2 * Copyright (c) 2019 Paul B Mahol
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 * Sierpinski carpet fractal renderer
30 #include "libavutil/imgutils.h"
31 #include "libavutil/intreadwrite.h"
32 #include "libavutil/opt.h"
33 #include "libavutil/parseutils.h"
34 #include "libavutil/lfg.h"
35 #include "libavutil/random_seed.h"
39 typedef struct SierpinskiContext {
42 AVRational frame_rate;
54 #define OFFSET(x) offsetof(SierpinskiContext, x)
55 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
57 static const AVOption sierpinski_options[] = {
58 {"size", "set frame size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="640x480"}, 0, 0, FLAGS },
59 {"s", "set frame size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="640x480"}, 0, 0, FLAGS },
60 {"rate", "set frame rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"}, 0, 0, FLAGS },
61 {"r", "set frame rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"}, 0, 0, FLAGS },
62 {"seed", "set the seed", OFFSET(seed), AV_OPT_TYPE_INT, {.i64=-1}, -1, UINT32_MAX, FLAGS },
63 {"jump", "set the jump", OFFSET(jump), AV_OPT_TYPE_INT, {.i64=100}, 1, 10000, FLAGS },
67 AVFILTER_DEFINE_CLASS(sierpinski);
69 static int query_formats(AVFilterContext *ctx)
71 static const enum AVPixelFormat pix_fmts[] = {
76 AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
78 return AVERROR(ENOMEM);
79 return ff_set_common_formats(ctx, fmts_list);
82 static int config_output(AVFilterLink *inlink)
84 AVFilterContext *ctx = inlink->src;
85 SierpinskiContext *s = ctx->priv;
87 if (av_image_check_size(s->w, s->h, 0, ctx) < 0)
88 return AVERROR(EINVAL);
92 inlink->time_base = av_inv_q(s->frame_rate);
93 inlink->sample_aspect_ratio = (AVRational) {1, 1};
95 s->seed = av_get_random_seed();
96 av_lfg_init(&s->lfg, s->seed);
101 static int fill_sierpinski(SierpinskiContext *s, int x, int y)
103 int pos_x = x + s->pos_x;
104 int pos_y = y + s->pos_y;
106 while (pos_x != 0 && pos_y != 0) {
107 if (FFABS(pos_x % 3) == 1 && FFABS(pos_y % 3) == 1)
117 static int draw_slice(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
119 SierpinskiContext *s = ctx->priv;
120 AVFrame *frame = arg;
121 const int width = frame->width;
122 const int height = frame->height;
123 const int start = (height * job ) / nb_jobs;
124 const int end = (height * (job+1)) / nb_jobs;
125 uint8_t *dst = frame->data[0] + start * frame->linesize[0];
127 for (int y = start; y < end; y++) {
128 for (int x = 0; x < width; x++) {
129 if (fill_sierpinski(s, x, y)) {
130 AV_WL32(&dst[x*4], 0x00000000);
132 AV_WL32(&dst[x*4], 0xFFFFFFFF);
136 dst += frame->linesize[0];
142 static void draw_sierpinski(AVFilterContext *ctx, AVFrame *frame)
144 SierpinskiContext *s = ctx->priv;
145 AVFilterLink *outlink = ctx->outputs[0];
147 if (s->pos_x == s->dest_x && s->pos_y == s->dest_y) {
148 unsigned int rnd = av_lfg_get(&s->lfg);
149 int mod = 2 * s->jump + 1;
151 s->dest_x += (int)((rnd & 0xffff) % mod) - s->jump;
152 s->dest_y += (int)((rnd >> 16) % mod) - s->jump;
154 if (s->pos_x < s->dest_x)
156 else if (s->pos_x > s->dest_x)
159 if (s->pos_y < s->dest_y)
161 else if (s->pos_y > s->dest_y)
165 ctx->internal->execute(ctx, draw_slice, frame, NULL, FFMIN(outlink->h, ff_filter_get_nb_threads(ctx)));
168 static int sierpinski_request_frame(AVFilterLink *link)
170 SierpinskiContext *s = link->src->priv;
171 AVFrame *frame = ff_get_video_buffer(link, s->w, s->h);
174 return AVERROR(ENOMEM);
176 frame->sample_aspect_ratio = (AVRational) {1, 1};
177 frame->pts = s->pts++;
179 draw_sierpinski(link->src, frame);
181 return ff_filter_frame(link, frame);
184 static const AVFilterPad sierpinski_outputs[] = {
187 .type = AVMEDIA_TYPE_VIDEO,
188 .request_frame = sierpinski_request_frame,
189 .config_props = config_output,
194 AVFilter ff_vsrc_sierpinski = {
195 .name = "sierpinski",
196 .description = NULL_IF_CONFIG_SMALL("Render a Sierpinski carpet fractal."),
197 .priv_size = sizeof(SierpinskiContext),
198 .priv_class = &sierpinski_class,
199 .query_formats = query_formats,
201 .outputs = sierpinski_outputs,
202 .flags = AVFILTER_FLAG_SLICE_THREADS,