SkiaSharp 之 WPF 自繪 投籃小遊戲（案例版）
此案例主要是針對光線投影法碰撞檢測功能的示例，順便做成了一個小遊戲，很簡單，但是，效果卻很不錯。
投籃小遊戲
規則，點擊投籃目標點，就會有一個球沿着相關拋物線，然後，判斷是否進入籃子里，其實就是一個矩形，直接是按照碰撞檢測來的，碰到就算進去了，對其增加了一個分數統計等功能。
Wpf 和 SkiaSharp
新建一個 WPF 項目，然後，Nuget 包即可
要添加 Nuget 包
Install-Package SkiaSharp.Views.WPF -Version 2.88.0
其中核心邏輯是這部分，會以我設置的 60FPS 來刷新當前的畫板。
skContainer.PaintSurface += SkContainer_PaintSurface;
_ = Task.Run(() =>
{
while (true)
{
try
{
Dispatcher.Invoke(() =>
{
skContainer.InvalidateVisual();
});
_ = SpinWait.SpinUntil(() => false, 1000 / 60);//每秒60幀
}
catch
{
break;
}
}
});
彈球實體代碼 (Ball.cs)
public class Ball
{
public double X { get; set; }
public double Y { get; set; }
public double VX { get; set; }
public double VY { get; set; }
public int Radius { get; set; }
}
粒子花園核心類 (ParticleGarden.cs)
/// <summary>
/// 光線投影法碰撞檢測
/// 投籃小遊戲
/// </summary>
public class RayProjection
{
public SKPoint centerPoint;
public double G = 0.3;
public double F = 0.98;
public double Easing = 0.03;
public bool IsMoving = false;
public SKPoint CurrentMousePoint = SKPoint.Empty;
public SKPoint lastPoint = SKPoint.Empty;
public Rect Box;
public Ball Ball;
public SKCanvas canvas;
public int ALLCount = 10;
public List<bool> bools = new List<bool>();
public bool IsOver = false;
/// <summary>
/// 渲染
/// </summary>
public void Render(SKCanvas canvas, SKTypeface Font, int Width, int Height)
{
canvas.Clear(SKColors.White);
this.canvas = canvas;
centerPoint = new SKPoint(Width / 2, Height / 2);
//球
if (Ball == null)
{
Ball = new Ball()
{
X = 50,
Y = Height - 50,
Radius = 30
};
}
//箱子
var boxX = Width - 170;
var boxY = Height - 80;
if (Box.X == 0)
{
Box = new Rect(boxX, boxY, 120, 70);
}
else
{
if (Box.X != boxX && Box.Y != boxY)
{
Box.X = boxX;
Box.Y = boxY;
}
}
if (bools.Count >= ALLCount)
{
IsOver = true;
}
if (!IsOver)
{
if (IsMoving)
{
BallMove(Width, Height);
}
else
{
DrawLine();
}
//彈球
DrawCircle(canvas, Ball);
//矩形
DrawRect(canvas, Box);
//計分
using var paint1 = new SKPaint
{
Color = SKColors.Blue,
IsAntialias = true,
Typeface = Font,
TextSize = 24
};
string count = $"總次數:{ALLCount} 剩餘次數:{ALLCount - bools.Count} 投中次數:{bools.Count(t => t)}";
canvas.DrawText(count, 100, 20, paint1);
}
else
{
SKColor sKColor = SKColors.Blue;
//計分
var SuccessCount = bools.Count(t => t);
string count = "";
switch (SuccessCount)
{
case 0:
{
count = $"太糗了吧，一個都沒投中！";
sKColor = SKColors.Black;
}
break;
case 1:
case 2:
case 3:
case 4:
case 5:
{
count = $"你才投中:{SuccessCount}次，繼續努力！";
sKColor = SKColors.Blue;
}
break;
case 6:
case 7:
case 8:
case 9:
{
count = $"恭喜 投中:{SuccessCount}次!!!";
sKColor = SKColors.YellowGreen;
}
break;
case 10: { count = $"全部投中，你太厲害了!";
sKColor = SKColors.Red;
} break;
}
using var paint1 = new SKPaint
{
Color = sKColor,
IsAntialias = true,
Typeface = Font,
TextSize = 48
};
var fontCenter = paint1.MeasureText(count);
canvas.DrawText(count, centerPoint.X - fontCenter / 2, centerPoint.Y, paint1);
}
using var paint = new SKPaint
{
Color = SKColors.Blue,
IsAntialias = true,
Typeface = Font,
TextSize = 24
};
string by = $"by 藍創精英團隊";
canvas.DrawText(by, 600, 20, paint);
}
/// <summary>
/// 畫一個圓
/// </summary>
public void DrawCircle(SKCanvas canvas, Ball ball)
{
using var paint = new SKPaint
{
Color = SKColors.Blue,
Style = SKPaintStyle.Fill,
IsAntialias = true,
StrokeWidth = 2
};
canvas.DrawCircle((float)ball.X, (float)ball.Y, ball.Radius, paint);
}
/// <summary>
/// 畫一個矩形
/// </summary>
public void DrawRect(SKCanvas canvas, Rect box)
{
using var paint = new SKPaint
{
Color = SKColors.Green,
Style = SKPaintStyle.Fill,
IsAntialias = true,
StrokeWidth = 2
};
canvas.DrawRect((float)box.X, (float)box.Y, (float)box.Width, (float)box.Height, paint);
}
/// <summary>
/// 劃線
/// </summary>
public void DrawLine()
{
//劃線
using var LinePaint = new SKPaint
{
Color = SKColors.Red,
Style = SKPaintStyle.Fill,
StrokeWidth = 2,
IsStroke = true,
StrokeCap = SKStrokeCap.Round,
IsAntialias = true
};
var path = new SKPath();
path.MoveTo((float)CurrentMousePoint.X, (float)CurrentMousePoint.Y);
path.LineTo((float)Ball.X, (float)Ball.Y);
path.Close();
canvas.DrawPath(path, LinePaint);
}
public void BallMove(int Width, int Height)
{
Ball.VX *= F;
Ball.VY *= F;
Ball.VY += G;
Ball.X += Ball.VX;
Ball.Y += Ball.VY;
var hit = CheckHit();
// 邊界處理和碰撞檢測
if (hit || Ball.X - Ball.Radius > Width || Ball.X + Ball.Radius < 0 || Ball.Y - Ball.Radius > Height || Ball.Y + Ball.Radius < 0)
{
bools.Add(hit);
IsMoving = false;
Ball.X = 50;
Ball.Y = Height - 50;
}
lastPoint.X = (float)Ball.X;
lastPoint.Y = (float)Ball.Y;
}
public bool CheckHit()
{
var k1 = (Ball.Y - lastPoint.Y) / (Ball.X - lastPoint.X);
var b1 = lastPoint.Y - k1 * lastPoint.X;
var k2 = 0;
var b2 = Ball.Y;
var cx = (b2 - b1) / (k1 - k2);
var cy = k1 * cx + b1;
if (cx - Ball.Radius / 2 > Box.X && cx + Ball.Radius / 2 < Box.X + Box.Width && Ball.Y - Ball.Radius > Box.Y)
{
return true;
}
return false;
}
public void MouseMove(SKPoint sKPoint)
{
CurrentMousePoint = sKPoint;
}
public void MouseDown(SKPoint sKPoint)
{
CurrentMousePoint = sKPoint;
}
public void MouseUp(SKPoint sKPoint)
{
if (bools.Count < ALLCount)
{
IsMoving = true;
Ball.VX = (sKPoint.X - Ball.X) * Easing;
Ball.VY = (sKPoint.Y - Ball.Y) * Easing;
lastPoint.X = (float)Ball.X;
lastPoint.Y = (float)Ball.Y;
}
}
}
效果如下:
還不錯，得了7分，當然，我也可以得10分的，不過，還好了。
總結
這個特效的案例重點是光線投影法碰撞檢測，同時又對其增加了遊戲的屬性，雖然東西都很簡單，但是作為一個雛形來講也是不錯的。
SkiaSharp 基礎系列算是告一段落了，基礎知識相關暫時都已經有了一個深度的了解，對於它的基礎應用已經有一個不錯的認識了，那麼，基於它的應用應該也會多起來，我這邊主要參考Avalonia的內部SkiaSharp使用原理，當然，用法肯定不局限的。
代碼地址
//github.com/kesshei/WPFSkiaRayProjectionDemo.git
//gitee.com/kesshei/WPFSkiaRayProjectionDemo.git
閱
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藍創精英團隊（公眾號同名，CSDN 同名，CNBlogs 同名）
