| #ifndef BT_CLIP_POLYGON_H_INCLUDED |
| #define BT_CLIP_POLYGON_H_INCLUDED |
| |
| /*! \file btClipPolygon.h |
| \author Francisco Len Nßjera |
| */ |
| /* |
| This source file is part of GIMPACT Library. |
| |
| For the latest info, see http://gimpact.sourceforge.net/ |
| |
| Copyright (c) 2007 Francisco Leon Najera. C.C. 80087371. |
| email: projectileman@yahoo.com |
| |
| |
| This software is provided 'as-is', without any express or implied warranty. |
| In no event will the authors be held liable for any damages arising from the use of this software. |
| Permission is granted to anyone to use this software for any purpose, |
| including commercial applications, and to alter it and redistribute it freely, |
| subject to the following restrictions: |
| |
| 1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required. |
| 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software. |
| 3. This notice may not be removed or altered from any source distribution. |
| */ |
| |
| #include "LinearMath/btTransform.h" |
| #include "LinearMath/btGeometryUtil.h" |
| |
| |
| SIMD_FORCE_INLINE btScalar bt_distance_point_plane(const btVector4 & plane,const btVector3 &point) |
| { |
| return point.dot(plane) - plane[3]; |
| } |
| |
| /*! Vector blending |
| Takes two vectors a, b, blends them together*/ |
| SIMD_FORCE_INLINE void bt_vec_blend(btVector3 &vr, const btVector3 &va,const btVector3 &vb, btScalar blend_factor) |
| { |
| vr = (1-blend_factor)*va + blend_factor*vb; |
| } |
| |
| //! This function calcs the distance from a 3D plane |
| SIMD_FORCE_INLINE void bt_plane_clip_polygon_collect( |
| const btVector3 & point0, |
| const btVector3 & point1, |
| btScalar dist0, |
| btScalar dist1, |
| btVector3 * clipped, |
| int & clipped_count) |
| { |
| bool _prevclassif = (dist0>SIMD_EPSILON); |
| bool _classif = (dist1>SIMD_EPSILON); |
| if(_classif!=_prevclassif) |
| { |
| btScalar blendfactor = -dist0/(dist1-dist0); |
| bt_vec_blend(clipped[clipped_count],point0,point1,blendfactor); |
| clipped_count++; |
| } |
| if(!_classif) |
| { |
| clipped[clipped_count] = point1; |
| clipped_count++; |
| } |
| } |
| |
| |
| //! Clips a polygon by a plane |
| /*! |
| *\return The count of the clipped counts |
| */ |
| SIMD_FORCE_INLINE int bt_plane_clip_polygon( |
| const btVector4 & plane, |
| const btVector3 * polygon_points, |
| int polygon_point_count, |
| btVector3 * clipped) |
| { |
| int clipped_count = 0; |
| |
| |
| //clip first point |
| btScalar firstdist = bt_distance_point_plane(plane,polygon_points[0]);; |
| if(!(firstdist>SIMD_EPSILON)) |
| { |
| clipped[clipped_count] = polygon_points[0]; |
| clipped_count++; |
| } |
| |
| btScalar olddist = firstdist; |
| for(int i=1;i<polygon_point_count;i++) |
| { |
| btScalar dist = bt_distance_point_plane(plane,polygon_points[i]); |
| |
| bt_plane_clip_polygon_collect( |
| polygon_points[i-1],polygon_points[i], |
| olddist, |
| dist, |
| clipped, |
| clipped_count); |
| |
| |
| olddist = dist; |
| } |
| |
| //RETURN TO FIRST point |
| |
| bt_plane_clip_polygon_collect( |
| polygon_points[polygon_point_count-1],polygon_points[0], |
| olddist, |
| firstdist, |
| clipped, |
| clipped_count); |
| |
| return clipped_count; |
| } |
| |
| //! Clips a polygon by a plane |
| /*! |
| *\param clipped must be an array of 16 points. |
| *\return The count of the clipped counts |
| */ |
| SIMD_FORCE_INLINE int bt_plane_clip_triangle( |
| const btVector4 & plane, |
| const btVector3 & point0, |
| const btVector3 & point1, |
| const btVector3& point2, |
| btVector3 * clipped // an allocated array of 16 points at least |
| ) |
| { |
| int clipped_count = 0; |
| |
| //clip first point0 |
| btScalar firstdist = bt_distance_point_plane(plane,point0);; |
| if(!(firstdist>SIMD_EPSILON)) |
| { |
| clipped[clipped_count] = point0; |
| clipped_count++; |
| } |
| |
| // point 1 |
| btScalar olddist = firstdist; |
| btScalar dist = bt_distance_point_plane(plane,point1); |
| |
| bt_plane_clip_polygon_collect( |
| point0,point1, |
| olddist, |
| dist, |
| clipped, |
| clipped_count); |
| |
| olddist = dist; |
| |
| |
| // point 2 |
| dist = bt_distance_point_plane(plane,point2); |
| |
| bt_plane_clip_polygon_collect( |
| point1,point2, |
| olddist, |
| dist, |
| clipped, |
| clipped_count); |
| olddist = dist; |
| |
| |
| |
| //RETURN TO FIRST point0 |
| bt_plane_clip_polygon_collect( |
| point2,point0, |
| olddist, |
| firstdist, |
| clipped, |
| clipped_count); |
| |
| return clipped_count; |
| } |
| |
| |
| |
| |
| |
| #endif // GIM_TRI_COLLISION_H_INCLUDED |