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Reference Guide
TGLLightSet.cxx
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1 // @(#)root/gl:$Id$
2 // Author: Matevz Tadel, Feb 2007
3 
4 /*************************************************************************
5  * Copyright (C) 1995-2004, Rene Brun and Fons Rademakers. *
6  * All rights reserved. *
7  * *
8  * For the licensing terms see $ROOTSYS/LICENSE. *
9  * For the list of contributors see $ROOTSYS/README/CREDITS. *
10  *************************************************************************/
11 
12 #include "TGLLightSet.h"
13 
14 #include "TGLBoundingBox.h"
15 #include "TGLOrthoCamera.h"
16 
17 #include "TGLIncludes.h"
18 
19 /** \class TGLLightSet
20 \ingroup opengl
21 Encapsulates a set of lights for OpenGL.
22 */
23 
25 
27  TObject(),
28 
29  fLightState(kLightMask), // All on
30  fUseSpecular(kTRUE),
31 
32  fFrontPower(0.4), fSidePower(0.7), fSpecularPower(0.8)
33 {
34  // Constructor.
35 }
36 
37 ////////////////////////////////////////////////////////////////////////////////
38 /// Toggle light on/off.
39 
41 {
42  if (light == kLightSpecular) {
44  } else if (light >= kLightMask) {
45  Error("TGLLightSet::ToggleLight", "invalid light type");
46  return;
47  } else {
48  fLightState ^= light;
49  }
50 }
51 
52 ////////////////////////////////////////////////////////////////////////////////
53 /// Set a light on/off.
54 
56 {
57  if (light == kLightSpecular) {
58  fUseSpecular = on;
59  } else if (light >= kLightMask) {
60  Error("TGLViewer::ToggleLight", "invalid light type");
61  return;
62  }
63 
64  if (on) {
65  fLightState |= light;
66  } else {
67  fLightState &= ~light;
68  }
69 }
70 
71 ////////////////////////////////////////////////////////////////////////////////
72 /// Setup lights for current given bounding box and camera.
73 /// This is called by standard GL viewer.
74 /// Expects matrix-mode to be model-view.
75 
77  const TGLCamera & camera, Bool_t debug)
78 {
79  glPushMatrix();
80 
81  if (!bbox.IsEmpty())
82  {
83  // Calculate a sphere radius to arrange lights round
84  Double_t lightRadius = bbox.Extents().Mag() * 2.9;
85  Double_t sideLightsZ, frontLightZ;
86 
87  const TGLOrthoCamera* orthoCamera = dynamic_cast<const TGLOrthoCamera*>(&camera);
88  if (orthoCamera) {
89  // Find distance from near clip plane to furstum center - i.e. vector of half
90  // clip depth. Ortho lights placed this distance from eye point
91  sideLightsZ =
93  frontLightZ = sideLightsZ;
94  } else {
95  // Perspective camera
96  // Extract vector from camera eye point to center.
97  // Camera must have been applied already.
98  TGLVector3 eyeVector = camera.EyePoint() - camera.FrustumCenter();
99 
100  // Pull forward slightly (0.85) to avoid to sharp a cutoff
101  sideLightsZ = eyeVector.Mag() * -0.85;
102  frontLightZ = 0.2 * lightRadius;
103  }
104 
105  // Reset the modelview so static lights are placed in fixed eye space
106  // This will destroy camera application.
107  glLoadIdentity();
108 
109  // 0: Front, 1: Top, 2: Bottom, 3: Left, 4: Right
110  TGLVertex3 c = bbox.Center();
111  TGLVector3 center(c.X(), c.Y(), c.Z());
112  camera.RefModelViewMatrix().MultiplyIP(center);
113  // Float_t pos0[] = { center.X(), center.Y(), frontLightZ, 1.0 };
114  Float_t pos0[] = { 0.0, 0.0, Float_t(frontLightZ), 1.0 };
115  Float_t pos1[] = { Float_t(center.X()), Float_t(center.Y() + lightRadius), Float_t(sideLightsZ), 1.0 };
116  Float_t pos2[] = { Float_t(center.X()), Float_t(center.Y() - lightRadius), Float_t(sideLightsZ), 1.0 };
117  Float_t pos3[] = { Float_t(center.X() - lightRadius), Float_t(center.Y()), Float_t(sideLightsZ), 1.0 };
118  Float_t pos4[] = { Float_t(center.X() + lightRadius), Float_t(center.Y()), Float_t(sideLightsZ), 1.0 };
119 
120  Float_t specular = fUseSpecular ? fSpecularPower : 0.0f;
121  const Float_t frontLightColor[] = { fFrontPower, fFrontPower, fFrontPower, 1.0f };
122  const Float_t sideLightColor[] = { fSidePower, fSidePower, fSidePower, 1.0f };
123  const Float_t specLightColor[] = { specular, specular, specular, 1.0f };
124 
125  glLightfv(GL_LIGHT0, GL_POSITION, pos0);
126  glLightfv(GL_LIGHT0, GL_DIFFUSE, frontLightColor);
127  glLightfv(GL_LIGHT0, GL_SPECULAR, specLightColor);
128 
129  glLightfv(GL_LIGHT1, GL_POSITION, pos1);
130  glLightfv(GL_LIGHT1, GL_DIFFUSE, sideLightColor);
131  glLightfv(GL_LIGHT2, GL_POSITION, pos2);
132  glLightfv(GL_LIGHT2, GL_DIFFUSE, sideLightColor);
133  glLightfv(GL_LIGHT3, GL_POSITION, pos3);
134  glLightfv(GL_LIGHT3, GL_DIFFUSE, sideLightColor);
135  glLightfv(GL_LIGHT4, GL_POSITION, pos4);
136  glLightfv(GL_LIGHT4, GL_DIFFUSE, sideLightColor);
137  }
138 
139  // Set light states every time - must be deferred until now when we know we
140  // are in the correct thread for GL context
141  // TODO: Could detect state change and only adjust if a change
142  for (UInt_t light = 0; (1<<light) < kLightMask; light++)
143  {
144  if ((1<<light) & fLightState)
145  {
146  glEnable(GLenum(GL_LIGHT0 + light));
147 
148  // Debug mode - show active lights in yellow
149  if (debug)
150  {
151  // Lighting itself needs to be disable so a single one can show...!
152  glDisable(GL_LIGHTING);
153  Float_t position[4]; // Only float parameters for lights (no double)....
154  glGetLightfv(GLenum(GL_LIGHT0 + light), GL_POSITION, position);
155  Double_t size = bbox.Extents().Mag() / 10.0;
156  TGLVertex3 dPosition(position[0], position[1], position[2]);
157  TGLUtil::DrawSphere(dPosition, size, TGLUtil::fgYellow);
158  glEnable(GL_LIGHTING);
159  }
160  }
161  else
162  {
163  glDisable(GLenum(GL_LIGHT0 + light));
164  }
165  }
166 
167  // Restore camera which was applied before we were called, and is disturbed
168  // by static light positioning above.
169  glPopMatrix();
170 }
Double_t DistanceTo(const TGLVertex3 &vertex) const
Distance from plane to vertex.
Definition: TGLUtil.cxx:493
TGLVertex3 Center() const
Abstract base camera class - concrete classes for orthographic and perspective cameras derive from it...
Definition: TGLCamera.h:43
TGLVector3 Extents() const
void SetLight(ELight light, Bool_t on)
Set a light on/off.
Definition: TGLLightSet.cxx:55
static const UChar_t fgYellow[4]
Definition: TGLUtil.h:1051
float Float_t
Definition: RtypesCore.h:53
void ToggleLight(ELight light)
Toggle light on/off.
Definition: TGLLightSet.cxx:40
bool Bool_t
Definition: RtypesCore.h:59
UInt_t fLightState
Definition: TGLLightSet.h:36
Encapsulates a set of lights for OpenGL.
Definition: TGLLightSet.h:21
Float_t fFrontPower
Definition: TGLLightSet.h:39
Bool_t IsEmpty() const
Float_t fSidePower
power of the front lamp
Definition: TGLLightSet.h:40
const TGLMatrix & RefModelViewMatrix() const
Definition: TGLCamera.h:121
3 component (x/y/z) vertex class.
Definition: TGLUtil.h:82
static void DrawSphere(const TGLVertex3 &position, Double_t radius, const UChar_t rgba[4])
Draw sphere, centered on vertex &#39;position&#39;, with radius &#39;radius&#39;, color &#39;rgba&#39;.
Definition: TGLUtil.cxx:2352
3 component (x/y/z) vector class.
Definition: TGLUtil.h:246
void MultiplyIP(TGLVector3 &v, Double_t w=1) const
Multiply vector in-place.
Definition: TGLUtil.cxx:1076
Double_t Mag() const
Definition: TGLUtil.h:297
Bool_t fUseSpecular
light states (on/off) mask
Definition: TGLLightSet.h:37
unsigned int GLenum
Definition: GL_glu.h:266
unsigned int UInt_t
Definition: RtypesCore.h:42
virtual void Error(const char *method, const char *msgfmt,...) const
Issue error message.
Definition: TObject.cxx:880
#define ClassImp(name)
Definition: Rtypes.h:365
double Double_t
Definition: RtypesCore.h:55
TGLVertex3 FrustumCenter() const
Find the center of the camera frustum from intersection of planes This method will work even with par...
Definition: TGLCamera.cxx:251
TGLVertex3 EyePoint() const
Return the camera eye point (vertex) in world space Camera must have valid frustum cache - call Apply...
Definition: TGLCamera.cxx:219
Orthographic projection camera.
Mother of all ROOT objects.
Definition: TObject.h:37
Concrete class describing an orientated (free) or axis aligned box of 8 vertices. ...
const TGLPlane & FrustumPlane(EFrustumPlane plane) const
Definition: TGLCamera.h:219
#define c(i)
Definition: RSha256.hxx:101
TGLLightSet()
power of specular lamp
Definition: TGLLightSet.cxx:26
const Bool_t kTRUE
Definition: RtypesCore.h:87
Float_t fSpecularPower
power of the side lamps
Definition: TGLLightSet.h:41
void StdSetupLights(const TGLBoundingBox &bbox, const TGLCamera &camera, Bool_t debug=kFALSE)
Setup lights for current given bounding box and camera.
Definition: TGLLightSet.cxx:76