source: trunk/geant4/visualization/OpenGL/src/G4OpenGLViewer.cc @ 542

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// $Id: G4OpenGLViewer.cc,v 1.29 2006/09/19 16:13:15 allison Exp $
// GEANT4 tag $Name: geant4-08-02-patch-01 $
//
// 
// Andrew Walkden  27th March 1996
// OpenGL view - opens window, hard copy, etc.

#ifdef G4VIS_BUILD_OPENGL_DRIVER

#include "G4ios.hh"
#include "G4OpenGLViewer.hh"
#include "G4OpenGLSceneHandler.hh"
#include "G4OpenGLTransform3D.hh"

#include "G4Scene.hh"
#include "G4VisExtent.hh"
#include "G4LogicalVolume.hh"
#include "G4VSolid.hh"
#include "G4Point3D.hh"
#include "G4Normal3D.hh"
#include "G4Plane3D.hh"

G4OpenGLViewer::G4OpenGLViewer (G4OpenGLSceneHandler& scene):
G4VViewer (scene, -1),
background (G4Colour(0.,0.,0.)),
transparency_enabled (true),
antialiasing_enabled (false),
haloing_enabled (false),
fStartTime(-DBL_MAX),
fEndTime(DBL_MAX),
fFadeFactor(0.),
fDisplayHeadTime(false),
fDisplayHeadTimeX(-0.9),
fDisplayHeadTimeY(-0.9),
fDisplayHeadTimeSize(24.),
fDisplayHeadTimeRed(0.),
fDisplayHeadTimeGreen(1.),
fDisplayHeadTimeBlue(1.),
fDisplayLightFront(false),
fDisplayLightFrontX(0.),
fDisplayLightFrontY(0.),
fDisplayLightFrontZ(0.),
fDisplayLightFrontT(0.),
fDisplayLightFrontRed(0.),
fDisplayLightFrontGreen(1.),
fDisplayLightFrontBlue(0.)
{
  // Make changes to view parameters for OpenGL...
  fVP.SetAutoRefresh(true);
  fDefaultVP.SetAutoRefresh(true);

  //  glClearColor (0.0, 0.0, 0.0, 0.0);
  //  glClearDepth (1.0);
  //  glDisable (GL_BLEND);
  //  glDisable (GL_LINE_SMOOTH);
  //  glDisable (GL_POLYGON_SMOOTH);

}

G4OpenGLViewer::~G4OpenGLViewer () {}

void G4OpenGLViewer::InitializeGLView () 
{
  glClearColor (0.0, 0.0, 0.0, 0.0);
  glClearDepth (1.0);
  glDisable (GL_BLEND);
  glDisable (GL_LINE_SMOOTH);
  glDisable (GL_POLYGON_SMOOTH);
}  

void G4OpenGLViewer::ClearView () {
  glClearColor (background.GetRed(),
                background.GetGreen(),
                background.GetBlue(),
                1.);
  glClearDepth (1.0);
  //Below line does not compile with Mesa includes. 
  //glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
  glClear (GL_COLOR_BUFFER_BIT);
  glClear (GL_DEPTH_BUFFER_BIT);
  glClear (GL_STENCIL_BUFFER_BIT);
  glFlush ();
}

void G4OpenGLViewer::SetView () {
  
  // Calculates view representation based on extent of object being
  // viewed and (initial) viewpoint.  (Note: it can change later due
  // to user interaction via visualization system's GUI.)
  
  // Lighting.
  GLfloat lightPosition [4];
  lightPosition [0] = fVP.GetActualLightpointDirection().x();
  lightPosition [1] = fVP.GetActualLightpointDirection().y();
  lightPosition [2] = fVP.GetActualLightpointDirection().z();
  lightPosition [3] = 0.;
  // Light position is "true" light direction, so must come after gluLookAt.
  GLfloat ambient [] = { 0.2, 0.2, 0.2, 1.};
  GLfloat diffuse [] = { 0.8, 0.8, 0.8, 1.};
  glEnable (GL_LIGHT0);
  glLightfv (GL_LIGHT0, GL_AMBIENT, ambient);
  glLightfv (GL_LIGHT0, GL_DIFFUSE, diffuse);
  
  // Get radius of scene, etc.
  // Note that this procedure properly takes into account zoom, dolly and pan.
  const G4Point3D targetPoint
    = fSceneHandler.GetScene()->GetStandardTargetPoint()
    + fVP.GetCurrentTargetPoint ();
  G4double radius = fSceneHandler.GetScene()->GetExtent().GetExtentRadius();
  if(radius<=0.) radius = 1.;
  const G4double cameraDistance = fVP.GetCameraDistance (radius);
  const G4Point3D cameraPosition =
    targetPoint + cameraDistance * fVP.GetViewpointDirection().unit();
  const GLdouble pnear   = fVP.GetNearDistance (cameraDistance, radius);
  const GLdouble pfar    = fVP.GetFarDistance  (cameraDistance, pnear, radius);
  const GLdouble right  = fVP.GetFrontHalfHeight (pnear, radius);
  const GLdouble left   = -right;
  const GLdouble bottom = left;
  const GLdouble top    = right;
  
  glMatrixMode (GL_PROJECTION); // set up Frustum.
  glLoadIdentity();

  const G4Vector3D scale = fVP.GetScaleFactor();
  glScaled(scale.x(),scale.y(),scale.z());
  
  if (fVP.GetFieldHalfAngle() == 0.) {
    glOrtho (left, right, bottom, top, pnear, pfar);
  }
  else {
    glFrustum (left, right, bottom, top, pnear, pfar);
  }
  
  glMatrixMode (GL_MODELVIEW); // apply further transformations to scene.
  glLoadIdentity();
  
  const G4Normal3D& upVector = fVP.GetUpVector ();  
  G4Point3D gltarget;
  if (cameraDistance > 1.e-6 * radius) {
    gltarget = targetPoint;
  }
  else {
    gltarget = targetPoint - radius * fVP.GetViewpointDirection().unit();
  }

  const G4Point3D& pCamera = cameraPosition;  // An alias for brevity.
  gluLookAt (pCamera.x(),  pCamera.y(),  pCamera.z(),       // Viewpoint.
             gltarget.x(), gltarget.y(), gltarget.z(),      // Target point.
             upVector.x(), upVector.y(), upVector.z());     // Up vector.
  
  // Light position is "true" light direction, so must come after gluLookAt.
  glLightfv (GL_LIGHT0, GL_POSITION, lightPosition);

  // OpenGL no longer seems to reconstruct clipped edges, so, when the
  // BooleanProcessor is up to it, abandon this and use generic
  // clipping in G4OpenGLSceneHandler::CreateSectionPolyhedron.  Also,
  // force kernel visit on change of clipping plane in
  // G4OpenGLStoredViewer::CompareForKernelVisit.
  if (fVP.IsSection () ) {  // pair of back to back clip planes.
    const G4Plane3D& s = fVP.GetSectionPlane ();
    double sArray[4];
    sArray[0] = s.a();
    sArray[1] = s.b();
    sArray[2] = s.c();
    sArray[3] = s.d() + radius * 1.e-05;
    glClipPlane (GL_CLIP_PLANE0, sArray);
    glEnable (GL_CLIP_PLANE0);
    sArray[0] = -s.a();
    sArray[1] = -s.b();
    sArray[2] = -s.c();
    sArray[3] = -s.d() + radius * 1.e-05;
    glClipPlane (GL_CLIP_PLANE1, sArray);
    glEnable (GL_CLIP_PLANE1);
  } else {
    glDisable (GL_CLIP_PLANE0);
    glDisable (GL_CLIP_PLANE1);
  }

  const G4Planes& cutaways = fVP.GetCutawayPlanes();
  size_t nPlanes = cutaways.size();
  if (fVP.IsCutaway() &&
      fVP.GetCutawayMode() == G4ViewParameters::cutawayIntersection &&
      nPlanes > 0) {
    double a[4];
    a[0] = cutaways[0].a();
    a[1] = cutaways[0].b();
    a[2] = cutaways[0].c();
    a[3] = cutaways[0].d();
    glClipPlane (GL_CLIP_PLANE2, a);
    glEnable (GL_CLIP_PLANE2);
    if (nPlanes > 1) {
      a[0] = cutaways[1].a();
      a[1] = cutaways[1].b();
      a[2] = cutaways[1].c();
      a[3] = cutaways[1].d();
      glClipPlane (GL_CLIP_PLANE3, a);
      glEnable (GL_CLIP_PLANE3);
    }
    if (nPlanes > 2) {
      a[0] = cutaways[2].a();
      a[1] = cutaways[2].b();
      a[2] = cutaways[2].c();
      a[3] = cutaways[2].d();
      glClipPlane (GL_CLIP_PLANE4, a);
      glEnable (GL_CLIP_PLANE4);
    }
  } else {
    glDisable (GL_CLIP_PLANE2);
    glDisable (GL_CLIP_PLANE3);
    glDisable (GL_CLIP_PLANE4);
  }

  // Background.
  background = fVP.GetBackgroundColour ();

}

void G4OpenGLViewer::HaloingFirstPass () {
  
  //To perform haloing, first Draw all information to the depth buffer
  //alone, using a chunky line width, and then Draw all info again, to
  //the colour buffer, setting a thinner line width an the depth testing 
  //function to less than or equal, so if two lines cross, the one 
  //passing behind the other will not pass the depth test, and so not
  //get rendered either side of the infront line for a short distance.

  //First, disable writing to the colo(u)r buffer...
  glColorMask (GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);

  //Now enable writing to the depth buffer...
  glDepthMask (GL_TRUE);
  glDepthFunc (GL_LESS);
  glClearDepth (1.0);

  //Finally, set the line width to something wide...
  glLineWidth (3.0);

}

void G4OpenGLViewer::HaloingSecondPass () {

  //And finally, turn the colour buffer back on with a sesible line width...
  glColorMask (GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
  glDepthFunc (GL_LEQUAL);
  glLineWidth (1.0);

}

#endif