[ts][construct3] Runtime development

[davidetan]

This issue tracks updates on the development of the Construct 3 official runtime for Spine.

The C3 renderer can now draw meshes and specify per-vertex colors (currently supported in the runtime, not yet in the editor), which are essential for a Spine runtime.

As development continues, we are encountering missing features and issues that could block an official release. For each, we have opened a GitHub issue, which will be listed here:

• Add Multiply and Screen blending modes Scirra/Construct-feature-requests#626 [blocker]
• WebGPU writeBuffer fails in drawMesh with odd number of index triplets Scirra/Construct-bugs#8746 [blocker]
• Allow addon to request a render Scirra/Construct-feature-requests#615 [non-blocker]
• Add per-vertex colors to editor DrawMesh Scirra/Construct-feature-requests#627 [non-blocker]
• Consistent projectfile PluginProperty value between editor and runtime Scirra/Construct-feature-requests#614 [non-blocker]
• Tween behavior not working with plugin SDKv2 Scirra/Construct-bugs#8851 [non-blocker]
• addChildren in scripting between a first-party addon and SDKv2 third-party addon not working Scirra/Construct-bugs#8852 [non-blocker]
• Expose project file sid of IProjectFile Scirra/Construct-feature-requests#693 [non-blocker]

[star2000]

I found a small problem. Construct's SDK.IProjectFile currently has no method to obtain the path. As a result, if the atlas file is placed in a subfolder, the image file cannot be loaded using a relative path.

[davidetan]

Thanks for reporting this.
I'm happy you are already testing this runtime, but right not it is still in early development and subject to heavy changes.

Right now we are giving priority to other Spine features, but I expect to resume its development soon.

[XHXIAIEIN]

share a method for building C3 plugins, if anyone is interested.

https://en.esotericsoftware.com/forum/d/26169-official-c3-addon--runtime/34

Version Notes

• Spine: 4.3+
• Construct 3: r459+

How to Build Spine-Construct3 addon

If you have claude, you can copy this to claude.

Hey, Claude. Please follow this guide to build a Spine-Construct plugin file.
https://github.com/EsotericSoftware/spine-runtimes/issues/2910#issuecomment-3542036441

Goal

• Fetch only spine-ts (not the entire spine-runtimes repo).
• Faster clone via shallow + blobless + sparse-checkout.
• Build only Construct 3 output (build:construct3), not the full workspace.

---

1) Pull spine-ts only (c3 branch)

Requires a modern Git version that supports sparse-checkout.

git clone --depth 1 --filter=blob:none --sparse --branch c3 https://github.com/EsotericSoftware/spine-runtimes.git tmp
cd tmp
git sparse-checkout set spine-ts

2) Build Construct3 output only

cd spine-ts
npm install --no-audit --no-fund
npm run build:construct3

Note: npm run build:construct3 may take a while (often several minutes). If it looks “stuck”, it’s usually still compiling/bundling.

Output:

• spine-construct3/dist

3) Pack .c3addon

Construct 3 addons are just zip packages with addon.json at the root (the .c3addon extension is basically a renamed zip).

Windows (PowerShell)

Run this inside spine-ts:

Set-Location spine-construct3\dist
Remove-Item ..\spine-construct3-dist.c3addon, ..\spine-construct3-dist.zip -ErrorAction SilentlyContinue
Compress-Archive -Path .\* -DestinationPath ..\spine-construct3-dist.zip -Force
Move-Item -Path ..\spine-construct3-dist.zip -Destination ..\spine-construct3-dist.c3addon -Force

The addon file will be:

• spine-construct3\spine-construct3-dist.c3addon

macOS / Linux (Bash / zsh / WSL)

cd spine-construct3/dist
rm -f ../spine-construct3-dist.c3addon
zip -r ../spine-construct3-dist.c3addon . -x "*.DS_Store" -x "__MACOSX/*"

4) Install in Construct 3

Drag & drop the .c3addon into Construct 3 editor. Restart.

https://editor.construct.net/

note

If you accidentally break the editor with a bad addon, open Construct 3 in safe mode:
https://editor.construct.net/?safe-mode

---

Releases

If this is difficult for you, I'll share a build here.

2025-12-16

spine-construct3-1.0.0.1.c3addon.zip

Example

I've created a sample project here to get you started quickly.

Spine-Example.c3p.zip

[davidetan]

Thanks for anticipating me :)
Feature-wise, it should be almost ready.
I need to make a couple of fixes and some polishing, and then I should be ready to publish it.

[XHXIAIEIN]

Just leaving some feedback from early feedback here.

---

- 1 Mouse object

I've noticed that it currently seems necessary to add a Mouse object to preview the project.

---

- 2 Change resource file folder

if the file path is changed midway through the process, the texture will remain on the canvas.

[davidetan]

Right now the addon is highly unstable. Latest commit is not guarantee to work out of the box.

[avatar45D]

Right now the addon is highly unstable. Latest commit is not guarantee to work out of the box.

We're all looking forward to it :)

[star2000]

@davidetan #2979 Two errors were found

[XHXIAIEIN]

The Constraints seems to still have some issues.
ATLAS AND SKELETON NOT CORRESPONDING Error: IK Constraint not found: aim-ik

issue-spineboy-constraints.zip

Observe

The SpineBoy on the left contains constraints
The SpineBoy on the right does not contain constraints

[davidetan]

This plugin works only with 4.3 assets. Are you exporting assets with 4.3-beta version?

[XHXIAIEIN]

This plugin works only with 4.3 assets. Are you exporting assets with 4.3-beta version?

Oh, I was using version 4.2.43. It worked when I switched to 4.3. Thanks!

[ibiz3091]

@davidetan @XHXIAIEIN Why does each copy of the spine object using the same atlas and skeleton increase the memory occupied by images in proportion to the number of copies of the object on the screen, shouldn't this be optimized?

[davidetan]

@davidetan @XHXIAIEIN Why does each copy of the spine object using the same atlas and skeleton increase the memory occupied by images in proportion to the number of copies of the object on the screen, shouldn't this be optimized?

The addon is still in development and we are not yet at profile/optimization phase.
But thanks for letting us know 👍