pr0g / unity-portal-rendering

Super small example of using offscreen render targets to achieve a portal effect in Unity

unity-portal-rendering

Overview

Super small example of using off-screen render targets to achieve a portal effect in Unity.

Info

Please see this accompanying blog post http://tomhulton.blogspot.co.uk/2015/08/portal-rendering-with-offscreen-render.html for an explanation of the techniques involved.

• UPDATE (2020/07/22,23): Upgraded Unity project, minor desktop camera improvements, fixed minor bug with Teleport.cs, renamed main branch.
• UPDATE (2019/01/28): Added touch screen camera controls when running on device.
• UPDATE (2019/01/21): Added teleportation (so moving through a portal will spit you out the other side).

Note: There's an artefact you'll encounter when moving through a portal where the near clip plane of the camera will clip with the portal texture quad. You wouldn't get this if using the portal stencil buffer technique but unfortunately with render buffers there's no clean way around it. The logic can still be applied if you'd like to use it elsewhere.

Controls

Desktop

WASD - Camera forward/backward/strafe
EQ - Camera adjust height
Right Mouse Button + Mouse Move - Look around
C - Cycle between main camera and portal camera views

Device

One Finger, Hold + Move - Look around
One Finger, Double Tap + Hold - Move forward
Two Fingers, Pinch - Move forward/backward
Two Fingers, Pan - Move up/down/left/right (Camera space)
Three Fingers, Tap - Cycle cameras

Extra

I highly recommend checking out this excellent YouTube video on Portals by Sebastian Lague.

It covers quite a few more details that you might need for a full game and also comes with its own GitHub repo.

The video also kindly gives a shout out to the original article posted along with this repo! 😄

unity-portal-rendering's Issues

Portal view upside down

Each portal's view is upside down, if I try to rotate it 180 degrees so that it becomes normal it stays the same in play mode.

Was it a bug I had while opening the project? Or it's a known bug?

RenderTexture Distorted in iPhone landscape mode.

When trying this awesome demo in my iPhone in landscape mode the render texture inside the portal appears distorted before entering inside the Portal…

Can this be fixed? Thanks a lot.

Portal Shader Stretched on iPad

Heya,

When compiled for iOS 11 metal, this shader is a bitch stretched on an iPad.
Anybody know why?

Cheers!

don't render objects between destination camera and frame

Every object that is located between the destination camera and destination portal should be clipped.

A way to do it in opengl:

• Shader-side (GLSL):

uniform vec4 clip;
...
gl_ClipDistance[0] = dot(clip, gl_Vertex);

• App-side, communicate the portal plane as the "clip" uniform.

Thanks!