Restore Lighting.j3md fog in SinglePass by fixing SPLighting varying linkage

[Copilot]

Lighting.j3md fog parameters (UseFog, LinearFog/ExpFog/ExpSqFog) were no longer taking effect in 3.10.0-alpha4 on the SinglePass path. The fog distance computed in SPLighting.vert was not reaching MaterialFog.glsllib due to a varying name mismatch.

• Root cause

  • SPLighting.vert exported fog distance as fog_distance, while fog consumers (MaterialFog.glsllib + fragment shaders) read fogDistance.

• Change

  • Updated Common/MatDefs/Light/SPLighting.vert to use fogDistance consistently for declaration and assignment.

• Impact

  • Reconnects vertex-to-fragment fog distance flow in SinglePass lighting, restoring effective fog blending for Lighting.j3md.

// SPLighting.vert
#ifdef USE_FOG
-varying float fog_distance;
+varying float fogDistance;
#endif

#ifdef USE_FOG
-    fog_distance = distance(g_CameraPosition, (TransformWorld(modelSpacePos)).xyz);
+    fogDistance = distance(g_CameraPosition, (TransformWorld(modelSpacePos)).xyz);
#endif

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• dl.google.com
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java /usr/lib/jvm/temurin-17-jdk-amd64/bin/java --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang.invoke=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-opens=java.base/java.nio.charset=ALL-UNNAMED --add-opens=java.base/java.net=ALL-UNNAMED --add-opens=java.base/java.util.concurrent=ALL-UNNAMED --add-opens=java.base/java.util.concurrent.atomic=ALL-UNNAMED --add-opens=java.xml/javax.xml.namespace=ALL-UNNAMED --add-opens=java.base/java.time=ALL-UNNAMED -XX:MaxMetaspaceSize=384m -XX:+HeapDumpOnOutOfMemoryError -Xms256m -Xmx512m -Dfile.encoding=UTF-8 (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)