GL Studio API
cull.h
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1 /*! \file
2  \brief The disti::Culler class. Implements view frustum culling.
3 
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39 */
40 #ifndef _CULL_H
41 #define _CULL_H
42 
43 #include "vertex.h"
44 #include "util.h"
45 
46 namespace disti
47 {
48 
49 /** The Culler class. Implements view frustum culling. */
50 class Culler
51 {
52 
53 public:
54 
55  /** Return type for culling function */
56  typedef enum
57  {
58  OUTSIDE_FRUSTUM, /** The object was entirely outside of the viewing frustum */
59  INTERSECTS_FRUSTUM, /** The object intersects the viewing frustum */
60  INSIDE_FRUSTUM /** The object was entirely inside the viewing frustum */
62 
63  /** Definitions for the six frustum clipping planes */
64  typedef enum
65  {
66  RIGHT_PLANE,
67  LEFT_PLANE,
68  BOTTOM_PLANE,
69  TOP_PLANE,
70  FAR_PLANE,
71  NEAR_PLANE
73 
74 
75 
76 protected:
77  bool _enabled; /** Whether or not culling is enabled */
78 
79  PlaneClass _planes[6]; /** Array of six clipping planes to define the frustum */
80 
81 public:
82  /** Culler constructor
83  * \param enabled Whether or not to actually to the culling test
84  */
85  GLS_EXPORT Culler(bool enabled=true);
86 
87  /** Reads the current OpenGL projection matrices and determines the six frustum planes
88  * Note: This assumes a perspective projection, but it will work with orthographic,
89  * though it could be optimized better if it was known that Ortho is being used.
90  */
91  GLS_EXPORT void ExtractFrustum(OpenGLMatrices &matrices);
92 
93  /** \return Whether the sphere is inside, outside or intersects the view frustum.
94  */
95  GLS_EXPORT CullResultEnum SphereInFrustum(const Vector &v,const float radius) const;
96 
97  /** Slightly faster sphere culling because it doesn't test seperately
98  * for intersection and it ignores the Enabled() state.
99  * \returns true if outside or intersecting, false if inside
100  */
101  inline bool SphereOutsideFrustum(const Vector &center,const float radius) const
102  {
103  if( (_planes[0].a * center.x + _planes[0].b * center.y + _planes[0].c * center.z + _planes[0].d) <= -radius )
104  return true;
105  if( (_planes[1].a * center.x + _planes[1].b * center.y + _planes[1].c * center.z + _planes[1].d) <= -radius )
106  return true;
107  if( (_planes[2].a * center.x + _planes[2].b * center.y + _planes[2].c * center.z + _planes[2].d) <= -radius )
108  return true;
109  if( (_planes[3].a * center.x + _planes[3].b * center.y + _planes[3].c * center.z + _planes[3].d) <= -radius )
110  return true;
111  if( (_planes[4].a * center.x + _planes[4].b * center.y + _planes[4].c * center.z + _planes[4].d) <= -radius )
112  return true;
113  if( (_planes[5].a * center.x + _planes[5].b * center.y + _planes[5].c * center.z + _planes[5].d) <= -radius )
114  return true;
115 
116  return false; // inside (or intersecting)
117  }
118 
119  /** Accessor method to get whether or not culling is enabled
120  * \return Whether or not culling is enabled
121  */
122  inline bool Enabled(void) const { return _enabled; }
123 
124  /** Accessor method to set whether or not culling is enabled
125  * Be carefull with this, because the Culler is usually passed
126  * by reference.
127  */
128  inline void Enabled(bool newVal) { _enabled = newVal; }
129 
130  /** \return A reference to the desired clipping plane for this view frustum */
131  GLS_EXPORT const PlaneClass &Plane(const ClippingPlanesEnum &whichPlane) const;
132 };
133 
134 } // namespace disti
135 
136 #endif
Definition: cull.h:50
Definition: vertex.h:494
Class to contain current OpenGL view, projection and draw matrices.
Definition: util.h:281
Culler(bool enabled=true)
Definition: cull.h:60
bool SphereOutsideFrustum(const Vector &center, const float radius) const
Definition: cull.h:101
void Enabled(bool newVal)
Definition: cull.h:128
void ExtractFrustum(OpenGLMatrices &matrices)
The disti::Vertex class. A class for manipulating 3D vertices.
Generally useful defines, macros, enumerations and function prototypes.
CullResultEnum
Definition: cull.h:56
PlaneClass _planes[6]
Definition: cull.h:79
CullResultEnum SphereInFrustum(const Vector &v, const float radius) const
const PlaneClass & Plane(const ClippingPlanesEnum &whichPlane) const
Definition: vertex.h:84
bool Enabled(void) const
Definition: cull.h:122
Definition: bmpimage.h:46
ClippingPlanesEnum
Definition: cull.h:64