This object provides anything neccessary to build viewable objects.

It is intended to derive from it, overloading the DrawTheObject() and probably Init() methods.

This is already OpenGL specific!

If we talk about a position, it's OpenGL's notion of a translation via glTranslatef, that means, that not the object but the object's coordinate system is translated! Take care of that!

Source:

../src/cVisibleObject.hh:40

public cVisibleObject ( const char * name = NULL ) ;

constructor with initialization for name (default constructor)

public cVisibleObject ( const cVisibleObject & ) ;

copy constructor

public cVisibleObject ( const cVertex & pos ,
                        const char * name = NULL ) ;

constructor with initialization for position and name

public cVisibleObject ( const cVertex & pos ,
                        const cQuaternion & rot ,
                        const char * name = NULL ) ;

constructor with initialization for position, rotation and name

public virtual ~ cVisibleObject ( ) ;

destructor

protected cQuaternion mRotation

actual rotation of the object

See Also:

cVisibleObject::Activate

protected cVertex mPosition

actual position of the object

See Also:

cVisibleObject::Activate

protected bool mVisible

Visibility of object

is the object visible (read: call DrawThisObject())

See Also:

DrawThisObject

protected cMaterial * mMaterial

the material to use for this object

NULL == do not use a material

protected cMatrix mGlobalTransformation

The resulting _global_ transformation of this object.

It is aquired via glGetFloatv (GL_MODELVIEW_MATRIX). It's purpose is to simplify interaction.

See Also:

Activate

public virtual int Init ( ) ;

initialize object and it's childs

(partially inherited from cObject)

public virtual void MoveTo ( const cVertex & pos ) ;

move object to given position

public virtual void MoveBy ( const cVertex & pos ) ;

move object by given amount

public virtual void RotateBy ( const GLfloat angle ,
                               const cVertex & axis ) ;

rotate object angle degrees around given vector ("adds" to current rotation)

public virtual void RotateBy ( const cQuaternion & quaternion ) ;

rotate object by applying a quaternion ("adds" to current rotation)

public virtual void SetRotation ( const GLfloat angle ,
                                  const cVertex & axis ) ;

set rotation to given values (replaces current rotation)

public virtual void SetRotation ( const cQuaternion & new_rotation ) ;

set rotation to given value (replaces current rotation)

public virtual void UseMaterial ( cMaterial * material ) ;

set material to use for this object (store reference only!)

public virtual void DontUseMaterial ( ) ;

disable use of material for this object

public void SetVisible ( bool visible ) ;

set visibility

public bool IsVisible ( ) const ;

get visibility

protected virtual void Activate ( ) ;

Activate the object. (here: draw it if visible)

The scene is drawn by pre-oder traversing the scene graph (an n-ary tree). Drawing is started by invoking Activate() which takes care that all childs are drawn as well.

Activate() works as follows: (see implementation for details)

1. - perform any steps neccessary to prepare for drawing (inherited, overloaded, may be overloaded)
2. Transform () - apply rotation and translation (might be overloaded to prefent transformation)
3. DrawThisObject () - perform actual drawing if object is visible (usually has to be overloaded)
4. call cObject::Activate() to activate all siblings
5. Deactivate () called by cObject::Activate() - undo special things done in Activate(), call cObject::Deactivate () (inherited, overloaded, may be overloaded)

You may overwrite this but make sure to call cVisibleObject::Activate() to get transformations right!

protected virtual void Transform ( ) ;

perform transformation neccessary before drawing

might be overloaded e.g. to prevent transformation

protected virtual void DrawThisObject ( ) = 0 ;

perform actual drawing of the object (has to be overloaded)

protected virtual void Deactivate ( ) ;

actions to perform after drawing the object and it's siblings (might be overloaded)

protected virtual const char * GetDefaultName ( ) const ;

return default name of object (the poor man's RTTI)

Every object within the scene graph can be associated a name. By default, the class of the object is used.