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robustified r_find_t, removed extraneous elses

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This commit is contained in:
Darren Ranalli 2002-05-11 01:43:59 +00:00
parent 3ed52cad07
commit 9ef80eec44
1 changed files with 76 additions and 65 deletions
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141
panda/src/parametrics/parametricCurve.cxx
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@ -718,28 +718,28 @@ r_calc_length(float t1, float t2, const LPoint3f &p1, const LPoint3f &p2,
// Stop recursing--we've just walked off the limit for
// representing smaller values of t.
return 0.0f;
}
float tmid;
LPoint3f pmid;
float left, right;
// Calculate the point on the curve midway between the two
// endpoints.
tmid = (t1+t2)*0.5f;
get_point(tmid, pmid);
// Did we increase the length of the segment measurably?
left = (p1 - pmid).length();
right = (pmid - p2).length();
if ((left + right) - seglength < length_tolerance) {
// No. We're done.
return seglength;
} else {
float tmid;
LPoint3f pmid;
float left, right;
// Calculate the point on the curve midway between the two
// endpoints.
tmid = (t1+t2)*0.5f;
get_point(tmid, pmid);
// Did we increase the length of the segment measurably?
left = (p1 - pmid).length();
right = (pmid - p2).length();
if ((left + right) - seglength < length_tolerance) {
// No. We're done.
return seglength;
} else {
// Yes. Keep going.
return r_calc_length(t1, tmid, p1, pmid, left) +
r_calc_length(tmid, t2, pmid, p2, right);
}
// Yes. Keep going.
return r_calc_length(t1, tmid, p1, pmid, left) +
r_calc_length(tmid, t2, pmid, p2, right);
}
}
@ -752,8 +752,8 @@ r_calc_length(float t1, float t2, const LPoint3f &p1, const LPoint3f &p2,
// find. If the indicated target_length falls within
// this segment, returns true and sets found_t to the
// point along the segment. Otherwise, updates
// seglength with the calculated length of the segment
// and returns false.
// seglength with the accurate calculated length of the
// segment and returns false.
////////////////////////////////////////////////////////////////////
bool ParametricCurve::
r_find_length(float target_length, float &found_t,
@ -769,52 +769,52 @@ r_find_length(float target_length, float &found_t,
found_t = t1;
return true;
} else {
float tmid;
LPoint3f pmid;
float left, right;
}
// Calculate the point on the curve midway between the two
// endpoints.
tmid = (t1+t2)*0.5f;
get_point(tmid, pmid);
float tmid;
LPoint3f pmid;
float left, right;
// Did we increase the length of the segment measurably?
left = (p1 - pmid).length();
right = (pmid - p2).length();
// Calculate the point on the curve midway between the two
// endpoints.
tmid = (t1+t2)*0.5f;
get_point(tmid, pmid);
if ((left + right) - seglength < length_tolerance) {
// No. Curve is relatively straight at this point.
if (target_length <= seglength) {
// Compute t value that corresponds to target_length
// Maybe the point is in the left half of the segment?
if (r_find_t(target_length, found_t, t1, tmid, p1, pmid)) {
return true;
}
// Maybe it's on the right half?
if (r_find_t(target_length - left, found_t, tmid, t2, pmid, p2)) {
return true;
}
}
return false;
} else {
// Yes. Keep going.
// Did we increase the length of the segment measurably?
left = (p1 - pmid).length();
right = (pmid - p2).length();
if ((left + right) - seglength < length_tolerance) {
// No. Curve is relatively straight at this point.
if (target_length <= seglength) {
// Compute t value that corresponds to target_length
// Maybe the point is in the left half of the segment?
if (r_find_length(target_length, found_t, t1, tmid, p1, pmid, left)) {
return true;
if (r_find_t(target_length, found_t, t1, tmid, p1, pmid)) {
return true;
}
// Maybe it's on the right half?
if (r_find_length(target_length - left, found_t, tmid, t2, pmid, p2, right)) {
return true;
if (r_find_t(target_length - left, found_t, tmid, t2, pmid, p2)) {
return true;
}
// Neither. Keep going.
seglength = left + right;
return false;
}
return false;
} else {
// Yes. Keep going.
// Maybe the point is in the left half of the segment?
if (r_find_length(target_length, found_t, t1, tmid, p1, pmid, left)) {
return true;
}
// Maybe it's on the right half?
if (r_find_length(target_length - left, found_t, tmid, t2, pmid, p2, right)) {
return true;
}
// Neither. Keep going.
seglength = left + right;
return false;
}
}
@ -823,8 +823,8 @@ r_find_length(float target_length, float &found_t,
////////////////////////////////////////////////////////////////////
// Function: ParametricCurve::r_find_t
// Access: Private
// Description: The recursive function to compute t value of a
// target point along a staight section of a curve.
// Description: computes the t value in the parametric domain of a
// target point along a straight section of a curve.
// This is similar to r_calc_length, above.
// target_length is the length along the curve past t1
// that we hope to find. If the indicated target_length
@ -835,7 +835,8 @@ bool ParametricCurve::
r_find_t(float target_length, float &found_t,
float t1, float t2,
const LPoint3f &p1, const LPoint3f &p2) const {
static const float t_tolerance = 0.001f;
static const float length_tolerance = 0.0001f;
static const float t_tolerance = 0.0001f;
if (parametrics_cat.is_spam()) {
parametrics_cat.spam()
@ -843,7 +844,7 @@ r_find_t(float target_length, float &found_t,
}
// Is the target point close to the near endpoint
if (target_length < t_tolerance) {
if (target_length < length_tolerance) {
found_t = t1;
return true;
}
@ -858,11 +859,18 @@ r_find_t(float target_length, float &found_t,
}
// Is the target point close to far endpoint?
if ( (point_dist - target_length ) < t_tolerance ) {
if ( (point_dist - target_length ) < length_tolerance ) {
found_t = t2;
return true;
}
// are we running out of parametric precision?
if ((t2 - t1) < t_tolerance) {
found_t = t1;
return true;
}
// No, subdivide and continue
float tmid;
LPoint3f pmid;
@ -882,6 +890,9 @@ r_find_t(float target_length, float &found_t,
if (r_find_t(target_length - left, found_t, tmid, t2, pmid, p2)) {
return true;
}
// not found in either half, keep looking
return false;
}