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#include <BH/Math/Ray3f.h>
#include <BH/Math/Vec3f.h>
#include <BH/Math/Box3f.h>
#include <BH/Math/Plane.h>
#include <string.h>
#include <math.h>
#define EPSILON 0.00001f
#define PI 3.14159265358979323846f
int BH_Ray3fIntersectPlane(const float start[3],
const float direction[3],
const float plane[4],
float *t,
float out[3])
{
float tmp1[3];
float denom, time;
/* Calculate intersection time */
denom = BH_Vec3fDot(direction, plane);
time = (plane[3] - BH_Vec3fDot(plane, start)) / denom;
/* Check for ray/plane parallel to each other or point is behing the ray. */
if (fabsf(denom) < EPSILON || time < 0.0f)
return BH_ERROR;
/* Compute intersection point */
BH_Vec3fScale(direction, time, tmp1);
BH_Vec3fAdd(start, tmp1, out);
*t = time;
return BH_OK;
}
int BH_Ray3fIntersectTriangle(const float start[3],
const float direction[3],
const float a[3],
const float b[3],
const float c[3],
float *t,
float out[3])
{
float plane[4];
float tmp1[3], tmp2[3], tmp3[3];
float time;
/* Compute plane */
if (BH_PlaneFromPoints(a, b, c, plane))
return BH_ERROR;
/* Compute intersection point in ray against plane */
if (BH_Ray3fIntersectPlane(start, direction, plane, &time, tmp3))
return BH_ERROR;
/* Check if point inside rectangle */
BH_Vec3fSub(b, a, tmp1);
BH_Vec3fSub(tmp3, a, tmp2);
BH_Vec3fCross(tmp2, tmp1, tmp1);
if (BH_Vec3fDot(tmp1, plane) < 0.0f)
return BH_ERROR;
BH_Vec3fSub(c, b, tmp1);
BH_Vec3fSub(tmp3, b, tmp2);
BH_Vec3fCross(tmp2, tmp1, tmp1);
if (BH_Vec3fDot(tmp1, plane) < 0.0f)
return BH_ERROR;
BH_Vec3fSub(a, c, tmp1);
BH_Vec3fSub(tmp3, c, tmp2);
BH_Vec3fCross(tmp2, tmp1, tmp1);
if (BH_Vec3fDot(tmp1, plane) < 0.0f)
return BH_ERROR;
/* Copy intersection point */
memcpy(out, tmp3, sizeof(tmp3));
*t = time;
return BH_OK;
}
int BH_Segment3fIntersectPlane(const float start[3],
const float end[3],
const float plane[4],
float *t,
float out[3])
{
float tmp[3];
float denom, time;
/* Calculate intersection time */
BH_Vec3fSub(end, start, tmp);
denom = BH_Vec3fDot(tmp, plane);
time = (plane[3] - BH_Vec3fDot(plane, start)) / denom;
/* Check for ray/plane parallel to each other or point is behing the ray. */
if (fabsf(denom) < EPSILON || time < 0.0f || time > 1.0f)
return BH_ERROR;
/* Compute intersection point */
BH_Vec3fScale(tmp, time, tmp);
BH_Vec3fAdd(start, tmp, out);
*t = time;
return BH_OK;
}
int BH_Segment3fIntersectTriangle(const float start[3],
const float end[3],
const float a[3],
const float b[3],
const float c[3],
float *t,
float out[3])
{
float plane[4];
float tmp1[3], tmp2[3], tmp3[3];
float time;
/* Compute plane */
if (BH_PlaneFromPoints(a, b, c, plane))
return BH_ERROR;
/* Compute intersection point in ray against plane */
if (BH_Segment3fIntersectPlane(start, end, plane, &time, tmp3))
return BH_ERROR;
/* Check if point inside rectangle */
BH_Vec3fSub(b, a, tmp1);
BH_Vec3fSub(tmp3, a, tmp2);
BH_Vec3fCross(tmp2, tmp1, tmp1);
if (BH_Vec3fDot(tmp1, plane) < 0.0f)
return BH_ERROR;
BH_Vec3fSub(c, b, tmp1);
BH_Vec3fSub(tmp3, b, tmp2);
BH_Vec3fCross(tmp2, tmp1, tmp1);
if (BH_Vec3fDot(tmp1, plane) < 0.0f)
return BH_ERROR;
BH_Vec3fSub(a, c, tmp1);
BH_Vec3fSub(tmp3, c, tmp2);
BH_Vec3fCross(tmp2, tmp1, tmp1);
if (BH_Vec3fDot(tmp1, plane) < 0.0f)
return BH_ERROR;
/* Copy intersection point */
memcpy(out, tmp3, sizeof(tmp3));
*t = time;
return BH_OK;
}
int BH_Ray3fIntersectBox3f(const float aStart[3],
const float aDirection[3],
const float bMin[3],
const float bMax[3],
float *t,
float out[3])
{
float timeNear, timeFar, hitNear, hitFar, denom, tmp;
int i;
timeNear = -1.0f / 0.0f;
timeFar = 1.0f / 0.0f;
/* Check if origin inside box */
if (!BH_Box3fContains(bMin, bMax, aStart))
{
memcpy(out, aStart, sizeof(float) * 3);
*t = 0.0f;
return BH_OK;
}
/* Check each axis for the minimal and maximum intersection time */
for (i = 0; i < 3; i++)
{
if (fabsf(aDirection[i]) < EPSILON)
{
if (aStart[i] < bMin[i] || aStart[i] > bMax[i])
return BH_ERROR;
continue;
}
denom = 1.0f / aDirection[i];
hitNear = (bMin[i] - aStart[i]) * denom;
hitFar = (bMax[i] - aStart[i]) * denom;
if (hitNear > hitFar)
{
tmp = hitNear;
hitNear = hitFar;
hitFar = tmp;
}
if (hitNear > timeNear)
timeNear = hitNear;
if (hitFar < timeFar)
timeFar = hitFar;
if (timeNear > timeFar || timeFar < 0.0f)
return BH_ERROR;
}
out[0] = aStart[0] + aDirection[0] * timeNear;
out[1] = aStart[1] + aDirection[1] * timeNear;
out[2] = aStart[2] + aDirection[2] * timeNear;
*t = timeNear;
return BH_OK;
}
int BH_Segment3fIntersectBox3f(const float aStart[3],
const float aEnd[3],
const float bMin[3],
const float bMax[3],
float *t,
float out[3])
{
float tmp[3];
float time;
BH_Vec3fSub(aEnd, aStart, tmp);
if (BH_Ray3fIntersectBox3f(aStart, tmp, bMin, bMax, &time, out))
return BH_ERROR;
if (time > 1.0f)
return BH_ERROR;
*t = time;
return BH_OK;
}
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