class TGLCamera


TGLCamera

Abstract base camera class - concrete classes for orthographic and
persepctive cameras derive from it. This class maintains values for
the current:
i)   Viewport
ii)  Projection, modelview and clip matricies - extracted from GL
iii) The 6 frustum planes
iv)  Expanded frustum interest box

It provides methods for various projection, overlap and intersection
tests for viewport and world locations, against the true frustum and
 expanded interest box, and for extracting eye position and direction.

It also defines the pure virtual manipulation interface methods the
concrete ortho and prespective classes must implement.

Function Members (Methods)

 
    This is an abstract class, constructors will not be documented.
    Look at the header to check for available constructors.

public:
virtual~TGLCamera()
Bool_tAdjustAndClampVal(Double_t& val, Double_t min, Double_t max, Int_t screenShift, Int_t screenShiftRange, Bool_t mod1, Bool_t mod2) const
Double_tAdjustDelta(Double_t screenShift, Double_t deltaFactor, Bool_t mod1, Bool_t mod2) const
virtual voidApply(const TGLBoundingBox& sceneBox, const TGLRect* pickRect = 0) const
static TClass*Class()
virtual voidConfigure(Double_t zoom, Double_t dolly, Double_t* center, Double_t hRotate, Double_t vRotate)
virtual Bool_tDolly(Int_t delta, Bool_t mod1, Bool_t mod2)
voidDrawDebugAids() const
TGLVector3EyeDirection() const
TGLVertex3EyePoint() const
TGLVertex3FrustumCenter() const
EOverlapFrustumOverlap(const TGLBoundingBox& box) const
const TGLPlane&FrustumPlane(TGLCamera::EFrustumPlane plane) const
const TGLMatrix&GetCamBase() const
const TGLMatrix&GetCamTrans() const
Double_t*GetCenterVec()
Bool_tGetExternalCenter()
Double_tGetFarClip() const
Double_tGetNearClip() const
Double_tGetTheta() const
Float_tGetVAxisMinAngle()
voidIncTimeStamp()
virtual TClass*IsA() const
Bool_tIsCacheDirty() const
virtual Bool_tIsOrthographic() const
virtual Bool_tIsPersepective() const
virtual voidMarkup(TGLCameraMarkupStyle*) const
Bool_tOfInterest(const TGLBoundingBox& box, Bool_t ignoreSize) const
TGLMatrix&RefLastNoPickProjM() const
const TGLMatrix&RefModelViewMatrix() const
TGLRect&RefViewport()
const TGLRect&RefViewport() const
virtual voidReset()
voidResetInterest()
virtual Bool_tRotate(Int_t xDelta, Int_t yDelta, Bool_t mod1, Bool_t mod2)
virtual Bool_tRotateRad(Double_t hRotate, Double_t vRotate)
voidSetCenterVec(Double_t x, Double_t y, Double_t z)
voidSetExternalCenter(Bool_t x)
virtual voidSetup(const TGLBoundingBox& box, Bool_t reset = kTRUE)
voidSetVAxisMinAngle(Float_t x)
voidSetViewport(const TGLRect& viewport)
virtual voidShowMembers(TMemberInspector& insp, char* parent)
virtual voidStreamer(TBuffer& b)
voidStreamerNVirtual(TBuffer& b)
UInt_tTimeStamp() const
virtual Bool_tTruck(Int_t xDelta, Int_t yDelta, Bool_t mod1, Bool_t mod2)
Bool_tUpdateInterest(Bool_t force)
TGLVector3ViewportDeltaToWorld(const TGLVertex3& worldRef, Double_t viewportXDelta, Double_t viewportYDelta, TGLMatrix* modviewMat = 0) const
EOverlapViewportOverlap(const TGLBoundingBox& box) const
pair<Bool_t,TGLVertex3>ViewportPlaneIntersection(const TPoint& viewport, const TGLPlane& worldPlane) const
pair<Bool_t,TGLVertex3>ViewportPlaneIntersection(Double_t viewportX, Double_t viewportY, const TGLPlane& worldPlane) const
TGLRectViewportRect(const TGLBoundingBox& box, TGLBoundingBox::EFace face) const
TGLRectViewportRect(const TGLBoundingBox& box, const TGLBoundingBox::EFace* face = 0) const
TGLLine3ViewportToWorld(const TPoint& viewport) const
TGLVertex3ViewportToWorld(const TGLVertex3& viewportVertex, TGLMatrix* modviewMat = 0) const
TGLLine3ViewportToWorld(Double_t viewportX, Double_t viewportY) const
voidWindowToViewport(TPoint& point) const
voidWindowToViewport(TGLRect& rect) const
voidWindowToViewport(TGLVertex3& vertex) const
voidWindowToViewport(Int_t&, Int_t& y) const
TGLVector3WorldDeltaToViewport(const TGLVertex3& worldRef, const TGLVector3& worldDelta) const
TGLVertex3WorldToViewport(const TGLVertex3& worldVertex, TGLMatrix* modviewMat = 0) const
virtual Bool_tZoom(Int_t delta, Bool_t mod1, Bool_t mod2)
protected:
voidUpdateCache() const
private:
TGLBoundingBoxFrustum(Bool_t asBox = kTRUE) const
TGLCamera&operator=(const TGLCamera&)

Data Members

public:
enum EFrustumPlane { kNear
kLeft
kRight
kTop
kBottom
kFar
kPlanesPerFrustum
};
protected:
Bool_tfCacheDirty! cached items dirty?
TGLMatrixfCamBase! tranformation to center and rotation from up to x vector
TGLMatrixfCamTrans! transformation relative to fCamTrans
TGLVector3*fCenter! current camera center
TGLMatrixfClipM! object space clip matrix (cached)
TGLVector3fDefCenter! deafult camera center
Double_tfDollyDefault! default distnce from viewing centre
Double_tfDollyDistance! unit distance for camera movement in fwd/bck direction
TGLVector3fExtCenter! external camera center
Bool_tfExternalCenter! use external center insead of scene center
Double_tfFarClip! last applied far-clip
TGLPlanefFrustumPlanes[6]! frustum planes (cached)
TGLBoundingBoxfInterestBox! the interest box - created in UpdateInterest()
Double_tfLargestSeen! largest box volume seen in OfInterest() - used when
TGLMatrixfLastNoPickProjM! no-pick projection matrix (cached)
TGLMatrixfModVM! modelView matrix (cached)
Double_tfNearClip! last applied near-clip
TGLMatrixfProjM! projection matrix (cached)
UInt_tfTimeStamp! timestamp
Float_tfVAxisMinAngle! minimal allowed angle between up and fCamTrans Z vector
TGLRectfViewport! viewport (GL coords - origin bottom left)
static UInt_tfgDollyDeltaSens
private:
TGLBoundingBoxfInterestFrustum! frustum basis of current interest box - NOT a true BB! (DEBUG)
TGLBoundingBoxfInterestFrustumAsBox! frustum basis (as box) of current interest box (DEBUG)
TGLBoundingBoxfPreviousInterestBox! previous interest box (DEBUG)
static const Double_tfgInterestBoxExpansion! expansion c.f. aligned current frustum box

Class Charts

Inheritance Inherited Members Includes Libraries
Class Charts

Function documentation

~TGLCamera()
 Base camera destructor.
void SetViewport(const TGLRect& viewport)
 Set viewport extents from passed 'viewport' rect.
void UpdateCache()
 Update internally cached frustum values
TGLBoundingBox Frustum(Bool_t asBox = kTRUE) const
 Return the the current camera frustum. If asBox == kFALSE return
 a true frustum (truncated square based pyramid). If asBox == kTRUE
 return a true box, using the far clipping plane intersection projected
 back to the near plane.

 Camera must have valid frustum cache - call Apply() after last modifcation, before using

 Note: TGLBoundingBox is not really valid when filled with truncated pyramid
 - this is used as a visual debug aid only so ok.
TGLVertex3 EyePoint()
 Return the camera eye point (vertex) in world space
 Camera must have valid frustum cache - call Apply() after last modifcation, before using
TGLVector3 EyeDirection()
 Extract the camera eye direction (vector), running from EyePoint()
 Camera must have valid frustum cache - call Apply() after last modifcation, before using
TGLVertex3 FrustumCenter()
 Find the center of the camera frustum from intersection of planes
 This method will work even with parallel left/right & top/bottom and
 infinite eye point of ortho cameras
 Camera must have valid frustum cache - call Apply() after last modifcation, before using
EOverlap FrustumOverlap(const TGLBoundingBox& box) const
 Calcaulte overlap (kInside, kOutside, kPartial) of box with camera
 frustum
 Camera must have valid frustum cache - call Apply() after last modifcation, before using
EOverlap ViewportOverlap(const TGLBoundingBox& box) const
 Calculate overlap (kInside, kOutside, kPartial) of box projection onto viewport
 (as rect) against the viewport rect.
 Camera must have valid frustum cache - call Apply() after last modifcation, before using.
TGLRect ViewportRect(const TGLBoundingBox & box, const TGLBoundingBox::EFace face)
 Calculate viewport rectangle which just contains projection of single 'face'
 of world frame bounding box 'box' onto the viewport. Note use other version
 of ViewportRect() if you want whole 'box' contained
TGLRect ViewportRect(const TGLBoundingBox & box, const TGLBoundingBox::EFace * face)
 Calculate viewport rectangle which just contains projection of
 world frame bounding box 'box' onto the viewport. If face is
 null the rect contains the whole bounding box (8 vertices/6
 faces). If face is non-null it indicates a box face, and the
 rect contains the single face (4 vertices). Note use other
 version of ViewportRect() if you wish to just pass a static
 EFace enum member (e.g. kFaceLowX)

 Note:
    i)   Rectangle is NOT clipped by viewport limits - so can result
         in rect with corners outside viewport - negative etc
    ii)  TGLRect provides int (pixel based) values - not subpxiel accurate
    iii) Camera must have valid frustum cache - call Apply() after last
         modifcation, before calling
TGLVertex3 WorldToViewport(const TGLVertex3& worldVertex, TGLMatrix* modviewMat = 0) const
 Convert a 3D world vertex to '3D' viewport (screen) one. The X()/Y()
 components of the viewport vertex are the horizontal/vertical pixel
 positions. The Z() component is the viewport depth value - for a
 default depth range this is 0.0 (at near clip plane) to 1.0 (at far
 clip plane). See OpenGL gluProject & glDepth documentation

 Camera must have valid frustum cache - call Apply() after last modifcation, before using
TGLVector3 WorldDeltaToViewport(const TGLVertex3& worldRef, const TGLVector3& worldDelta) const
 Convert a 3D vector worldDelta (shift) about vertex worldRef to a viewport
(screen) '3D' vector. The X()/Y() components of the vector are the horizontal
 vertical pixel deltas. The Z() component is the viewport depth delta - for a
 default depth range between 0.0 (at near clip plane) to 1.0 (at far clip plane)
 See OpenGL gluProject & glDepth documentation

 Camera must have valid frustum cache - call Apply()
TGLVertex3 ViewportToWorld(const TGLVertex3 & viewportVertex, TGLMatrix* modviewMat)
 Convert a '3D' viewport vertex to 3D world one. The X()/Y() components
 of viewportVertex are the horizontal/vertical pixel position.
TGLLine3 ViewportToWorld(Double_t viewportX, Double_t viewportY)
 Convert a 2D viewport position to 3D world line - the projection of the
 viewport point into 3D space. Line runs from near to far camera clip planes
 (the minimum and maximum visible depth). See also
    TGLVertex3 TGLCamera::ViewportToWorld(const TGLVertex3 & viewportVertex) const
 for 3D viewport -> 3D world vertex conversions.
 See also OpenGL gluUnProject & glDepth documentation

 Camera must have valid frustum cache - call Apply() after last modifcation, before using
TGLLine3 ViewportToWorld(const TPoint& viewport) const
 Convert a 2D viewport position to 3D world line - the projection of the
 viewport point into 3D space. Line runs from near to far camera clip planes
 (the minimum and maximum visible depth). See also
    TGLVertex3 TGLCamera::ViewportToWorld(const TGLVertex3 & viewportVertex) const
 for 3D viewport -> 3D world vertex conversions.
 See also OpenGL gluUnProject & glDepth documentation

 Camera must have valid frustum cache - call Apply() after last modifcation, before using
std::pair<Bool_t, TGLVertex3> ViewportPlaneIntersection(Double_t viewportX, Double_t viewportY, const TGLPlane& worldPlane) const
 Find the intersection of projection of supplied viewport point (a 3D world
 line - see ViewportToWorld) with supplied world plane. Returns std::pair
 of Bool_t and TGLVertex3. If line intersects std::pair.first (Bool_t) is
 kTRUE, and std::pair.second (TGLVertex) contains the intersection vertex.
 If line does not intersect (line and plane parallel) std::pair.first
 (Bool_t) if kFALSE, and std::pair.second (TGLVertex) is invalid.

 NOTE: The projection lines is extended for the plane intersection test
 hence the intersection vertex can lie outside the near/far clip regions
 (not visible)

 Camera must have valid frustum cache - call Apply() after last modifcation, before using
std::pair<Bool_t, TGLVertex3> ViewportPlaneIntersection(const TPoint& viewport, const TGLPlane& worldPlane) const
 Find the intersection of projection of supplied viewport TPoint (a 3D world
 line - see ViewportToWorld) with supplied world plane. Returns std::pair
 of bool and vertex. If line intersects

 Camera must have valid frustum cache - call Apply() after last modifcation, before using
TGLVector3 ViewportDeltaToWorld(const TGLVertex3& worldRef, Double_t viewportXDelta, Double_t viewportYDelta, TGLMatrix* modviewMat = 0) const
 Apply a 2D viewport delta (shift) to the projection of worldRef onto viewport,
 returning the resultant world vector which equates to it. Useful for making
 3D world objects track mouse moves.

 Camera must have valid frustum cache - call Apply()
Bool_t OfInterest(const TGLBoundingBox& box, Bool_t ignoreSize) const
 Calculate if the an object defined by world frame bounding box
 is 'of interest' to the camera. This is defined as box:

 i) intersecting completely or partially (kInside/kPartial) with
 cameras interest box (fInterestBox)
 ii) having significant length OR volume ratio compared to this
 interest box

 If a box is 'of interest' returns kTRUE, kFALSE otherwise.  See
 TGLCamera::UpdateInterest() for more details of camera interest
 box.

 Note: Length/volume ratios NOT dependent on the projected size
 of box at current camera configuration as we do not want
 continual changes.  This is used when (re) populating the scene
 with objects from external client.

 TODO: Might be more logical to move this test out to client -
 and have accessor for fInterestBox instead?
Bool_t UpdateInterest(Bool_t force)
 Update the internal interest box (fInterestBox) of the camera.
 The interest box is an orientated bounding box, calculated as
 an expanded container round the frustum. It is used to test if
 if object bounding boxes are of interest (should be accepted
 into viewer scene) for a camera - see TGLCamera::OfInterest()

 The interest box is updated if the frustum is no longer contained
 in the existing one, or a new one calculated on the current frustum
 differs significantly in volume (camera has been zoomed/dollyed
 sizable amount).

 If the interest box is updated we return kTRUE - kFALSE otherwise.

void ResetInterest()
 Clear out the existing interest box
Bool_t AdjustAndClampVal(Double_t& val, Double_t min, Double_t max, Int_t screenShift, Int_t screenShiftRange, Bool_t mod1, Bool_t mod2) const
 Adjust a passed REFERENCE value 'val', based on screenShift delta.
 Two modifier flags ('mod1' / 'mod2' ) for sensitivity:

 mod1 = kFALSE, mod2 = kFALSE : normal sensitivity (screenShift/screenShiftRange)
 mod1 = kTRUE,  mod2 = kFALSE : 0.1x sensitivity
 mod1 = kTRUE,  mod2 = kTRUE  : 0.01x sensitivity
 mod1 = kFALSE, mod2 = kTRUE  : 10.0x sensitivity

 'val' is modified and clamped to 'min' / 'max' range.
 Return bool kTRUE if val actually changed.

 Used as common interaction function for adjusting zoom/dolly etc
Double_t AdjustDelta(Double_t screenShift, Double_t deltaFactor, Bool_t mod1, Bool_t mod2) const
 Adjust a passed screen value and apply modifiers.
 See AdjustAndClampVal() for details.
void DrawDebugAids()
 Draw out some debugging aids for the camera:

 i) The frustum used to create the current interest box (RED)
 ii) The same frustum as a squared off box (ORANGE)
 iii) The axis aligned version of the frustum used as interest box basis (YELLOW)
 iv) The current interest box (BLUE)
void SetExternalCenter(Bool_t x)
 Set camera center diffrent than scene center, if enable is kTRUE.
void SetCenterVec(Double_t x, Double_t y, Double_t z)
 Set camera center vector.
Double_t GetTheta()
 Get angle between camera up axis.
Bool_t Rotate(Int_t xDelta, Int_t yDelta, Bool_t mod1, Bool_t mod2)
 Rotate the camera round view volume center established in Setup().
 Arguments are:
 xDelta - horizontal delta (pixels)
 YDelta - vertical delta (pixels)
Bool_t RotateRad(Double_t hRotate, Double_t vRotate)
 Rotate camera around center.
Bool_t Dolly(Int_t delta, Bool_t mod1, Bool_t mod2)
 Dolly the camera - 'move camera along eye line, retaining lens focal length'.
 Arguments are:

 'delta' - mouse viewport delta (pixels) - +ive dolly in, -ive dolly out
 'mod1' / 'mod2' - sensitivity modifiers - see TGLCamera::AdjustAndClampVal()

 Returns kTRUE is redraw required (camera change), kFALSE otherwise.
const TGLPlane & FrustumPlane(TGLCamera::EFrustumPlane plane) const
 Return one of the planes forming the camera frustum
TGLCamera & operator=(const TGLCamera& )
Bool_t IsOrthographic()
{ return kFALSE; }
Bool_t IsPersepective()
{ return kFALSE; }
const TGLMatrix& RefModelViewMatrix()
{ return fModVM; }
Bool_t IsCacheDirty()
{ return fCacheDirty; }
void IncTimeStamp()
{ fCacheDirty = kTRUE; ++fTimeStamp; }
UInt_t TimeStamp()
{ return fTimeStamp; }
TGLRect& RefViewport()
{ return fViewport; }
void Setup(const TGLBoundingBox& box, Bool_t reset = kTRUE)
 Camera manipulation interface (GL coord - origin bottom left)
void Reset()
Bool_t Zoom(Int_t delta, Bool_t mod1, Bool_t mod2)
Bool_t Truck(Int_t xDelta, Int_t yDelta, Bool_t mod1, Bool_t mod2)
void Apply(const TGLBoundingBox& sceneBox, const TGLRect* pickRect = 0) const
void Markup(TGLCameraMarkupStyle* ) const
{}
Bool_t GetExternalCenter()
{ return fExternalCenter; }
Double_t* GetCenterVec()
{ return fCenter->Arr(); }
Double_t GetNearClip()
{ return fNearClip; }
Double_t GetFarClip()
{ return fFarClip; }
const TGLMatrix& GetCamBase()
{ return fCamBase; }
const TGLMatrix& GetCamTrans()
{ return fCamTrans; }
TGLMatrix& RefLastNoPickProjM()
{ return fLastNoPickProjM; }
void WindowToViewport(Int_t& , Int_t& y) const
 Window to GL viewport conversion - invert Y
{ y = fViewport.Height() - y; }
void WindowToViewport(TPoint & point)
{ point.SetY(fViewport.Height() - point.GetY()); }
void WindowToViewport(TGLRect & rect)
{ rect.Y() = fViewport.Height() - rect.Y(); }
void WindowToViewport(TGLVertex3 & vertex)
{ vertex.Y() = fViewport.Height() - vertex.Y(); }
const TGLRect& RefViewport()
{ return fViewport; }
Float_t GetVAxisMinAngle()
{return fVAxisMinAngle;}
void SetVAxisMinAngle(Float_t x)
{fVAxisMinAngle = x;}
void Configure(Double_t zoom, Double_t dolly, Double_t* center, Double_t hRotate, Double_t vRotate)
 Cameras expanded-frustum interest box

Author: Richard Maunder 25/05/2005
Last change: root/gl:$Id: TGLCamera.h 24158 2008-06-05 17:16:56Z matevz $
Last generated: 2008-06-25 08:40
Copyright (C) 1995-2004, Rene Brun and Fons Rademakers. *

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