Godot: shadow/matte material - no render, only shadow, reflection etc.

[Gibbz]

So this trick has been around for many years in software such as blender and 3ds max. They have a material that receives shadows, or reflections and effects. As the user chooses.

It would be really handy to have a material like this! Im working on something where I need an invisible ground plane. But I want reflections and shadows on the invisible ground.....

Is there anything like this in gd3?

[rredesigns]

How could you have reflections on something that is not visible? Doesn't make sense to me. If it is some kind of mirror then it couldn't be invisible anyway.

You might get away with that using just a reflective plane.

[supagu]

so for example

Say I have an image of a desk. I want to overlay a 3d mug on that desk. But I want to have a plane for the shadow and reflection to appear to make it look like they are falling on the desk. While the desk is in 2d space, i need a shadow and reflection to appear without blocking the 2d image of the desk.

[rredesigns]

That's called a shadow catcher. :)

[reduz]

you can do this fine by sampling the screen texture currently

On Wed, Jul 12, 2017 at 12:11 AM, rredesigns [e-mail]
wrote:

That's called a shadow catcher. :)

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[pgregory]

Would really appreciate some guidance on how to do this. I don't understand the comment "sampling the screen texture", any step by step tutorial or at least pointers would be great. I've got a 2D game that would really shine with some 3D in it, but I need to have the 3D cast a shadow onto the 2D background.

[siamak-s]

Any idea about Shadow Catcher on Godot? or any tutorial on @reduz idea's?
It seems this issue doesn't take any decision yet, no bug label, no milestone, no idea ...

[siamak-s]

I found that!
Simple shader something like below can do Shadow Capturing:
`
shader_type spatial;

void fragment() {
ALBEDO = texture(SCREEN_TEXTURE, SCREEN_UV).rgb;
}
`

[akien-mga]

Feature and improvement proposals for the Godot Engine are now being discussed and reviewed in a dedicated Godot Improvement Proposals (GIP) (godotengine/godot-proposals) issue tracker. The GIP tracker has a detailed issue template designed so that proposals include all the relevant information to start a productive discussion and help the community assess the validity of the proposal for the engine.

The main (godotengine/godot) tracker is now solely dedicated to bug reports and Pull Requests, enabling contributors to have a better focus on bug fixing work. Therefore, we are now closing all older feature proposals on the main issue tracker.

If you are interested in this feature proposal, please open a new proposal on the GIP tracker following the given issue template (after checking that it doesn't exist already). Be sure to reference this closed issue if it includes any relevant discussion (which you are also encouraged to summarize in the new proposal). Thanks in advance!

[clayjohn]

Note, that this suggestion is already in the engine as siamak-s pointed out.