BizHawk/BizHawk.Client.MultiHawk/DisplayManager/SwappableDisplaySurfaceSet.cs

82 lines
2.1 KiB
C#

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using BizHawk.Common;
using BizHawk.Client.Common;
namespace BizHawk.Client.MultiHawk
{
/// <summary>
/// encapsulates thread-safe concept of pending/current display surfaces, reusing buffers where matching
/// sizes are available and keeping them cleaned up when they dont seem like theyll need to be used anymore
/// </summary>
class SwappableDisplaySurfaceSet
{
DisplaySurface Pending, Current;
bool IsPending;
Queue<DisplaySurface> ReleasedSurfaces = new Queue<DisplaySurface>();
/// <summary>
/// retrieves a surface with the specified size, reusing an old buffer if available and clearing if requested
/// </summary>
public DisplaySurface AllocateSurface(int width, int height, bool needsClear = true)
{
for (; ; )
{
DisplaySurface trial;
lock (this)
{
if (ReleasedSurfaces.Count == 0) break;
trial = ReleasedSurfaces.Dequeue();
}
if (trial.Width == width && trial.Height == height)
{
if (needsClear) trial.Clear();
return trial;
}
trial.Dispose();
}
return new DisplaySurface(width, height);
}
/// <summary>
/// sets the provided buffer as pending. takes control of the supplied buffer
/// </summary>
public void SetPending(DisplaySurface newPending)
{
lock (this)
{
if (Pending != null) ReleasedSurfaces.Enqueue(Pending);
Pending = newPending;
IsPending = true;
}
}
public void ReleaseSurface(DisplaySurface surface)
{
lock (this) ReleasedSurfaces.Enqueue(surface);
}
/// <summary>
/// returns the current buffer, making the most recent pending buffer (if there is such) as the new current first.
/// </summary>
public DisplaySurface GetCurrent()
{
lock (this)
{
if (IsPending)
{
if (Current != null) ReleasedSurfaces.Enqueue(Current);
Current = Pending;
Pending = null;
IsPending = false;
}
}
return Current;
}
}
}