【賣技向】用Visual Basic編時變向量場
本帖最后由 Capt.Murasa 于 2014-8-25 19:20 编辑場函數F(x,y,t):
i分量: Cos(1.5 * y) * Sin(3 * t)
j分量: Sin(1.5 * x) * Cos(3 * t)
抱歉渣片質
http://v.youku.com/v_show/id_XNzYxNTY3ODMy.html
上次也發過了圖片...這次就加入了時間參數..
另外, 為了顯示,箭矢實際長度被統一
哂技能向，除此之外，無其他用意
最近的新人令我發現..........我真的是技窮了
完整程式碼如下:
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Math
'除form之外,還外加了1個timer,label
Form1
Dim p1 As PointF
Dim p2 As PointF
Dim x As Double
Dim y As Double
Public time As Double
Dim pen1 As New Pen(Color.Red, 1)
Function Xdirect(Optional ByVal x As Double = 0, Optional ByVal y As Double = 0, Optional ByVal t As Double = 0) As Double
'此函式計算 i 分量值
Dim s As Double
s = Cos(1.5 * y) * Sin(3 * t)' i 分量
Return s
End Function
Function Ydirect(Optional ByVal x As Double = 0, Optional ByVal y As Double = 0, Optional ByVal t As Double = 0) As Double
'此函式計算 j 分量值
Dim s As Double
s = Sin(1.5 * x) * Cos(3 * t) ' j 分量
Return s
End Function
Sub Adjusting(ByVal a As Double, ByVal b As Double) '此副程式用作 調整箭矢長度
Dim m As Double
If (a = 0 And b = 0) Then
y = 0 : x = 0
Else
m = Sqrt((a ^ 2) + (b ^ 2))
x = 0.2 * a / m
y = 0.2 * b / m
End If
End Sub
Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint
Dim myArrow As New AdjustableArrowCap(3, 6) '
Dim customArrow As CustomLineCap = myArrow
Dim capPen As New Pen(Color.Black) '
capPen.CustomStartCap = myArrow
e.Graphics.DrawLine(pen1, 0, 450, 970, 450)
e.Graphics.DrawLine(pen1, 450, 0, 450, 970)
For i As Double = -5 To 5 Step 0.3
For j As Double = -5 To 5 Step 0.3
Adjusting(Xdirect(i, j, time), Ydirect(i, j, time))
p1 = New PointF((i * 100 + 450), (450 - j * 100))
p2 = New PointF((i + x) * 100 + 450, 450 - (j + y) * 100)
e.Graphics.DrawLine(capPen, p2, p1)
Next
Next
End Sub
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
time += 0.05
Label1.Text = time '顯示參數t值
Me.Refresh()
End Sub
End Class
本帖最后由 drzzm32 于 2014-8-25 19:06 编辑
喂，楼主，这个是算法编程哦。。。
最好给出部分代码。。。
尤其是绘制部分。。。因为很少有人意识到绘制的重要性
PS：等我电脑好了我准备把物理引擎给实现，模拟一个重力场。。。也是VB哦 本帖最后由 ofz 于 2014-8-26 12:47 编辑
不错的说，我也来我也来~
先看结果：
在线演示：http://glsl.heroku.com/e#19414.1
然后是代码（其实在演示页面里就有）：
// 以下是 glsl
#ifdef GL_ES
precision mediump float;
#endif
#define GRID 100.0
uniform float time;
uniform vec2 resolution;
void main( void ) {
vec2 pos = (gl_FragCoord.xy - resolution) * 4.;
vec2 src = floor(pos / GRID) * GRID + GRID / 2.;
vec2 tgt = vec2(cos(1.5 * src.y) + sin(3. * time), sin(1.5 * src.x) + cos(3. * time)) * GRID / 2. + src;
vec3 color = distance(pos, src) + distance(pos, tgt) - distance(src, tgt) < 0.1 ? vec3(1., 1., 1.) : vec3(0., 0., 0.);
gl_FragColor = vec4(color, 1.0);
}
。抱歉。有点晕。但我还是努力盯着看着
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