Physics: Revolute joint busted when using Image Point 0

Problem Description

If you add revolute joints to physics objects and tell it to use image point 0 as hinge (and you moved the center correctly), it will still use an imaginary midpoint instead of image point 0. If you add another image point and use that one instead, it works as expected. Tested on Box2D web, and Box2D asm.js.

Attach a Capx

http://honigmilch.com/capx/revolute_joint.capx

Description of Capx

Left rope uses image point 0, right rope uses image point 1, to show the difference.

Steps to Reproduce Bug

Hit F5.

Observed Result

An imaginary midpoint is used as hinge

Expected Result

The correct image point 0 should be used as a hinge

Affected Browsers

• Chrome: (YES)
• FireFox: (n/a)
• Internet Explorer: (n/a)

Operating System and Service Pack

Win7 64

Construct 2 Version ID

R165

I'm glad you took the time to make this. I was having a lot of trouble using revolute joints too. I thought it was broken but the image point stuff is true.!

It's actually by design that image point 0 refers to the centre of gravity, not the origin. However there's a workaround: enter -1 for the image point and it uses the origin.

That is really good to know, Thanks!