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MATH: Make implementation of Segment2d more robust

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- prevent division by zero
This commit is contained in:
Christian Krause 2014-10-05 02:55:31 +02:00 • committed by Paweł Kołodziejski
parent 6098b45776
commit f2195d8dbf
2 changed files with 11 additions and 2 deletions
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4
math/line2d.cpp
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@ -169,14 +169,14 @@ bool Segment2d::intersectsSegment(const Segment2d &other, Vector2d *pos) {
float nume_b = ((_end.getX() - _begin.getX()) * (other._begin.getY() - _begin.getY())) - float nume_b = ((_end.getX() - _begin.getX()) * (other._begin.getY() - _begin.getY())) -
((_end.getY() - _begin.getY()) * (other._begin.getX() - _begin.getX())); ((_end.getY() - _begin.getY()) * (other._begin.getX() - _begin.getX()));
if (denom == 0.0f) { if (denom == 0.0f || d == 0.0f ) {
return false; return false;
} }
float ua = nume_a / denom; float ua = nume_a / denom;
float ub = nume_b / d; float ub = nume_b / d;
if (ua < 0 || ua > 1 || ub < 0 || ub > 1) { if (ua < 0.0f || ua > 1.0f || ub < 0.0f || ub > 1.0f) {
return false; return false;
} }

9
math/utils.h
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@ -27,6 +27,15 @@
namespace Math { namespace Math {
/* Math::epsilon is a constant with a small value which is used for comparing
* floating point numbers.
*
* The value is based on the previous hard-coded numbers in
* Line2d.cpp. Smaller numbers could be used unless they are
* smaller than the float granularity.
*/
static const float epsilon = 0.0001f;
inline float square(float x) { inline float square(float x) {
return x * x; return x * x;
} }