DRTVWR-559 Revert skies to be very close to release and disable tone mapping when probe ambiance is zero.

Hack for desaturating legacy materials has been removed for performance and quality reasons.

Adds a new setting for auto adjusting legacy skies.  This is the PBR "opt out" button.  If disabled, legacy skies will disable tonemapping, automatic probe ambiance, and HDR/exposure.  If enabled, legacy skies will behave as if probe ambiance and HDR scale are 1.0, and ambient will be cut in half.  

HDR scale will act as a sky brightener, but will automatically adjust dynamic exposure so the sky will be properly exposed.  If you want relatively even exposure all the time, set HDR Scale to 1.0.  If you want a high range of exposures between indoor/dark areas and outdoor/bright areas, increase HDR Scale.

Also tuned up SSAO (thanks Rye!).

Reviewed with Brad.

1 files changed, 11 insertions, 2 deletions

diff --git a/indra/llinventory/llsettingssky.h b/indra/llinventory/llsettingssky.h
index 7ae569dd4c..f55e9f0631 100644
--- a/indra/llinventory/llsettingssky.h
+++ b/indra/llinventory/llsettingssky.h
@@ -134,10 +134,12 @@ public:
     F32 getSkyIceLevel() const;
 
     // get the probe ambiance setting as stored in the sky settings asset
-    F32 getReflectionProbeAmbiance() const;
+    // auto_adjust - if true and canAutoAdjust() is true, return 1.0
+    F32 getReflectionProbeAmbiance(bool auto_adjust = false) const;
 
     // get the probe ambiance setting to use for rendering (adjusted by cloud shadow, aka cloud coverage)
-    F32 getTotalReflectionProbeAmbiance(F32 cloud_shadow_scale) const;
+    // auto_adjust - if true and canAutoAdjust() is true, return 1.0
+    F32 getTotalReflectionProbeAmbiance(F32 cloud_shadow_scale, bool auto_adjust = false) const;
 
     // Return first (only) profile layer represented in LLSD
     LLSD getRayleighConfig() const;
@@ -334,6 +336,10 @@ public:
                     F32 aniso_factor = 0.0f);
 
     virtual void        updateSettings() SETTINGS_OVERRIDE;
+
+    // if true, this sky is a candidate for auto-adjustment
+    bool canAutoAdjust() const { return mCanAutoAdjust; }
+
 protected:
     static const std::string SETTING_LEGACY_EAST_ANGLE;
     static const std::string SETTING_LEGACY_ENABLE_CLOUD_SCROLL;
@@ -377,6 +383,9 @@ private:
     mutable LLColor4    mTotalAmbient;
     mutable LLColor4    mHazeColor;
 
+    // if true, this sky is a candidate for auto adjustment
+    bool mCanAutoAdjust = true;
+
     typedef std::map<std::string, S32> mapNameToUniformId_t;
 
     static mapNameToUniformId_t sNameToUniformMapping;