const int width = frame->width;
const int height = frame->height;
const int start = (height * job ) / nb_jobs;
const int end = (height * (job+1)) / nb_jobs;
uint8_t *dst = frame->data[0] + start * frame->linesize[0];
for (int y = start; y < end; y++) {
for (int x = 0; x < width; x++) {
if ((s->pos_x + x) & (s->pos_y + y)) {
AV_WL32(&dst[x*4], 0x00000000);
} else {
AV_WL32(&dst[x*4], 0xFFFFFFFF);
}
}
dst += frame->linesize[0];
}
return 0;
}
static int draw_carpet_slice(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
{
SierpinskiContext *s = ctx->priv;
AVFrame *frame = arg;
const int width = frame->width;
const int height = frame->height;
const int start = (height * job ) / nb_jobs;
const int end = (height * (job+1)) / nb_jobs;
uint8_t *dst = frame->data[0] + start * frame->linesize[0];
for (int y = start; y < end; y++) {
for (int x = 0; x < width; x++) {
if (fill_sierpinski(s, x, y)) {
AV_WL32(&dst[x*4], 0x00000000);
} else {
AV_WL32(&dst[x*4], 0xFFFFFFFF);
}
}
dst += frame->linesize[0];
}
return 0;
}
static int config_output(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
SierpinskiContext *s = ctx->priv;
if (av_image_check_size(s->w, s->h, 0, ctx) < 0)
return AVERROR(EINVAL);
outlink->w = s->w;
outlink->h = s->h;
outlink->time_base = av_inv_q(s->frame_rate);
outlink->sample_aspect_ratio = (AVRational) {1, 1};
outlink->frame_rate = s->frame_rate;
if (s->seed == -1)
s->seed = av_get_random_seed();
av_lfg_init(&s->lfg, s->seed);
s->draw_slice = s->type ? draw_triangle_slice : draw_carpet_slice;
return 0;
}
static void draw_sierpinski(AVFilterContext *ctx, AVFrame *frame)
{
SierpinskiContext *s = ctx->priv;
AVFilterLink *outlink = ctx->outputs[0];
if (s->pos_x == s->dest_x && s->pos_y == s->dest_y) {
unsigned int rnd = av_lfg_get(&s->lfg);
int mod = 2 * s->jump + 1;
s->dest_x += (int)((rnd & 0xffff) % mod) - s->jump;
s->dest_y += (int)((rnd >> 16) % mod) - s->jump;
} else {
if (s->pos_x < s->dest_x)
s->pos_x++;
else if (s->pos_x > s->dest_x)
s->pos_x--;
if (s->pos_y < s->dest_y)
s->pos_y++;
else if (s->pos_y > s->dest_y)
s->pos_y--;
}
ff_filter_execute(ctx, s->draw_slice, frame, NULL,
FFMIN(outlink->h, ff_filter_get_nb_threads(ctx)));
}
static int sierpinski_request_frame(AVFilterLink *link)
{
SierpinskiContext *s = link->src->priv;
AVFrame *frame = ff_get_video_buffer(link, s->w, s->h);
if (!frame)
return AVERROR(ENOMEM);
frame->sample_aspect_ratio = (AVRational) {1, 1};
frame->pts = s->pts++;
frame->duration = 1;
draw_sierpinski(link->src, frame);
return ff_filter_frame(link, frame);
}
static const AVFilterPad sierpinski_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.request_frame = sierpinski_request_frame,
.config_props = config_output,
},
};
const AVFilter ff_vsrc_sierpinski = {
.name = "sierpinski",
.description = NULL_IF_CONFIG_SMALL("Render a Sierpinski fractal."),
.priv_size = sizeof(SierpinskiContext),
.priv_class = &sierpinski_class,
.inputs = NULL,
FILTER_OUTPUTS(sierpinski_outputs),
FILTER_SINGLE_PIXFMT(AV_PIX_FMT_0BGR32),
.flags = AVFILTER_FLAG_SLICE_THREADS,
};
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