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Diffstat (limited to 'extern/bullet2/src/BulletCollision/Gimpact/gim_box_set.cpp')
| -rw-r--r-- | extern/bullet2/src/BulletCollision/Gimpact/gim_box_set.cpp | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/extern/bullet2/src/BulletCollision/Gimpact/gim_box_set.cpp b/extern/bullet2/src/BulletCollision/Gimpact/gim_box_set.cpp new file mode 100644 index 00000000000..1ffc2bbad78 --- /dev/null +++ b/extern/bullet2/src/BulletCollision/Gimpact/gim_box_set.cpp @@ -0,0 +1,182 @@ + +/* +----------------------------------------------------------------------------- +This source file is part of GIMPACT Library. + +For the latest info, see http://gimpact.sourceforge.net/ + +Copyright (c) 2006 Francisco Leon Najera. C.C. 80087371. +email: projectileman@yahoo.com + + This library is free software; you can redistribute it and/or + modify it under the terms of EITHER: + (1) The GNU Lesser General Public License as published by the Free + Software Foundation; either version 2.1 of the License, or (at + your option) any later version. The text of the GNU Lesser + General Public License is included with this library in the + file GIMPACT-LICENSE-LGPL.TXT. + (2) The BSD-style license that is included with this library in + the file GIMPACT-LICENSE-BSD.TXT. + (3) The zlib/libpng license that is included with this library in + the file GIMPACT-LICENSE-ZLIB.TXT. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the files + GIMPACT-LICENSE-LGPL.TXT, GIMPACT-LICENSE-ZLIB.TXT and GIMPACT-LICENSE-BSD.TXT for more details. + +----------------------------------------------------------------------------- +*/ + + +#include "gim_box_set.h" + + +GUINT GIM_BOX_TREE::_calc_splitting_axis( + gim_array<GIM_AABB_DATA> & primitive_boxes, GUINT startIndex, GUINT endIndex) +{ + GUINT i; + + btVector3 means(btScalar(0.),btScalar(0.),btScalar(0.)); + btVector3 variance(btScalar(0.),btScalar(0.),btScalar(0.)); + GUINT numIndices = endIndex-startIndex; + + for (i=startIndex;i<endIndex;i++) + { + btVector3 center = btScalar(0.5)*(primitive_boxes[i].m_bound.m_max + + primitive_boxes[i].m_bound.m_min); + means+=center; + } + means *= (btScalar(1.)/(btScalar)numIndices); + + for (i=startIndex;i<endIndex;i++) + { + btVector3 center = btScalar(0.5)*(primitive_boxes[i].m_bound.m_max + + primitive_boxes[i].m_bound.m_min); + btVector3 diff2 = center-means; + diff2 = diff2 * diff2; + variance += diff2; + } + variance *= (btScalar(1.)/ ((btScalar)numIndices-1) ); + + return variance.maxAxis(); +} + + +GUINT GIM_BOX_TREE::_sort_and_calc_splitting_index( + gim_array<GIM_AABB_DATA> & primitive_boxes, GUINT startIndex, + GUINT endIndex, GUINT splitAxis) +{ + GUINT i; + GUINT splitIndex =startIndex; + GUINT numIndices = endIndex - startIndex; + + // average of centers + btScalar splitValue = 0.0f; + for (i=startIndex;i<endIndex;i++) + { + splitValue+= 0.5f*(primitive_boxes[i].m_bound.m_max[splitAxis] + + primitive_boxes[i].m_bound.m_min[splitAxis]); + } + splitValue /= (btScalar)numIndices; + + //sort leafNodes so all values larger then splitValue comes first, and smaller values start from 'splitIndex'. + for (i=startIndex;i<endIndex;i++) + { + btScalar center = 0.5f*(primitive_boxes[i].m_bound.m_max[splitAxis] + + primitive_boxes[i].m_bound.m_min[splitAxis]); + if (center > splitValue) + { + //swap + primitive_boxes.swap(i,splitIndex); + splitIndex++; + } + } + + //if the splitIndex causes unbalanced trees, fix this by using the center in between startIndex and endIndex + //otherwise the tree-building might fail due to stack-overflows in certain cases. + //unbalanced1 is unsafe: it can cause stack overflows + //bool unbalanced1 = ((splitIndex==startIndex) || (splitIndex == (endIndex-1))); + + //unbalanced2 should work too: always use center (perfect balanced trees) + //bool unbalanced2 = true; + + //this should be safe too: + GUINT rangeBalancedIndices = numIndices/3; + bool unbalanced = ((splitIndex<=(startIndex+rangeBalancedIndices)) || (splitIndex >=(endIndex-1-rangeBalancedIndices))); + + if (unbalanced) + { + splitIndex = startIndex+ (numIndices>>1); + } + + bool unbal = (splitIndex==startIndex) || (splitIndex == (endIndex)); + btAssert(!unbal); + + return splitIndex; +} + + +void GIM_BOX_TREE::_build_sub_tree(gim_array<GIM_AABB_DATA> & primitive_boxes, GUINT startIndex, GUINT endIndex) +{ + GUINT current_index = m_num_nodes++; + + btAssert((endIndex-startIndex)>0); + + if((endIndex-startIndex) == 1) //we got a leaf + { + m_node_array[current_index].m_left = 0; + m_node_array[current_index].m_right = 0; + m_node_array[current_index].m_escapeIndex = 0; + + m_node_array[current_index].m_bound = primitive_boxes[startIndex].m_bound; + m_node_array[current_index].m_data = primitive_boxes[startIndex].m_data; + return; + } + + //configure inner node + + GUINT splitIndex; + + //calc this node bounding box + m_node_array[current_index].m_bound.invalidate(); + for (splitIndex=startIndex;splitIndex<endIndex;splitIndex++) + { + m_node_array[current_index].m_bound.merge(primitive_boxes[splitIndex].m_bound); + } + + //calculate Best Splitting Axis and where to split it. Sort the incoming 'leafNodes' array within range 'startIndex/endIndex'. + + //split axis + splitIndex = _calc_splitting_axis(primitive_boxes,startIndex,endIndex); + + splitIndex = _sort_and_calc_splitting_index( + primitive_boxes,startIndex,endIndex,splitIndex); + + //configure this inner node : the left node index + m_node_array[current_index].m_left = m_num_nodes; + //build left child tree + _build_sub_tree(primitive_boxes, startIndex, splitIndex ); + + //configure this inner node : the right node index + m_node_array[current_index].m_right = m_num_nodes; + + //build right child tree + _build_sub_tree(primitive_boxes, splitIndex ,endIndex); + + //configure this inner node : the escape index + m_node_array[current_index].m_escapeIndex = m_num_nodes - current_index; +} + +//! stackless build tree +void GIM_BOX_TREE::build_tree( + gim_array<GIM_AABB_DATA> & primitive_boxes) +{ + // initialize node count to 0 + m_num_nodes = 0; + // allocate nodes + m_node_array.resize(primitive_boxes.size()*2); + + _build_sub_tree(primitive_boxes, 0, primitive_boxes.size()); +} + |