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Rotate game object

Started by Baris YILMAZ Aug 21, 2011 at 8:07 AM 1 replies 1.4k views

Original Post

Aug 21, 2011 at 8:07 AM

Hi guys!

I'm trying to rotate my object its own local Y axis but it is rotating in world Y axis. If i could made it, then i want to translate the object in direction where it is look at. i have copied my camera class movement logic to my object class, but it is not working as my camera.

Here is my code:


 
 void Object::setPositionMatrix(){
 Math::normalize(&m_Look, &m_Look);
 
 Math::cross(&m_Up, &m_Look, &m_Right);
 Math::normalize(&m_Up, &m_Up);
 
 Math::cross(&m_Right, &m_Up, &m_Look);
 Math::normalize(&m_Right, &m_Right);
 
 float x = -Math::dot(&m_Right, &m_Pos);
 float y = -Math::dot(&m_Up, &m_Pos);
 float z = -Math::dot(&m_Look, &m_Pos);
 
 m_Coord(0, 0) = m_Right.x;
 m_Coord(0, 1) = m_Up.x;
 m_Coord(0, 2) = m_Look.x;
 m_Coord(0, 3) = 0.0f;
 
 m_Coord(1, 0) = m_Right.y;
 m_Coord(1, 1) = m_Up.y;
 m_Coord(1, 2) = m_Look.y;
 m_Coord(1, 3) = 0.0f;
 
 m_Coord(2, 0) = m_Right.z;
 m_Coord(2, 1) = m_Up.z;
 m_Coord(2, 2) = m_Look.z;
 m_Coord(2, 3) = 0.0f;
 
 m_Coord(3, 0) = x;
 m_Coord(3, 1) = y;
 m_Coord(3, 2) = z;
 m_Coord(3, 3) = 1.0f;
 }


 
 void Object::rotateY(float angle){
 
 Math::matrix T;
 Math::identity(&T);
 Math::rotation(&T, &m_Up, angle);
 
 Math::transformCoord(&m_Right, &m_Right, &T);
 Math::transformCoord(&m_Look, &m_Look, &T);
 
 Math::multiply(&m_Coord, &m_Coord, &T );
 
 setPositionMatrix();
 }
 
 
 void Object::walk(float unit){
 m_Pos += m_Look * unit;
 
 setPositionMatrix();
 }

L. Spiro

Aug 21, 2011 at 9:18 AM

The matrix for a camera is the inverse of its view direction/position.
You need to create a matrix that represents the object’s orientation, not the inverse of its orientation.

For starters, m_Coord(3, 0) should be set to m_Pos.x, not -Math::dot(&m_Right, &m_Pos);.
All of m_Coord(0, X) should be set to the values in m_Right.

L. Spiro

Baris YILMAZ

Aug 21, 2011 at 10:10 AM

The matrix for a camera is the inverse of its view direction/position.
You need to create a matrix that represents the object’s orientation, not the inverse of its orientation.

For starters, m_Coord(3, 0) should be set to m_Pos.x, not -Math::dot(&m_Right, &m_Pos);.
All of m_Coord(0, X) should be set to the values in m_Right.

L. Spiro

That's worked! But i have another issue: It's rotating its on local Y axis but does not go to the direction where the object is looking at. Do you have any solution for this, too =)
(Türk müsün bu arada?)

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