Source/Contrib/Techniques/OSGClusterShadingStage.inl

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  36
  37 //---------------------------------------------------------------------------
  38 //  Includes
  39 //---------------------------------------------------------------------------
  40
  41 OSG_BEGIN_NAMESPACE
  42
  43 /*---------------------  Plane and Frustums Test --------------------------*/
  44
  45 //
  46 // Check to see if a point is fully behind (inside the negative halfspace of) a plane.
  47 //
  48 inline bool ClusterShadingStage::PointInsidePlane(
  49     const Pnt3f& p,
  50     const Plane& plane)
  51 {
  52     Real32 val = plane.getNormal().dot(p) - plane.getDistanceFromOrigin();
  53     return val < 0;
  54 }
  55
  56 //
  57 // Check to see if a sphere is fully behind (inside the negative halfspace of) a plane.
  58 //
  59 inline bool ClusterShadingStage::SphereInsidePlane(
  60     const Sphere& sphere,
  61     const Plane&  plane)
  62 {
  63     Real32 val = plane.getNormal().dot(sphere.c) - plane.getDistanceFromOrigin();
  64     return val < -sphere.r;
  65 }
  66
  67 //
  68 // Check to see if a cone if fully behind (inside the negative halfspace of) a plane.
  69 //
  70 inline bool ClusterShadingStage::ConeInsidePlane(
  71     const Cone&  cone,
  72     const Plane& plane)
  73 {
  74     // Compute the farthest point on the end of the cone to the positive space of the plane.
  75     Vec3f m = plane.getNormal().cross(cone.d).cross(cone.d);
  76     Pnt3f Q = cone.T + cone.d * cone.h - m * cone.r;
  77
  78     // The cone is in the negative halfspace of the plane if both
  79     // the tip of the cone and the farthest point on the end of the cone to the
  80     // positive halfspace of the plane are both inside the negative halfspace
  81     // of the plane.
  82     return PointInsidePlane(cone.T, plane) && PointInsidePlane(Q, plane);
  83 }
  84
  85 //
  86 // Check to see of a point light is partially contained within the frustum.
  87 //
  88 inline bool ClusterShadingStage::SphereInsideFrustum(
  89     const Sphere&  sphere,
  90     const Frustum& frustum,
  91     Real32         zNear,
  92     Real32         zFar)
  93 {
  94     bool result = true;
  95
  96     if (sphere.c.z() - sphere.r > zNear || zFar > sphere.c.z() + sphere.r)
  97     {
  98         result = false;
  99     }
 100
 101     for (int i = 0; i < 4 && result; i++)
 102     {
 103         if (SphereInsidePlane(sphere, frustum.planes[i]))
 104         {
 105             result = false;
 106         }
 107     }
 108
 109     return result;
 110 }
 111
 112 inline bool ClusterShadingStage::ConeInsideFrustum(
 113     const Cone&    cone,
 114     const Frustum& frustum,
 115     Real32         zNear,
 116     Real32         zFar)
 117 {
 118     bool result = true;
 119
 120     Plane nearPlane(Vec3f(0, 0,-1),-zNear);
 121     Plane farPlane (Vec3f(0, 0, 1), zFar );
 122
 123     if (ConeInsidePlane(cone, nearPlane) || ConeInsidePlane(cone, farPlane))
 124     {
 125         result = false;
 126     }
 127
 128     for (int i = 0; i < 4 && result; i++)
 129     {
 130         if (ConeInsidePlane(cone, frustum.planes[i]))
 131         {
 132             result = false;
 133         }
 134     }
 135
 136     return result;
 137 }
 138
 139 OSG_END_NAMESPACE