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osu-lazer/osu.Game/Graphics/Backgrounds/SeasonalBackgroundLoader.cs
Dean Herbert a9a3489e92 Fix potential null reference when loading background
As seen in
https://discordapp.com/channels/188630481301012481/188630652340404224/772094427342569493.
Caused due to async load of the loader, which means it may not be ready
before Next() is called.
2020-10-31 22:51:35 +09:00

104 lines
3.7 KiB
C#

// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.
using System;
using System.Linq;
using osu.Framework.Allocation;
using osu.Framework.Bindables;
using osu.Framework.Graphics;
using osu.Framework.Graphics.Textures;
using osu.Framework.Utils;
using osu.Game.Configuration;
using osu.Game.Online.API;
using osu.Game.Online.API.Requests;
using osu.Game.Online.API.Requests.Responses;
namespace osu.Game.Graphics.Backgrounds
{
public class SeasonalBackgroundLoader : Component
{
/// <summary>
/// Fired when background should be changed due to receiving backgrounds from API
/// or when the user setting is changed (as it might require unloading the seasonal background).
/// </summary>
public event Action SeasonalBackgroundChanged;
[Resolved]
private IAPIProvider api { get; set; }
private readonly IBindable<APIState> apiState = new Bindable<APIState>();
private Bindable<SeasonalBackgroundMode> seasonalBackgroundMode;
private Bindable<APISeasonalBackgrounds> seasonalBackgrounds;
private int current;
[BackgroundDependencyLoader]
private void load(OsuConfigManager config, SessionStatics sessionStatics)
{
seasonalBackgroundMode = config.GetBindable<SeasonalBackgroundMode>(OsuSetting.SeasonalBackgroundMode);
seasonalBackgroundMode.BindValueChanged(_ => SeasonalBackgroundChanged?.Invoke());
seasonalBackgrounds = sessionStatics.GetBindable<APISeasonalBackgrounds>(Static.SeasonalBackgrounds);
seasonalBackgrounds.BindValueChanged(_ => SeasonalBackgroundChanged?.Invoke());
apiState.BindTo(api.State);
apiState.BindValueChanged(fetchSeasonalBackgrounds, true);
}
private void fetchSeasonalBackgrounds(ValueChangedEvent<APIState> stateChanged)
{
if (seasonalBackgrounds.Value != null || stateChanged.NewValue != APIState.Online)
return;
var request = new GetSeasonalBackgroundsRequest();
request.Success += response =>
{
seasonalBackgrounds.Value = response;
current = RNG.Next(0, response.Backgrounds?.Count ?? 0);
};
api.PerformAsync(request);
}
public SeasonalBackground LoadNextBackground()
{
if (seasonalBackgroundMode.Value == SeasonalBackgroundMode.Never
|| (seasonalBackgroundMode.Value == SeasonalBackgroundMode.Sometimes && !isInSeason))
{
return null;
}
var backgrounds = seasonalBackgrounds.Value?.Backgrounds;
if (backgrounds == null || !backgrounds.Any())
return null;
current = (current + 1) % backgrounds.Count;
string url = backgrounds[current].Url;
return new SeasonalBackground(url);
}
private bool isInSeason => seasonalBackgrounds.Value != null && DateTimeOffset.Now < seasonalBackgrounds.Value.EndDate;
}
[LongRunningLoad]
public class SeasonalBackground : Background
{
private readonly string url;
private const string fallback_texture_name = @"Backgrounds/bg1";
public SeasonalBackground(string url)
{
this.url = url;
}
[BackgroundDependencyLoader]
private void load(LargeTextureStore textures)
{
Sprite.Texture = textures.Get(url) ?? textures.Get(fallback_texture_name);
// ensure we're not loading in without a transition.
this.FadeInFromZero(200, Easing.InOutSine);
}
}
}