Screen size in shader?

I remember seeing builtin screen size variables in some shader code at some point. They are equivalent to Screen.height and Screen.width but i cant find anything about them now. Are there really any builtin variables for these values? if not there should be. I really dont want to have to assign these as global shader values because i need it to work without any code besides the shader itself.

 

As far as I know, the only built-in values available from shaders are documented here.

 

Thanks, this is for my visual shader editor. I want to make a ScreenSize node. I guess I will have to let the end user make their own node for this if they need it.

 

For anyone looking, the answer to this question as of Unity3.5 is _ScreenParams.x and _ScreenParams.y

 

Thank you Jeff! Was helpful.

 

for anyone coming from google, the url is 404 now.
it can now be found here: https://docs.unity3d.com/462/Documentation/Manual/SL-BuiltinValues.html

 

Or here if you want the documentation for the latest version of Unity instead of the version from 4 years ago:
https://docs.unity3d.com/Manual/SL-UnityShaderVariables.html

 

thanks sooooo much!

 

As documentation said :
"x is the width of the camera’s target texture in pixels, y is the height of the camera’s target texture in pixels, z is 1.0 + 1.0/width and w is 1.0 + 1.0/height."

So if I understand the _ScreenParams refer more to a target texture than the screen size.

In my case I create a RenderTexture on which the camera will render, so I set the target texture size of that camera and it's not the same as the screen size.
I may missed something but as I undertand I don't have a way to get the screen size ?