# 3D Point rotation

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Sorry... This is more of a math question, really.

I made a simple little 3d box that you can move around in, I intend on being able to create objects and stuff in it, but I put that off because I don't know how to do point rotations.

I want to transform/rotate a set of points, given the center and the rotation angle.

I did some googling, and I came up with lots of "3D Rotation Matrix" stuff but with a geometry-level education, I'm not understanding it.

Can anyone give me a tip?

Heres my code, incase you want to know what it's for.

```#include <GUIConstantsEx.au3>
#include <StaticConstants.au3>
#include <WindowsConstants.au3>
#include <Array.au3>
#include <Misc.au3>
Global \$w = 1000
Global \$h = 800
Global \$d = 800
Global \$x_center = Round(\$w/2,0)
Global \$y_center = Round(\$h/2,0)
\$dll = DllOpen("User32.dll")
\$Form1 = GUICreate("Form1", \$w+100, \$h + 100, -1, -1)
\$Stats_1 = GUICtrlCreateLabel("",0,100,200,200)
GUICtrlSetBkColor(-1, \$GUI_BKCOLOR_TRANSPARENT)
GUISetState(@SW_SHOW)
Dim \$ava[1][3]
\$ava[0][0] = 0
\$ava[0][1] = 0
\$ava[0][2] = 0
\$f_skip = 2 ;frame skip
\$fc= 0
#cs
;Draw Grid
For \$z_x = 0 to \$w
For \$z_y = 2 to 800
For \$z_z = 0 to 150
drawPoint(\$z_x,\$z_y,\$z_z)
\$z_z += 50
Next
\$z_y += 50
Next
\$z_x += 50
Next
#ce
;Draw Cube
drawPoint(0,0,0)
drawPoint(\$w,0,0)
drawPoint(\$w,\$h,0)
drawPoint(0,\$h,0)
drawPoint(0,0,\$d)
drawPoint(\$w,0,\$d)
drawPoint(\$w,\$h,\$d)
drawPoint(0,\$h,\$d)
\$x_vel = 0
\$y_vel = 0
\$z_vel = 0
\$lastpoint = drawPoint(0,0,0)
\$posChange = False
While 1
calcInput()
calcPhys()
\$nMsg = GUIGetMsg()
\$Stats = "X: " & Round( \$ava[0][0] , 2)
\$Stats &= @CRLF & "Y: " & Round( \$ava[0][1] , 2)
\$Stats &= @CRLF & "Z: " & Round( \$ava[0][2] , 2)
\$Stats &= @CRLF & "Xvel: " & Round( \$x_vel , 2)
\$Stats &= @CRLF & "Yvel: " & Round( \$y_vel , 2)
\$Stats &= @CRLF & "Zvel: " & Round( \$z_vel , 2)
GUICtrlSetData(\$Stats_1,\$Stats)
Switch \$nMsg
Case \$GUI_EVENT_CLOSE
Exit

EndSwitch
WEnd

GUISetState(@SW_SHOW)
Func drawObject(\$obj)
For \$i = 0 to UBound(\$obj) - 1
\$obj[\$i][0] = drawPoint(\$obj[\$i][1],\$obj[\$i][2],\$obj[\$i][3])
Next
Return \$obj
EndFunc
Func drawPoint(\$x,\$y,\$z)
\$y = (\$h-\$y)
\$x_dist = (\$x_center - \$x) / 10
\$y_dist = (\$y_center - \$y) / 10
\$point = GUICtrlCreateLabel("+", \$x + (\$x_dist * (\$z/100)), \$y + (\$y_dist * (\$z/100)), 50, 50,\$SS_CENTER)
\$size = 50 - ((32 / \$d) * \$z)
If \$size < 1 Then \$size = 1
GUICtrlSetFont(-1, \$size)
\$color = Round( (\$z / \$d) * 99, 0 )
If \$color > 99 then \$color = 99
If \$color < 0 Then \$color = 0
GUICtrlSetColor(-1, "0x00" & \$color & "00")
GUICtrlSetBkColor(-1, \$GUI_BKCOLOR_TRANSPARENT)
Return \$point
EndFunc
Func calcPhys()
\$ava[0][0] += \$x_vel
\$ava[0][1] += \$y_vel
\$ava[0][2] += \$z_vel
If \$x_vel > 1 Then
\$x_vel -= 0.5
ElseIf \$x_vel < -1 Then
\$x_vel += 0.5
Else
\$x_vel = 0
EndIf

If \$z_vel > 1 Then
\$z_vel -= 0.5
ElseIf \$z_vel < -1 Then
\$z_vel += 0.5
Else
\$z_vel = 0
EndIf
If \$ava[0][0] < 0 Then
\$ava[0][0] = 0
\$x_vel *= -2/3
ElseIf \$ava[0][0] > \$w Then
\$ava[0][0] = \$w
\$x_vel *= -2/3
EndIf
If \$ava[0][1] < 0 Then
\$ava[0][1] = 0
If Abs(\$y_vel) < 1 Then
\$y_vel = 0
Else
\$y_vel *= -2/3
EndIf
ElseIf \$ava[0][1] > \$h Then
\$ava[0][1] = \$h
\$y_vel *= -1
EndIf
If \$ava[0][2] < 0 Then
\$ava[0][2] = 0
\$z_vel *= -2/3
ElseIf \$ava[0][2] > \$d Then
\$ava[0][2] = \$d
\$z_vel *= -2/3
EndIf
If \$fc = \$f_skip Then
GUICtrlDelete(\$lastpoint)
\$lastpoint = drawPoint(\$ava[0][0],\$ava[0][1],\$ava[0][2])
\$fc = 0
Else
\$fc +=1
EndIf
\$y_vel -= 2
EndFunc
Func calcInput()
If _IsPressed(25,\$dll) Then
\$x_vel -= 2
EndIf
If _IsPressed(27,\$dll) Then
\$x_vel += 2
EndIf
If _IsPressed(26,\$dll) Then
\$z_vel += 2
EndIf
If _IsPressed(28,\$dll) Then
\$z_vel -= 2
EndIf
If _IsPressed(20,\$dll) Then
\$y_vel += 6
EndIf
EndFunc```

[center]"When you look at old, classic games like Snake, you often put it off because it's such a simple game, but it's only when you actually try and create your own unique game from scratch, do you finally appreciate those games."[/center][center]Don't ask for answers if you haven't TRIED yet![/center][center]Most answers can be answered in the help file! Use it![/center]

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Or have a look to #09 Rotating Cube in Some Graphical Examples Using GDI+!

UEZ

The own fart smells best!
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Sorry... This is more of a math question, really.

No problem so far.

I want to transform/rotate a set of points, given the center and the rotation angle.

I did some googling, and I came up with lots of "3D Rotation Matrix" stuff but with a geometry-level education, I'm not understanding it.

In short, you need to know that rotations in 3-D space are not commutative. Then, there are two main common approaches to computing 3-D rotations: the [messy] so-called Euler angles and the _much_ simpler quaternions. You'll have to do you own searches for all these terms, concepts and possible implementations. Honestly, it isn't very difficult and if you have a ounce of motivation, you'll do it.

Euler angles: here (gimbal lock included, free of charge)

Quaternions used for computing rotations: here

I'd like to have more time to help you on this, but I'm currently too busy for doing so. Sorry for that.

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