Custom multi camera view shape - triangle / trapeze

Gacu007

Hi,

Im new in Godot and I have problem.
How can I make camera view which is not rectangle?
I want to be able to make many triangle or trapeze shape cameras views in one screen - some sort of weird split screen 😃

I tried those:

Lego Split Screen
ViewportTexture tutorial.
Official Viewport as Texture tutorial - this one is tough and i couldn't get from it the parts which are needed

Do you know what Godot knowledge should I get to achieve my goal?

cybereality

One way would be to use a Viewport to render the 3D scene, get the Texture from the Viewport, and then map this onto a triangle or any 3D shape. However, keep in mind that viewports are expensive (it can be like rendering the whole scene an additional time for each viewport) so it gets rather expensive. 2 viewports is okay, once you get to 3 or above the frame rate drops a lot. You can reduce the resolution on the portal viewports, like half resolution, or only render some objects, which helps. But it still costs a lot of performance.

Gacu007

cybereality

How can I Map the viewport texture?
I got things like below:

I set viewport resolution 1920x1080
And then I attach viewport texture to sprite3D:

But how get desired shape?

vmjcv

Gacu007
you need use shader

vmjcv

Megalomaniak
i know it.
this is git: https://github.com/godotengine/godot-demo-projects/tree/master/viewport
Gacu007

Megalomaniak

vmjcv To add to that, what OP is likely looking to implement is a voronoi split screen, here s a tutorial, albeit not for godot but cocos2D, but it gives a good overview:

edit: and a whitepaper:
https://conference.imp.fu-berlin.de/eurocg18/download/paper_34.pdf

and lo and behold, a godot demo for a dynamic split screen:
https://godotengine.org/asset-library/asset/541

cybereality

No, you don't need shaders. This is all the code that is needed (for example on _ready()):

var view_tex = viewport.get_texture()
triangle.get_node("Plane").get_surface_material(0).albedo_texture = view_tex

Megalomaniak

cybereality No, you don't need shaders.

For the n-user use-case it might offer some benefits though I'm not 100% sure.

Tomcat

cybereality No, you don't need shaders. This is all the code that is needed (for example on _ready()):

On this principle can a reflection be made in shards of a mirror?

vmjcv

cybereality
I thought what he needed was dynamic_ split_ screen, so i think he need shader, like this : https://github.com/godotengine/godot-demo-projects/blob/master/viewport/dynamic_split_screen/split_screen.shader

But if he just needs to show the image of the camera, you are right

cybereality

Megalomaniak For the n-user use-case it might offer some benefits though I'm not 100% sure.

You can generate viewports in code, all in GDScript, so a shader is not strictly needed. Though you could possibly do some more advanced effects using shaders, in the base case a viewport texture mapped to a mesh is enough.

cybereality

Tomcat On this principle can a reflection be made in shards of a mirror?

Yes, that same code I posted could be used as a mirror (however you would have to update the viewport camera to be the reflection of the real camera every frame, but that is also like 1 line of code).

cybereality

Yes, for dynamic split screen you would need a shader. But the author was not exactly clear about what they needed or what the use case was, so I gave them a simple example.

Gacu007

Thank you all for replies!
I can now show some more details.
I need to have trapzeze/triangle screens to simulate Holographic Pyramid view as presented on image below.
The screen should show 3 viewports: 2 trapezes and 1 triangle combined together.

Screen should show some 3D object from 3 sides.
So left trapeze - left side, triangle - front side, right trapeze - right side.
Blank on the upper center should stay blank.
I couldn't share more details before, but now I can 🙂

So to do this I tried to put viewport textures on 3 elements, and then place a camera which look on those elements - in result i got 3views of the object on the screen. But if it is possible to obtain with shaders - It would be better idea.

Could you tell me more about it?

Gacu007

Hey, I still don't know the answer, can somebody help me? 🙂

cybereality

Did you try my sample I made? That should work.