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#include <BH/Math.h>
#include <string.h>
#include <math.h>
#define EPSILON 0.00001f
#define PI 3.14159265358979323846f
int BH_Ray2fIntersectLine(const float start[2],
const float direction[2],
const float line[3],
float *t,
float out[2])
{
float tmp1[2];
float denom, time;
/* Calculate intersection time */
denom = BH_Vec2fDot(direction, line);
time = (line[2] - BH_Vec2fDot(line, 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_Vec2fScale(direction, time, tmp1);
BH_Vec2fAdd(start, tmp1, out);
*t = time;
return BH_OK;
}
int BH_Ray2fIntersectTime(const float aStart[2],
const float aDirection[2],
const float bStart[2],
const float bDirection[2],
float *time1,
float *time2)
{
float tmp1[2], tmp2[2], tmp3[2];
float denom;
/* Rotate directions by 90 degrees and caluclate denom */
tmp1[0] = -aDirection[1]; tmp1[1] = aDirection[0];
tmp2[0] = -bDirection[1]; tmp2[1] = bDirection[0];
denom = BH_Vec2fDot(tmp1, bDirection);
if (fabsf(denom) < EPSILON)
return BH_ERROR;
/* Calculate segments offset and intersection times */
BH_Vec2fSub(aStart, bStart, tmp3);
*time1 = BH_Vec2fDot(tmp3, tmp2) / denom;
*time2 = BH_Vec2fDot(tmp3, tmp1) / denom;
return BH_OK;
}
int BH_Ray2fIntersectRay(const float aStart[2],
const float aDirection[2],
const float bStart[2],
const float bDirection[2],
float *t,
float out[2])
{
float tmp[2];
float time1, time2;
if (BH_Ray2fIntersectTime(aStart, aDirection, bStart, bDirection, &time1, &time2))
return BH_ERROR;
if (time1 < 0.0f || time2 < 0.0f)
return BH_ERROR;
BH_Vec2fScale(aDirection, time1, tmp);
BH_Vec2fAdd(aStart, tmp, out);
*t = time1;
return BH_OK;
}
int BH_Ray2fIntersectSegment(const float aStart[2],
const float aDirection[2],
const float bStart[2],
const float bEnd[2],
float *t,
float out[2])
{
float tmp[2];
float time1, time2;
BH_Vec2fSub(bEnd, bStart, tmp);
if (BH_Ray2fIntersectTime(aStart, aDirection, bStart, tmp, &time1, &time2))
return BH_ERROR;
if (time1 < 0.0f || time2 < 0.0f || time2 > 1.0f)
return BH_ERROR;
BH_Vec2fScale(aDirection, time1, tmp);
BH_Vec2fAdd(aStart, tmp, out);
*t = time1;
return BH_OK;
}
int BH_Segment2fIntersectLine(const float start[2],
const float end[2],
const float line[3],
float *t,
float out[2])
{
float tmp[2];
float denom, time;
/* Calculate intersection time */
BH_Vec2fSub(end, start, tmp);
denom = BH_Vec2fDot(tmp, line);
time = (line[2] - BH_Vec2fDot(line, 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_Vec2fScale(tmp, time, tmp);
BH_Vec2fAdd(start, tmp, out);
*t = time;
return BH_OK;
}
int BH_Segment2fIntersectSegment(const float aStart[2],
const float aEnd[2],
const float bStart[2],
const float bEnd[2],
float *t,
float out[2])
{
float tmp1[2], tmp2[2];
float time1, time2;
BH_Vec2fSub(aEnd, aStart, tmp1);
BH_Vec2fSub(bEnd, bStart, tmp2);
if (BH_Ray2fIntersectTime(aStart, tmp1, bStart, tmp2, &time1, &time2))
return BH_ERROR;
if (time1 < 0.0f || time1 > 1.0f || time2 < 0.0f || time2 > 1.0f)
return BH_ERROR;
BH_Vec2fLerp(aStart, aEnd, time1, out);
*t = time1;
return BH_OK;
}
int BH_Ray2fIntersectBox2f(const float aStart[2],
const float aDirection[2],
const float bMin[2],
const float bMax[2],
float *t,
float out[2])
{
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_Box2fContains(bMin, bMax, aStart))
{
memcpy(out, aStart, sizeof(float) * 2);
*t = 0.0f;
return BH_OK;
}
/* Check each axis for the minimal and maximum intersection time */
for (i = 0; i < 2; 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;
*t = timeNear;
return BH_OK;
}
int BH_Segment2fIntersectBox2f(const float aStart[2],
const float aEnd[2],
const float bMin[2],
const float bMax[2],
float *t,
float out[2])
{
float tmp[3];
float time;
BH_Vec2fSub(aEnd, aStart, tmp);
if (BH_Ray2fIntersectBox2f(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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