mirror of
https://github.com/scratchfoundation/bgfx.git
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262 lines
6.2 KiB
C++
262 lines
6.2 KiB
C++
/*
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* Copyright 2011-2014 Branimir Karadzic. All rights reserved.
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* License: http://www.opensource.org/licenses/BSD-2-Clause
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*/
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#include <bx/rng.h>
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#include "bounds.h"
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#include "fpumath.h"
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void aabbToObb(Obb& _obb, const Aabb& _aabb)
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{
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memset(_obb.m_mtx, 0, sizeof(_obb.m_mtx) );
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_obb.m_mtx[ 0] = (_aabb.m_max[0] - _aabb.m_min[0]) * 0.5f;
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_obb.m_mtx[ 5] = (_aabb.m_max[1] - _aabb.m_min[1]) * 0.5f;
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_obb.m_mtx[10] = (_aabb.m_max[2] - _aabb.m_min[2]) * 0.5f;
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_obb.m_mtx[12] = (_aabb.m_min[0] + _aabb.m_max[0]) * 0.5f;
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_obb.m_mtx[13] = (_aabb.m_min[1] + _aabb.m_max[1]) * 0.5f;
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_obb.m_mtx[14] = (_aabb.m_min[2] + _aabb.m_max[2]) * 0.5f;
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_obb.m_mtx[15] = 1.0f;
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}
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void sphereToAabb(Aabb& _aabb, const Sphere& _sphere)
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{
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float xx = _sphere.m_center[0];
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float yy = _sphere.m_center[1];
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float zz = _sphere.m_center[2];
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float radius = _sphere.m_radius;
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_aabb.m_min[0] = xx - radius;
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_aabb.m_min[1] = yy - radius;
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_aabb.m_min[2] = zz - radius;
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_aabb.m_max[0] = xx + radius;
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_aabb.m_max[1] = yy + radius;
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_aabb.m_max[2] = zz + radius;
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}
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void aabbTransformToObb(Obb& _obb, const Aabb& _aabb, const float* _mtx)
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{
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aabbToObb(_obb, _aabb);
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float result[16];
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mtxMul(result, _obb.m_mtx, _mtx);
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memcpy(_obb.m_mtx, result, sizeof(result) );
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}
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float calcAreaAabb(Aabb& _aabb)
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{
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float ww = _aabb.m_max[0] - _aabb.m_min[0];
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float hh = _aabb.m_max[1] - _aabb.m_min[1];
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float dd = _aabb.m_max[2] - _aabb.m_min[2];
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return 2.0f * (ww*hh + ww*dd + hh*dd);
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}
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void calcAabb(Aabb& _aabb, const void* _vertices, uint32_t _numVertices, uint32_t _stride)
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{
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float min[3], max[3];
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uint8_t* vertex = (uint8_t*)_vertices;
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float* position = (float*)vertex;
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min[0] = max[0] = position[0];
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min[1] = max[1] = position[1];
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min[2] = max[2] = position[2];
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vertex += _stride;
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for (uint32_t ii = 1; ii < _numVertices; ++ii)
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{
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position = (float*)vertex;
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vertex += _stride;
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float xx = position[0];
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float yy = position[1];
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float zz = position[2];
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min[0] = fminf(xx, min[0]);
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min[1] = fminf(yy, min[1]);
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min[2] = fminf(zz, min[2]);
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max[0] = fmaxf(xx, max[0]);
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max[1] = fmaxf(yy, max[1]);
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max[2] = fmaxf(zz, max[2]);
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}
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_aabb.m_min[0] = min[0];
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_aabb.m_min[1] = min[1];
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_aabb.m_min[2] = min[2];
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_aabb.m_max[0] = max[0];
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_aabb.m_max[1] = max[1];
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_aabb.m_max[2] = max[2];
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}
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void calcAabb(Aabb& _aabb, const float* _mtx, const void* _vertices, uint32_t _numVertices, uint32_t _stride)
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{
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float min[3], max[3];
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uint8_t* vertex = (uint8_t*)_vertices;
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float position[3];
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vec3MulMtx(position, (float*)vertex, _mtx);
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min[0] = max[0] = position[0];
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min[1] = max[1] = position[1];
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min[2] = max[2] = position[2];
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vertex += _stride;
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for (uint32_t ii = 1; ii < _numVertices; ++ii)
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{
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vec3MulMtx(position, (float*)vertex, _mtx);
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vertex += _stride;
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float xx = position[0];
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float yy = position[1];
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float zz = position[2];
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min[0] = fminf(xx, min[0]);
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min[1] = fminf(yy, min[1]);
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min[2] = fminf(zz, min[2]);
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max[0] = fmaxf(xx, max[0]);
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max[1] = fmaxf(yy, max[1]);
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max[2] = fmaxf(zz, max[2]);
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}
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_aabb.m_min[0] = min[0];
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_aabb.m_min[1] = min[1];
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_aabb.m_min[2] = min[2];
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_aabb.m_max[0] = max[0];
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_aabb.m_max[1] = max[1];
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_aabb.m_max[2] = max[2];
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}
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void calcObb(Obb& _obb, const void* _vertices, uint32_t _numVertices, uint32_t _stride, uint32_t _steps)
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{
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Aabb aabb;
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calcAabb(aabb, _vertices, _numVertices, _stride);
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float minArea = calcAreaAabb(aabb);
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Obb best;
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aabbToObb(best, aabb);
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float angleStep = float(M_PI_2/_steps);
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float ax = 0.0f;
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float mtx[16];
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for (uint32_t ii = 0; ii < _steps; ++ii)
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{
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float ay = 0.0f;
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for (uint32_t jj = 0; jj < _steps; ++jj)
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{
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float az = 0.0f;
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for (uint32_t kk = 0; kk < _steps; ++kk)
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{
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mtxRotateXYZ(mtx, ax, ay, az);
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float mtxT[16];
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mtxTranspose(mtxT, mtx);
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calcAabb(aabb, mtxT, _vertices, _numVertices, _stride);
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float area = calcAreaAabb(aabb);
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if (area < minArea)
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{
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minArea = area;
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aabbTransformToObb(best, aabb, mtx);
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}
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az += angleStep;
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}
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ay += angleStep;
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}
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ax += angleStep;
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}
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memcpy(&_obb, &best, sizeof(Obb) );
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}
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void calcMaxBoundingSphere(Sphere& _sphere, const void* _vertices, uint32_t _numVertices, uint32_t _stride)
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{
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Aabb aabb;
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calcAabb(aabb, _vertices, _numVertices, _stride);
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float center[3];
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center[0] = (aabb.m_min[0] + aabb.m_max[0]) * 0.5f;
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center[1] = (aabb.m_min[1] + aabb.m_max[1]) * 0.5f;
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center[2] = (aabb.m_min[2] + aabb.m_max[2]) * 0.5f;
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float maxDistSq = 0.0f;
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uint8_t* vertex = (uint8_t*)_vertices;
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for (uint32_t ii = 0; ii < _numVertices; ++ii)
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{
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float* position = (float*)vertex;
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vertex += _stride;
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float xx = position[0] - center[0];
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float yy = position[1] - center[1];
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float zz = position[2] - center[2];
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float distSq = xx*xx + yy*yy + zz*zz;
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maxDistSq = fmaxf(distSq, maxDistSq);
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}
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_sphere.m_center[0] = center[0];
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_sphere.m_center[1] = center[1];
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_sphere.m_center[2] = center[2];
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_sphere.m_radius = sqrtf(maxDistSq);
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}
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void calcMinBoundingSphere(Sphere& _sphere, const void* _vertices, uint32_t _numVertices, uint32_t _stride, float _step)
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{
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bx::RngMwc rng;
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uint8_t* vertex = (uint8_t*)_vertices;
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float center[3];
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float* position = (float*)&vertex[0];
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center[0] = position[0];
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center[1] = position[1];
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center[2] = position[2];
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position = (float*)&vertex[1*_stride];
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center[0] += position[0];
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center[1] += position[1];
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center[2] += position[2];
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center[0] *= 0.5f;
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center[1] *= 0.5f;
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center[2] *= 0.5f;
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float xx = position[0] - center[0];
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float yy = position[1] - center[1];
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float zz = position[2] - center[2];
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float maxDistSq = xx*xx + yy*yy + zz*zz;
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float radiusStep = _step * 0.37f;
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bool done;
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do
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{
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done = true;
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for (uint32_t ii = 0, index = rng.gen()%_numVertices; ii < _numVertices; ++ii, index = (index + 1)%_numVertices)
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{
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position = (float*)&vertex[index*_stride];
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float xx = position[0] - center[0];
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float yy = position[1] - center[1];
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float zz = position[2] - center[2];
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float distSq = xx*xx + yy*yy + zz*zz;
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if (distSq > maxDistSq)
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{
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done = false;
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center[0] += xx * radiusStep;
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center[1] += yy * radiusStep;
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center[2] += zz * radiusStep;
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maxDistSq = flerp(maxDistSq, distSq, _step);
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break;
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}
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}
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} while (!done);
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_sphere.m_center[0] = center[0];
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_sphere.m_center[1] = center[1];
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_sphere.m_center[2] = center[2];
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_sphere.m_radius = sqrtf(maxDistSq);
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}
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