Remove nonlinear fog from FL0 (#9658)

* Remove fog and lighting uniforms from FL0

---------

Co-authored-by: Mathias Agopian <mathias@google.com>

Author: PatRibas

libs/filamat/src/shaders/UibGenerator.cpp

@@ -182,16 +182,16 @@ BufferInterfaceBlock const& UibGenerator::getPerViewUib() noexcept  {
             // ------------------------------------------------------------------------------------
             // Fog [variant: FOG]
             // ------------------------------------------------------------------------------------
-            { "fogDensity",              0, Type::FLOAT3,Precision::HIGH, FeatureLevel::FEATURE_LEVEL_0 },
+            { "fogDensity",              0, Type::FLOAT3,Precision::HIGH },
             { "fogStart",                0, Type::FLOAT, Precision::HIGH, FeatureLevel::FEATURE_LEVEL_0 },
-            { "fogMaxOpacity",           0, Type::FLOAT, Precision::DEFAULT, FeatureLevel::FEATURE_LEVEL_0 },
+            { "fogMaxOpacity",           0, Type::FLOAT, Precision::DEFAULT },
             { "fogMinMaxMip",            0, Type::UINT,  Precision::HIGH },
-            { "fogHeightFalloff",        0, Type::FLOAT, Precision::HIGH, FeatureLevel::FEATURE_LEVEL_0 },
+            { "fogHeightFalloff",        0, Type::FLOAT, Precision::HIGH },
             { "fogCutOffDistance",       0, Type::FLOAT, Precision::HIGH, FeatureLevel::FEATURE_LEVEL_0 },
             { "fogColor",                0, Type::FLOAT3, Precision::DEFAULT, FeatureLevel::FEATURE_LEVEL_0 },
-            { "fogColorFromIbl",         0, Type::FLOAT, Precision::DEFAULT, FeatureLevel::FEATURE_LEVEL_0 },
-            { "fogInscatteringStart",    0, Type::FLOAT, Precision::HIGH, FeatureLevel::FEATURE_LEVEL_0 },
-            { "fogInscatteringSize",     0, Type::FLOAT, Precision::DEFAULT, FeatureLevel::FEATURE_LEVEL_0 },
+            { "fogColorFromIbl",         0, Type::FLOAT, Precision::DEFAULT },
+            { "fogInscatteringStart",    0, Type::FLOAT, Precision::HIGH },
+            { "fogInscatteringSize",     0, Type::FLOAT, Precision::DEFAULT },
             { "fogOneOverFarMinusNear",  0, Type::FLOAT, Precision::HIGH },
             { "fogNearOverFarMinusNear", 0, Type::FLOAT, Precision::HIGH },
             { "fogFromWorldMatrix",      0, Type::MAT3, Precision::HIGH, FeatureLevel::FEATURE_LEVEL_0 },

shaders/src/surface_fog.fs

@@ -3,12 +3,9 @@
 // see: Real-time Atmospheric Effects in Games (Carsten Wenzel)
 //------------------------------------------------------------------------------
 
-vec4 fog(highp vec3 view
 #if MATERIAL_FEATURE_LEVEL > 0
-    , const mediump samplerCube fogColorTexture
-#endif
-)
-{
+
+vec4 fog(highp vec3 view, const mediump samplerCube fogColorTexture) {
     // note: d can be +inf with the skybox
     highp float d = length(view);
 
@@ -86,6 +83,8 @@ vec4 fog(highp vec3 view
     return vec4(fogColor, fogOpacity);
 }
 
+#endif  // MATERIAL_FEATURE_LEVEL > 0
+
 // A linear approximation of the fog function
 vec4 fogLinear(highp vec3 view
 #if MATERIAL_FEATURE_LEVEL > 0

shaders/src/surface_main.fs

@@ -73,11 +73,7 @@ void main() {
     vec4 fogColor = fog(view, sampler0_fog);
 #   endif
 #else
-#   if defined (FILAMENT_LINEAR_FOG)
     vec4 fogColor = fogLinear(view);
-#   else
-    vec4 fogColor = fog(view);
-#   endif
 #endif
 
 #   if   defined(BLEND_MODE_OPAQUE)