FFMpegCore/FFMpegCore.Test/Utilities/BitmapSources.cs

using System.Drawing;
using System.Drawing.Imaging;
using System.Numerics;
using System.Runtime.Versioning;
using FFMpegCore.Pipes;
using SkiaSharp;

namespace FFMpegCore.Test.Utilities
{
    internal static class BitmapSource
    {
        [SupportedOSPlatform("windows")]
        public static IEnumerable<IVideoFrame> CreateBitmaps(int count, PixelFormat fmt, int w, int h)
        {
            for (var i = 0; i < count; i++)
            {
                using (var frame = CreateVideoFrame(i, fmt, w, h, 0.025f, 0.025f * w * 0.03f))
                {
                    yield return frame;
                }
            }
        }

        public static IEnumerable<IVideoFrame> CreateBitmaps(int count, SKColorType fmt, int w, int h)
        {
            for (var i = 0; i < count; i++)
            {
                using (var frame = CreateVideoFrame(i, fmt, w, h, 0.025f, 0.025f * w * 0.03f))
                {
                    yield return frame;
                }
            }
        }

        [SupportedOSPlatform("windows")]
        public static Extensions.System.Drawing.Common.BitmapVideoFrameWrapper CreateVideoFrame(int index, PixelFormat fmt, int w, int h, float scaleNoise, float offset)
        {
            var bitmap = new Bitmap(w, h, fmt);

            foreach (var (x, y, red, green, blue) in GenerateVideoFramePixels(index, w, h, scaleNoise, offset))
            {
                var color = Color.FromArgb(red, blue, green);
                bitmap.SetPixel(x, y, color);
            }

            return new Extensions.System.Drawing.Common.BitmapVideoFrameWrapper(bitmap);
        }

        public static Extensions.SkiaSharp.BitmapVideoFrameWrapper CreateVideoFrame(int index, SKColorType fmt, int w, int h, float scaleNoise, float offset)
        {
            var bitmap = new SKBitmap(w, h, fmt, SKAlphaType.Opaque);

            bitmap.Pixels = GenerateVideoFramePixels(index, w, h, scaleNoise, offset)
                .Select(args => new SKColor(args.red, args.blue, args.green))
                .ToArray();

            return new Extensions.SkiaSharp.BitmapVideoFrameWrapper(bitmap);
        }

        private static IEnumerable<(int x, int y, byte red, byte green, byte blue)> GenerateVideoFramePixels(int index, int w, int h, float scaleNoise, float offset)
        {
            offset = offset * index;

            for (var y = 0; y < h; y++)
            {
                for (var x = 0; x < w; x++)
                {
                    var xf = x / (float)w;
                    var yf = y / (float)h;
                    var nx = x * scaleNoise + offset;
                    var ny = y * scaleNoise + offset;

                    var value = (byte)((Perlin.Noise(nx, ny) + 1.0f) / 2.0f * 255);

                    yield return ((x, y, (byte)(value * xf), (byte)(value * yf), value));
                }
            }
        }

        //
        // Perlin noise generator for Unity
        // Keijiro Takahashi, 2013, 2015
        // https://github.com/keijiro/PerlinNoise
        //
        // Based on the original implementation by Ken Perlin
        // http://mrl.nyu.edu/~perlin/noise/
        //
        private static class Perlin
        {
            #region Noise functions

            public static float Noise(float x)
            {
                var X = (int)MathF.Floor(x) & 0xff;
                x -= MathF.Floor(x);
                var u = Fade(x);
                return Lerp(u, Grad(perm[X], x), Grad(perm[X + 1], x - 1)) * 2;
            }

            public static float Noise(float x, float y)
            {
                var X = (int)MathF.Floor(x) & 0xff;
                var Y = (int)MathF.Floor(y) & 0xff;
                x -= MathF.Floor(x);
                y -= MathF.Floor(y);
                var u = Fade(x);
                var v = Fade(y);
                var A = (perm[X] + Y) & 0xff;
                var B = (perm[X + 1] + Y) & 0xff;
                return Lerp(v, Lerp(u, Grad(perm[A], x, y), Grad(perm[B], x - 1, y)),
                               Lerp(u, Grad(perm[A + 1], x, y - 1), Grad(perm[B + 1], x - 1, y - 1)));
            }

            public static float Noise(Vector2 coord)
            {
                return Noise(coord.X, coord.Y);
            }

            public static float Noise(float x, float y, float z)
            {
                var X = (int)MathF.Floor(x) & 0xff;
                var Y = (int)MathF.Floor(y) & 0xff;
                var Z = (int)MathF.Floor(z) & 0xff;
                x -= MathF.Floor(x);
                y -= MathF.Floor(y);
                z -= MathF.Floor(z);
                var u = Fade(x);
                var v = Fade(y);
                var w = Fade(z);
                var A = (perm[X] + Y) & 0xff;
                var B = (perm[X + 1] + Y) & 0xff;
                var AA = (perm[A] + Z) & 0xff;
                var BA = (perm[B] + Z) & 0xff;
                var AB = (perm[A + 1] + Z) & 0xff;
                var BB = (perm[B + 1] + Z) & 0xff;
                return Lerp(w, Lerp(v, Lerp(u, Grad(perm[AA], x, y, z), Grad(perm[BA], x - 1, y, z)),
                                       Lerp(u, Grad(perm[AB], x, y - 1, z), Grad(perm[BB], x - 1, y - 1, z))),
                               Lerp(v, Lerp(u, Grad(perm[AA + 1], x, y, z - 1), Grad(perm[BA + 1], x - 1, y, z - 1)),
                                       Lerp(u, Grad(perm[AB + 1], x, y - 1, z - 1), Grad(perm[BB + 1], x - 1, y - 1, z - 1))));
            }

            public static float Noise(Vector3 coord)
            {
                return Noise(coord.X, coord.Y, coord.Z);
            }

            #endregion

            #region fBm functions

            public static float Fbm(float x, int octave)
            {
                var f = 0.0f;
                var w = 0.5f;
                for (var i = 0; i < octave; i++)
                {
                    f += w * Noise(x);
                    x *= 2.0f;
                    w *= 0.5f;
                }

                return f;
            }

            public static float Fbm(Vector2 coord, int octave)
            {
                var f = 0.0f;
                var w = 0.5f;
                for (var i = 0; i < octave; i++)
                {
                    f += w * Noise(coord);
                    coord *= 2.0f;
                    w *= 0.5f;
                }

                return f;
            }

            public static float Fbm(float x, float y, int octave)
            {
                return Fbm(new Vector2(x, y), octave);
            }

            public static float Fbm(Vector3 coord, int octave)
            {
                var f = 0.0f;
                var w = 0.5f;
                for (var i = 0; i < octave; i++)
                {
                    f += w * Noise(coord);
                    coord *= 2.0f;
                    w *= 0.5f;
                }

                return f;
            }

            public static float Fbm(float x, float y, float z, int octave)
            {
                return Fbm(new Vector3(x, y, z), octave);
            }

            #endregion

            #region Private functions

            private static float Fade(float t)
            {
                return t * t * t * (t * (t * 6 - 15) + 10);
            }

            private static float Lerp(float t, float a, float b)
            {
                return a + t * (b - a);
            }

            private static float Grad(int hash, float x)
            {
                return (hash & 1) == 0 ? x : -x;
            }

            private static float Grad(int hash, float x, float y)
            {
                return ((hash & 1) == 0 ? x : -x) + ((hash & 2) == 0 ? y : -y);
            }

            private static float Grad(int hash, float x, float y, float z)
            {
                var h = hash & 15;
                var u = h < 8 ? x : y;
                var v = h < 4 ? y : (h == 12 || h == 14 ? x : z);
                return ((h & 1) == 0 ? u : -u) + ((h & 2) == 0 ? v : -v);
            }

            private static readonly int[] perm = {
        151,160,137,91,90,15,
        131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
        190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
        88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
        77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
        102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
        135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
        5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
        223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
        129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
        251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
        49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
        138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180,
        151
    };

            #endregion
        }
    }
}