diff --git a/docs/shaderManual/stage-directives.html b/docs/shaderManual/stage-directives.html index 28345e97..549125ee 100644 --- a/docs/shaderManual/stage-directives.html +++ b/docs/shaderManual/stage-directives.html @@ -311,7 +311,7 @@
A constant vertex alpha is assigned to the affected surface. This modifies the transparency of the texture.
This rendering stage keyword is normally used in conjunction with the surface parameter keyword portal. The function accomplishes the "fade" that causes the scene in the portal/mirror to fade from view. Specifically, it means "Generate alpha values based on the distance from the viewer to the portal". Viewer distance 0 maps to alpha 0, when distance is more than "distance" parameter value, alpha is 1. While latter is the case, portal/mirror content is not rendering at all, this optimization is original purpose of the keyword, though it may be utilized for other distance dependent effects.
+This rendering stage keyword is normally used in conjunction with the surface parameter keyword portal. It is mandatory for portals to work (but not for mirrors). The function accomplishes the "fade" that causes the scene in the portal/mirror to fade from view. Specifically, it means "Generate alpha values based on the distance from the viewer to the portal". Viewer distance 0 maps to alpha 0, when distance is more than "distance" parameter value, alpha is 1. While latter is the case, portal/mirror content is not rendering at all, this optimization is original purpose of the keyword, though it may be utilized for other distance dependent effects.
Basic fading portal/mirror shader example:
@@ -323,14 +323,10 @@