Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:113429
MIME-Version: 1.0
References: <CABLJ+14_JBZNT8Yj-SKB-CX3Y8LVt-edurR4MQi=xVbzxH1_xw@mail.gmail.com>
 <b217a544-6e18-c52d-37a4-594580841b01@php.net>
In-Reply-To: <b217a544-6e18-c52d-37a4-594580841b01@php.net>
Date: Tue, 9 Mar 2021 22:09:30 -0800
Message-ID: <CABLJ+15t5yuPX=KyLiuATnNZa=ahDkKL8p-4NfE9gdzvmVn4Zg@mail.gmail.com>
To: Michael Wallner <mike@php.net>
Cc: internals@lists.php.net
Content-Type: multipart/alternative; boundary="00000000000034711805bd28834c"
Subject: Re: [PHP-DEV] Tracking Object Property Changes
From: sutabi@gmail.com (Joseph Montanez)

--00000000000034711805bd28834c
Content-Type: text/plain; charset="UTF-8"

Michael,

Thanks for the feedback! The part about having Zend Object at the end of a
struct saved me because I was starting to have issues with cloning objects.

This is for an extension I was working on and have picked back up, I was
just isolating it to make it easy to work with. Its bindings for
https://www.raylib.com/. The general issue is that I won't be able to
change RayLib's structs (embedded vs pointers), so what I showed was an
isolated example. There is another author who also has a RayLib binding in
PHP and has a similar issue:

https://github.com/oraoto/raylib-phpcpp
<?php

$v = Vector2(1, 2);
// $v->x += 1; doesn't work
$v->x = $v->x + 1;

$camera = Camera2D(Vector2(1, 1), Vector2(0, 0), 1.0, 1.0);
// $camera->target->x = 1; // doesn't work
$target = $camera->target;
$target->x = 1;
$camera->target = $target;

This is far from ideal, and I can only assume people will run into this and
assume it's a bug. On my end, I've written my own (incomplete) bindings
https://github.com/joseph-montanez/raylib-php |
https://joseph-montanez.github.io/raylib-php-docs/ I am working towards
those issues, this is just a stumbling block.

The more I think about this, I probably don't need a listening system,
rather when the object is used for an internal RayLib function call, I can
unravel the sub-objects and write back to the original struct. For example
in RayLib there is a function DrawRay(Ray ray, Color color), when I
implement DrawRay, I can do the unravel work to pull the values from
position and direction PHP objects back into the Ray struct, and then pass
the Ray struct to DrawRay.



Thanks,
Joseph Montanez


On Tue, Mar 9, 2021 at 3:03 AM Michael Wallner <mike@php.net> wrote:

> Hi Joseph!
>
> Is this for educational purposes or real world usage?
>
> I ask, because, if you don't have to adhere to a predefined C-API you
> would avoid lots of headache by baking all this stuff into your PHP
> objects with the APIs provided by Zend. But then again, it would be way
> more efficient to just write it all in PHP code.
>
> More comments following inline.
>
> On 09/03/2021 03.32, Joseph Montanez wrote:
> > I am not sure what to title this but the gist is that I have two structs
> > with a one way dependency:
> >
> > // Vector3 type
> > typedef struct Vector3 {
> >     float x;
> >     float y;
> >     float z;
> > } Vector3;
> >
> > // Ray type (useful for raycast)
> > typedef struct Ray {
> >     Vector3 position;       // Ray position (origin)
> >     Vector3 direction;      // Ray direction
> > } Ray;
>
> As these are embedded structs instead of pointers to, neither do point
> to the memory of the other.
>
>
> > The PHP Ray object is defined as so:
> > typedef struct _skeleton_ray_object {
> >     Ray ray;
> >     HashTable *prop_handler;
> >     zend_object std;
>       ^^^^^^^^^^^^^^^^
> NOTE: This has to be the last line in your object struct because of an
> VLA at the end of the zend_object struct. See your xyz_new() function
> where you allocate additional zend_object_properties_size() bytes for
> that VLA (variable length array).
>
> >
> >     skeleton_vector3_object *position;
> >     skeleton_vector3_object *direction;
> > } skeleton_ray_object;
> >
> > When I update either vector3 object, I don't have a way to propagate the
> > changes back to the parent object(Ray). This means the raw Ray struct is
> > never updated. Is there a built-in way to handle propagation (listeners)
> in
> > a PHP extension or will I need to hand roll this?
>
> Yes, you gotta write all of this on your own, but let me repeat that
> this is a lot of boilerplate which also may entail lots of headache.
>
>
> --
> Regards,
> Mike
>
>

--00000000000034711805bd28834c--