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gtkradiant/libs/mathlib/bbox.c
TTimo 12b372f89c ok 
git-svn-id: svn://svn.icculus.org/gtkradiant/GtkRadiant@1 8a3a26a2-13c4-0310-b231-cf6edde360e5
2006-02-10 22:01:20 +00:00

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/*
Copyright (C) 2001-2006, William Joseph.
All Rights Reserved.
This file is part of GtkRadiant.
GtkRadiant is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
GtkRadiant 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
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GtkRadiant; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <float.h>
#include "mathlib.h"
const aabb_t g_aabb_null = {
{ 0, 0, 0, },
{ -FLT_MAX, -FLT_MAX, -FLT_MAX, },
};
void aabb_construct_for_vec3(aabb_t *aabb, const vec3_t min, const vec3_t max)
{
VectorMid(min, max, aabb->origin);
VectorSubtract(max, aabb->origin, aabb->extents);
}
void aabb_clear(aabb_t *aabb)
{
VectorCopy(g_aabb_null.origin, aabb->origin);
VectorCopy(g_aabb_null.extents, aabb->extents);
}
void aabb_extend_by_point(aabb_t *aabb, const vec3_t point)
{
#if 1
int i;
vec_t min, max, displacement;
for(i=0; i<3; i++)
{
displacement = point[i] - aabb->origin[i];
if(fabs(displacement) > aabb->extents[i])
{
if(aabb->extents[i] < 0) // degenerate
{
min = max = point[i];
}
else if(displacement > 0)
{
min = aabb->origin[i] - aabb->extents[i];
max = aabb->origin[i] + displacement;
}
else
{
max = aabb->origin[i] + aabb->extents[i];
min = aabb->origin[i] + displacement;
}
aabb->origin[i] = (min + max) * 0.5f;
aabb->extents[i] = max - aabb->origin[i];
}
}
#else
unsigned int i;
for(i=0; i<3; ++i)
{
if(aabb->extents[i] < 0) // degenerate
{
aabb->origin[i] = point[i];
aabb->extents[i] = 0;
}
else
{
vec_t displacement = point[i] - aabb->origin[i];
vec_t increment = (vec_t)fabs(displacement) - aabb->extents[i];
if(increment > 0)
{
increment *= (vec_t)((displacement > 0) ? 0.5 : -0.5);
aabb->extents[i] += increment;
aabb->origin[i] += increment;
}
}
}
#endif
}
void aabb_extend_by_aabb(aabb_t *aabb, const aabb_t *aabb_src)
{
int i;
vec_t min, max, displacement, difference;
for(i=0; i<3; i++)
{
displacement = aabb_src->origin[i] - aabb->origin[i];
difference = aabb_src->extents[i] - aabb->extents[i];
if(aabb->extents[i] < 0
|| difference >= fabs(displacement))
{
// 2nd contains 1st
aabb->extents[i] = aabb_src->extents[i];
aabb->origin[i] = aabb_src->origin[i];
}
else if(aabb_src->extents[i] < 0
|| -difference >= fabs(displacement))
{
// 1st contains 2nd
continue;
}
else
{
// not contained
if(displacement > 0)
{
min = aabb->origin[i] - aabb->extents[i];
max = aabb_src->origin[i] + aabb_src->extents[i];
}
else
{
min = aabb_src->origin[i] - aabb_src->extents[i];
max = aabb->origin[i] + aabb->extents[i];
}
aabb->origin[i] = (min + max) * 0.5f;
aabb->extents[i] = max - aabb->origin[i];
}
}
}
void aabb_extend_by_vec3(aabb_t *aabb, vec3_t extension)
{
VectorAdd(aabb->extents, extension, aabb->extents);
}
int aabb_test_point(const aabb_t *aabb, const vec3_t point)
{
int i;
for(i=0; i<3; i++)
if(fabs(point[i] - aabb->origin[i]) >= aabb->extents[i])
return 0;
return 1;
}
int aabb_test_aabb(const aabb_t *aabb, const aabb_t *aabb_src)
{
int i;
for (i=0; i<3; i++)
if ( fabs(aabb_src->origin[i] - aabb->origin[i]) > (fabs(aabb->extents[i]) + fabs(aabb_src->extents[i])) )
return 0;
return 1;
}
int aabb_test_plane(const aabb_t *aabb, const float *plane)
{
float fDist, fIntersect;
// calc distance of origin from plane
fDist = DotProduct(plane, aabb->origin) + plane[3];
// calc extents distance relative to plane normal
fIntersect = (vec_t)(fabs(plane[0] * aabb->extents[0]) + fabs(plane[1] * aabb->extents[1]) + fabs(plane[2] * aabb->extents[2]));
// accept if origin is less than or equal to this distance
if (fabs(fDist) < fIntersect) return 1; // partially inside
else if (fDist < 0) return 2; // totally inside
return 0; // totally outside
}
/*
Fast Ray-Box Intersection
by Andrew Woo
from "Graphics Gems", Academic Press, 1990
*/
#define NUMDIM 3
#define RIGHT 0
#define LEFT 1
#define MIDDLE 2
int aabb_intersect_ray(const aabb_t *aabb, const ray_t *ray, vec3_t intersection)
{
int inside = 1;
char quadrant[NUMDIM];
register int i;
int whichPlane;
double maxT[NUMDIM];
double candidatePlane[NUMDIM];
const float *origin = ray->origin;
const float *direction = ray->direction;
/* Find candidate planes; this loop can be avoided if
rays cast all from the eye(assume perpsective view) */
for (i=0; i<NUMDIM; i++)
{
if(origin[i] < (aabb->origin[i] - aabb->extents[i]))
{
quadrant[i] = LEFT;
candidatePlane[i] = (aabb->origin[i] - aabb->extents[i]);
inside = 0;
}
else if (origin[i] > (aabb->origin[i] + aabb->extents[i]))
{
quadrant[i] = RIGHT;
candidatePlane[i] = (aabb->origin[i] + aabb->extents[i]);
inside = 0;
}
else
{
quadrant[i] = MIDDLE;
}
}
/* Ray origin inside bounding box */
if(inside == 1)
{
VectorCopy(ray->origin, intersection);
return 1;
}
/* Calculate T distances to candidate planes */
for (i = 0; i < NUMDIM; i++)
{
if (quadrant[i] != MIDDLE && direction[i] !=0.)
maxT[i] = (candidatePlane[i] - origin[i]) / direction[i];
else
maxT[i] = -1.;
}
/* Get largest of the maxT's for final choice of intersection */
whichPlane = 0;
for (i = 1; i < NUMDIM; i++)
if (maxT[whichPlane] < maxT[i])
whichPlane = i;
/* Check final candidate actually inside box */
if (maxT[whichPlane] < 0.)
return 0;
for (i = 0; i < NUMDIM; i++)
{
if (whichPlane != i)
{
intersection[i] = (vec_t)(origin[i] + maxT[whichPlane] * direction[i]);
if (fabs(intersection[i] - aabb->origin[i]) > aabb->extents[i])
return 0;
}
else
{
intersection[i] = (vec_t)candidatePlane[i];
}
}
return 1; /* ray hits box */
}
int aabb_test_ray(const aabb_t* aabb, const ray_t* ray)
{
vec3_t displacement, ray_absolute;
vec_t f;
displacement[0] = ray->origin[0] - aabb->origin[0];
if(fabs(displacement[0]) > aabb->extents[0] && displacement[0] * ray->direction[0] >= 0.0f)
return 0;
displacement[1] = ray->origin[1] - aabb->origin[1];
if(fabs(displacement[1]) > aabb->extents[1] && displacement[1] * ray->direction[1] >= 0.0f)
return 0;
displacement[2] = ray->origin[2] - aabb->origin[2];
if(fabs(displacement[2]) > aabb->extents[2] && displacement[2] * ray->direction[2] >= 0.0f)
return 0;
ray_absolute[0] = (float)fabs(ray->direction[0]);
ray_absolute[1] = (float)fabs(ray->direction[1]);
ray_absolute[2] = (float)fabs(ray->direction[2]);
f = ray->direction[1] * displacement[2] - ray->direction[2] * displacement[1];
if((float)fabs(f) > aabb->extents[1] * ray_absolute[2] + aabb->extents[2] * ray_absolute[1])
return 0;
f = ray->direction[2] * displacement[0] - ray->direction[0] * displacement[2];
if((float)fabs(f) > aabb->extents[0] * ray_absolute[2] + aabb->extents[2] * ray_absolute[0])
return 0;
f = ray->direction[0] * displacement[1] - ray->direction[1] * displacement[0];
if((float)fabs(f) > aabb->extents[0] * ray_absolute[1] + aabb->extents[1] * ray_absolute[0])
return 0;
return 1;
}
void aabb_orthogonal_transform(aabb_t* dst, const aabb_t* src, const m4x4_t transform)
{
VectorCopy(src->origin, dst->origin);
m4x4_transform_point(transform, dst->origin);
dst->extents[0] = (vec_t)(fabs(transform[0] * src->extents[0])
+ fabs(transform[4] * src->extents[1])
+ fabs(transform[8] * src->extents[2]));
dst->extents[1] = (vec_t)(fabs(transform[1] * src->extents[0])
+ fabs(transform[5] * src->extents[1])
+ fabs(transform[9] * src->extents[2]));
dst->extents[2] = (vec_t)(fabs(transform[2] * src->extents[0])
+ fabs(transform[6] * src->extents[1])
+ fabs(transform[10] * src->extents[2]));
}
void aabb_for_bbox(aabb_t *aabb, const bbox_t *bbox)
{
int i;
vec3_t temp[3];
VectorCopy(bbox->aabb.origin, aabb->origin);
// calculate the AABB extents in local coord space from the OBB extents and axes
VectorScale(bbox->axes[0], bbox->aabb.extents[0], temp[0]);
VectorScale(bbox->axes[1], bbox->aabb.extents[1], temp[1]);
VectorScale(bbox->axes[2], bbox->aabb.extents[2], temp[2]);
for(i=0;i<3;i++) aabb->extents[i] = (vec_t)(fabs(temp[0][i]) + fabs(temp[1][i]) + fabs(temp[2][i]));
}
void aabb_for_area(aabb_t *aabb, vec3_t area_tl, vec3_t area_br, int axis)
{
aabb_clear(aabb);
aabb->extents[axis] = FLT_MAX;
aabb_extend_by_point(aabb, area_tl);
aabb_extend_by_point(aabb, area_br);
}
int aabb_oriented_intersect_plane(const aabb_t *aabb, const m4x4_t transform, const vec_t* plane)
{
vec_t fDist, fIntersect;
// calc distance of origin from plane
fDist = DotProduct(plane, aabb->origin) + plane[3];
// calc extents distance relative to plane normal
fIntersect = (vec_t)(fabs(aabb->extents[0] * DotProduct(plane, transform))
+ fabs(aabb->extents[1] * DotProduct(plane, transform+4))
+ fabs(aabb->extents[2] * DotProduct(plane, transform+8)));
// accept if origin is less than this distance
if (fabs(fDist) < fIntersect) return 1; // partially inside
else if (fDist < 0) return 2; // totally inside
return 0; // totally outside
}
void aabb_corners(const aabb_t* aabb, vec3_t corners[8])
{
vec3_t min, max;
VectorSubtract(aabb->origin, aabb->extents, min);
VectorAdd(aabb->origin, aabb->extents, max);
VectorSet(corners[0], min[0], max[1], max[2]);
VectorSet(corners[1], max[0], max[1], max[2]);
VectorSet(corners[2], max[0], min[1], max[2]);
VectorSet(corners[3], min[0], min[1], max[2]);
VectorSet(corners[4], min[0], max[1], min[2]);
VectorSet(corners[5], max[0], max[1], min[2]);
VectorSet(corners[6], max[0], min[1], min[2]);
VectorSet(corners[7], min[0], min[1], min[2]);
}
void bbox_update_radius(bbox_t *bbox)
{
bbox->radius = VectorLength(bbox->aabb.extents);
}
void aabb_for_transformed_aabb(aabb_t* dst, const aabb_t* src, const m4x4_t transform)
{
if(src->extents[0] < 0
|| src->extents[1] < 0
|| src->extents[2] < 0)
{
aabb_clear(dst);
return;
}
VectorCopy(src->origin, dst->origin);
m4x4_transform_point(transform, dst->origin);
dst->extents[0] = (vec_t)(fabs(transform[0] * src->extents[0])
+ fabs(transform[4] * src->extents[1])
+ fabs(transform[8] * src->extents[2]));
dst->extents[1] = (vec_t)(fabs(transform[1] * src->extents[0])
+ fabs(transform[5] * src->extents[1])
+ fabs(transform[9] * src->extents[2]));
dst->extents[2] = (vec_t)(fabs(transform[2] * src->extents[0])
+ fabs(transform[6] * src->extents[1])
+ fabs(transform[10] * src->extents[2]));
}
void bbox_for_oriented_aabb(bbox_t *bbox, const aabb_t *aabb, const m4x4_t matrix, const vec3_t euler, const vec3_t scale)
{
double rad[3];
double pi_180 = Q_PI / 180;
double A, B, C, D, E, F, AD, BD;
VectorCopy(aabb->origin, bbox->aabb.origin);
m4x4_transform_point(matrix, bbox->aabb.origin);
bbox->aabb.extents[0] = aabb->extents[0] * scale[0];
bbox->aabb.extents[1] = aabb->extents[1] * scale[1];
bbox->aabb.extents[2] = aabb->extents[2] * scale[2];
rad[0] = euler[0] * pi_180;
rad[1] = euler[1] * pi_180;
rad[2] = euler[2] * pi_180;
A = cos(rad[0]);
B = sin(rad[0]);
C = cos(rad[1]);
D = sin(rad[1]);
E = cos(rad[2]);
F = sin(rad[2]);
AD = A * -D;
BD = B * -D;
bbox->axes[0][0] = (vec_t)(C*E);
bbox->axes[0][1] = (vec_t)(-BD*E + A*F);
bbox->axes[0][2] = (vec_t)(AD*E + B*F);
bbox->axes[1][0] = (vec_t)(-C*F);
bbox->axes[1][1] = (vec_t)(BD*F + A*E);
bbox->axes[1][2] = (vec_t)(-AD*F + B*E);
bbox->axes[2][0] = (vec_t)D;
bbox->axes[2][1] = (vec_t)(-B*C);
bbox->axes[2][2] = (vec_t)(A*C);
bbox_update_radius(bbox);
}
int bbox_intersect_plane(const bbox_t *bbox, const vec_t* plane)
{
vec_t fDist, fIntersect;
// calc distance of origin from plane
fDist = DotProduct(plane, bbox->aabb.origin) + plane[3];
// trivial accept/reject using bounding sphere
if (fabs(fDist) > bbox->radius)
{
if (fDist < 0)
return 2; // totally inside
else
return 0; // totally outside
}
// calc extents distance relative to plane normal
fIntersect = (vec_t)(fabs(bbox->aabb.extents[0] * DotProduct(plane, bbox->axes[0]))
+ fabs(bbox->aabb.extents[1] * DotProduct(plane, bbox->axes[1]))
+ fabs(bbox->aabb.extents[2] * DotProduct(plane, bbox->axes[2])));
// accept if origin is less than this distance
if (fabs(fDist) < fIntersect) return 1; // partially inside
else if (fDist < 0) return 2; // totally inside
return 0; // totally outside
}
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