Godot: Bullet PR: Ray shape logic is different than in Godot

[kubecz3k]

Operating system or device, Godot version, GPU Model and driver (if graphics related):
Ubuntu 17.04, This issue is related to bullet pr, it's present in: e6655f4
tested on release_debug build

Issue description:
As far as I know ray shapes in Godot are a special kind of shapes ~that propagate/receives forces only along the ray normal~ (might be wrong, hope @reduz will clarify). Those are very handful in dynamic controller scenario, to deal with slopes or create hovers in a very easy way.
Quick Video: https://www.youtube.com/watch?v=Ff0qlG55t_E&feature=youtu.be

Steps to reproduce:

1. Download sample project
2. Run RayShapeTest.tscn

Link to minimal example project:
BulletRayShapeSlopes.zip

[kubecz3k]

@reduz can you give some details on how ray shape should exactly behave?
cc @AndreaCatania

[reduz]

Rayshape just pushes away the object in the ray direction

On Oct 16, 2017 2:46 PM, "kubecz3k" [e-mail] wrote:

@reduz https://github.com/reduz can you give some details on how ray
shape should exactly behave?
cc @AndreaCatania https://github.com/andreacatania

—
You are receiving this because you were mentioned.
Reply to this email directly, view it on GitHub
https://github.com/godotengine/godot/issues/12156#issuecomment-336967363,
or mute the thread
https://github.com/notifications/unsubscribe-auth/AF-Z26zqFbpp2gE6en4CFZkEp_Kn1PG5ks5ss5Z8gaJpZM4P6_dt
.

[AndreaCatania]

I can change it. @reduz the ray shape should receive forces only along its axis?

[reduz]

The ray shape just generates a contact pair between the cast intersection
and the endpoint. That needs to be fed to the manifold

On Oct 16, 2017 2:58 PM, "Andrea Catania" [e-mail] wrote:

I can change it. @reduz https://github.com/reduz the ray shape should
receive forces only along its axis?

—
You are receiving this because you were mentioned.
Reply to this email directly, view it on GitHub
https://github.com/godotengine/godot/issues/12156#issuecomment-336972644,
or mute the thread
https://github.com/notifications/unsubscribe-auth/AF-Z2xAibmb4ouGuBZS_eT-EbKpVsumhks5ss5ljgaJpZM4P6_dt
.

[AndreaCatania]

@reduz So in this moment the shape behaviour is wrong and must be addressed?

[reduz]

@AndreaCatania I have no idea, as @kubecz3k mentions it doesn't work for him.
I was just explaining how it's implemented in the Godot physics. Basically it uses a custom narrowphase where it shoots a ray towrds the opposite shape. If a ray hits into somehting, it puts both the hit position and the ray endpoint (position + direction * length) as a contact pair and adds it to the manifold between both shapes.

[AndreaCatania]

In bullet it does the same thing, with the exception that it reacts to the floor shape that in this case slide along the downhill. I should implement narrowphase algorithms to change this behavior.
I'll ask to Erwien if this is possible in an easier way.

[reduz]

Ah yeah, it should not slide downhill

On Tue, Oct 17, 2017 at 3:59 AM, Andrea Catania [e-mail]
wrote:

In bullet it does the same thing, with the exception that it reacts to the
floor shape that in this case slide along the downhill. I should implement
narrowphase algorithms to change this behavior.
I'll ask to Erwien if this is possible in an easier way.

—
You are receiving this because you were mentioned.
Reply to this email directly, view it on GitHub
https://github.com/godotengine/godot/issues/12156#issuecomment-337136549,
or mute the thread
https://github.com/notifications/unsubscribe-auth/AF-Z2wbILFGL7N7znvSe6MQHyzAIyXtnks5stFA3gaJpZM4P6_dt
.

[AndreaCatania]

Fixed: ce367016f4d1d97d998049287e70fe694377c061

[reduz]

Wow, amazing work

On Mon, Oct 30, 2017 at 10:37 AM, Andrea Catania [e-mail]
wrote:

Fixed: ce36701
https://github.com/godotengine/godot/commit/ce367016f4d1d97d998049287e70fe694377c061

—
You are receiving this because you were mentioned.
Reply to this email directly, view it on GitHub
https://github.com/godotengine/godot/issues/12156#issuecomment-340445670,
or mute the thread
https://github.com/notifications/unsubscribe-auth/AF-Z2w8audMP3QWKZMfgLwMd_92m40WVks5sxdEQgaJpZM4P6_dt
.

[kubecz3k]

Just tested! It works so beautifully now! You are truly awesome!!