avfilter: add mandelbrot fraktal source

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavfilter/Makefile

@@ -84,6 +84,7 @@ OBJS-$(CONFIG_YADIF_FILTER)                  += vf_yadif.o
 OBJS-$(CONFIG_BUFFER_FILTER)                 += vsrc_buffer.o
 OBJS-$(CONFIG_COLOR_FILTER)                  += vsrc_color.o
 OBJS-$(CONFIG_FREI0R_SRC_FILTER)             += vf_frei0r.o
+OBJS-$(CONFIG_MANDELBROT_FILTER)             += vsrc_mandelbrot.o
 OBJS-$(CONFIG_MOVIE_FILTER)                  += src_movie.o
 OBJS-$(CONFIG_MPTESTSRC_FILTER)              += vsrc_mptestsrc.o
 OBJS-$(CONFIG_NULLSRC_FILTER)                += vsrc_testsrc.o

libavfilter/allfilters.c

@@ -95,6 +95,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER (BUFFER,      buffer,      vsrc);
     REGISTER_FILTER (COLOR,       color,       vsrc);
     REGISTER_FILTER (FREI0R,      frei0r_src,  vsrc);
+    REGISTER_FILTER (MANDELBROT,  mandelbrot,  vsrc);
     REGISTER_FILTER (MOVIE,       movie,       vsrc);
     REGISTER_FILTER (MPTESTSRC,   mptestsrc,   vsrc);
     REGISTER_FILTER (NULLSRC,     nullsrc,     vsrc);

libavfilter/vsrc_mandelbrot.c

+/*
+ * Copyright (c) 2011 Michael Niedermayer
+ *
+ * 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
+ *
+ * The vsrc_color filter from Stefano Sabatini was used as template to create
+ * this
+ */
+
+/**
+ * @file
+ * Mandelbrot fraktal renderer
+ */
+
+#include "avfilter.h"
+#include "libavutil/imgutils.h"
+#include "libavutil/parseutils.h"
+
+typedef struct {
+    int w, h;
+    AVRational time_base;
+    uint64_t pts;
+    int maxiter;
+    double start_x;
+    double start_y;
+    double start_scale;
+} MBContext;
+
+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+    MBContext *mb = ctx->priv;
+    char frame_size  [128] = "320x240";
+    char frame_rate  [128] = "25";
+    AVRational frame_rate_q;
+    int ret;
+
+    mb->maxiter=1024;
+    mb->start_x=-2.0;
+    mb->start_y=-1.5;
+    mb->start_scale=3.0;
+    if (args)
+        sscanf(args, "%127[^:]:%127[^:]:%d,%lf:%lf:%lf", frame_size, frame_rate, &mb->maxiter, &mb->start_x, &mb->start_y, &mb->start_scale);
+
+    if (av_parse_video_size(&mb->w, &mb->h, frame_size) < 0) {
+        av_log(ctx, AV_LOG_ERROR, "Invalid frame size: %s\n", frame_size);
+        return AVERROR(EINVAL);
+    }
+    mb->start_scale /=mb->h;
+
+    if (av_parse_video_rate(&frame_rate_q, frame_rate) < 0 ||
+        frame_rate_q.den <= 0 || frame_rate_q.num <= 0) {
+        av_log(ctx, AV_LOG_ERROR, "Invalid frame rate: %s\n", frame_rate);
+        return AVERROR(EINVAL);
+    }
+    mb->time_base.num = frame_rate_q.den;
+    mb->time_base.den = frame_rate_q.num;
+
+    return 0;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    MBContext *mb = ctx->priv;
+    int i;
+
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum PixelFormat pix_fmts[] = {
+        PIX_FMT_BGR32,
+        PIX_FMT_NONE
+    };
+
+    avfilter_set_common_pixel_formats(ctx, avfilter_make_format_list(pix_fmts));
+    return 0;
+}
+
+static int config_props(AVFilterLink *inlink)
+{
+    AVFilterContext *ctx = inlink->src;
+    MBContext *mb = ctx->priv;
+
+    if (av_image_check_size(mb->w, mb->h, 0, ctx) < 0)
+        return AVERROR(EINVAL);
+
+    inlink->w = mb->w;
+    inlink->h = mb->h;
+    inlink->time_base = mb->time_base;
+
+    return 0;
+}
+
+static void draw_mandelbrot(AVFilterContext *ctx, uint32_t *color, int linesize, int64_t pts)
+{
+    MBContext *mb = ctx->priv;
+    int x,y,i;
+
+    for(y=0; y<mb->h; y++){
+        for(x=0; x<mb->w; x++){
+            double cr=mb->start_x+mb->start_scale*x;
+            double ci=mb->start_y+mb->start_scale*y;
+            double zr=cr;
+            double zi=ci;
+            const double B=100;
+            uint32_t c=0;
+
+            for(i=0; i<256; i++){
+                double t;
+                if(zr*zr + zi*zi > B){
+                    zr= i + (log(log(B)) - log(log(sqrt(zr*zr + zi*zi))))/log(2);
+                    c= lrintf((sin(zr)+1)*127) + lrintf((sin(zr/1.234)+1)*127)*256*256 + lrintf((sin(zr/100)+1)*127)*256;
+                    break;
+                }
+                t= zr*zr - zi*zi;
+                zi= 2*zr*zi + ci;
+                zr=       t + cr;
+            }
+            color[x + y*linesize]= c;
+        }
+    }
+}
+
+static int request_frame(AVFilterLink *link)
+{
+    MBContext *mb = link->src->priv;
+    AVFilterBufferRef *picref = avfilter_get_video_buffer(link, AV_PERM_WRITE, mb->w, mb->h);
+    picref->video->sample_aspect_ratio = (AVRational) {1, 1};
+    picref->pts = mb->pts++;
+    picref->pos = -1;
+
+    avfilter_start_frame(link, avfilter_ref_buffer(picref, ~0));
+    draw_mandelbrot(link->src, picref->data[0], picref->linesize[0]/4, picref->pts);
+    avfilter_draw_slice(link, 0, mb->h, 1);
+    avfilter_end_frame(link);
+    avfilter_unref_buffer(picref);
+
+    return 0;
+}
+
+AVFilter avfilter_vsrc_mandelbrot = {
+    .name        = "mandelbrot",
+    .description = NULL_IF_CONFIG_SMALL("Mandelbrot renderer"),
+
+    .priv_size = sizeof(MBContext),
+    .init      = init,
+    .uninit    = uninit,
+
+    .query_formats = query_formats,
+
+    .inputs    = (const AVFilterPad[]) {{ .name = NULL}},
+
+    .outputs   = (const AVFilterPad[]) {{ .name      = "default",
+                                    .type            = AVMEDIA_TYPE_VIDEO,
+                                    .request_frame   = request_frame,
+                                    .config_props    = config_props },
+                                  { .name = NULL}},
+};