Box2D ChainShape is broken

Issue details

The latest Box2D version (1.9.7) fails to create correct chain shapes that used to work with previous versions.

Reproduction steps/code

import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.physics.box2d.BodyDef;
import com.badlogic.gdx.physics.box2d.ChainShape;
import com.badlogic.gdx.physics.box2d.FixtureDef;
import com.badlogic.gdx.physics.box2d.World;

public class Test extends ApplicationAdapter {
	@Override
	public void create () {
		World world = new World(new Vector2(), true);
		BodyDef bodyDef = new BodyDef();
		FixtureDef fixtureDef = new FixtureDef();
		ChainShape shape = new ChainShape();
		float[] vertices = {0f, 0f, 1f, 1f, 0f, 1f};
		shape.createChain(vertices);
		fixtureDef.shape = shape;
		world.createBody(bodyDef).createFixture(fixtureDef);
	}
}

This code snippet works correctly on LibGDX 1.9.6, but fails on LibGDX 1.9.7 with a native error.

Version of LibGDX and/or relevant dependencies

1.9.7 (LibGDX + Box2D).

Stacktrace

java: /var/lib/jenkins/workspace/libgdx/extensions/gdx-box2d/gdx-box2d/jni/Box2D/Collision/Shapes/b2ChainShape.cpp:62: void b2ChainShape::CreateChain(const b2Vec2*, int32): Assertion `count >= 2' failed.

Affected platforms

Note that I checked only on Linux Mint, but other platforms are expected to be affected as well.

• Android
• iOS (robovm)
• iOS (MOE)
• HTML/GWT
• Windows
• Linux
• MacOS

[czyzby]

@Tom-Ski Is a hotfix release planned or should we wait a few months for 1.9.8?

[Tom-Ski]

This issue is a duplicate. See issue referred too for the tracking of this issue. Fixed and released in 1.9.8 as the tag on the commit shows.