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D3D Quaternion problem ???

Started by yyh Jan 4, 2003 at 11:56 AM 3 replies 400+ views

Original Post

Jan 4, 2003 at 11:56 AM

code [1] result is equal to code [2] //temp2 == temp1 ////////// //code 1// ////////// vAxis.x = 1.0f; vAxis.y = 0.0f; vAxis.z = 0.0f; fAngle = 0.785398; //45 degree D3DXQuaternionRotationAxis( &qCursor, &vAxis, fAngle ); D3DXMatrixRotationQuaternion( &matCursor, &qCursor ); D3DXMatrixMultiply( &temp2, &temp2, &matCursor ); vAxis.x = 0.0f; vAxis.y = 1.0f; vAxis.z = 0.0f; fAngle = 0.785398; //45 degree D3DXQuaternionRotationAxis( &qCursor, &vAxis, fAngle ); D3DXMatrixRotationQuaternion( &matCursor, &qCursor ); D3DXMatrixMultiply( &temp2, &temp2, &matCursor ); vAxis.x = 0.0f; vAxis.y = 0.0f; vAxis.z = 1.0f; fAngle = 0.785398; //45 degree D3DXQuaternionRotationAxis( &qCursor, &vAxis, fAngle ); D3DXMatrixRotationQuaternion( &matCursor, &qCursor ); D3DXMatrixMultiply( &temp2, &temp2, &matCursor ); ////////// //code 2// ////////// m_RotX = 0.785398f; //45 degree D3DXMatrixRotationX(&matRot,m_RotX); D3DXMatrixMultiply( &temp1, &temp1, &matRot ); m_RotY = 0.785398f; //45 degree D3DXMatrixRotationY(&matRot,m_RotY); D3DXMatrixMultiply( &temp1, &temp1, &matRot ); m_RotZ = 0.785398f; //45 degree D3DXMatrixRotationZ(&matRot,m_RotZ); D3DXMatrixMultiply( &temp1, &temp1, &matRot ); So my problem is what are the use of Quaternion and different of rotation ????? please !!!! thanks a lots..

Yann L

219

Yann L

Jan 4, 2003 at 8:37 PM

quote:

code [1] result is equal to code [2] //temp2 == temp1

Of course they are equal. You are rotating around the same axes, using the same angles. So, what else did you expect ?

yyh

Author

yyh

Jan 5, 2003 at 4:38 AM

So why use Quaternion ???????

serg3d

Jan 5, 2003 at 6:14 AM

To interpolate rotations. There is no easy way to interpolate rotation with matrices.

Yann L

219

Yann L

Jan 5, 2003 at 8:06 AM

Quaternions are mostly used to specify rotations in a convenient and intuitive angle/axis format. While still being able to easily interpolate and concatenate rotations, they completely avoid the gimbal lock problem (as it is very often encountered when using Euler angles).

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