[英]Is there a way to calculate 3D rotation on X and Y axis from a 4x4 matrix
首先,我根本不是數學專家。 請容忍我的數學錯誤並在必要時糾正我,我很樂意學習。
我有一個立方體,它使用帶有變換的 css 動畫旋轉:matrix3d(4x4)。 我還可以手動旋轉立方體,將用戶操作轉換為相同的 matrix3d 轉換。
當用戶停止從用戶離開它的地方開始交互時,我想要的是一個帶有 css 的旋轉立方體。 這是我通過獲取多維數據集的變換 matrix3d 值並使用乘法動態設置 css 的關鍵幀來成功完成的事情。
然而,當用戶開始與立方體交互時,立方體會跳轉到它最后一個已知的手動旋轉點並從那里繼續,因為我無法弄清楚如何從 4x4 矩陣獲得 X 和 Y 軸上的旋轉。
我目前正在使用以下庫Rematrix ,它可以幫助我從手動旋轉到 css 旋轉,如上所述。
我一直在研究關於歐拉的文章,以及如何從歐拉到矩陣,反之亦然,但就像我之前提到的,這是我缺乏數學知識阻礙我思考的地方。 我似乎無法弄清楚。
作為參考,這里有一些我讀過的文章,試圖解決我的問題。
最后一個來源對我來說最有意義,但是,如果我是對的,在這種情況下沒有用,因為它是關於 2D 轉換,而不是 3D。
我通過以下方式獲得當前的 matrix3d:
const style = getComputedStyle(this.element).transform
const matrix = Rematrix.parse(style)
對於手動旋轉,我使用基於用戶鼠標位置(positionY、positionX)的矩陣乘法。
const r1 = Rematrix.rotateX(this.positionY)
const r2 = Rematrix.rotateY(this.positionX)
const transform = [r1, r2].reduce(Rematrix.multiply)
this.element.style[userPrefix.js + 'Transform'] = Rematrix.toString(transform)
從手動到 css 旋轉,我使用以下函數:
const setCssAnimationKeyframes = (lastTransform, animationData) => {
const rotationIncrement = 90
let matrixes = []
for (let i = 0; i < 5; i++) {
const rX = Rematrix.rotateX(rotationIncrement * i)
const rY = Rematrix.rotateY(rotationIncrement * i)
const matrix = [lastTransform, rX, rY].reduce(Rematrix.multiply);
matrixes.push(matrix)
}
animationData.innerHTML = `
@keyframes rotateCube {
0% {
transform: ${Rematrix.toString(matrixes[0])};
}
25% {
transform: ${Rematrix.toString(matrixes[1])};
}
50% {
transform: ${Rematrix.toString(matrixes[2])};
}
75% {
transform: ${Rematrix.toString(matrixes[3])}};
}
100% {
transform: ${Rematrix.toString(matrixes[4])};
}
}
`;
}
請提供任何有用信息的答案或評論。 盡管這是最受歡迎的,但我不希望您提供一個完整的代碼示例。 任何形式的任何有用信息都非常感謝。
先讀:
因為我使用那里的術語。
好吧,我懶得將所有內容與我的環境等同起來,但基於此:
對於任何旋轉順序,生成的m
3D 旋轉子矩陣將始終具有以下溫度:
(+/-)sin(a)
(+/-)sin(b)cos(a)
(+/-)cos(b)cos(a)
(+/-)sin(c)cos(a)
(+/-)cos(c)cos(a)
只有它們的符號和位置會隨着變換順序和約定而改變。 因此,要識別它們,請執行以下操作:
讓我們先設置一些重要的歐拉角
他們的|sin|
, |cos|
值必須不同,所以 6 個值都不相同,否則這將不起作用!!!
我選擇了這些:
ex = 10 [deg] ey = 20 [deg] ez = 30 [deg]
計算旋轉矩陣m
因此,按順序在單位矩陣上應用 3 次歐拉旋轉。 在我的設置中,結果矩陣如下所示:
double m[16] = { 0.813797652721405, 0.543838143348694,-0.204874128103256, 0, // Xx,Xy,Xz,0.0 -0.469846308231354, 0.823172926902771, 0.318795770406723, 0, // Yx,Yy,Yz,0.0 0.342020153999329,-0.163175910711288, 0.925416529178619, 0, // Zx,Zy,Zz,0.0 0 , 0 , 0 , 1 // Ox,Oy,Oz,1.0 };
請注意,我使用 OpenGL 約定,基向量X,Y,Z
和原點O
由矩陣線表示,矩陣是直接的。
識別(+/-)sin(a)
熱
a
可以是任何歐拉角,所以打印它們的sin
:
sin(ex) = 0.17364817766693034885171662676931 sin(ey) = 0.34202014332566873304409961468226 sin(ez) = 0.5
現在看到m[8] = sin(ey)
所以我們找到了我們的熱量……現在我們知道了:
ey = a = asin(m[8]);
識別(+/-)???(?)*cos(a)
therms
只需為未使用的角度打印 cos(?)*cos(ey) 。 所以如果ey
是 20 度,我會打印 10 度和 30 度...
sin(10 deg)*cos(20 deg) = 0.16317591116653482557414168661534 cos(10 deg)*cos(20 deg) = 0.92541657839832335306523309767123 sin(30 deg)*cos(20 deg) = 0.46984631039295419202705463866237 cos(30 deg)*cos(20 deg) = 0.81379768134937369284469321724839
當我們再次查看m
時,我們可以交叉匹配:
sin(ex)*cos(ey) = 0.16317591116653482557414168661534 = -m[9] cos(ex)*cos(ey) = 0.92541657839832335306523309767123 = +m[10] sin(ez)*cos(ey) = 0.46984631039295419202705463866237 = -m[4] cos(ez)*cos(ey) = 0.81379768134937369284469321724839 = +m[0]
從中我們可以計算角度......
sin(ex)*cos(ey) = -m[ 9] cos(ex)*cos(ey) = +m[10] sin(ez)*cos(ey) = -m[ 4] cos(ez)*cos(ey) = +m[ 0] ------------------------ sin(ex) = -m[ 9]/cos(ey) cos(ex) = +m[10]/cos(ey) sin(ez) = -m[ 4]/cos(ey) cos(ez) = +m[ 0]/cos(ey)
所以最后:
--------------------------------------------- ey = asin(m[8]); ex = atan2( -m[ 9]/cos(ey) , +m[10]/cos(ey) ) ez = atan2( -m[ 4]/cos(ey) , +m[ 0]/cos(ey) ) ---------------------------------------------
就是這樣。 如果你有不同的布局/約定/轉換順序,這種方法仍然應該有效......只有索引和符號發生了變化。 這里有一個小的C++/VCL OpenGL示例,我對此進行了測試( X,Y,Z
順序):
//---------------------------------------------------------------------------
#include <vcl.h>
#include <math.h>
#pragma hdrstop
#include "Unit1.h"
#include "gl_simple.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
bool _redraw=true; // need repaint?
//---------------------------------------------------------------------------
double m[16]= // uniform 4x4 matrix
{
1.0,0.0,0.0,0.0, // Xx,Xy,Xz,0.0
0.0,1.0,0.0,0.0, // Yx,Yy,Yz,0.0
0.0,0.0,1.0,0.0, // Zx,Zy,Zz,0.0
0.0,0.0,0.0,1.0 // Ox,Oy,Oz,1.0
};
double e[3]={0.0,0.0,0.0}; // euler angles x,y,z order
//---------------------------------------------------------------------------
const double deg=M_PI/180.0;
const double rad=180.0/M_PI;
void matrix2euler(double *e,double *m)
{
double c;
e[1]=asin(+m[ 8]);
c=cos(e[1]); if (fabs(c>1e-20)) c=1.0/c; else c=0.0;
e[0]=atan2(-m[ 9]*c,m[10]*c);
e[2]=atan2(-m[ 4]*c,m[ 0]*c);
}
//---------------------------------------------------------------------------
void gl_draw()
{
_redraw=false;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_PROJECTION);
// glLoadIdentity();
glMatrixMode(GL_TEXTURE);
glLoadIdentity();
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslated(0.0,0.0,-10.0); // some distance from camera ...
glDisable(GL_DEPTH_TEST);
glDisable(GL_TEXTURE_2D);
int i;
// draw source matrix:
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glTranslated(-1.0,0.0,0.0); // source matrix on the left
glMultMatrixd(m);
glBegin(GL_LINES);
glColor3f(1.0,0.0,0.0); glVertex3d(0.0,0.0,0.0); glVertex3d(1.0,0.0,0.0);
glColor3f(0.0,1.0,0.0); glVertex3d(0.0,0.0,0.0); glVertex3d(0.0,1.0,0.0);
glColor3f(0.0,0.0,1.0); glVertex3d(0.0,0.0,0.0); glVertex3d(0.0,0.0,1.0);
glEnd();
glPopMatrix();
// draw source matrix:
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glTranslated(m[12],m[13],m[14]); // source matrix in the middle
glBegin(GL_LINES);
glColor3f(1.0,0.0,0.0); glVertex3d(0.0,0.0,0.0); glVertex3dv(m+0);
glColor3f(0.0,1.0,0.0); glVertex3d(0.0,0.0,0.0); glVertex3dv(m+4);
glColor3f(0.0,0.0,1.0); glVertex3d(0.0,0.0,0.0); glVertex3dv(m+8);
glEnd();
glPopMatrix();
// draw euler angles
matrix2euler(e,m);
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glTranslated(+1.0,0.0,0.0); // euler angles on the right
glRotated(e[0]*rad,1.0,0.0,0.0);
glRotated(e[1]*rad,0.0,1.0,0.0);
glRotated(e[2]*rad,0.0,0.0,1.0);
glBegin(GL_LINES);
glColor3f(1.0,0.0,0.0); glVertex3d(0.0,0.0,0.0); glVertex3d(1.0,0.0,0.0);
glColor3f(0.0,1.0,0.0); glVertex3d(0.0,0.0,0.0); glVertex3d(0.0,1.0,0.0);
glColor3f(0.0,0.0,1.0); glVertex3d(0.0,0.0,0.0); glVertex3d(0.0,0.0,1.0);
glEnd();
glPopMatrix();
// glFlush();
glFinish();
SwapBuffers(hdc);
}
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner):TForm(Owner)
{
gl_init(Handle);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glRotated(10.0,1.0,0.0,0.0);
glRotated(20.0,0.0,1.0,0.0);
glRotated(30.0,0.0,0.0,1.0);
glGetDoublev(GL_MODELVIEW_MATRIX,m);
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormDestroy(TObject *Sender)
{
gl_exit();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormPaint(TObject *Sender)
{
gl_draw();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Timer1Timer(TObject *Sender)
{
if (_redraw) gl_draw();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormResize(TObject *Sender)
{
gl_resize(ClientWidth,ClientHeight);
_redraw=true;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormKeyDown(TObject *Sender, WORD &Key, TShiftState Shift)
{
// Caption=Key;
const double da=5.0;
if (Key==37){ _redraw=true; glMatrixMode(GL_MODELVIEW); glPushMatrix(); glLoadMatrixd(m); glRotated(+da,0.0,1.0,0.0); glGetDoublev(GL_MODELVIEW_MATRIX,m); glPopMatrix(); }
if (Key==39){ _redraw=true; glMatrixMode(GL_MODELVIEW); glPushMatrix(); glLoadMatrixd(m); glRotated(-da,0.0,1.0,0.0); glGetDoublev(GL_MODELVIEW_MATRIX,m); glPopMatrix(); }
if (Key==38){ _redraw=true; glMatrixMode(GL_MODELVIEW); glPushMatrix(); glLoadMatrixd(m); glRotated(+da,1.0,0.0,0.0); glGetDoublev(GL_MODELVIEW_MATRIX,m); glPopMatrix(); }
if (Key==40){ _redraw=true; glMatrixMode(GL_MODELVIEW); glPushMatrix(); glLoadMatrixd(m); glRotated(-da,1.0,0.0,0.0); glGetDoublev(GL_MODELVIEW_MATRIX,m); glPopMatrix(); }
}
//---------------------------------------------------------------------------
它唯一重要的東西是matrix2euler
函數將矩陣m
轉換為x,y,z
順序的歐拉角。 它呈現 3 個坐標系軸。 左邊是m
用作模型視圖矩陣,中間是使用恆等模型視圖的m
基向量,右邊是由計算的歐拉角構建的模型視圖......
所有 3 個都應該匹配。 如果左側和中間不匹配,那么您將獲得不同的矩陣或布局約定。
這里預覽(10,20,30) [deg]
測試用例:
即使經過多次旋轉(箭頭鍵),它仍然匹配......
gl_simple.h
可以在這里找到:
附注。 根據平台/環境,計算可能需要一些邊緣情況處理,例如大於1
asin
舍入幅度,除以零等。 atan2
也有它的怪癖......
[Edit1] 這是自動完成所有這些的終極 C++ 示例:
//---------------------------------------------------------------------------
enum _euler_cfg_enum
{
_euler_cfg_a=0,
_euler_cfg_b,
_euler_cfg_c,
_euler_cfg__sina,
_euler_cfg_ssina,
_euler_cfg__sinb_cosa,
_euler_cfg_ssinb_cosa,
_euler_cfg__cosb_cosa,
_euler_cfg_scosb_cosa,
_euler_cfg__sinc_cosa,
_euler_cfg_ssinc_cosa,
_euler_cfg__cosc_cosa,
_euler_cfg_scosc_cosa,
_euler_cfgs
};
//---------------------------------------------------------------------------
void matrix2euler_init(double *e,double *m,int *cfg) // cross match euler angles e[3] and resulting m[16] transform matrix into cfg[_euler_cfgs]
{
int i,j;
double a,tab[4];
const double _zero=1e-6;
for (i=0;i<_euler_cfgs;i++) cfg[i]=-1; // clear cfg
// find (+/-)sin(a)
for (i=0;i<3;i++) // test all angles in e[]
{
a=sin(e[i]);
for (j=0;j<16;j++) // test all elements in m[]
if (fabs(fabs(a)-fabs(m[j]))<=_zero) // find match in |m[j]| = |sin(e[i])|
{ // store configuration
cfg[_euler_cfg_a]=i;
cfg[_euler_cfg__sina]=j;
cfg[_euler_cfg_ssina]=(a*m[j]<0.0);
j=-1; break;
}
if (j<0){ i=-1; break; } // stop on match found
}
if (i>=0){ cfg[0]=-1; return; } // no match !!!
// find (+/-)???(?)*cos(a)
a=cos(e[cfg[_euler_cfg_a]]);
i=0; if (i==cfg[_euler_cfg_a]) i++; tab[0]=sin(e[i])*a; tab[1]=cos(e[i])*a; cfg[_euler_cfg_b]=i;
i++; if (i==cfg[_euler_cfg_a]) i++; tab[2]=sin(e[i])*a; tab[3]=cos(e[i])*a; cfg[_euler_cfg_c]=i;
for (i=0;i<4;i++)
{
a=tab[i];
for (j=0;j<16;j++) // test all elements in m[]
if (fabs(fabs(a)-fabs(m[j]))<=_zero) // find match in |m[j]| = |tab[i]|
{ // store configuration
cfg[_euler_cfg__sinb_cosa+i+i]=j;
cfg[_euler_cfg_ssinb_cosa+i+i]=(a*m[j]<0.0);
j=-1; break;
}
if (j>=0){ cfg[0]=-1; return; } // no match !!!
}
}
//---------------------------------------------------------------------------
void matrix2euler(double *e,double *m,int *cfg) // compute euler angles e[3] from transform matrix m[16] using confing cfg[_euler_cfgs]
{
double c;
//-----angle------ --------------sign-------------- ----------index----------
e[cfg[_euler_cfg_a]]=asin ((cfg[_euler_cfg_ssina]?-1.0:+1.0) *m[cfg[_euler_cfg__sina ]]);
c=cos(e[cfg[_euler_cfg_a]]); if (fabs(c>1e-20)) c=1.0/c; else c=0.0;
e[cfg[_euler_cfg_b]]=atan2((cfg[_euler_cfg_ssinb_cosa]?-c:+c)*m[cfg[_euler_cfg__sinb_cosa]],
(cfg[_euler_cfg_scosb_cosa]?-c:+c)*m[cfg[_euler_cfg__cosb_cosa]]);
e[cfg[_euler_cfg_c]]=atan2((cfg[_euler_cfg_ssinc_cosa]?-c:+c)*m[cfg[_euler_cfg__sinc_cosa]],
(cfg[_euler_cfg_scosc_cosa]?-c:+c)*m[cfg[_euler_cfg__cosc_cosa]]);
}
//---------------------------------------------------------------------------
用法:
const double deg=M_PI/180.0;
const double rad=180.0/M_PI;
// variables
double e[3],m[16];
int euler_cfg[_euler_cfgs];
// init angles
e[0]=10.0*deg;
e[1]=20.0*deg;
e[2]=30.0*deg;
// compute coresponding rotation matrix
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glRotated(e[0]*rad,1.0,0.0,0.0);
glRotated(e[1]*rad,0.0,1.0,0.0);
glRotated(e[2]*rad,0.0,0.0,1.0);
glGetDoublev(GL_MODELVIEW_MATRIX,m);
// cross match e,m -> euler_cfg
matrix2euler_init(e,m,euler_cfg);
// now we can use
matrix2euler(e,m,euler_cfg);
這適用於任何轉換順序和/或約定/布局。 init 只調用一次,然后您可以將轉換用於任何變換矩陣...您還可以根據您的環境的euler_cfg
結果編寫自己的優化版本。
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