// @(#)root/gl:$Id: TGLPerspectiveCamera.cxx 20882 2007-11-19 11:31:26Z rdm $ // Author: Richard Maunder 25/05/2005 /************************************************************************* * Copyright (C) 1995-2000, Rene Brun and Fons Rademakers. * * All rights reserved. * * * * For the licensing terms see $ROOTSYS/LICENSE. * * For the list of contributors see $ROOTSYS/README/CREDITS. * *************************************************************************/ #include "TGLPerspectiveCamera.h" #include "TGLUtil.h" #include "TGLIncludes.h" #include "TMath.h" #include "TError.h" ////////////////////////////////////////////////////////////////////////// // // // TGLPerspectiveCamera // // // // Perspective projection camera - with characteristic foreshortening. // // // // TODO: Currently constrains YOZ plane to be floor - this is never // // 'tipped'. While useful we really need to extend so can: // // i) Pick any one of the three natural planes of the world to be floor.// // ii) Can use a free arcball style camera with no contraint - integrate// // TArcBall. // ////////////////////////////////////////////////////////////////////////// ClassImp(TGLPerspectiveCamera) Double_t TGLPerspectiveCamera::fgFOVMin = 0.01; Double_t TGLPerspectiveCamera::fgFOVDefault = 30; Double_t TGLPerspectiveCamera::fgFOVMax = 120.0; UInt_t TGLPerspectiveCamera::fgFOVDeltaSens = 500; //______________________________________________________________________________ TGLPerspectiveCamera::TGLPerspectiveCamera(const TGLVector3 & hAxes, const TGLVector3 & vAxes) : TGLCamera(hAxes, vAxes), fFOV(fgFOVDefault) { // Construct perspective camera Setup(TGLBoundingBox(TGLVertex3(-100,-100,-100), TGLVertex3(100,100,100))); fCamTrans.MoveLF(1, fDollyDefault); } //______________________________________________________________________________ TGLPerspectiveCamera::~TGLPerspectiveCamera() { // Destroy perspective camera } //______________________________________________________________________________ void TGLPerspectiveCamera::Setup(const TGLBoundingBox & box, Bool_t reset) { // Setup camera limits suitible to view the world volume defined by 'box' // and call Reset() to initialise camera. if (fExternalCenter == kFALSE) { TGLVertex3 center = box.Center(); SetCenterVec(center.X(), center.Y(), center.Z()); } // At default FOV, the maximum dolly should just encapsulate the longest side of box with // offset for next longetst side TGLVector3 extents = box.Extents(); Int_t sortInd[3]; TMath::Sort(3, extents.CArr(), sortInd); Double_t longest = extents[sortInd[0]]; Double_t nextLongest = extents[sortInd[1]]; fDollyDefault = longest/(2.0*tan(fgFOVDefault*TMath::Pi()/360)); fDollyDefault += nextLongest/2.0; fDollyDistance = 0.002 * fDollyDefault; if (reset) Reset(); } //______________________________________________________________________________ void TGLPerspectiveCamera::Reset() { // Reset the camera to defaults - reframe the world volume established in Setup() // in default state. Note: limits defined in Setup() are not adjusted. fFOV = fgFOVDefault; fCamTrans.SetIdentity(); fCamTrans.MoveLF(1, fDollyDefault); IncTimeStamp(); } //______________________________________________________________________________ Bool_t TGLPerspectiveCamera::Zoom(Int_t delta, Bool_t mod1, Bool_t mod2) { // Zoom the camera - 'adjust lens focal length, retaining camera position'. // Arguments are: // // 'delta' - mouse viewport delta (pixels) - +ive zoom in, -ive zoom out // 'mod1' / 'mod2' - sensitivity modifiers - see TGLCamera::AdjustAndClampVal() // // Returns kTRUE is redraw required (camera change), kFALSE otherwise. // TODO: Bring all mouse handling into camera classes - would simplify interface and // remove these non-generic cases. if (AdjustAndClampVal(fFOV, fgFOVMin, fgFOVMax, delta, fgFOVDeltaSens, mod1, mod2)) { IncTimeStamp(); return kTRUE; } else { return kFALSE; } } //______________________________________________________________________________ void TGLPerspectiveCamera::Apply(const TGLBoundingBox & sceneBox, const TGLRect * pickRect) const { // Apply the camera to the current GL context, setting the viewport, projection // and modelview matricies. After this verticies etc can be directly entered // in the world frame. This also updates the cached frustum values, enabling // all the projection, overlap tests etc defined in TGLCamera to be used. // // Arguments are: // 'box' - view volume box - used to adjust near/far clipping // 'pickRect' - optional picking rect. If non-null, restrict drawing to this // viewport rect. // TODO: If we retained the box from Setup first argument could be dropped? // MT This whole thing is convoluted. We can calculate camera postion // and look-at direction without calling unproject and seeking clipping // plane intersection. // Besides, this would give as a proper control over camera transforamtion // matrix. // // Much better since Oct 2007, the clipping planes stuff still // needs to be cleaned. glViewport(fViewport.X(), fViewport.Y(), fViewport.Width(), fViewport.Height()); if(fViewport.Width() == 0 || fViewport.Height() == 0) { glMatrixMode(GL_PROJECTION); glLoadIdentity(); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); return; } glMatrixMode(GL_PROJECTION); glLoadIdentity(); // To find decent near/far clip plane distances we construct the // frustum thus: // i) first setup perspective with arbitary near/far planes gluPerspective(fFOV, fViewport.Aspect(), 1.0, 1000.0); // printf("FIRST STEP FOV %f, aspect %f, nearClip %f, farClip %f \n", fFOV, fViewport.Aspect(), 1., 1000.); // ii) setup modelview glMatrixMode(GL_MODELVIEW); glLoadIdentity(); TGLMatrix mx = fCamBase*fCamTrans; TGLVector3 pos = mx.GetTranslation(); TGLVector3 fwd = mx.GetBaseVec(1); TGLVector3 center = pos - fwd; TGLVector3 up = fCamBase.GetBaseVec(3); gluLookAt(pos[0], pos[1], pos[2], center[0], center[1], center[2], up[0], up[1], up[2]); // iii) update the cached frustum planes so we can get eye point/direction Bool_t modifiedCache = kFALSE; if (fCacheDirty) { UpdateCache(); modifiedCache = kTRUE; } // iv) Create a clip plane, using the eye direction as normal, passing through eye point TGLPlane clipPlane(EyeDirection(), EyePoint()); fCacheDirty = modifiedCache; // v) find the near/far distance which just encapsulate the passed bounding box vertexes // not ideal - should really find the nearest/further points on box surface // which intersect frustum - however this much more complicated Double_t currentDist; for (UInt_t i=0; i<8; i++) { currentDist = clipPlane.DistanceTo(sceneBox[i]); if (i==0) { fNearClip = currentDist; fFarClip = fNearClip; } if (currentDist < fNearClip) fNearClip = currentDist; if (currentDist > fFarClip) fFarClip = currentDist; } // Add 1% each way to avoid any rounding conflicts with drawn objects fNearClip *= 0.49; // 0.99; TODO Look at - avoid removing clipping + manip objs fFarClip *= 2.01; // 1.01; if (fFarClip < 2.0) fFarClip = 2.0; if (fNearClip < fFarClip/1000.0) fNearClip = fFarClip/1000.0; glMatrixMode(GL_PROJECTION); glLoadIdentity(); // Load up any picking rect if (pickRect) { TGLRect rect(*pickRect); WindowToViewport(rect); gluPickMatrix(rect.X(), rect.Y(), rect.Width(), rect.Height(), (Int_t*) fViewport.CArr()); } // vi) reset the perspective using the correct near/far clips distances // and restore modelview mode gluPerspective(fFOV, fViewport.Aspect(), fNearClip, fFarClip); glMatrixMode(GL_MODELVIEW); if (fCacheDirty) UpdateCache(); } //______________________________________________________________________________ void TGLPerspectiveCamera::Configure(Double_t fov, Double_t dolly, Double_t center[3], Double_t hRotate, Double_t vRotate) { // Configure the camera state fFOV = fov; // Don't generally constrain external configuration // However exceeding the vRotate limits or silly FOV values will // cause very weird behaviour or projections so fix these if (fFOV > 170.0) { fFOV = 170.0; } else if (fFOV < 0.1) { fFOV = 0.1; } SetCenterVec(center[0], center[1], center[2]); fCamTrans.MoveLF(1, dolly); RotateRad(hRotate, vRotate); IncTimeStamp(); }