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osu/osu.Game/Graphics/Backgrounds/Triangles.cs
2017-04-06 09:57:34 +09:00

129 lines
4.6 KiB
C#

// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
using System.Linq;
using osu.Framework.Extensions.IEnumerableExtensions;
using osu.Framework.Graphics;
using osu.Framework.Graphics.Containers;
using osu.Framework.Graphics.Sprites;
using osu.Framework.MathUtils;
using OpenTK;
using OpenTK.Graphics;
using System;
namespace osu.Game.Graphics.Backgrounds
{
public class Triangles : Container<Triangle>
{
public override bool HandleInput => false;
public Color4 ColourLight = Color4.White;
public Color4 ColourDark = Color4.Black;
/// <summary>
/// Whether we want to expire triangles as they exit our draw area completely.
/// </summary>
protected virtual bool ExpireOffScreenTriangles => true;
/// <summary>
/// Whether we should create new triangles as others expire.
/// </summary>
protected virtual bool CreateNewTriangles => true;
/// <summary>
/// The amount of triangles we want compared to the default distribution.
/// </summary>
protected virtual float SpawnRatio => 1;
private float triangleScale = 1;
/// <summary>
/// Whether we should drop-off alpha values of triangles more quickly to improve
/// the visual appearance of fading. This defaults to on as it is generally more
/// aesthetically pleasing, but should be turned off in <see cref="BufferedContainer{T}"/>s.
/// </summary>
public bool HideAlphaDiscrepancies = true;
public float TriangleScale
{
get { return triangleScale; }
set
{
float change = value / triangleScale;
triangleScale = value;
if (change != 1)
Children.ForEach(t => t.Scale *= change);
}
}
protected override void LoadComplete()
{
base.LoadComplete();
addTriangles(true);
}
private int aimTriangleCount => (int)(DrawWidth * DrawHeight * 0.002f / (triangleScale * triangleScale) * SpawnRatio);
protected override void Update()
{
base.Update();
float adjustedAlpha = HideAlphaDiscrepancies ?
// Cubically scale alpha to make it drop off more sharply.
(float)Math.Pow(DrawInfo.Colour.AverageColour.Linear.A, 3) :
1;
foreach (var t in Children)
{
t.Alpha = adjustedAlpha;
t.Position -= new Vector2(0, (float)(t.Scale.X * (50 / DrawHeight) * (Time.Elapsed / 950)) / triangleScale);
if (ExpireOffScreenTriangles && t.DrawPosition.Y + t.DrawSize.Y * t.Scale.Y < 0)
t.Expire();
}
if (CreateNewTriangles)
addTriangles(false);
}
protected virtual Triangle CreateTriangle()
{
const float std_dev = 0.16f;
const float mean = 0.5f;
float u1 = 1 - RNG.NextSingle(); //uniform(0,1] random floats
float u2 = 1 - RNG.NextSingle();
float randStdNormal = (float)(Math.Sqrt(-2.0 * Math.Log(u1)) * Math.Sin(2.0 * Math.PI * u2)); //random normal(0,1)
var scale = Math.Max(triangleScale * (mean + std_dev * randStdNormal), 0.1f); //random normal(mean,stdDev^2)
const float size = 100;
return new EquilateralTriangle
{
Origin = Anchor.TopCentre,
RelativePositionAxes = Axes.Both,
Size = new Vector2(size),
Scale = new Vector2(scale),
EdgeSmoothness = new Vector2(1),
Colour = GetTriangleShade(),
Depth = scale,
};
}
protected virtual Color4 GetTriangleShade() => Interpolation.ValueAt(RNG.NextSingle(), ColourDark, ColourLight, 0, 1);
private void addTriangles(bool randomY)
{
int addCount = aimTriangleCount - Children.Count();
for (int i = 0; i < addCount; i++)
{
var sprite = CreateTriangle();
float triangleHeight = sprite.DrawHeight / DrawHeight;
sprite.Position = new Vector2(RNG.NextSingle(), randomY ? RNG.NextSingle() * (1 + triangleHeight) - triangleHeight : 1);
Add(sprite);
}
}
}
}