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りき萌 2023-09-10 23:42:13 +02:00
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% id = "01H9R1KJESR2F420HE67HW4AVR"
- design lessons from the best programming language of all time that everyone loves (not really)
% id = "programming/cxx/access-modifiers-as-labels"
+ access modifiers as labels (`private:`, `protected:`, and `public:`)
% id = "01H9R1KJES39Z6RBCKY4E71PYD"
- although Java and C#'s approach to symbol privacy may be verbose, it has one great advantage: it is stateless.
% id = "01H9R1KJES17626QXYEGM7XBC7"
- the way they're implemented in C++, it's essentially a bit more parsing state you have to keep track of
% id = "01H9R1KJESG4K8T1K1G36T7HBP"
- and you know what other parsing state you have to keep track of in C++? - that's right, the preprocessor.\
access modifiers, like all tokens, are affected by the preprocessor, and you have to take that into account.
% id = "01H9R1KJESJ0G0VQAW994ZHR0S"
- take the following example:
```cpp
class ComfyZone
{
std::vector<SoftBed> _soft_beds;
#if ENABLE_HUGS
public:
void hug(Person& person);
#endif
int _remaining_hugs = 10;
};
```
% id = "01H9R1KJESDDX4089WVHVV8N3H"
+ although quite contrived, it illustrates the problem pretty well
% id = "01H9R1KJESD2KED5TAFBY426A6"
- (before you ask, `_remaining_hugs` needs to be always present because it has to be (de)serialized no matter if hugging functionality is compiled in. otherwise we'd get data loss.)
% id = "01H9R1KJESES27VKVW4A0ZVM11"
- we intended for `_remaining_hugs` to be private, but if hugs are enabled, it becomes public.
% id = "01H9R1KJESTKW90R788SSPMNC6"
- this can be _very_ hard to spot if you have a big class with lots of declarations inside.
% id = "01H9R1KJESCJ3VC8ATPYFDCPSP"
- this can be worked around by banning access modifiers from appearing in `#ifdef`s, but you have to *realize* that this might happen
% id = "01H9R1KJES4ZYHVADDF80WAXH6"
- and I've seen instances of this exact thing occurring in the Unreal Engine codebase, which is *full* of long lists of declarations (made even longer by the prevalence of `UPROPERTY()` specifiers)
% id = "01H9R1KJES182MCV2V0A4VHKKX"
- even if we didn't have the preprocessor, that access modifier is state _you_ have to keep track of
% id = "01H9R1KJESH7PWNKCKW3H0WJHW"
- I very often find myself needing to scroll upward after <kbd>Ctrl</kbd>-clicking on a field or function declaration, just to find out if I can use it
% id = "01H9R1KJESFE6F1D4J5PA5Q381"
- (thankfully IDEs are helpful here and Rider shows you a symbol's visibility in the tooltip on hover, but I don't have Rider on code reviews)

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@ -36,81 +36,80 @@
I had no reason to revisit it since so I simply don't know if it's any better now, but if it is, [let's chat][branch:hello]!)
% id = "01H8Y0CKD1G06CG62XWZ02JREC"
+ writing Blueprints is actually pretty darn nice and there's a lot to learn from the editor UX
+ writing Blueprints is actually pretty darn nice and there's a lot to learn from the editor UX and basic refactoring tools
% id = "01H8Y0CKD1G86TY8AF6Z2SQ85P"
- I say this mainly with regards to writing new nodes. it's as simple as dragging your mouse out of a pin, and a window will pop up giving you suggestions on what could be connected there
+ when you drag your mouse out of a pin, and a window will pop up giving you suggestions on what could be connected there
% id = "01H8Y0CKD1P9SNK3TV967M705C"
- then you select from the list and it creates the node, autoconnecting stuff as necessary
% id = "01H8Y0CKD1P9SNK3TV967M705C"
+ then you select from the list and it creates the node, autoconnecting stuff as necessary
% id = "01H8Y0CKD1PQS2J2WB22ASZY17"
- one of the nicer autoconnections it can do is when you want to call a function on an actor component
% id = "01H8Y0CKD1PQS2J2WB22ASZY17"
- one of the nicer autoconnections it can do is when you want to call a function on an actor component
% id = "01H8Y0CKD16PFNWJ6EAARHA7BD"
- instance functions require you to pass in a `self` to call the function on
% id = "01H8Y0CKD16PFNWJ6EAARHA7BD"
- instance functions require you to pass in a `self` to call the function on
% id = "01H8Y0CKD1FVPCA5NBY5KK1F5X"
- so what it does is it suggests functions to call on all the _concrete components
you already have in your actor_, and when you select something like `Destroy Component (DefaultSceneRoot)`,
it'll not only create a function call node, but also hook up `DefaultSceneRoot` as its `self` parameter
% id = "01H8Y0CKD1FVPCA5NBY5KK1F5X"
- so what it does is it suggests functions to call on all the _concrete components
you already have in your actor_, and when you select something like `Destroy Component (DefaultSceneRoot)`,
it'll not only create a function call node, but also hook up `DefaultSceneRoot` as its `self` parameter
% id = "01H8Y0CKD1KM42PKVSGB4QASG3"
+ another cool thing that happens with nodes (or pins rather) is when you try to connect two pins of incompatible types
+ when you try to connect two pins of incompatible types, it'll automatically insert a conversion node for you
% id = "01H8Y0CKD1NES5RBGVTPRH3F0Q"
- Blueprint is strongly typed so you can't just pass in a `Float` where a `String` is expected
- Blueprint is strongly typed so you can't just pass in a `Float` where a `String` is expected, but luckily this makes the system way less painful
% id = "01H8Y0CKD1VVMB8RVECVGZP0V2"
- but instead of having you explicitly type out "o dear Blueprint I would like to convert this `Float` to a `String`", you can just join the two pins together and it'll insert a
conversion node for you automatically
% id = "01H8Y0CKD10GQBNNP0RBJEWKW4"
- I do have a gripe with this though and it's where it places the node. it tries very hard to center it but unfortunately never succeeds.
% id = "01H8Y0CKD10GQBNNP0RBJEWKW4"
- I do have a gripe with this though and it's where it places the node. it tries very hard to center it but unfortunately never succeeds. perhaps a bug I could fix one day?
% id = "01H987QXFE445XNN5YDS2FYR5F"
+ perhaps a bug I could fix one day?
% id = "01H8Y0CKD1G3PV1NMWV590H6Y3"
+ in the end most of the time writing Blueprints is very ergonomic
% id = "01H987QXFEYSE260S996BE84DV"
- from [Oskar Kogut](https://github.com/kretoskar): if you change a `BlueprintCallable` function to `const` (or otherwise make it pure,) the editor will automatically correct the `Exec` pin flow for you
% id = "01H8Y0CKD1C5TJXXD40B99WQ3C"
+ except when it isn't because Blueprint is still an imperative language and has a concept similar to statements (`Exec` pins), which breaks the entire idea of pure data flow and
introduces control flow into the mix
% id = "01H8Y0CKD1C5TJXXD40B99WQ3C"
+ the design of Blueprint the Language is pretty dated - it is still an imperative language and has a concept similar to statements (`Exec` pins), which breaks the entire idea of pure data
flow and introduces control flow into the mix
% id = "01H8Y0CKD1J2P2HZ507YBSNVKK"
- this split is called _pure_ and _impure_ nodes, where impure nodes are those that perform control flow (ie. those with `Exec` pins)
% id = "01H8Y0CKD1J2P2HZ507YBSNVKK"
- this split is called _pure_ and _impure_ nodes, where impure nodes are those that perform control flow (ie. those with `Exec` pins)
% id = "01H8Y0CKD1P5JQCGHEY405KKPH"
- this results in weird edge cases like needing two separate node types to handle branching (one that can have side effects - `Branch`, and another that can't - `Select`)
% id = "01H8Y0CKD1P5JQCGHEY405KKPH"
+ this results in weird edge cases like needing two separate node types to handle branching (one that can have side effects - `Branch`, and another that can't - `Select`)
% id = "01H8Y0CKD1EGWTQYHT2WYQSZY5"
- `Branch` is used to shuttle control flow between two `Exec` lines, based on a `Bool`. you get a `True` branch and a `False` branch
% id = "01H8Y0CKD1EGWTQYHT2WYQSZY5"
- `Branch` is used to shuttle control flow between two `Exec` lines, based on a `Bool`. you get a `True` branch and a `False` branch
% id = "01H8Y0CKD1WFEWNYPZWGCH3N7X"
- and `Select` is used to choose a value based on another value, kind of like a ternary in C++
% id = "01H8Y0CKD1WFEWNYPZWGCH3N7X"
+ and `Select` is used to choose a value based on another value, kind of like a ternary in C++
% id = "01H8Y0CKD156C0ZAXK7JS9W81D"
- however it is quite annoying because you can only switch on enums (and other stuff that has a finite set of values,) whereas with `Branch` you can use any `Bool` condition you want
% id = "01H8Y0CKD156C0ZAXK7JS9W81D"
- however it is quite annoying because you can only switch on enums (and other stuff that has a finite set of values,) whereas with `Branch` you can use any `Bool` condition you want
% id = "01H8Y0CKD1YP7Q3HVJJZNJAJKG"
- this would be fine if not for the existence of Gameplay Tags, which precisely _do not_ have a finite set of values
% id = "01H8Y0CKD1YP7Q3HVJJZNJAJKG"
+ this would be fine if not for the existence of Gameplay Tags, which precisely _do not_ have a finite set of values
% id = "01H8Y0CKD1P7D9QMPVQYWSDFT5"
- there is a `Switch on Gameplay Tag` node, but that is for control flow and not data flow!
% id = "01H8Y0CKD1P7D9QMPVQYWSDFT5"
- there is a `Switch on Gameplay Tag` node, but that is for control flow and not data flow!
% id = "01H8Y0CKD126918N282MNBXD2C"
- this isn't an unsolvable problem but it illustrates the pure vs impure issue pretty well - you'd have to duplicate the implementation of `Switch on Gameplay Tag` to have
a version without an `Exec` pin
% id = "01H8Y0CKD126918N282MNBXD2C"
- this isn't an unsolvable problem but it illustrates the pure vs impure issue pretty well - you'd have to duplicate the implementation of `Switch on Gameplay Tag` to have
a version without an `Exec` pin
% id = "01H8Y0CKD1N37WTCY66CM7R198"
+ in fact I'm seeing a bit of a semblance to the classic [function coloring problem][def:article/function_coloring]
% id = "01H8Y0CKD1N37WTCY66CM7R198"
+ I'm seeing a bit of a semblance to the classic [function coloring problem][def:article/function_coloring]
% id = "01H8Y0CKD19JMY87YY50M3RCQF"
+ except where it usually applies to the `async` concept found in most modern programming languages, here it applies to the concept of control flow vs data flow
% id = "01H8Y0CKD19JMY87YY50M3RCQF"
+ except where it usually applies to the `async` concept found in most modern programming languages, here it applies to the concept of control flow vs data flow
% id = "01H8Y0CKD1Q8RXXK3KE4F4XAFF"
- and speaking of `async`, [Blueprint handles the classic `async` problem very gracefully][branch:01H8Y0CKD106HXQAJK87XV0H93]!
% id = "01H8Y0CKD1Q8RXXK3KE4F4XAFF"
- and speaking of `async`, [Blueprint handles the classic `async` problem very gracefully][branch:01H8Y0CKD106HXQAJK87XV0H93]!
% id = "01H8Y0CKD106HXQAJK87XV0H93"
+ did I mention how well Blueprints handle latent tasks?
+ despite its flaws, one of Blueprint's strengths is asynchronous and latent tasks
% id = "01H8Y427B03JNPTWW025ES176K"
- since control flow is based on those `Exec` pins, you can easily map your classic concept of callbacks to simply firing off the appropriate `Exec` pin
@ -128,7 +127,7 @@
- which is annoying but not terrible, since most of that latent, high level gameplay logic happens inside the main event graph anyways
% id = "01H8Y96DGCWWTAP5X8ZYPCJZQC"
+ that isn't to say the editor UI is perfect
+ the editor UI, despite [being helpful as it is][branch:01H8Y0CKD1G06CG62XWZ02JREC], is far from perfect
% id = "01H8Y96DGCRP0W6YWJ3PYJ2GES"
- it's actually quite janky and there tend to be brief flashes of content falling into place
@ -137,16 +136,16 @@
- this is true of other parts of the Unreal editor UI but I'll focus on Blueprint here
% id = "01H8Y96DGDDRA8DD6PRGDCF8GP"
+ the annoying thing is that node UIs are laid out lazily, by default using an algorithm that does not produce precise results for pin locations
+ node UIs are laid out lazily, by default using an algorithm that does not produce precise results for pin locations
% id = "01H8Y96DGDT0Y23G86HEKNWF4H"
- which means that when you first load a Blueprint, some of the wires will be bent in weird ways, and will fall into place as you zoom out and explore the graph more
% id = "01H8Y96DGDCEF6FEQWGX2BQ6AH"
- the effect looks quite janky and really upsets my inner perfectionist
% id = "01H8Y96DGDCEF6FEQWGX2BQ6AH"
- the effect looks quite janky and really upsets my inner perfectionist
% id = "01H8Y96DGDJG41P3XTFE8F4Y1M"
+ another annoyance I have is that as you zoom out, the nodes start looking just a little bit differently due to font sizes being snapped to integers.
+ as you zoom out, the nodes start looking just a little bit different due to font sizes being snapped to integers
% id = "01H8Y96DGDRCBKWBXC7AXZV43E"
- at very low zoom levels, nodes stop rendering their text altogether, which makes their layout shift even more.
@ -164,7 +163,7 @@
- so what'll happen with it sometimes is you'll straighten a connection, then zoom in, and the connection won't be quite straight because of the aforementioned layout shift
% id = "01H8Y0CKD1103FHF332M2Q4MG7"
+ maintaining Blueprints in a large project though could be a lot better
+ maintaining Blueprints in a large project could be a lot better
% id = "01H8Y0CKD1PPEPX8EEFRAM2VE1"
+ with regards to your graphs becoming really large
@ -173,10 +172,10 @@
- everybody kinda sorta just formats nodes however they see fit, and there is no unified autoformatter
% id = "01H8Y0CKD1VRVNMZ827RF7XBCA"
- there's a reason people say Go's tooling is frickin' amazing, you know
- there's a reason people say Go's tooling is frickin' amazing, you know. it keeps codebases consistent!
% id = "01H8Y0CKD1980VGHFBYGM8PN3E"
+ this results in what we Hat in Time modders used to call _Kismetti_ in the Unreal Engine 3 days but now we'd call _Blueprintti_
+ this results in what we Hat in Time modders used to call _Kismetti_ in the Unreal Engine 3 days but nowadays we'd call _Blueprintti_
% id = "01H8Y0CKD179SBZ58F5JMDC5F3"
+ which is a portmanteau of Blueprint and spaghetti.
@ -203,7 +202,7 @@
- and not asynchronously in the background, you will have to _wait_ for it to finish loading. which is pretty annoying
% id = "01H8Y0CKD16HEQKQX1NJG9GG42"
+ and the runtime performance isn't the best for a few reasons
+ the runtime performance isn't the best for a few reasons
% id = "01H8Y427B1ZKJA16V17NG80QHS"
- the VM isn't implemented in the most optimal way
@ -221,7 +220,7 @@
- and it's not hard to extract the performance sensitive parts to C++ because Blueprint offers tools for refactoring your code
% id = "01H8YT7R15MFW3RRQAF8CM4EP6"
- but that doesn't prevent me from liking it!
- but all that doesn't prevent me from liking it!
% id = "01H8YT7R15ZJWBY0TN6F6HN95Y"
- since it's way more pleasant to write game logic in than C++, given that you don't need to wait a minute for your code to recompile.