bgfx/examples/common/bounds.cpp
2019-01-03 22:03:42 -08:00

843 lines
19 KiB
C++

/*
* Copyright 2011-2018 Branimir Karadzic. All rights reserved.
* License: https://github.com/bkaradzic/bgfx#license-bsd-2-clause
*/
#include <bx/rng.h>
#include <bx/math.h>
#include "bounds.h"
void aabbToObb(Obb& _obb, const Aabb& _aabb)
{
bx::memSet(_obb.m_mtx, 0, sizeof(_obb.m_mtx) );
_obb.m_mtx[ 0] = (_aabb.m_max.x - _aabb.m_min.x) * 0.5f;
_obb.m_mtx[ 5] = (_aabb.m_max.y - _aabb.m_min.y) * 0.5f;
_obb.m_mtx[10] = (_aabb.m_max.z - _aabb.m_min.z) * 0.5f;
_obb.m_mtx[12] = (_aabb.m_min.x + _aabb.m_max.x) * 0.5f;
_obb.m_mtx[13] = (_aabb.m_min.y + _aabb.m_max.y) * 0.5f;
_obb.m_mtx[14] = (_aabb.m_min.z + _aabb.m_max.z) * 0.5f;
_obb.m_mtx[15] = 1.0f;
}
void toAabb(Aabb& _aabb, const Obb& _obb)
{
bx::Vec3 xyz = { 1.0f, 1.0f, 1.0f };
bx::Vec3 tmp = bx::mul(xyz, _obb.m_mtx);
_aabb.m_min = tmp;
_aabb.m_max = tmp;
for (uint32_t ii = 1; ii < 8; ++ii)
{
xyz.x = ii & 1 ? -1.0f : 1.0f;
xyz.y = ii & 2 ? -1.0f : 1.0f;
xyz.z = ii & 4 ? -1.0f : 1.0f;
tmp = bx::mul(xyz, _obb.m_mtx);
_aabb.m_min = bx::min(_aabb.m_min, tmp);
_aabb.m_max = bx::max(_aabb.m_max, tmp);
}
}
void toAabb(Aabb& _aabb, const Sphere& _sphere)
{
const float radius = _sphere.m_radius;
_aabb.m_min = bx::sub(_sphere.m_center, radius);
_aabb.m_max = bx::add(_sphere.m_center, radius);
}
void toAabb(Aabb& _aabb, const Disk& _disk)
{
// Reference(s):
// - https://web.archive.org/web/20181113055756/http://iquilezles.org/www/articles/diskbbox/diskbbox.htm
//
const bx::Vec3 nsq = bx::mul(_disk.m_normal, _disk.m_normal);
const bx::Vec3 one = { 1.0f, 1.0f, 1.0f };
const bx::Vec3 tmp = bx::sub(one, nsq);
const float inv = 1.0f / (tmp.x*tmp.y*tmp.z);
const bx::Vec3 extent =
{
_disk.m_radius * tmp.x * bx::sqrt((nsq.x + nsq.y * nsq.z) * inv),
_disk.m_radius * tmp.y * bx::sqrt((nsq.y + nsq.z * nsq.x) * inv),
_disk.m_radius * tmp.z * bx::sqrt((nsq.z + nsq.x * nsq.y) * inv),
};
_aabb.m_min = bx::sub(_disk.m_center, extent);
_aabb.m_max = bx::add(_disk.m_center, extent);
}
void toAabb(Aabb& _aabb, const Cylinder& _cylinder)
{
// Reference(s):
// - https://web.archive.org/web/20181113055756/http://iquilezles.org/www/articles/diskbbox/diskbbox.htm
//
const bx::Vec3 axis = bx::sub(_cylinder.m_end, _cylinder.m_pos);
const bx::Vec3 asq = bx::mul(axis, axis);
const bx::Vec3 nsq = bx::mul(asq, 1.0f/bx::dot(axis, axis) );
const bx::Vec3 one = { 1.0f, 1.0f, 1.0f };
const bx::Vec3 tmp = bx::sub(one, nsq);
const float inv = 1.0f / (tmp.x*tmp.y*tmp.z);
const bx::Vec3 extent =
{
_cylinder.m_radius * tmp.x * bx::sqrt( (nsq.x + nsq.y * nsq.z) * inv),
_cylinder.m_radius * tmp.y * bx::sqrt( (nsq.y + nsq.z * nsq.x) * inv),
_cylinder.m_radius * tmp.z * bx::sqrt( (nsq.z + nsq.x * nsq.y) * inv),
};
const bx::Vec3 minP = bx::sub(_cylinder.m_pos, extent);
const bx::Vec3 minE = bx::sub(_cylinder.m_end, extent);
const bx::Vec3 maxP = bx::add(_cylinder.m_pos, extent);
const bx::Vec3 maxE = bx::add(_cylinder.m_end, extent);
_aabb.m_min = bx::min(minP, minE);
_aabb.m_max = bx::max(maxP, maxE);
}
void aabbTransformToObb(Obb& _obb, const Aabb& _aabb, const float* _mtx)
{
aabbToObb(_obb, _aabb);
float result[16];
bx::mtxMul(result, _obb.m_mtx, _mtx);
bx::memCopy(_obb.m_mtx, result, sizeof(result) );
}
void toAabb(Aabb& _aabb, const void* _vertices, uint32_t _numVertices, uint32_t _stride)
{
bx::Vec3 min, max;
uint8_t* vertex = (uint8_t*)_vertices;
float* position = (float*)vertex;
min.x = max.x = position[0];
min.y = max.y = position[1];
min.z = max.z = position[2];
vertex += _stride;
for (uint32_t ii = 1; ii < _numVertices; ++ii)
{
position = (float*)vertex;
vertex += _stride;
bx::Vec3 pos =
{
position[0],
position[1],
position[2],
};
min = bx::min(pos, min);
max = bx::max(pos, max);
}
_aabb.m_min = min;
_aabb.m_max = max;
}
void toAabb(Aabb& _aabb, const float* _mtx, const void* _vertices, uint32_t _numVertices, uint32_t _stride)
{
bx::Vec3 min, max;
uint8_t* vertex = (uint8_t*)_vertices;
min = max = bx::mul(bx::load<bx::Vec3>(vertex), _mtx);
vertex += _stride;
for (uint32_t ii = 1; ii < _numVertices; ++ii)
{
bx::Vec3 pos = bx::mul(bx::load<bx::Vec3>(vertex), _mtx);
vertex += _stride;
min = bx::min(pos, min);
max = bx::max(pos, max);
}
_aabb.m_min = min;
_aabb.m_max = max;
}
float calcAreaAabb(const Aabb& _aabb)
{
const float ww = _aabb.m_max.x - _aabb.m_min.x;
const float hh = _aabb.m_max.y - _aabb.m_min.y;
const float dd = _aabb.m_max.z - _aabb.m_min.z;
return 2.0f * (ww*hh + ww*dd + hh*dd);
}
void aabbExpand(Aabb& _aabb, float _factor)
{
_aabb.m_min.x -= _factor;
_aabb.m_min.y -= _factor;
_aabb.m_min.z -= _factor;
_aabb.m_max.x += _factor;
_aabb.m_max.y += _factor;
_aabb.m_max.z += _factor;
}
void aabbExpand(Aabb& _aabb, const float* _pos)
{
const bx::Vec3 pos = { _pos[0], _pos[1], _pos[2] };
_aabb.m_min = bx::min(_aabb.m_min, pos);
_aabb.m_max = bx::max(_aabb.m_max, pos);
}
uint32_t aabbOverlapTest(const Aabb& _aabb0, const Aabb& _aabb1)
{
const uint32_t ltMinX = _aabb0.m_max.x < _aabb1.m_min.x;
const uint32_t gtMaxX = _aabb0.m_min.x > _aabb1.m_max.x;
const uint32_t ltMinY = _aabb0.m_max.y < _aabb1.m_min.y;
const uint32_t gtMaxY = _aabb0.m_min.y > _aabb1.m_max.y;
const uint32_t ltMinZ = _aabb0.m_max.z < _aabb1.m_min.z;
const uint32_t gtMaxZ = _aabb0.m_min.z > _aabb1.m_max.z;
return 0
| (ltMinX<<0)
| (gtMaxX<<1)
| (ltMinY<<2)
| (gtMaxY<<3)
| (ltMinZ<<4)
| (gtMaxZ<<5)
;
}
void calcObb(Obb& _obb, const void* _vertices, uint32_t _numVertices, uint32_t _stride, uint32_t _steps)
{
Aabb aabb;
toAabb(aabb, _vertices, _numVertices, _stride);
float minArea = calcAreaAabb(aabb);
Obb best;
aabbToObb(best, aabb);
float angleStep = float(bx::kPiHalf/_steps);
float ax = 0.0f;
float mtx[16];
for (uint32_t ii = 0; ii < _steps; ++ii)
{
float ay = 0.0f;
for (uint32_t jj = 0; jj < _steps; ++jj)
{
float az = 0.0f;
for (uint32_t kk = 0; kk < _steps; ++kk)
{
bx::mtxRotateXYZ(mtx, ax, ay, az);
float mtxT[16];
bx::mtxTranspose(mtxT, mtx);
toAabb(aabb, mtxT, _vertices, _numVertices, _stride);
float area = calcAreaAabb(aabb);
if (area < minArea)
{
minArea = area;
aabbTransformToObb(best, aabb, mtx);
}
az += angleStep;
}
ay += angleStep;
}
ax += angleStep;
}
bx::memCopy(&_obb, &best, sizeof(Obb) );
}
void calcMaxBoundingSphere(Sphere& _sphere, const void* _vertices, uint32_t _numVertices, uint32_t _stride)
{
Aabb aabb;
toAabb(aabb, _vertices, _numVertices, _stride);
bx::Vec3 center =
{
(aabb.m_min.x + aabb.m_max.x) * 0.5f,
(aabb.m_min.y + aabb.m_max.y) * 0.5f,
(aabb.m_min.z + aabb.m_max.z) * 0.5f,
};
float maxDistSq = 0.0f;
uint8_t* vertex = (uint8_t*)_vertices;
for (uint32_t ii = 0; ii < _numVertices; ++ii)
{
float* position = (float*)vertex;
vertex += _stride;
const float xx = position[0] - center.x;
const float yy = position[1] - center.y;
const float zz = position[2] - center.z;
const float distSq = xx*xx + yy*yy + zz*zz;
maxDistSq = bx::max(distSq, maxDistSq);
}
_sphere.m_center = center;
_sphere.m_radius = bx::sqrt(maxDistSq);
}
void calcMinBoundingSphere(Sphere& _sphere, const void* _vertices, uint32_t _numVertices, uint32_t _stride, float _step)
{
bx::RngMwc rng;
uint8_t* vertex = (uint8_t*)_vertices;
bx::Vec3 center;
float* position = (float*)&vertex[0];
center.x = position[0];
center.y = position[1];
center.z = position[2];
position = (float*)&vertex[1*_stride];
center.x += position[0];
center.y += position[1];
center.z += position[2];
center.x *= 0.5f;
center.y *= 0.5f;
center.z *= 0.5f;
float xx = position[0] - center.x;
float yy = position[1] - center.y;
float zz = position[2] - center.z;
float maxDistSq = xx*xx + yy*yy + zz*zz;
float radiusStep = _step * 0.37f;
bool done;
do
{
done = true;
for (uint32_t ii = 0, index = rng.gen()%_numVertices; ii < _numVertices; ++ii, index = (index + 1)%_numVertices)
{
position = (float*)&vertex[index*_stride];
xx = position[0] - center.x;
yy = position[1] - center.y;
zz = position[2] - center.z;
float distSq = xx*xx + yy*yy + zz*zz;
if (distSq > maxDistSq)
{
done = false;
center.x += xx * radiusStep;
center.y += yy * radiusStep;
center.z += zz * radiusStep;
maxDistSq = bx::lerp(maxDistSq, distSq, _step);
break;
}
}
} while (!done);
_sphere.m_center = center;
_sphere.m_radius = bx::sqrt(maxDistSq);
}
void buildFrustumPlanes(bx::Plane* _result, const float* _viewProj)
{
const float xw = _viewProj[ 3];
const float yw = _viewProj[ 7];
const float zw = _viewProj[11];
const float ww = _viewProj[15];
const float xz = _viewProj[ 2];
const float yz = _viewProj[ 6];
const float zz = _viewProj[10];
const float wz = _viewProj[14];
bx::Plane& near = _result[0];
bx::Plane& far = _result[1];
bx::Plane& left = _result[2];
bx::Plane& right = _result[3];
bx::Plane& top = _result[4];
bx::Plane& bottom = _result[5];
near.normal.x = xw - xz;
near.normal.y = yw - yz;
near.normal.z = zw - zz;
near.dist = ww - wz;
far.normal.x = xw + xz;
far.normal.y = yw + yz;
far.normal.z = zw + zz;
far.dist = ww + wz;
const float xx = _viewProj[ 0];
const float yx = _viewProj[ 4];
const float zx = _viewProj[ 8];
const float wx = _viewProj[12];
left.normal.x = xw - xx;
left.normal.y = yw - yx;
left.normal.z = zw - zx;
left.dist = ww - wx;
right.normal.x = xw + xx;
right.normal.y = yw + yx;
right.normal.z = zw + zx;
right.dist = ww + wx;
const float xy = _viewProj[ 1];
const float yy = _viewProj[ 5];
const float zy = _viewProj[ 9];
const float wy = _viewProj[13];
top.normal.x = xw + xy;
top.normal.y = yw + yy;
top.normal.z = zw + zy;
top.dist = ww + wy;
bottom.normal.x = xw - xy;
bottom.normal.y = yw - yy;
bottom.normal.z = zw - zy;
bottom.dist = ww - wy;
bx::Plane* plane = _result;
for (uint32_t ii = 0; ii < 6; ++ii)
{
const float len = bx::length(plane->normal);
plane->normal = bx::normalize(plane->normal);
float invLen = 1.0f / len;
plane->dist *= invLen;
++plane;
}
}
bx::Vec3 intersectPlanes(const bx::Plane& _pa, const bx::Plane& _pb, const bx::Plane& _pc)
{
const bx::Vec3 axb = bx::cross(_pa.normal, _pb.normal);
const bx::Vec3 bxc = bx::cross(_pb.normal, _pc.normal);
const bx::Vec3 cxa = bx::cross(_pc.normal, _pa.normal);
const bx::Vec3 tmp0 = bx::mul(bxc, _pa.dist);
const bx::Vec3 tmp1 = bx::mul(cxa, _pb.dist);
const bx::Vec3 tmp2 = bx::mul(axb, _pc.dist);
const bx::Vec3 tmp3 = bx::add(tmp0, tmp1);
const bx::Vec3 tmp4 = bx::add(tmp3, tmp2);
const float denom = bx::dot(_pa.normal, bxc);
const bx::Vec3 result = bx::mul(tmp4, -1.0f/denom);
return result;
}
Ray makeRay(float _x, float _y, const float* _invVp)
{
Ray ray;
const bx::Vec3 near = { _x, _y, 0.0f };
ray.m_pos = bx::mulH(near, _invVp);
const bx::Vec3 far = { _x, _y, 1.0f };
bx::Vec3 tmp = bx::mulH(far, _invVp);
const bx::Vec3 dir = bx::sub(tmp, ray.m_pos);
ray.m_dir = bx::normalize(dir);
return ray;
}
inline bx::Vec3 getPointAt(const Ray& _ray, float _t)
{
return bx::add(bx::mul(_ray.m_dir, _t), _ray.m_pos);
}
bool intersect(const Ray& _ray, const Aabb& _aabb, Hit* _hit)
{
const bx::Vec3 invDir = bx::rcp(_ray.m_dir);
const bx::Vec3 tmp0 = bx::sub(_aabb.m_min, _ray.m_pos);
const bx::Vec3 t0 = bx::mul(tmp0, invDir);
const bx::Vec3 tmp1 = bx::sub(_aabb.m_max, _ray.m_pos);
const bx::Vec3 t1 = bx::mul(tmp1, invDir);
const bx::Vec3 min = bx::min(t0, t1);
const bx::Vec3 max = bx::max(t0, t1);
const float tmin = bx::max(min.x, min.y, min.z);
const float tmax = bx::min(max.x, max.y, max.z);
if (tmax < 0.0f
|| tmin > tmax)
{
return false;
}
if (NULL != _hit)
{
_hit->m_normal.x = float( (t1.x == tmin) - (t0.x == tmin) );
_hit->m_normal.y = float( (t1.y == tmin) - (t0.y == tmin) );
_hit->m_normal.z = float( (t1.z == tmin) - (t0.z == tmin) );
_hit->m_dist = tmin;
_hit->m_pos = getPointAt(_ray, tmin);
}
return true;
}
static const Aabb s_kUnitAabb =
{
{ -1.0f, -1.0f, -1.0f },
{ 1.0f, 1.0f, 1.0f },
};
bool intersect(const Ray& _ray, const Obb& _obb, Hit* _hit)
{
Aabb aabb;
toAabb(aabb, _obb);
if (!intersect(_ray, aabb) )
{
return false;
}
float mtxInv[16];
bx::mtxInverse(mtxInv, _obb.m_mtx);
Ray obbRay;
obbRay.m_pos = bx::mul(_ray.m_pos, mtxInv);
obbRay.m_dir = bx::mulXyz0(_ray.m_dir, mtxInv);
if (intersect(obbRay, s_kUnitAabb, _hit) )
{
if (NULL != _hit)
{
_hit->m_pos = bx::mul(_hit->m_pos, _obb.m_mtx);
const bx::Vec3 tmp = bx::mulXyz0(_hit->m_normal, _obb.m_mtx);
_hit->m_normal = bx::normalize(tmp);
}
return true;
}
return false;
}
bool intersect(const Ray& _ray, const Disk& _disk, Hit* _hit)
{
bx::Plane plane;
plane.normal = _disk.m_normal;
plane.dist = -bx::dot(_disk.m_center, _disk.m_normal);
Hit tmpHit;
_hit = NULL != _hit ? _hit : &tmpHit;
if (intersect(_ray, plane, _hit) )
{
const bx::Vec3 tmp = bx::sub(_disk.m_center, _hit->m_pos);
return bx::dot(tmp, tmp) <= bx::square(_disk.m_radius);
}
return false;
}
static bool intersect(const Ray& _ray, const Cylinder& _cylinder, bool _capsule, Hit* _hit)
{
bx::Vec3 axis = bx::sub(_cylinder.m_end, _cylinder.m_pos);
const bx::Vec3 rc = bx::sub(_ray.m_pos, _cylinder.m_pos);
const bx::Vec3 dxa = bx::cross(_ray.m_dir, axis);
const float len = bx::length(dxa);
const bx::Vec3 normal = bx::normalize(dxa);
const float dist = bx::abs(bx::dot(rc, normal) );
if (dist > _cylinder.m_radius)
{
return false;
}
bx::Vec3 vo = bx::cross(rc, axis);
const float t0 = -bx::dot(vo, normal) / len;
vo = bx::normalize(bx::cross(normal, axis) );
const float rsq = bx::square(_cylinder.m_radius);
const float ddoto = bx::dot(_ray.m_dir, vo);
const float ss = t0 - bx::abs(bx::sqrt(rsq - bx::square(dist) ) / ddoto);
if (0.0f > ss)
{
return false;
}
const bx::Vec3 point = getPointAt(_ray, ss);
const float axisLen = bx::length(axis);
axis = bx::normalize(axis);
const float pdota = bx::dot(_cylinder.m_pos, axis);
const float height = bx::dot(point, axis) - pdota;
if (height > 0.0f
&& height < axisLen)
{
if (NULL != _hit)
{
const float t1 = height / axisLen;
const bx::Vec3 pointOnAxis = bx::lerp(_cylinder.m_pos, _cylinder.m_end, t1);
_hit->m_pos = point;
const bx::Vec3 tmp = bx::sub(point, pointOnAxis);
_hit->m_normal = bx::normalize(tmp);
_hit->m_dist = ss;
}
return true;
}
if (_capsule)
{
const float rdota = bx::dot(_ray.m_pos, axis);
const float pp = rdota - pdota;
const float t1 = pp / axisLen;
const bx::Vec3 pointOnAxis = bx::lerp(_cylinder.m_pos, _cylinder.m_end, t1);
const bx::Vec3 axisToRay = bx::sub(_ray.m_pos, pointOnAxis);
if (_cylinder.m_radius < bx::length(axisToRay)
&& 0.0f > ss)
{
return false;
}
Sphere sphere;
sphere.m_radius = _cylinder.m_radius;
sphere.m_center = 0.0f >= height
? _cylinder.m_pos
: _cylinder.m_end
;
return intersect(_ray, sphere, _hit);
}
bx::Plane plane;
bx::Vec3 pos;
if (0.0f >= height)
{
plane.normal = bx::neg(axis);
pos = _cylinder.m_pos;
}
else
{
plane.normal = axis;
pos = _cylinder.m_end;
}
plane.dist = -bx::dot(pos, plane.normal);
Hit tmpHit;
_hit = NULL != _hit ? _hit : &tmpHit;
if (intersect(_ray, plane, _hit) )
{
const bx::Vec3 tmp = bx::sub(pos, _hit->m_pos);
return bx::dot(tmp, tmp) <= rsq;
}
return false;
}
bool intersect(const Ray& _ray, const Cylinder& _cylinder, Hit* _hit)
{
return intersect(_ray, _cylinder, false, _hit);
}
bool intersect(const Ray& _ray, const Capsule& _capsule, Hit* _hit)
{
BX_STATIC_ASSERT(sizeof(Capsule) == sizeof(Cylinder) );
return intersect(_ray, *( (const Cylinder*)&_capsule), true, _hit);
}
bool intersect(const Ray& _ray, const Cone& _cone, Hit* _hit)
{
const bx::Vec3 axis = bx::sub(_cone.m_pos, _cone.m_end);
const float len = bx::length(axis);
const bx::Vec3 normal = bx::normalize(axis);
Disk disk;
disk.m_center = _cone.m_pos;
disk.m_normal = normal;
disk.m_radius = _cone.m_radius;
Hit tmpInt;
Hit* out = NULL != _hit ? _hit : &tmpInt;
bool hit = intersect(_ray, disk, out);
const bx::Vec3 ro = bx::sub(_ray.m_pos, _cone.m_end);
const float hyp = bx::sqrt(bx::square(_cone.m_radius) + bx::square(len) );
const float cosaSq = bx::square(len/hyp);
const float ndoto = bx::dot(normal, ro);
const float ndotd = bx::dot(normal, _ray.m_dir);
const float aa = bx::square(ndotd) - cosaSq;
const float bb = 2.0f * (ndotd*ndoto - bx::dot(_ray.m_dir, ro)*cosaSq);
const float cc = bx::square(ndoto) - bx::dot(ro, ro)*cosaSq;
float det = bb*bb - 4.0f*aa*cc;
if (0.0f > det)
{
return hit;
}
det = bx::sqrt(det);
const float invA2 = 1.0f / (2.0f*aa);
const float t1 = (-bb - det) * invA2;
const float t2 = (-bb + det) * invA2;
float tt = t1;
if (0.0f > t1
|| (0.0f < t2 && t2 < t1) )
{
tt = t2;
}
if (0.0f > tt)
{
return hit;
}
const bx::Vec3 hitPos = getPointAt(_ray, tt);
const bx::Vec3 point = bx::sub(hitPos, _cone.m_end);
const float hh = bx::dot(normal, point);
if (0.0f > hh
|| len < hh)
{
return hit;
}
if (NULL != _hit)
{
if (!hit
|| tt < _hit->m_dist)
{
_hit->m_dist = tt;
_hit->m_pos = hitPos;
const float scale = hh / bx::dot(point, point);
const bx::Vec3 pointScaled = bx::mul(point, scale);
const bx::Vec3 tmp = bx::sub(pointScaled, normal);
_hit->m_normal = bx::normalize(tmp);
}
}
return true;
}
bool intersect(const Ray& _ray, const bx::Plane& _plane, Hit* _hit)
{
float equation = bx::dot(_ray.m_pos, _plane.normal) + _plane.dist;
if (0.0f > equation)
{
return false;
}
float ndotd = bx::dot(_ray.m_dir, _plane.normal);
if (0.0f < ndotd)
{
return false;
}
if (NULL != _hit)
{
_hit->m_normal = _plane.normal;
float tt = -equation/ndotd;
_hit->m_dist = tt;
_hit->m_pos = getPointAt(_ray, tt);
}
return true;
}
bool intersect(const Ray& _ray, const Sphere& _sphere, Hit* _hit)
{
const bx::Vec3 rs = bx::sub(_ray.m_pos, _sphere.m_center);
const float bb = bx::dot(rs, _ray.m_dir);
if (0.0f < bb)
{
return false;
}
const float aa = bx::dot(_ray.m_dir, _ray.m_dir);
const float cc = bx::dot(rs, rs) - bx::square(_sphere.m_radius);
const float discriminant = bb*bb - aa*cc;
if (0.0f >= discriminant)
{
return false;
}
const float sqrtDiscriminant = bx::sqrt(discriminant);
const float invA = 1.0f / aa;
const float tt = -(bb + sqrtDiscriminant)*invA;
if (0.0f >= tt)
{
return false;
}
if (NULL != _hit)
{
_hit->m_dist = tt;
const bx::Vec3 point = getPointAt(_ray, tt);
_hit->m_pos = point;
const bx::Vec3 tmp = bx::sub(point, _sphere.m_center);
_hit->m_normal = bx::normalize(tmp);
}
return true;
}
bool intersect(const Ray& _ray, const Tris& _triangle, Hit* _hit)
{
const bx::Vec3 edge10 = bx::sub(_triangle.m_v1, _triangle.m_v0);
const bx::Vec3 edge02 = bx::sub(_triangle.m_v0, _triangle.m_v2);
const bx::Vec3 normal = bx::cross(edge02, edge10);
const bx::Vec3 vo = bx::sub(_triangle.m_v0, _ray.m_pos);
const bx::Vec3 dxo = bx::cross(_ray.m_dir, vo);
const float det = bx::dot(normal, _ray.m_dir);
if (det > 0.0f)
{
return false;
}
const float invDet = 1.0f/det;
const float bz = bx::dot(dxo, edge02) * invDet;
const float by = bx::dot(dxo, edge10) * invDet;
const float bx = 1.0f - by - bz;
if (bx < 0.0f || by < 0.0f || bz < 0.0f)
{
return false;
}
if (NULL != _hit)
{
_hit->m_normal = bx::normalize(normal);
const float tt = bx::dot(normal, vo) * invDet;
_hit->m_dist = tt;
_hit->m_pos = getPointAt(_ray, tt);
}
return true;
}