You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
227 lines
7.1 KiB
C++
227 lines
7.1 KiB
C++
/********************************************************/
|
|
/* AABB-triangle overlap test code */
|
|
/* by Tomas Akenine-Möller */
|
|
/* Function: int triBoxOverlap(float boxcenter[3], */
|
|
/* float boxhalfsize[3],float triverts[3][3]); */
|
|
/* History: */
|
|
/* 2001-03-05: released the code in its first version */
|
|
/* 2001-06-18: changed the order of the tests, faster */
|
|
/* */
|
|
/* Acknowledgement: Many thanks to Pierre Terdiman for */
|
|
/* suggestions and discussions on how to optimize code. */
|
|
/* Thanks to David Hunt for finding a ">="-bug! */
|
|
/********************************************************/
|
|
|
|
#include <nvmath/Vector.h>
|
|
#include <nvmath/Triangle.h>
|
|
|
|
using namespace nv;
|
|
|
|
#define X 0
|
|
#define Y 1
|
|
#define Z 2
|
|
|
|
#define FINDMINMAX(x0,x1,x2,min,max) \
|
|
min = max = x0; \
|
|
if(x1<min) min=x1;\
|
|
if(x1>max) max=x1;\
|
|
if(x2<min) min=x2;\
|
|
if(x2>max) max=x2;
|
|
|
|
|
|
static bool planeBoxOverlap(Vector3::Arg normal, Vector3::Arg vert, Vector3::Arg maxbox) // -NJMP-
|
|
{
|
|
Vector3 vmin, vmax;
|
|
|
|
float signs[3] = {1, 1, 1};
|
|
if (normal.x() <= 0.0f) signs[0] = -1;
|
|
if (normal.y() <= 0.0f) signs[1] = -1;
|
|
if (normal.z() <= 0.0f) signs[2] = -1;
|
|
|
|
Vector3 sign(signs[0], signs[1], signs[2]);
|
|
vmin = -scale(sign, maxbox) - vert;
|
|
vmax = scale(sign, maxbox) - vert;
|
|
|
|
if (dot(normal, vmin) > 0.0f) return false;
|
|
if (dot(normal, vmax) >= 0.0f) return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
|
|
/*======================== X-tests ========================*/
|
|
#define AXISTEST_X01(a, b, fa, fb) \
|
|
p0 = a*v0.y() - b*v0.z(); \
|
|
p2 = a*v2.y() - b*v2.z(); \
|
|
if(p0<p2) {min=p0; max=p2;} else {min=p2; max=p0;} \
|
|
rad = fa * boxhalfsize.y() + fb * boxhalfsize.z(); \
|
|
if(min>rad || max<-rad) return false;
|
|
|
|
#define AXISTEST_X2(a, b, fa, fb) \
|
|
p0 = a*v0.y() - b*v0.z(); \
|
|
p1 = a*v1.y() - b*v1.z(); \
|
|
if(p0<p1) {min=p0; max=p1;} else {min=p1; max=p0;} \
|
|
rad = fa * boxhalfsize.y() + fb * boxhalfsize.z(); \
|
|
if(min>rad || max<-rad) return false;
|
|
|
|
/*======================== Y-tests ========================*/
|
|
#define AXISTEST_Y02(a, b, fa, fb) \
|
|
p0 = -a*v0.x() + b*v0.z(); \
|
|
p2 = -a*v2.x() + b*v2.z(); \
|
|
if(p0<p2) {min=p0; max=p2;} else {min=p2; max=p0;} \
|
|
rad = fa * boxhalfsize.x() + fb * boxhalfsize.z(); \
|
|
if(min>rad || max<-rad) return false;
|
|
|
|
#define AXISTEST_Y1(a, b, fa, fb) \
|
|
p0 = -a*v0.x() + b*v0.z(); \
|
|
p1 = -a*v1.x() + b*v1.z(); \
|
|
if(p0<p1) {min=p0; max=p1;} else {min=p1; max=p0;} \
|
|
rad = fa * boxhalfsize.x() + fb * boxhalfsize.z(); \
|
|
if(min>rad || max<-rad) return false;
|
|
|
|
/*======================== Z-tests ========================*/
|
|
|
|
#define AXISTEST_Z12(a, b, fa, fb) \
|
|
p1 = a*v1.x() - b*v1.y(); \
|
|
p2 = a*v2.x() - b*v2.y(); \
|
|
if(p2<p1) {min=p2; max=p1;} else {min=p1; max=p2;} \
|
|
rad = fa * boxhalfsize.x() + fb * boxhalfsize.y(); \
|
|
if(min>rad || max<-rad) return false;
|
|
|
|
#define AXISTEST_Z0(a, b, fa, fb) \
|
|
p0 = a*v0.x() - b*v0.y(); \
|
|
p1 = a*v1.x() - b*v1.y(); \
|
|
if(p0<p1) {min=p0; max=p1;} else {min=p1; max=p0;} \
|
|
rad = fa * boxhalfsize.x() + fb * boxhalfsize.y(); \
|
|
if(min>rad || max<-rad) return false;
|
|
|
|
|
|
bool nv::triBoxOverlap(Vector3::Arg boxcenter, Vector3::Arg boxhalfsize, const Triangle & tri)
|
|
{
|
|
// use separating axis theorem to test overlap between triangle and box
|
|
// need to test for overlap in these directions:
|
|
// 1) the {x,y,z}-directions (actually, since we use the AABB of the triangle
|
|
// we do not even need to test these)
|
|
// 2) normal of the triangle
|
|
// 3) crossproduct(edge from tri, {x,y,z}-directin)
|
|
// this gives 3x3=9 more tests
|
|
Vector3 v0, v1, v2;
|
|
float min, max, p0, p1, p2, rad, fex, fey, fez;
|
|
Vector3 normal, e0, e1, e2;
|
|
|
|
// This is the fastest branch on Sun.
|
|
// move everything so that the boxcenter is in (0,0,0)
|
|
v0 = tri.v[0] - boxcenter;
|
|
v1 = tri.v[1] - boxcenter;
|
|
v2 = tri.v[2] - boxcenter;
|
|
|
|
// Compute triangle edges.
|
|
e0 = v1 - v0; // tri edge 0
|
|
e1 = v2 - v1; // tri edge 1
|
|
e2 = v0 - v2; // tri edge 2
|
|
|
|
// Bullet 3:
|
|
// test the 9 tests first (this was faster)
|
|
fex = fabsf(e0.x());
|
|
fey = fabsf(e0.y());
|
|
fez = fabsf(e0.z());
|
|
AXISTEST_X01(e0.z(), e0.y(), fez, fey);
|
|
AXISTEST_Y02(e0.z(), e0.x(), fez, fex);
|
|
AXISTEST_Z12(e0.y(), e0.x(), fey, fex);
|
|
|
|
fex = fabsf(e1.x());
|
|
fey = fabsf(e1.y());
|
|
fez = fabsf(e1.z());
|
|
AXISTEST_X01(e1.z(), e1.y(), fez, fey);
|
|
AXISTEST_Y02(e1.z(), e1.x(), fez, fex);
|
|
AXISTEST_Z0(e1.y(), e1.x(), fey, fex);
|
|
|
|
fex = fabsf(e2.x());
|
|
fey = fabsf(e2.y());
|
|
fez = fabsf(e2.z());
|
|
AXISTEST_X2(e2.z(), e2.y(), fez, fey);
|
|
AXISTEST_Y1(e2.z(), e2.x(), fez, fex);
|
|
AXISTEST_Z12(e2.y(), e2.x(), fey, fex);
|
|
|
|
// Bullet 1:
|
|
// first test overlap in the {x,y,z}-directions
|
|
// find min, max of the triangle each direction, and test for overlap in
|
|
// that direction -- this is equivalent to testing a minimal AABB around
|
|
// the triangle against the AABB
|
|
|
|
// test in X-direction
|
|
FINDMINMAX(v0.x(), v1.x(), v2.x(), min, max);
|
|
if(min > boxhalfsize.x() || max < -boxhalfsize.x()) return false;
|
|
|
|
// test in Y-direction
|
|
FINDMINMAX(v0.y(), v1.y(), v2.y(), min, max);
|
|
if(min > boxhalfsize.y() || max < -boxhalfsize.y()) return false;
|
|
|
|
// test in Z-direction
|
|
FINDMINMAX(v0.z(), v1.z(), v2.z(), min, max);
|
|
if(min > boxhalfsize.z() || max < -boxhalfsize.z()) return false;
|
|
|
|
// Bullet 2:
|
|
// test if the box intersects the plane of the triangle
|
|
// compute plane equation of triangle: normal*x+d=0
|
|
normal = cross(e0, e1);
|
|
|
|
return planeBoxOverlap(normal, v0, boxhalfsize);
|
|
}
|
|
|
|
|
|
bool nv::triBoxOverlapNoBounds(Vector3::Arg boxcenter, Vector3::Arg boxhalfsize, const Triangle & tri)
|
|
{
|
|
// use separating axis theorem to test overlap between triangle and box
|
|
// need to test for overlap in these directions:
|
|
// 1) the {x,y,z}-directions (actually, since we use the AABB of the triangle
|
|
// we do not even need to test these)
|
|
// 2) normal of the triangle
|
|
// 3) crossproduct(edge from tri, {x,y,z}-directin)
|
|
// this gives 3x3=9 more tests
|
|
Vector3 v0, v1, v2;
|
|
float min, max, p0, p1, p2, rad, fex, fey, fez;
|
|
Vector3 normal, e0, e1, e2;
|
|
|
|
// This is the fastest branch on Sun.
|
|
// move everything so that the boxcenter is in (0,0,0)
|
|
v0 = tri.v[0] - boxcenter;
|
|
v1 = tri.v[1] - boxcenter;
|
|
v2 = tri.v[2] - boxcenter;
|
|
|
|
// Compute triangle edges.
|
|
e0 = v1 - v0; // tri edge 0
|
|
e1 = v2 - v1; // tri edge 1
|
|
e2 = v0 - v2; // tri edge 2
|
|
|
|
// Bullet 3:
|
|
// test the 9 tests first (this was faster)
|
|
fex = fabsf(e0.x());
|
|
fey = fabsf(e0.y());
|
|
fez = fabsf(e0.z());
|
|
AXISTEST_X01(e0.z(), e0.y(), fez, fey);
|
|
AXISTEST_Y02(e0.z(), e0.x(), fez, fex);
|
|
AXISTEST_Z12(e0.y(), e0.x(), fey, fex);
|
|
|
|
fex = fabsf(e1.x());
|
|
fey = fabsf(e1.y());
|
|
fez = fabsf(e1.z());
|
|
AXISTEST_X01(e1.z(), e1.y(), fez, fey);
|
|
AXISTEST_Y02(e1.z(), e1.x(), fez, fex);
|
|
AXISTEST_Z0(e1.y(), e1.x(), fey, fex);
|
|
|
|
fex = fabsf(e2.x());
|
|
fey = fabsf(e2.y());
|
|
fez = fabsf(e2.z());
|
|
AXISTEST_X2(e2.z(), e2.y(), fez, fey);
|
|
AXISTEST_Y1(e2.z(), e2.x(), fez, fex);
|
|
AXISTEST_Z12(e2.y(), e2.x(), fey, fex);
|
|
|
|
// Bullet 2:
|
|
// test if the box intersects the plane of the triangle
|
|
// compute plane equation of triangle: normal*x+d=0
|
|
normal = cross(e0, e1);
|
|
|
|
return planeBoxOverlap(normal, v0, boxhalfsize);
|
|
}
|