diff options
Diffstat (limited to 'Opcode/OPC_PlanesAABBOverlap.h')
-rw-r--r-- | Opcode/OPC_PlanesAABBOverlap.h | 100 |
1 files changed, 50 insertions, 50 deletions
diff --git a/Opcode/OPC_PlanesAABBOverlap.h b/Opcode/OPC_PlanesAABBOverlap.h index 27d0055..2bc70d7 100644 --- a/Opcode/OPC_PlanesAABBOverlap.h +++ b/Opcode/OPC_PlanesAABBOverlap.h @@ -1,50 +1,50 @@ -///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
-/**
- * Planes-AABB overlap test.
- * - original code by Ville Miettinen, from Umbra/dPVS (released on the GD-Algorithms mailing list)
- * - almost used "as-is", I even left the comments (hence the frustum-related notes)
- *
- * \param center [in] box center
- * \param extents [in] box extents
- * \param out_clip_mask [out] bitmask for active planes
- * \param in_clip_mask [in] bitmask for active planes
- * \return TRUE if boxes overlap planes
- */
-///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
-inline_ BOOL PlanesCollider::PlanesAABBOverlap(const IcePoint& center, const IcePoint& extents, udword& out_clip_mask, udword in_clip_mask)
-{
- // Stats
- mNbVolumeBVTests++;
-
- const IcePlane* p = mPlanes;
-
- // Evaluate through all active frustum planes. We determine the relation
- // between the AABB and a plane by using the concept of "near" and "far"
- // vertices originally described by Zhang (and later by Möller). Our
- // variant here uses 3 fabs ops, 6 muls, 7 adds and two floating IcePoint
- // comparisons per plane. The routine early-exits if the AABB is found
- // to be outside any of the planes. The loop also constructs a new output
- // clip mask. Most FPUs have a native single-cycle fabsf() operation.
-
- udword Mask = 1; // current mask index (1,2,4,8,..)
- udword TmpOutClipMask = 0; // initialize output clip mask into empty.
-
- while(Mask<=in_clip_mask) // keep looping while we have active planes left...
- {
- if(in_clip_mask & Mask) // if clip plane is active, process it..
- {
- float NP = extents.x*fabsf(p->n.x) + extents.y*fabsf(p->n.y) + extents.z*fabsf(p->n.z); // ### fabsf could be precomputed
- float MP = center.x*p->n.x + center.y*p->n.y + center.z*p->n.z + p->d;
-
- if(NP < MP) // near vertex behind the clip plane...
- return FALSE; // .. so there is no intersection..
- if((-NP) < MP) // near and far vertices on different sides of plane..
- TmpOutClipMask |= Mask; // .. so update the clip mask...
- }
- Mask+=Mask; // mk = (1<<plane)
- p++; // advance to next plane
- }
-
- out_clip_mask = TmpOutClipMask; // copy output value (temp used to resolve aliasing!)
- return TRUE; // indicate that AABB intersects frustum
-}
+/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// +/** + * Planes-AABB overlap test. + * - original code by Ville Miettinen, from Umbra/dPVS (released on the GD-Algorithms mailing list) + * - almost used "as-is", I even left the comments (hence the frustum-related notes) + * + * \param center [in] box center + * \param extents [in] box extents + * \param out_clip_mask [out] bitmask for active planes + * \param in_clip_mask [in] bitmask for active planes + * \return TRUE if boxes overlap planes + */ +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// +inline_ BOOL PlanesCollider::PlanesAABBOverlap(const IcePoint& center, const IcePoint& extents, udword& out_clip_mask, udword in_clip_mask) +{ + // Stats + mNbVolumeBVTests++; + + const IcePlane* p = mPlanes; + + // Evaluate through all active frustum planes. We determine the relation + // between the AABB and a plane by using the concept of "near" and "far" + // vertices originally described by Zhang (and later by Möller). Our + // variant here uses 3 fabs ops, 6 muls, 7 adds and two floating IcePoint + // comparisons per plane. The routine early-exits if the AABB is found + // to be outside any of the planes. The loop also constructs a new output + // clip mask. Most FPUs have a native single-cycle fabsf() operation. + + udword Mask = 1; // current mask index (1,2,4,8,..) + udword TmpOutClipMask = 0; // initialize output clip mask into empty. + + while(Mask<=in_clip_mask) // keep looping while we have active planes left... + { + if(in_clip_mask & Mask) // if clip plane is active, process it.. + { + float NP = extents.x*fabsf(p->n.x) + extents.y*fabsf(p->n.y) + extents.z*fabsf(p->n.z); // ### fabsf could be precomputed + float MP = center.x*p->n.x + center.y*p->n.y + center.z*p->n.z + p->d; + + if(NP < MP) // near vertex behind the clip plane... + return FALSE; // .. so there is no intersection.. + if((-NP) < MP) // near and far vertices on different sides of plane.. + TmpOutClipMask |= Mask; // .. so update the clip mask... + } + Mask+=Mask; // mk = (1<<plane) + p++; // advance to next plane + } + + out_clip_mask = TmpOutClipMask; // copy output value (temp used to resolve aliasing!) + return TRUE; // indicate that AABB intersects frustum +} |