[BACKEND] New scripting backend using `cppia` #5087

lemz1 · 2025-05-14T16:15:17Z

Linked Issues

Description

This pr changes the scripting backend from hscript to cppia.
cppia is more performant, more type-safe than hscript, and has much better haxe language support.

Problem

It seems as if functions arguments are not passed correctly to the cppia scripts. I noticed some bizarre problems, for example TankmanBloodyCharacter.hx: event in onUpdate is null, which does not make sense.
OtisSpeakerCharacter.hx: scriptEvent in onSongEvent is of type Int with the value 1.

The above seems to rather be an issue with hxcpp, when i tried debugging it, it mentioned that it was trying to access instance fields as static. I dont know why this happens, since i do not see a pattern which leads to this happening. I'm gonna see if i can figure why this happens.

Note

A few scripts had some changes that i deemed necessary to mention, so just look in the scripts for // CPPIA:.

Todo

port base game scripts
fetch the haxe compiler using environment variable
make base game scripts work with cppia
figure out how to properly block access to blacklisted classes
mod support

AbnormalPoof · 2025-05-14T16:16:35Z

HOLY

lemz1 · 2025-05-14T16:16:48Z

hmm.json

+      "ref": "d914cac17779efad8b3aa6f4a12dff566518d1b9",
+      "url": "https://github.com/lemz1/hscript"


temporary compilation fix
will be removed when we remove hscript entirely

lemz1 · 2025-05-14T16:17:35Z

project.hxp

@@ -503,7 +503,7 @@ class Project extends HXProject {
 		FEATURE_POLYMOD_MODS.apply(this, true);
 		FEATURE_FUNKVIS.apply(this, true);
 		FEATURE_PARTIAL_SOUNDS.apply(this, true);
-		FEATURE_VIDEO_PLAYBACK.apply(this, true);
+		FEATURE_VIDEO_PLAYBACK.apply(this, false);


temporary change to fix compilation issues

lemz1 · 2025-05-14T16:17:40Z

project.hxp

@@ -525,7 +525,7 @@ class Project extends HXProject {

 		// Should be true on desktop, release, non-tester builds.
 		// We don't want testers to accidentally leak songs to their Discord friends!
-		FEATURE_DISCORD_RPC.apply(this, isDesktop() && !FEATURE_DEBUG_FUNCTIONS.isEnabled(this));
+		FEATURE_DISCORD_RPC.apply(this, isDesktop() && !FEATURE_DEBUG_FUNCTIONS.isEnabled(this) && false);


temporary change to fix compilation issues

source/funkin/modding/ScriptHandler.hx

Hundrec · 2025-05-21T02:54:11Z

Promoted to huge!

maybe need to include definition for abstracts

AbnormalPoof

Would it be possible to just use the haxe installation the user already has? Copying the entire haxe repository seems a bit much, especially considering it'll be extremely difficult to maintain.

lemz1 · 2025-05-25T20:50:22Z

Would it be possible to just use the haxe installation the user already has?

No, since this would require people to install haxe when they want to play friday night funkin. Also every user, should have the same haxe version, and by shipping the game with the compiler this requirement is satisfied.

Copying the entire haxe repository seems a bit much, especially considering it'll be extremely difficult to maintain.

We aren't copying the entire haxe repository, later on i will implement fetching the binaries from the releases in the haxe repository.

lemz1 · 2025-05-27T19:16:26Z

source/PostbuildCppia.hx

+  {
+    trace('Initializing Haxe compiler...');
+
+    var haxeCompilerSrc:String = Path.normalize(Sys.getEnv("HAXEPATH"));


not sure whether it's better to use the installed haxe compiler,
or to fetch a specific version using git

using git would be nicer, because we have a consistent haxe version and not some useless files like lime.exe, hmm.cmd, etc.

however, we'd need a constant internet connection, and it might be a bit slower than directly copying files

you could always fetch from git on first compile, save it somewhere for other compiles, and update it only if the commit has been changed

i will have to revert to using the previous technique (generating extern classes myself)

not finished though, yet

TheoDevelops · 2025-06-24T20:04:37Z

This is impressive, ngl !
If this ends working properly this would be a huge step for FNF scripting

github-actions bot added status: pending triage Awaiting review. pr: haxe PR modifies game code. size: medium A medium pull request with 100 or fewer changes. labels May 14, 2025

lemz1 changed the base branch from main to develop May 14, 2025 16:15

lemz1 marked this pull request as draft May 14, 2025 16:16

lemz1 commented May 14, 2025

View reviewed changes

Hundrec added the type: enhancement Involves an enhancement or new feature. label May 14, 2025

AbnormalPoof added the topic: mods Related to the creation or use of mods. label May 14, 2025

EliteMasterEric added size: medium A medium pull request with 100 or fewer changes. and removed size: medium A medium pull request with 100 or fewer changes. labels May 14, 2025

github-actions bot added size: large A large pull request with more than 100 changes. and removed size: medium A medium pull request with 100 or fewer changes. labels May 14, 2025

lemz1 force-pushed the feature/cppia branch from 143029c to 1bca3f4 Compare May 14, 2025 23:32

AbnormalPoof reviewed May 15, 2025

View reviewed changes

source/funkin/modding/ScriptHandler.hx Outdated Show resolved Hide resolved

lemz1 added 3 commits May 17, 2025 00:12

Create ScriptHandler.hx

60fe27d

fix compilation

d417f74

use dll_export

375b708

HostClasses macro

c10f9fb

lemz1 and others added 6 commits May 21, 2025 22:58

some fixes

7e284a0

fix

736af9b

another fix

e581877

Create AbstractBuilder.hx

b9dedb5

weirdness with abstracts

a1e448c

maybe need to include definition for abstracts

Update HostClasses.hx

f54f438

github-actions bot added size: large A large pull request with more than 100 changes. and removed size: huge A huge pull request with more than 500 changes. labels May 24, 2025

Update HostClasses.hx

fa0c09e

github-actions bot added size: huge A huge pull request with more than 500 changes. and removed size: large A large pull request with more than 100 changes. labels May 24, 2025

lemz1 added 2 commits May 25, 2025 15:52

add haxe compiler

e364def

still not fully working

633d65a

AbnormalPoof added the topic: breaking change Introduces a change that is not compatible with older versions. Existing code may need revision. label May 25, 2025

AbnormalPoof requested changes May 25, 2025

View reviewed changes

lemz1 added 2 commits May 27, 2025 00:05

works somewhat, but im gonna need to change this

dda6ee3

some nicer stuff

e3a75ce

lemz1 commented May 27, 2025

View reviewed changes

lemz1 added 6 commits May 27, 2025 23:35

i wasted so much time

6158c50

i will have to revert to using the previous technique (generating extern classes myself)

back to the roots, but better

875bce3

not finished though, yet

instead of expr().toString(true), we need to do our own

b1cb458

fix some erros

33c2c6e

some more fixes

f5ec264

finally scripts compile

92e6fdd

AbnormalPoof added status: needs revision Cannot be approved because it is awaiting some work by the contributor. and removed status: pending triage Awaiting review. labels Jun 24, 2025

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[BACKEND] New scripting backend using `cppia` #5087

[BACKEND] New scripting backend using `cppia` #5087

lemz1 commented May 14, 2025 •

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		"ref": "d914cac17779efad8b3aa6f4a12dff566518d1b9",
		"url": "https://github.com/lemz1/hscript"

[BACKEND] New scripting backend using cppia #5087

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[BACKEND] New scripting backend using cppia #5087

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[BACKEND] New scripting backend using `cppia` #5087

[BACKEND] New scripting backend using `cppia` #5087

lemz1 commented May 14, 2025 •

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lemz1 commented May 25, 2025 •

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