public static DustCloud[] Generate(Random rand, int count)
{
float minRad = 1f;
float maxRad = 16f;
float near = 20f;
float far = 32f;
var clrPairs = new Color4[, ] {
{ Color4.Red, Color4.Blue }
};
int variation = rand.Next(16, 32);
var seta = new Vector3[variation];
var setb = new Vector3[variation];
for (int i = 0; i < variation; ++i)
{
seta[i] = Starfield.GetRandomPosition(rand, near, far);
setb[i] = Starfield.GetRandomPosition(rand, near, far);
}
int index = rand.Next(clrPairs.GetLength(0));
var clra = clrPairs[index, 0];
var clrb = clrPairs[index, 1];
var dusts = new DustCloud[count];
for (int i = 0; i < count; ++i)
{
var pos = Starfield.GetRandomPosition(rand, near, far);
float scale = (float)Math.Pow(rand.NextDouble(), 4);
float rad = minRad + scale * (maxRad - minRad);
float alpha = (1 - scale) / 96f;
var suma = seta.Sum(x => 1f / Math.Max(0.125f, (pos - x).LengthSquared));
var sumb = setb.Sum(x => 1f / Math.Max(0.125f, (pos - x).LengthSquared));
var shift = (suma * suma) / ((suma * suma) + (sumb * sumb));
var clr = new Color4(
clra.R * shift + clrb.R * (1f - shift),
clra.G * shift + clrb.G * (1f - shift),
clra.B * shift + clrb.B * (1f - shift),
alpha);
var dust = new DustCloud(pos, rad, clr);
dusts[i] = dust;
}
Array.Sort(dusts, Starfield.Comparer);
return(dusts);
}
public static CubeMapTexture Generate(int seed, int resolution, int samples)
{
var rand = seed == 0 ? new Random() : new Random(seed);
var stars = Star.Generate(rand, rand.Next(16384, 32768));
var dusts = DustCloud.Generate(rand, rand.Next(4096, 8192));
int renderResolution = resolution * samples;
var camera = new Camera(renderResolution, renderResolution, MathHelper.PiOver2, 4f, 64f);
var starShader = new StarShader {
Camera = camera
};
var dustShader = new DustCloudShader {
Camera = camera
};
var target = new FrameBuffer(new BitmapTexture2D(new Bitmap(renderResolution, renderResolution)), 16);
var angles = new[] {
Tuple.Create(0f, MathHelper.PiOver2),
Tuple.Create(0f, -MathHelper.PiOver2),
Tuple.Create(MathHelper.PiOver2, 0f),
Tuple.Create(-MathHelper.PiOver2, 0f),
Tuple.Create(0f, 0f),
Tuple.Create(0f, MathHelper.Pi)
};
var bmps = new Bitmap[6];
target.Begin();
GL.ClearColor(Color.Black);
var bmp = new Bitmap(renderResolution, renderResolution);
for (int i = 0; i < 6; ++i)
{
camera.Pitch = angles[i].Item1;
camera.Yaw = angles[i].Item2;
GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
dustShader.BeginBatch();
foreach (var dust in dusts)
{
dustShader.Render(dust);
}
dustShader.EndBatch();
starShader.BeginBatch();
foreach (var star in stars)
{
starShader.Render(star);
}
starShader.EndBatch();
var data = bmp.LockBits(new Rectangle(0, 0, renderResolution, renderResolution), ImageLockMode.WriteOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
GL.ReadPixels(0, 0, renderResolution, renderResolution, OpenTK.Graphics.OpenGL.PixelFormat.Bgra, PixelType.UnsignedByte, data.Scan0);
bmp.UnlockBits(data);
bmps[i] = new Bitmap(bmp, new Size(resolution, resolution));
}
bmp.Dispose();
target.End();
target.Dispose();
return(new CubeMapTexture(bmps[0], bmps[1], bmps[2], bmps[3], bmps[4], bmps[5]));
}
