avfilter: add gradients source video filter

6 files changed, 321 insertions, 1 deletions

diff --git a/Changelog b/Changelog
index c53d03dc01..69c5dacda7 100644
--- a/Changelog
+++ b/Changelog
@@ -68,6 +68,7 @@ version <next>:
 - pcm_rechunk bitstream filter
 - scdet filter
 - NotchLC decoder
+- gradients source video filter
 
 
 version 4.2:
diff --git a/doc/filters.texi b/doc/filters.texi
index f73d4057c1..53303f6867 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -22281,6 +22281,33 @@ need for a nullsrc video source.
 @end itemize
 
 
+@section gradients
+Generate several gradients.
+
+@table @option
+@item size, s
+Set frame size. For the syntax of this option, check the @ref{video size syntax,,"Video
+size" section in the ffmpeg-utils manual,ffmpeg-utils}. Default value is "640x480".
+
+@item rate, r
+Set frame rate, expressed as number of frames per second. Default
+value is "25".
+
+@item c0, c1, c2, c3, c4, c5, c6, c7
+Set 8 colors. Default values for colors is to pick random one.
+
+@item x0, y0, y0, y1
+Set gradient line source and destination points. If negative or out of range, random ones
+are picked.
+
+@item nb_colors, n
+Set number of colors to use at once. Allowed range is from 2 to 8. Default value is 2.
+
+@item seed
+Set seed for picking gradient line points.
+@end table
+
+
 @section mandelbrot
 
 Generate a Mandelbrot set fractal, and progressively zoom towards the
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index b2086f6fa9..4d07bb6948 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -471,6 +471,7 @@ OBJS-$(CONFIG_CELLAUTO_FILTER)               += vsrc_cellauto.o
 OBJS-$(CONFIG_COLOR_FILTER)                  += vsrc_testsrc.o
 OBJS-$(CONFIG_COREIMAGESRC_FILTER)           += vf_coreimage.o
 OBJS-$(CONFIG_FREI0R_SRC_FILTER)             += vf_frei0r.o
+OBJS-$(CONFIG_GRADIENTS_FILTER)              += vsrc_gradients.o
 OBJS-$(CONFIG_HALDCLUTSRC_FILTER)            += vsrc_testsrc.o
 OBJS-$(CONFIG_LIFE_FILTER)                   += vsrc_life.o
 OBJS-$(CONFIG_MANDELBROT_FILTER)             += vsrc_mandelbrot.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 8830c8d871..6d7ad68f38 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -449,6 +449,7 @@ extern AVFilter ff_vsrc_cellauto;
 extern AVFilter ff_vsrc_color;
 extern AVFilter ff_vsrc_coreimagesrc;
 extern AVFilter ff_vsrc_frei0r_src;
+extern AVFilter ff_vsrc_gradients;
 extern AVFilter ff_vsrc_haldclutsrc;
 extern AVFilter ff_vsrc_life;
 extern AVFilter ff_vsrc_mandelbrot;
diff --git a/libavfilter/version.h b/libavfilter/version.h
index 8bb22c380f..e2083200eb 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   7
-#define LIBAVFILTER_VERSION_MINOR  81
+#define LIBAVFILTER_VERSION_MINOR  82
 #define LIBAVFILTER_VERSION_MICRO 100
 
 
diff --git a/libavfilter/vsrc_gradients.c b/libavfilter/vsrc_gradients.c
new file mode 100644
index 0000000000..984227017e
--- /dev/null
+++ b/libavfilter/vsrc_gradients.c
@@ -0,0 +1,290 @@
+/*
+ * Copyright (c) 2020 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
+ */
+
+#include "avfilter.h"
+#include "formats.h"
+#include "video.h"
+#include "internal.h"
+#include "libavutil/imgutils.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/opt.h"
+#include "libavutil/parseutils.h"
+#include "libavutil/lfg.h"
+#include "libavutil/random_seed.h"
+#include <float.h>
+#include <math.h>
+
+typedef struct GradientsContext {
+    const AVClass *class;
+    int w, h;
+    int type;
+    AVRational frame_rate;
+    uint64_t pts;
+
+    uint8_t color_rgba[8][4];
+    int nb_colors;
+    int x0, y0, x1, y1;
+    float fx0, fy0, fx1, fy1;
+
+    int64_t seed;
+
+    AVLFG lfg;
+    int (*draw_slice)(AVFilterContext *ctx, void *arg, int job, int nb_jobs);
+} GradientsContext;
+
+#define OFFSET(x) offsetof(GradientsContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption gradients_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 },
+    {"c0",        "set 1st color",  OFFSET(color_rgba[0]), AV_OPT_TYPE_COLOR,      {.str = "random"}, 0, 0, FLAGS },
+    {"c1",        "set 2nd color",  OFFSET(color_rgba[1]), AV_OPT_TYPE_COLOR,      {.str = "random"}, 0, 0, FLAGS },
+    {"c2",        "set 3rd color",  OFFSET(color_rgba[2]), AV_OPT_TYPE_COLOR,      {.str = "random"}, 0, 0, FLAGS },
+    {"c3",        "set 4th color",  OFFSET(color_rgba[3]), AV_OPT_TYPE_COLOR,      {.str = "random"}, 0, 0, FLAGS },
+    {"c4",        "set 5th color",  OFFSET(color_rgba[4]), AV_OPT_TYPE_COLOR,      {.str = "random"}, 0, 0, FLAGS },
+    {"c5",        "set 6th color",  OFFSET(color_rgba[5]), AV_OPT_TYPE_COLOR,      {.str = "random"}, 0, 0, FLAGS },
+    {"c6",        "set 7th color",  OFFSET(color_rgba[6]), AV_OPT_TYPE_COLOR,      {.str = "random"}, 0, 0, FLAGS },
+    {"c7",        "set 8th color",  OFFSET(color_rgba[7]), AV_OPT_TYPE_COLOR,      {.str = "random"}, 0, 0, FLAGS },
+    {"x0",        "set gradient line source x0",      OFFSET(x0), AV_OPT_TYPE_INT, {.i64=-1},        -1, INT_MAX, FLAGS },
+    {"y0",        "set gradient line source y0",      OFFSET(y0), AV_OPT_TYPE_INT, {.i64=-1},        -1, INT_MAX, FLAGS },
+    {"x1",        "set gradient line destination x1", OFFSET(x1), AV_OPT_TYPE_INT, {.i64=-1},        -1, INT_MAX, FLAGS },
+    {"y1",        "set gradient line destination y1", OFFSET(y1), AV_OPT_TYPE_INT, {.i64=-1},        -1, INT_MAX, FLAGS },
+    {"nb_colors", "set the number of colors", OFFSET(nb_colors), AV_OPT_TYPE_INT,  {.i64=2},          2, 8, FLAGS },
+    {"n",         "set the number of colors", OFFSET(nb_colors), AV_OPT_TYPE_INT,  {.i64=2},          2, 8, FLAGS },
+    {"seed",      "set the seed",   OFFSET(seed),          AV_OPT_TYPE_INT64,      {.i64=-1},        -1, UINT32_MAX, FLAGS },
+    {NULL},
+};
+
+AVFILTER_DEFINE_CLASS(gradients);
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pix_fmts[] = {
+        AV_PIX_FMT_RGBA,
+        AV_PIX_FMT_RGBA64,
+        AV_PIX_FMT_NONE
+    };
+
+    AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
+    if (!fmts_list)
+        return AVERROR(ENOMEM);
+    return ff_set_common_formats(ctx, fmts_list);
+}
+
+static uint32_t lerp_color(uint8_t c0[4], uint8_t c1[4], float x)
+{
+    const float y = 1.f - x;
+
+    return (lrint(c0[0] * y + c1[0] * x)) << 0  |
+           (lrint(c0[1] * y + c1[1] * x)) << 8  |
+           (lrint(c0[2] * y + c1[2] * x)) << 16 |
+           (lrint(c0[3] * y + c1[3] * x)) << 24;
+}
+
+static uint64_t lerp_color16(uint8_t c0[4], uint8_t c1[4], float x)
+{
+    const float y = 1.f - x;
+
+    return (llrint((c0[0] * y + c1[0] * x) * 256)) << 0  |
+           (llrint((c0[1] * y + c1[1] * x) * 256)) << 16 |
+           (llrint((c0[2] * y + c1[2] * x) * 256)) << 32 |
+           (llrint((c0[3] * y + c1[3] * x) * 256)) << 48;
+}
+
+static uint32_t lerp_colors(uint8_t arr[3][4], int nb_colors, float step)
+{
+    float scl;
+    int i;
+
+    if (nb_colors == 1 || step <= 0.0) {
+        return arr[0][0] | (arr[0][1] << 8) | (arr[0][2] << 16) | (arr[0][3] << 24);
+    } else if (step >= 1.0) {
+        i = nb_colors - 1;
+        return arr[i][0] | (arr[i][1] << 8) | (arr[i][2] << 16) | (arr[i][3] << 24);
+    }
+
+    scl = step * (nb_colors - 1);
+    i = floorf(scl);
+
+    return lerp_color(arr[i], arr[i + 1], scl - i);
+}
+
+static uint64_t lerp_colors16(uint8_t arr[3][4], int nb_colors, float step)
+{
+    float scl;
+    int i;
+
+    if (nb_colors == 1 || step <= 0.0) {
+        return ((uint64_t)arr[0][0] << 8) | ((uint64_t)arr[0][1] << 24) | ((uint64_t)arr[0][2] << 40) | ((uint64_t)arr[0][3] << 56);
+    } else if (step >= 1.0) {
+        i = nb_colors - 1;
+        return ((uint64_t)arr[i][0] << 8) | ((uint64_t)arr[i][1] << 24) | ((uint64_t)arr[i][2] << 40) | ((uint64_t)arr[i][3] << 56);
+    }
+
+    scl = step * (nb_colors - 1);
+    i = floorf(scl);
+
+    return lerp_color16(arr[i], arr[i + 1], scl - i);
+}
+
+static float project(float origin_x, float origin_y,
+                     float dest_x, float dest_y,
+                     int point_x, int point_y)
+{
+    // Rise and run of line.
+    float od_x = dest_x - origin_x;
+    float od_y = dest_y - origin_y;
+
+    // Distance-squared of line.
+    float od_s_q = od_x * od_x + od_y * od_y;
+
+    // Rise and run of projection.
+    float op_x = point_x - origin_x;
+    float op_y = point_y - origin_y;
+    float op_x_od = op_x * od_x + op_y * od_y;
+
+    // Normalize and clamp range.
+    return av_clipf(op_x_od / od_s_q, 0.f, 1.f);
+}
+
+static int draw_gradients_slice(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
+{
+    GradientsContext *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;
+    const int linesize = frame->linesize[0] / 4;
+    uint32_t *dst = (uint32_t *)frame->data[0] + start * linesize;
+
+    for (int y = start; y < end; y++) {
+        for (int x = 0; x < width; x++) {
+            float factor = project(s->fx0, s->fy0, s->fx1, s->fy1, x, y);
+            dst[x] = lerp_colors(s->color_rgba, s->nb_colors, factor);;
+        }
+
+        dst += linesize;
+    }
+
+    return 0;
+}
+
+static int draw_gradients_slice16(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
+{
+    GradientsContext *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;
+    const int linesize = frame->linesize[0] / 8;
+    uint64_t *dst = (uint64_t *)frame->data[0] + start * linesize;
+
+    for (int y = start; y < end; y++) {
+        for (int x = 0; x < width; x++) {
+            float factor = project(s->fx0, s->fy0, s->fx1, s->fy1, x, y);
+            dst[x] = lerp_colors16(s->color_rgba, s->nb_colors, factor);;
+        }
+
+        dst += linesize;
+    }
+
+    return 0;
+}static int config_output(AVFilterLink *inlink)
+{
+    AVFilterContext *ctx = inlink->src;
+    GradientsContext *s = ctx->priv;
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
+
+    if (av_image_check_size(s->w, s->h, 0, ctx) < 0)
+        return AVERROR(EINVAL);
+
+    inlink->w = s->w;
+    inlink->h = s->h;
+    inlink->time_base = av_inv_q(s->frame_rate);
+    inlink->sample_aspect_ratio = (AVRational) {1, 1};
+    if (s->seed == -1)
+        s->seed = av_get_random_seed();
+    av_lfg_init(&s->lfg, s->seed);
+
+    s->draw_slice = desc->comp[0].depth == 16 ? draw_gradients_slice16 : draw_gradients_slice;
+
+    if (s->x0 < 0 || s->x0 >= s->w)
+        s->x0 = av_lfg_get(&s->lfg) % s->w;
+    if (s->y0 < 0 || s->y0 >= s->h)
+        s->y0 = av_lfg_get(&s->lfg) % s->h;
+    if (s->x1 < 0 || s->x1 >= s->w)
+        s->x1 = av_lfg_get(&s->lfg) % s->w;
+    if (s->y1 < 0 || s->y1 >= s->h)
+        s->y1 = av_lfg_get(&s->lfg) % s->h;
+
+    return 0;
+}
+
+static int gradients_request_frame(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    GradientsContext *s = ctx->priv;
+    AVFrame *frame = ff_get_video_buffer(outlink, s->w, s->h);
+    float angle = fmodf(s->pts / 100.f, 2.f * M_PI);
+    const float w2 = s->w / 2.f;
+    const float h2 = s->h / 2.f;
+
+    s->fx0 = (s->x0 - w2) * cosf(angle) - (s->y0 - h2) * sinf(angle) + w2;
+    s->fy0 = (s->x0 - w2) * sinf(angle) + (s->y0 - h2) * cosf(angle) + h2;
+
+    s->fx1 = (s->x1 - w2) * cosf(angle) - (s->y1 - h2) * sinf(angle) + w2;
+    s->fy1 = (s->x1 - w2) * sinf(angle) + (s->y1 - h2) * cosf(angle) + h2;
+
+    if (!frame)
+        return AVERROR(ENOMEM);
+
+    frame->sample_aspect_ratio = (AVRational) {1, 1};
+    frame->pts = s->pts++;
+
+    ctx->internal->execute(ctx, s->draw_slice, frame, NULL, FFMIN(outlink->h, ff_filter_get_nb_threads(ctx)));
+
+    return ff_filter_frame(outlink, frame);
+}
+
+static const AVFilterPad gradients_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .request_frame = gradients_request_frame,
+        .config_props  = config_output,
+    },
+    { NULL }
+};
+
+AVFilter ff_vsrc_gradients = {
+    .name          = "gradients",
+    .description   = NULL_IF_CONFIG_SMALL("Draw a gradients."),
+    .priv_size     = sizeof(GradientsContext),
+    .priv_class    = &gradients_class,
+    .query_formats = query_formats,
+    .inputs        = NULL,
+    .outputs       = gradients_outputs,
+    .flags         = AVFILTER_FLAG_SLICE_THREADS,
+};