用C# GDI编写粒子效果-编程知识

用C# GDI编写粒子效果

news/2025/2/4 19:29:37/文章来源:https://www.cnblogs.com/tuyile006/p/18698404

C#语言能不能画一动画呢？闲来无事，特过一把编程瘾。一共写了6个例子特效动画，界面如下，程序在文末供下载。

拿一个粒子效果“鼓泡泡效果”的类讲解，其他类似：

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;namespace CSharpGDI
{/// <summary>/// 粒子效果2/// </summary>internal class Particle2{public struct ParticleObj{public int px;//圆点坐标xpublic int py;//圆点坐标ypublic int d;//直径public int c;//颜色标识 1有颜色，0无色public int a;//透明度public Brush b;//画刷public int vx; //原xpublic int vy; //原ypublic int vd; //原直径
        }static List<ParticleObj> particles = new List<ParticleObj>();static int speed =1;static Bitmap bmp = null; static Graphics g = null;/// <summary>/// 初始化/// </summary>/// <param name="w">宽</param>/// <param name="h">高</param>/// <param name="span">间距</param>public static void Init(int w,int h,int size=15,int span=5){particles.Clear();Random rnd=new Random();int r0 = Math.Min(w / size, h / size);for (var x = 0; x < w / r0; x++){for (var y = 0; y < h / r0; y++){ParticleObj p = new ParticleObj(){px = x * r0 + (r0 - span)/2,py = y * r0 + (r0 - span)/2,d = r0-span,c = rnd.Next(2),a = rnd.Next(100, 255)};p.vx = p.px;p.vy = p.py;p.vd = p.d;Brush b = new SolidBrush(Color.FromArgb(p.a, 255, 255, 255));if (p.c == 1)b = new SolidBrush(Color.FromArgb(p.a,72,209,204));p.b = b;particles.Add(p);}}bmp = new Bitmap(w, h, PixelFormat.Format32bppArgb);g = Graphics.FromImage(bmp);}/// <summary>/// 动画 /// </summary>/// <param name="mouseX">鼠标x坐标</param>/// <param name="mouseY"></param>/// <param name="w">宽</param>/// <param name="h">高</param>/// <param name="R">圆的半径</param>public static Bitmap Start(int mouseX, int mouseY, int w, int h, int R=150){if (particles.Count == 0) Init(w,h);g.Clear(Color.Black);g.SmoothingMode = SmoothingMode.AntiAlias;Random rnd = new Random();for (var i = 0; i < particles.Count; i++){var p = particles[i];if (R * R > (p.px - mouseX) * (p.px - mouseX) + (p.py - mouseY) * (p.py - mouseY)){if (p.px > mouseX)p.px += speed ;if (p.px < mouseX)p.px -= speed;if (p.py > mouseY)p.py += speed ;if (p.py < mouseY)p.py -= speed;if (rnd.Next(2) == 1){p.d = (p.d+speed*5 >w/2?w/2:p.d+speed*5);}else{p.d =(p.d- speed*5<=0?10:p.d-speed*5);}}else{if (p.px > p.vx)p.px = p.px - speed < p.vx ? p.vx : p.px - speed;if (p.px < p.vx)p.px = p.px + speed > p.vx ? p.vx : p.px + speed;if (p.py > p.vy)p.py = p.py - speed < p.vy ? p.vy : p.py - speed;if (p.py < p.vy)p.py = p.py + speed > p.vy ? p.vy : p.py + speed;if (p.d > p.vd){p.d -= speed;}if (p.d < p.vd){p.d += speed;}}particles[i] = p;g.FillEllipse(p.b, p.px - p.d / 2, p.py - p.d / 2, p.d, p.d);}return bmp;}}
}

效果如下：

思想很简单，Init() 方法根据屏幕大小和相关粒子大小参数产生粒子对象数组particles，然后再Onpait事件中反复调用Start()绘制粒子即可。其中可以根据鼠标位置，改变粒子大小和位置。

当点击“”鼓泡泡“”按钮事件：其实核心只是调用了pictureBox1.Refresh()方法而已，其他逻辑都不重要。

 private void btnParticle2_Click(object sender, EventArgs e){if (btnParticle2.Text.Contains("停止")){btnParticle2.Text = "鼓泡泡效果";animations.Clear();}else{animations.Clear();ResetButtons();btnParticle2.Text = "停止鼓泡泡效果";animations.Add("鼓泡泡");ReStartCalFps();pictureBox1.Refresh();}}

pictureBox1.Refresh()方法会触发pictureBox1的pictureBox1_Paint事件，在该事件中添加逻辑：

//重绘事件
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{if(animations.Count==0) return;if (animations.Contains("抹纱窗")){currbmp=Particle1.Start(mousePoint.X,mousePoint.Y,pictureBox1.Width,pictureBox1.Height,100,V);pictureBox1.Image = currbmp;CalFps();}if (animations.Contains("鼓泡泡")){currbmp = Particle2.Start(mousePoint.X, mousePoint.Y, pictureBox1.Width, pictureBox1.Height,150);pictureBox1.Image = currbmp;CalFps();}……}

其他几个效果展示：

文字粒子效果：

爱心效果：

写完之后感受就是，C#也是可以写出炫酷的粒子效果的，而且不卡顿很丝滑。

其中几个关键点：

1. 窗体设置双缓存：

 public Form1(){DoubleBuffered = true;  //设置双缓冲
     InitializeComponent();}

2. 在Paint事件中重绘粒子，不要在While（true）之类的循环里无间隔调用。Winform中的Paint事件就相当于JavaScript中的requestAnimationFrame事件。

3. 重绘方法统一返回一张Bitmap图片，换句话说就是把全部的粒子画到一张Bitmap中，不能直接用pictureBox1.CreateGraphics()的对象来画粒子。否则会出现卡顿。而且这个Bitmap要用公共变量，不能每次调用都重新创建，否则内存会疯涨。

4.取像素点的数据要用内存拷贝法，不可直接调用img.GetPixel(i ,j).R ，否则性能极差，也会出现卡顿。

内存拷贝法取像素点代码如下：

 Bitmap bmp=new Bitmap(w,h, PixelFormat.Format24bppRgb);BitmapData data = bmp.LockBits(new Rectangle(0, 0, w, h), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);int length = h * data.Stride;byte[] RGB = new byte[length];System.IntPtr Scan0 = data.Scan0;System.Runtime.InteropServices.Marshal.Copy(Scan0, RGB, 0, length);for (int y = 0; y < h; y++){int index = y * data.Stride;for (int x = 0; x < w; x++){if (x % span == 0 && y % span == 0){particles.Add(new ParticleObj(){x = x,y = y,vx = x,vy = y,vspeed = 2});//改变颜色。RGB[index + 3 * x] = 255;RGB[index + 3 * x+1] = 255;RGB[index + 3 * x+2] = 255;}}}System.Runtime.InteropServices.Marshal.Copy(RGB, 0, Scan0, length);bmp.UnlockBits(data);g.DrawImage(bmp,0,0);