Re: [HACKERS] [PATCH] Improve geometric types

At Sun, 21 Jan 2018 21:59:19 +0100, Emre Hasegeli <emre(at)hasegeli(dot)com> wrote in <CAE2gYzxDYs5tcvc4uErsWaFTb3UTYS0ERt_fFyi-28Ldvs5d4A(at)mail(dot)gmail(dot)com>
> New versions are attached including all changes we discussed.

Thanks for the new version.

# there's many changes from the previous version..

About 0001 and 0002.

1."COPT=-DGEODEBUG make" complains as follows.

| geo_ops.c:2445:62: error: invalid type argument of unary ‘*’ (have ‘float8 {aka double}’)
| printf("dist_ppoly_internal- segment 0/n distance is %f\n", *result);

2. line_construct_pm has been renamed to line_construct. I
noticed that the patch adds the second block for "(m == 0.0)"
(from the ealier versions) but it seems to work exactly as the
same to the "else" block. We need a comment about the reason
for the seemingly redundant second block.

3. point_sl can return -0.0 and that is a thing that this patch
intends to avoid. line_invsl has the same problem.

4. lseg_interpt_line is doing as follows.

> if (FPeq(lseg->p[0].x, interpt.x) && FPeq(lseg->p[0].y, interpt.y))
> *result = lseg->p[0];
> else if (FPeq(lseg->p[1].x, interpt.x) && FPeq(lseg->p[1].y, interpt.y))
> *result = lseg->p[1];

I suppose we can use point_pt_point for this purpose.

> if (point_eq_point(&lseg->p[0], &interpt))
> *result = lseg->p[0];
> else if (point_eq_point(&lseg->p[1], &interpt))
> *result = lseg->p[1];

However I'm not sure that adjusting the intersection to the
tips of the segment is good or not. Adjusting onto the line
can be better in another case. lseg_interpt_lseg, for
instance, checks lseg_contain_point on the line parameter of
lseg_interpt_line.

# I'll be back later..

regards

--
Kyotaro Horiguchi
NTT Open Source Software Center