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.

36 files changed, 277 insertions, 215 deletions

diff --git a/indra/llinventory/llsettingssky.cpp b/indra/llinventory/llsettingssky.cpp
index eb8385281c..6521ec8b43 100644
--- a/indra/llinventory/llsettingssky.cpp
+++ b/indra/llinventory/llsettingssky.cpp
@@ -403,6 +403,7 @@ LLSettingsSky::LLSettingsSky(const LLSD &data) :
     mNextRainbowTextureId(),
     mNextHaloTextureId()
 {
+    mCanAutoAdjust = !data.has(SETTING_REFLECTION_PROBE_AMBIANCE);
 }
 
 LLSettingsSky::LLSettingsSky():
@@ -425,6 +426,8 @@ void LLSettingsSky::replaceSettings(LLSD settings)
     mNextBloomTextureId.setNull();
     mNextRainbowTextureId.setNull();
     mNextHaloTextureId.setNull();
+
+    mCanAutoAdjust = !settings.has(SETTING_REFLECTION_PROBE_AMBIANCE);
 }
 
 void LLSettingsSky::replaceWithSky(LLSettingsSky::ptr_t pother)
@@ -437,6 +440,7 @@ void LLSettingsSky::replaceWithSky(LLSettingsSky::ptr_t pother)
     mNextBloomTextureId = pother->mNextBloomTextureId;
     mNextRainbowTextureId = pother->mNextRainbowTextureId;
     mNextHaloTextureId = pother->mNextHaloTextureId;
+    mCanAutoAdjust = pother->mCanAutoAdjust;
 }
 
 void LLSettingsSky::blend(const LLSettingsBase::ptr_t &end, F64 blendf) 
@@ -1429,18 +1433,23 @@ F32 LLSettingsSky::getSkyIceLevel() const
     return mSettings[SETTING_SKY_ICE_LEVEL].asReal();
 }
 
-F32 LLSettingsSky::getReflectionProbeAmbiance() const
+F32 LLSettingsSky::getReflectionProbeAmbiance(bool auto_adjust) const
 {
+    if (auto_adjust && canAutoAdjust())
+    {
+        return 1.f;
+    }
+
     return mSettings[SETTING_REFLECTION_PROBE_AMBIANCE].asReal();
 }
 
-F32 LLSettingsSky::getTotalReflectionProbeAmbiance(F32 cloud_shadow_scale) const
+F32 LLSettingsSky::getTotalReflectionProbeAmbiance(F32 cloud_shadow_scale, bool auto_adjust) const
 {
     // feed cloud shadow back into reflection probe ambiance to mimic pre-reflection-probe behavior 
     // without brightening dark/interior spaces
-    F32 probe_ambiance = getReflectionProbeAmbiance();
+    F32 probe_ambiance = getReflectionProbeAmbiance(auto_adjust);
 
-    if (probe_ambiance > 0.f)
+    if (probe_ambiance > 0.f && probe_ambiance < 1.f)
     {
         probe_ambiance += (1.f - probe_ambiance) * getCloudShadow() * cloud_shadow_scale;
     }
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;
diff --git a/indra/llrender/llshadermgr.cpp b/indra/llrender/llshadermgr.cpp
index 01bad3a684..f398526b41 100644
--- a/indra/llrender/llshadermgr.cpp
+++ b/indra/llrender/llshadermgr.cpp
@@ -1266,13 +1266,11 @@ void LLShaderMgr::initAttribsAndUniforms()
 	mReservedUniforms.push_back("lightnorm");
 	mReservedUniforms.push_back("sunlight_color");
 	mReservedUniforms.push_back("ambient_color");
+    mReservedUniforms.push_back("sky_hdr_scale");
 	mReservedUniforms.push_back("blue_horizon");
-    mReservedUniforms.push_back("blue_horizon_linear");
-	mReservedUniforms.push_back("blue_density");
-    mReservedUniforms.push_back("blue_density_linear");
-	mReservedUniforms.push_back("haze_horizon");
+    mReservedUniforms.push_back("blue_density");
+    mReservedUniforms.push_back("haze_horizon");
 	mReservedUniforms.push_back("haze_density");
-    mReservedUniforms.push_back("haze_density_linear");
 	mReservedUniforms.push_back("cloud_shadow");
 	mReservedUniforms.push_back("density_multiplier");
 	mReservedUniforms.push_back("distance_multiplier");
@@ -1460,9 +1458,6 @@ void LLShaderMgr::initAttribsAndUniforms()
     mReservedUniforms.push_back("water_edge");
     mReservedUniforms.push_back("sun_up_factor");
     mReservedUniforms.push_back("moonlight_color");
-    mReservedUniforms.push_back("moonlight_linear");
-    mReservedUniforms.push_back("sunlight_linear");
-    mReservedUniforms.push_back("ambient_linear");
 
 	llassert(mReservedUniforms.size() == END_RESERVED_UNIFORMS);
 
diff --git a/indra/llrender/llshadermgr.h b/indra/llrender/llshadermgr.h
index 8c19c80cb0..5d7ab7c53d 100644
--- a/indra/llrender/llshadermgr.h
+++ b/indra/llrender/llshadermgr.h
@@ -102,13 +102,11 @@ public:
         LIGHTNORM,                          //  "lightnorm"
         SUNLIGHT_COLOR,                     //  "sunlight_color"
         AMBIENT,                            //  "ambient_color"
+        SKY_HDR_SCALE,                      //  "sky_hdr_scale"
         BLUE_HORIZON,                       //  "blue_horizon"
-        BLUE_HORIZON_LINEAR,                //  "blue_horizon_linear"
         BLUE_DENSITY,                       //  "blue_density"
-        BLUE_DENSITY_LINEAR,                //  "blue_density_linear"
         HAZE_HORIZON,                       //  "haze_horizon"
         HAZE_DENSITY,                       //  "haze_density"
-        HAZE_DENSITY_LINEAR,                //  "haze_density_linear"
         CLOUD_SHADOW,                       //  "cloud_shadow"
         DENSITY_MULTIPLIER,                 //  "density_multiplier"
         DISTANCE_MULTIPLIER,                //  "distance_multiplier"
@@ -285,9 +283,6 @@ public:
         WATER_EDGE_FACTOR,                  //  "water_edge"
         SUN_UP_FACTOR,                      //  "sun_up_factor"
         MOONLIGHT_COLOR,                    //  "moonlight_color"
-        MOONLIGHT_LINEAR,                    //  "moonlight_LINEAR"
-        SUNLIGHT_LINEAR,                     //  "sunlight_linear"
-        AMBIENT_LINEAR,                     //  "ambient_linear"
         END_RESERVED_UNIFORMS
     } eGLSLReservedUniforms;
     // clang-format on
diff --git a/indra/newview/app_settings/settings.xml b/indra/newview/app_settings/settings.xml
index 79e150a6f2..f27444ca27 100644
--- a/indra/newview/app_settings/settings.xml
+++ b/indra/newview/app_settings/settings.xml
@@ -9116,6 +9116,28 @@
     <key>Value</key>
     <real>500.0</real>
   </map>
+  <key>RenderSSAOIrradianceScale</key>
+  <map>
+    <key>Comment</key>
+    <string>Scaling factor for irradiance input to SSAO</string>
+    <key>Persist</key>
+    <integer>0</integer>
+    <key>Type</key>
+    <string>F32</string>
+    <key>Value</key>
+    <real>0.6</real>
+  </map>
+  <key>RenderSSAOIrradianceMax</key>
+  <map>
+    <key>Comment</key>
+    <string>Max factor for irradiance input to SSAO</string>
+    <key>Persist</key>
+    <integer>0</integer>
+    <key>Type</key>
+    <string>F32</string>
+    <key>Value</key>
+    <real>0.18</real>
+  </map>
   <key>RenderSSAOMaxScale</key>
   <map>
     <key>Comment</key>
@@ -10566,40 +10588,29 @@
     <key>Type</key>
     <string>F32</string>
     <key>Value</key>
-    <real>1.25</real>
-  </map>
-  <key>RenderReflectionProbeMaxLocalLightAmbiance</key>
-  <map>
-    <key>Comment</key>
-    <string>Maximum effective probe ambiance for local lights</string>
-    <key>Persist</key>
-    <integer>0</integer>
-    <key>Type</key>
-    <string>F32</string>
-    <key>Value</key>
-    <real>4.0</real>
+    <real>1.0</real>
   </map>
-  <key>RenderDynamicExposureMin</key>
+  <key>RenderSkyAutoAdjustLegacy</key>
   <map>
     <key>Comment</key>
-    <string>Minimum dynamic exposure amount</string>
+    <string>If true, automatically adjust legacy skies (those without a probe ambiance value) to take advantage of probes and HDR.</string>
     <key>Persist</key>
-    <integer>0</integer>
+    <integer>1</integer>
     <key>Type</key>
-    <string>F32</string>
+    <string>Boolean</string>
     <key>Value</key>
-    <real>0.6</real>
+    <integer>1</integer>
   </map>
-  <key>RenderDynamicExposureMax</key>
+  <key>RenderReflectionProbeMaxLocalLightAmbiance</key>
   <map>
     <key>Comment</key>
-    <string>Maximum dynamic exposure amount</string>
+    <string>Maximum effective probe ambiance for local lights</string>
     <key>Persist</key>
     <integer>0</integer>
     <key>Type</key>
     <string>F32</string>
     <key>Value</key>
-    <real>1.5</real>
+    <real>4.0</real>
   </map>
   <key>RenderDynamicExposureCoefficient</key>
   <map>
diff --git a/indra/newview/app_settings/shaders/class1/deferred/fullbrightF.glsl b/indra/newview/app_settings/shaders/class1/deferred/fullbrightF.glsl
index 385cd51969..b752307d13 100644
--- a/indra/newview/app_settings/shaders/class1/deferred/fullbrightF.glsl
+++ b/indra/newview/app_settings/shaders/class1/deferred/fullbrightF.glsl
@@ -44,7 +44,7 @@ vec3 legacy_adjust_fullbright(vec3 c);
 vec3 legacy_adjust(vec3 c);
 vec3 linear_to_srgb(vec3 cl);
 vec3 atmosFragLighting(vec3 light, vec3 additive, vec3 atten);
-void calcAtmosphericVars(vec3 inPositionEye, vec3 light_dir, float ambFactor, out vec3 sunlit, out vec3 amblit, out vec3 additive, out vec3 atten, bool use_ao);
+void calcAtmosphericVars(vec3 inPositionEye, vec3 light_dir, float ambFactor, out vec3 sunlit, out vec3 amblit, out vec3 additive, out vec3 atten);
 
 #ifdef HAS_ALPHA_MASK
 uniform float minimum_alpha;
@@ -85,7 +85,7 @@ void main()
     vec3 amblit;
     vec3 additive;
     vec3 atten;
-    calcAtmosphericVars(pos.xyz, vec3(0), 1.0, sunlit, amblit, additive, atten, false);
+    calcAtmosphericVars(pos.xyz, vec3(0), 1.0, sunlit, amblit, additive, atten);
 #endif
 
 #ifdef WATER_FOG
diff --git a/indra/newview/app_settings/shaders/class1/deferred/postDeferredGammaCorrect.glsl b/indra/newview/app_settings/shaders/class1/deferred/postDeferredGammaCorrect.glsl
index a32296369c..53e4f02314 100644
--- a/indra/newview/app_settings/shaders/class1/deferred/postDeferredGammaCorrect.glsl
+++ b/indra/newview/app_settings/shaders/class1/deferred/postDeferredGammaCorrect.glsl
@@ -102,16 +102,12 @@ vec3 toneMap(vec3 color)
 {
 #ifndef NO_POST
     float exp_scale = texture(exposureMap, vec2(0.5,0.5)).r;
-
+    
     color *= exposure * exp_scale;
 
     color = toneMapACES_Hill(color);
-#else
-    color *= 0.6;
 #endif
 
-    color = linear_to_srgb(color);
-
     return color;
 }
 
@@ -158,10 +154,10 @@ float noise(vec2 x) {
 
 vec3 legacyGamma(vec3 color)
 {
-    color = 1. - clamp(color, vec3(0.), vec3(1.));
-    color = 1. - pow(color, vec3(gamma)); // s/b inverted already CPU-side
+    vec3 c = 1. - clamp(color, vec3(0.), vec3(1.));
+    c = 1. - pow(c, vec3(gamma)); // s/b inverted already CPU-side
 
-    return color;
+    return c;
 }
 
 void main() 
@@ -169,12 +165,14 @@ void main()
     //this is the one of the rare spots where diffuseRect contains linear color values (not sRGB)
     vec4 diff = texture(diffuseRect, vary_fragcoord);
 
-    diff.rgb = toneMap(diff.rgb);
-
 #ifdef LEGACY_GAMMA
-#ifndef NO_POST
+    diff.rgb = linear_to_srgb(diff.rgb);
     diff.rgb = legacyGamma(diff.rgb);
+#else
+#ifndef NO_POST
+    diff.rgb = toneMap(diff.rgb);
 #endif
+    diff.rgb = linear_to_srgb(diff.rgb);
 #endif
 
     vec2 tc = vary_fragcoord.xy*screen_res*4.0;
diff --git a/indra/newview/app_settings/shaders/class1/environment/srgbF.glsl b/indra/newview/app_settings/shaders/class1/environment/srgbF.glsl
index 7111a822c8..31b02377da 100644
--- a/indra/newview/app_settings/shaders/class1/environment/srgbF.glsl
+++ b/indra/newview/app_settings/shaders/class1/environment/srgbF.glsl
@@ -113,18 +113,31 @@ vec3 inv_toneMapACES_Hill(vec3 color)
     return color;
 }
 
+// adjust legacy colors to back out tonemapping and exposure 
+//   NOTE: obsolete now that setting probe ambiance to zero removes tonemapping and exposure, but keeping for a minute
+//   while that change goes through testing - davep 6/1/2023
+#define LEGACY_ADJUST 0
+
 vec3 legacy_adjust(vec3 c)
 {
+#if LEGACY_ADJUST
     vec3 desat = rgb2hsv(c.rgb);
     desat.g *= 1.0-(1.0-desat.b)*0.5;
     desat.b += (1.0-desat.b)*0.1f;
     desat.rgb = hsv2rgb(desat);
     return desat;
+#else
+    return c;
+#endif
 }
 
 vec3 legacy_adjust_fullbright(vec3 c)
 {
+#if LEGACY_ADJUST
     float exp_scale = clamp(texture(exposureMap, vec2(0.5, 0.5)).r, 0.01, 10.0);
     return c / exp_scale * 1.34; //magic 1.34 arrived at by binary search for a value that reproduces midpoint grey consistenty
+#else
+    return c;
+#endif
 }
 
diff --git a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsF.glsl b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsF.glsl
index e314555ef9..48cf234aa0 100644
--- a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsF.glsl
+++ b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsF.glsl
@@ -30,7 +30,7 @@ vec3 scaleSoftClipFrag(vec3 light);
 vec3 srgb_to_linear(vec3 col);
 vec3 linear_to_srgb(vec3 col);
 
-uniform int sun_up_factor;
+uniform float sky_hdr_scale;
 
 vec3 atmosFragLighting(vec3 light, vec3 additive, vec3 atten)
 { 
@@ -38,7 +38,7 @@ vec3 atmosFragLighting(vec3 light, vec3 additive, vec3 atten)
     additive = srgb_to_linear(additive*2.0);
     // magic 1.25 here is to match the default RenderSkyHDRScale -- this parameter needs to be plumbed into sky settings or something
     // so it's available to all shaders that call atmosFragLighting instead of just softenLightF.glsl
-    additive *= sun_up_factor*1.25 + 1.0; 
+    additive *= sky_hdr_scale;
     light += additive;
     return light;
 }
diff --git a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsFuncs.glsl b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsFuncs.glsl
index 4e0933f922..437fa0a6d5 100644
--- a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsFuncs.glsl
+++ b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsFuncs.glsl
@@ -25,27 +25,21 @@
 
 uniform vec3  lightnorm;
 uniform vec3  sunlight_color;
-uniform vec3 sunlight_linear;
 uniform vec3  moonlight_color;
-uniform vec3 moonlight_linear;
 uniform int   sun_up_factor;
 uniform vec3  ambient_color;
-uniform vec3 ambient_linear;
 uniform vec3  blue_horizon;
-uniform vec3 blue_horizon_linear;
 uniform vec3  blue_density;
-uniform vec3 blue_density_linear;
 uniform float haze_horizon;
 uniform float haze_density;
-uniform float haze_density_linear;
 uniform float cloud_shadow;
 uniform float density_multiplier;
 uniform float distance_multiplier;
 uniform float max_y;
 uniform vec3  glow;
 uniform float scene_light_strength;
-uniform mat3  ssao_effect_mat;
 uniform float sun_moon_glow_factor;
+uniform float sky_hdr_scale;
 
 float getAmbientClamp() { return 1.0f; }
 
@@ -54,7 +48,7 @@ vec3 legacy_adjust(vec3 col);
 
 // return colors in sRGB space
 void calcAtmosphericVars(vec3 inPositionEye, vec3 light_dir, float ambFactor, out vec3 sunlit, out vec3 amblit, out vec3 additive,
-                         out vec3 atten, bool use_ao)
+                         out vec3 atten)
 {
     vec3 rel_pos = inPositionEye;
 
@@ -64,7 +58,7 @@ void calcAtmosphericVars(vec3 inPositionEye, vec3 light_dir, float ambFactor, ou
     vec3  rel_pos_norm = normalize(rel_pos);
     float rel_pos_len  = length(rel_pos);
     
-    vec3  sunlight     = (sun_up_factor == 1) ? sunlight_color: moonlight_color * 0.7;  // magic 0.7 to match legacy color
+    vec3  sunlight     = (sun_up_factor == 1) ? sunlight_color: moonlight_color;
     
     // sunlight attenuation effect (hue and brightness) due to atmosphere
     // this is used later for sunlight modulation at various altitudes
@@ -117,20 +111,6 @@ void calcAtmosphericVars(vec3 inPositionEye, vec3 light_dir, float ambFactor, ou
     // increase ambient when there are more clouds
     vec3 tmpAmbient = amb_color + (vec3(1.) - amb_color) * cloud_shadow * 0.5;
 
-    /*  decrease value and saturation (that in HSV, not HSL) for occluded areas
-     * // for HSV color/geometry used here, see http://gimp-savvy.com/BOOK/index.html?node52.html
-     * // The following line of code performs the equivalent of:
-     * float ambAlpha = tmpAmbient.a;
-     * float ambValue = dot(vec3(tmpAmbient), vec3(0.577)); // projection onto <1/rt(3), 1/rt(3), 1/rt(3)>, the neutral white-black axis
-     * vec3 ambHueSat = vec3(tmpAmbient) - vec3(ambValue);
-     * tmpAmbient = vec4(RenderSSAOEffect.valueFactor * vec3(ambValue) + RenderSSAOEffect.saturationFactor *(1.0 - ambFactor) * ambHueSat,
-     * ambAlpha);
-     */
-    if (use_ao)
-    {
-        tmpAmbient = mix(ssao_effect_mat * tmpAmbient.rgb, tmpAmbient.rgb, ambFactor);
-    }
-
     // Similar/Shared Algorithms:
     //     indra\llinventory\llsettingssky.cpp                                        -- LLSettingsSky::calculateLightSettings()
     //     indra\newview\app_settings\shaders\class1\windlight\atmosphericsFuncs.glsl -- calcAtmosphericVars()
@@ -141,7 +121,7 @@ void calcAtmosphericVars(vec3 inPositionEye, vec3 light_dir, float ambFactor, ou
     // brightness of surface both sunlight and ambient
     
     sunlit = sunlight.rgb;
-    amblit = vec3(1,0,1); //should no longer be used, filled in by calcAtmosphericVarsLinear
+    amblit = tmpAmbient;
 
     additive *= vec3(1.0 - combined_haze);
 }
@@ -164,15 +144,16 @@ float ambientLighting(vec3 norm, vec3 light_dir)
 void calcAtmosphericVarsLinear(vec3 inPositionEye, vec3 norm, vec3 light_dir, out vec3 sunlit, out vec3 amblit, out vec3 additive,
                          out vec3 atten)
 {
-    calcAtmosphericVars(inPositionEye, light_dir, 1.0, sunlit, amblit, additive, atten, false);
+    calcAtmosphericVars(inPositionEye, light_dir, 1.0, sunlit, amblit, additive, atten);
 
-    // multiply by 2 to get same colors as when the "scaleSoftClip" implementation was doubling color values
+    // multiply to get similar colors as when the "scaleSoftClip" implementation was doubling color values
     // (allows for mixing of light sources other than sunlight e.g. reflection probes)
-    sunlit *= 2.0;
-
-    // squash ambient to approximate whatever weirdness legacy atmospherics were doing
-    amblit = ambient_color; // * (1.0+sun_up_factor*0.3);
+    sunlit *= 1.5;
+    amblit *= 0.5;
+    
+    // override amblit with ambient_color if sky probe ambiance is not zero
+    amblit = mix(amblit, ambient_color, clamp(sky_hdr_scale-1.0, 0.0, 1.0));
 
-    amblit *= ambientLighting(norm, light_dir);
     amblit = srgb_to_linear(amblit);
+    amblit *= ambientLighting(norm, light_dir);
 }
diff --git a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsHelpersF.glsl b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsHelpersF.glsl
index 800d08047a..800d08047a 100644
--- a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsHelpersF.glsl
+++ b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsHelpersF.glsl
diff --git a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsHelpersV.glsl b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsHelpersV.glsl
index 6ecbfaecb1..6ecbfaecb1 100644
--- a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsHelpersV.glsl
+++ b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsHelpersV.glsl
diff --git a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsV.glsl b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsV.glsl
index 3773f191e8..cc3617ba61 100644
--- a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsV.glsl
+++ b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsV.glsl
@@ -38,7 +38,7 @@ void setPositionEye(vec3 v);
 
 vec3 getAdditiveColor();
 
-void calcAtmosphericVars(vec3 inPositionEye, vec3 light_dir, float ambFactor, out vec3 sunlit, out vec3 amblit, out vec3 additive, out vec3 atten, bool use_ao);
+void calcAtmosphericVars(vec3 inPositionEye, vec3 light_dir, float ambFactor, out vec3 sunlit, out vec3 amblit, out vec3 additive, out vec3 atten);
 
 void calcAtmospherics(vec3 inPositionEye) {
     vec3 P = inPositionEye;
@@ -48,7 +48,7 @@ void calcAtmospherics(vec3 inPositionEye) {
     vec3 tmpaddlit = vec3(1);
     vec3 tmpattenlit = vec3(1);
 	vec3 light_dir = (sun_up_factor == 1) ? sun_dir : moon_dir;	
-    calcAtmosphericVars(inPositionEye, light_dir, 1, tmpsunlit, tmpamblit, tmpaddlit, tmpattenlit, false);
+    calcAtmosphericVars(inPositionEye, light_dir, 1, tmpsunlit, tmpamblit, tmpaddlit, tmpattenlit);
     setSunlitColor(tmpsunlit);
     setAmblitColor(tmpamblit);
     setAdditiveColor(tmpaddlit);
diff --git a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsVarsF.glsl b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsVarsF.glsl
index 34669a6796..34669a6796 100644
--- a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsVarsF.glsl
+++ b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsVarsF.glsl
diff --git a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsVarsV.glsl b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsVarsV.glsl
index 1b854d80b3..1b854d80b3 100644
--- a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsVarsV.glsl
+++ b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsVarsV.glsl
diff --git a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsVarsWaterF.glsl b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsVarsWaterF.glsl
index 7a6741fe0e..7a6741fe0e 100644
--- a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsVarsWaterF.glsl
+++ b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsVarsWaterF.glsl
diff --git a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsVarsWaterV.glsl b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsVarsWaterV.glsl
index 23c3aed4d8..23c3aed4d8 100644
--- a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsVarsWaterV.glsl
+++ b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsVarsWaterV.glsl
diff --git a/indra/newview/app_settings/shaders/class2/windlight/gammaF.glsl b/indra/newview/app_settings/shaders/class1/windlight/gammaF.glsl
index 027bfb866f..027bfb866f 100644
--- a/indra/newview/app_settings/shaders/class2/windlight/gammaF.glsl
+++ b/indra/newview/app_settings/shaders/class1/windlight/gammaF.glsl
diff --git a/indra/newview/app_settings/shaders/class3/deferred/fullbrightShinyF.glsl b/indra/newview/app_settings/shaders/class3/deferred/fullbrightShinyF.glsl
index 1c79748b49..0d77e88831 100644
--- a/indra/newview/app_settings/shaders/class3/deferred/fullbrightShinyF.glsl
+++ b/indra/newview/app_settings/shaders/class3/deferred/fullbrightShinyF.glsl
@@ -42,7 +42,7 @@ uniform samplerCube environmentMap;
 vec3 atmosFragLighting(vec3 light, vec3 additive, vec3 atten);
 vec3 legacy_adjust_fullbright(vec3 c);
 vec3 legacy_adjust(vec3 c);
-void calcAtmosphericVars(vec3 inPositionEye, vec3 light_dir, float ambFactor, out vec3 sunlit, out vec3 amblit, out vec3 additive, out vec3 atten, bool use_ao);
+void calcAtmosphericVars(vec3 inPositionEye, vec3 light_dir, float ambFactor, out vec3 sunlit, out vec3 amblit, out vec3 additive, out vec3 atten);
 
 vec3 linear_to_srgb(vec3 c);
 vec3 srgb_to_linear(vec3 c);
@@ -71,7 +71,7 @@ void main()
     vec3 additive;
     vec3 atten;
     vec3 pos = vary_position;
-    calcAtmosphericVars(pos.xyz, vec3(0), 1.0, sunlit, amblit, additive, atten, false);
+    calcAtmosphericVars(pos.xyz, vec3(0), 1.0, sunlit, amblit, additive, atten);
 
     float env_intensity = vertex_color.a;
 
diff --git a/indra/newview/app_settings/shaders/class3/deferred/softenLightF.glsl b/indra/newview/app_settings/shaders/class3/deferred/softenLightF.glsl
index 3945e34d7a..53c5b1b801 100644
--- a/indra/newview/app_settings/shaders/class3/deferred/softenLightF.glsl
+++ b/indra/newview/app_settings/shaders/class3/deferred/softenLightF.glsl
@@ -44,9 +44,14 @@ uniform sampler2D     lightFunc;
 uniform float blur_size;
 uniform float blur_fidelity;
 
+#if defined(HAS_SSAO)
+uniform float ssao_irradiance_scale;
+uniform float ssao_irradiance_max;
+#endif
+
 // Inputs
 uniform mat3 env_mat;
-
+uniform mat3  ssao_effect_mat;
 uniform vec3 sun_dir;
 uniform vec3 moon_dir;
 uniform int  sun_up_factor;
@@ -112,6 +117,16 @@ vec3 pbrPunctual(vec3 diffuseColor, vec3 specularColor,
                     vec3 l); //surface point to light
 
 
+void adjustIrradiance(inout vec3 irradiance, vec3 amblit_linear, float ambocc)
+{
+    // use sky settings ambient or irradiance map sample, whichever is brighter
+    irradiance = max(amblit_linear, irradiance);
+
+#if defined(HAS_SSAO)
+    irradiance = mix(ssao_effect_mat * min(irradiance.rgb*ssao_irradiance_scale, vec3(ssao_irradiance_max)), irradiance.rgb, ambocc);
+#endif
+}
+
 void main()
 {
     vec2  tc           = vary_fragcoord.xy;
@@ -173,7 +188,7 @@ void main()
         vec3 orm = texture(specularRect, tc).rgb; 
         float perceptualRoughness = orm.g;
         float metallic = orm.b;
-        float ao = orm.r * ambocc;
+        float ao = orm.r;
 
         vec3 colorEmissive = texture(emissiveRect, tc).rgb;
         // PBR IBL
@@ -181,9 +196,7 @@ void main()
         
         sampleReflectionProbes(irradiance, radiance, tc, pos.xyz, norm.xyz, gloss);
         
-        // Take maximium of legacy ambient vs irradiance sample as irradiance
-        // NOTE: ao is applied in pbrIbl (see pbrBaseLight), do not apply here
-        irradiance       = max(amblit_linear,irradiance);
+        adjustIrradiance(irradiance, amblit_linear, ambocc);
 
         vec3 diffuseColor;
         vec3 specularColor;
@@ -203,17 +216,15 @@ void main()
         //should only be true of WL sky, just port over base color value
         color = texture(emissiveRect, tc).rgb;
         color = srgb_to_linear(color);
-        if (sun_up_factor > 0)
-        {
-           color *= sky_hdr_scale + 1.0;
-        }
+        color *= sky_hdr_scale;
     }
     else
     {
         // legacy shaders are still writng sRGB to gbuffer
         baseColor.rgb = legacy_adjust(baseColor.rgb);
-
+        
         baseColor.rgb = srgb_to_linear(baseColor.rgb);
+        
         spec.rgb = srgb_to_linear(spec.rgb);
 
         float da          = clamp(dot(norm.xyz, light_dir.xyz), 0.0, 1.0);
@@ -224,11 +235,10 @@ void main()
 
         sampleReflectionProbesLegacy(irradiance, glossenv, legacyenv, tc, pos.xyz, norm.xyz, spec.a, envIntensity);
         
-        // use sky settings ambient or irradiance map sample, whichever is brighter
-        irradiance = max(amblit_linear, irradiance);
+        adjustIrradiance(irradiance, amblit_linear, ambocc);
 
         // apply lambertian IBL only (see pbrIbl)
-        color.rgb = irradiance * ambocc;
+        color.rgb = irradiance;
 
         vec3 sun_contrib = min(da, scol) * sunlit_linear;
         color.rgb += sun_contrib;
diff --git a/indra/newview/featuretable.txt b/indra/newview/featuretable.txt
index 6f09beea4a..ec2467200a 100644
--- a/indra/newview/featuretable.txt
+++ b/indra/newview/featuretable.txt
@@ -1,4 +1,4 @@
-version 56
+version 57
 // The version number above should be incremented IF AND ONLY IF some
 // change has been made that is sufficiently important to justify
 // resetting the graphics preferences of all users to the recommended
@@ -275,7 +275,7 @@ RenderShadowDetail			1	2
 RenderFSAASamples			1	2
 RenderReflectionsEnabled    1   1
 RenderReflectionProbeDetail	1	1
-RenderScreenSpaceReflections 1  1
+RenderScreenSpaceReflections 1  0
 RenderReflectionProbeLevel  1   3
 
 //
diff --git a/indra/newview/featuretable_mac.txt b/indra/newview/featuretable_mac.txt
index c4677de7bb..0687a3cea1 100644
--- a/indra/newview/featuretable_mac.txt
+++ b/indra/newview/featuretable_mac.txt
@@ -1,4 +1,4 @@
-version 51
+version 52
 // The version number above should be incremented IF AND ONLY IF some
 // change has been made that is sufficiently important to justify
 // resetting the graphics preferences of all users to the recommended
@@ -273,7 +273,7 @@ RenderShadowDetail			1	2
 RenderFSAASamples			1	2
 RenderReflectionsEnabled    1   1
 RenderReflectionProbeDetail	1	1
-RenderScreenSpaceReflections 1  1
+RenderScreenSpaceReflections 1  0
 RenderReflectionProbeLevel  1   3
 
 //
diff --git a/indra/newview/llenvironment.cpp b/indra/newview/llenvironment.cpp
index 58da164b5a..d73a486877 100644
--- a/indra/newview/llenvironment.cpp
+++ b/indra/newview/llenvironment.cpp
@@ -1748,19 +1748,8 @@ void LLEnvironment::updateGLVariablesForSettings(LLShaderUniforms* uniforms, con
             //_WARNS("RIDER") << "pushing '" << (*it).first << "' as " << value << LL_ENDL;
             break;
         case LLSD::TypeReal:
-        {
-            F32 v = value.asReal();
-            switch (it.second.getShaderKey())
-            { // convert to linear color space if this is a color parameter
-            case LLShaderMgr::HAZE_HORIZON:
-            case LLShaderMgr::HAZE_DENSITY:
-            case LLShaderMgr::CLOUD_SHADOW:
-                //v = sRGBtoLinear(v);
-                break;
-            }
-            shader->uniform1f(it.second.getShaderKey(), v);
+            shader->uniform1f(it.second.getShaderKey(), value.asReal());
             //_WARNS("RIDER") << "pushing '" << (*it).first << "' as " << value << LL_ENDL;
-        }
             break;
 
         case LLSD::TypeBoolean:
diff --git a/indra/newview/llfloaterenvironmentadjust.cpp b/indra/newview/llfloaterenvironmentadjust.cpp
index 4d11399867..f9e8963479 100644
--- a/indra/newview/llfloaterenvironmentadjust.cpp
+++ b/indra/newview/llfloaterenvironmentadjust.cpp
@@ -201,6 +201,8 @@ void LLFloaterEnvironmentAdjust::refresh()
     getChild<LLUICtrl>(FIELD_SKY_MOON_AZIMUTH)->setValue(azimuth);
     getChild<LLUICtrl>(FIELD_SKY_MOON_ELEVATION)->setValue(elevation);
     getChild<LLVirtualTrackball>(FIELD_SKY_MOON_ROTATION)->setRotation(quat);
+
+    updateGammaLabel();
 }
 
 
@@ -478,9 +480,25 @@ void LLFloaterEnvironmentAdjust::onReflectionProbeAmbianceChanged()
     if (!mLiveSky) return;
     F32 ambiance = getChild<LLUICtrl>(FIELD_REFLECTION_PROBE_AMBIANCE)->getValue().asReal();
     mLiveSky->setReflectionProbeAmbiance(ambiance);
+
+    updateGammaLabel();
     mLiveSky->update();
 }
 
+void LLFloaterEnvironmentAdjust::updateGammaLabel()
+{
+    if (!mLiveSky) return;
+    F32 ambiance = mLiveSky->getReflectionProbeAmbiance();
+    if (ambiance != 0.f)
+    {
+        childSetValue("scene_gamma_label", getString("hdr_string"));
+    }
+    else
+    {
+        childSetValue("scene_gamma_label", getString("brightness_string"));
+    }
+}
+
 void LLFloaterEnvironmentAdjust::onEnvironmentUpdated(LLEnvironment::EnvSelection_t env, S32 version)
 {
     if (env == LLEnvironment::ENV_LOCAL)
diff --git a/indra/newview/llfloaterenvironmentadjust.h b/indra/newview/llfloaterenvironmentadjust.h
index 43c0ba0495..db893cca12 100644
--- a/indra/newview/llfloaterenvironmentadjust.h
+++ b/indra/newview/llfloaterenvironmentadjust.h
@@ -83,7 +83,7 @@ private:
     void                        onWaterMapChanged();
 
     void                        onReflectionProbeAmbianceChanged();
-
+    void                        updateGammaLabel();
     void                        onButtonReset();
 
     void                        onEnvironmentUpdated(LLEnvironment::EnvSelection_t env, S32 version);
diff --git a/indra/newview/llpaneleditsky.cpp b/indra/newview/llpaneleditsky.cpp
index d17845ebc5..a14af27e59 100644
--- a/indra/newview/llpaneleditsky.cpp
+++ b/indra/newview/llpaneleditsky.cpp
@@ -213,6 +213,8 @@ void LLPanelSettingsSkyAtmosTab::refresh()
     getChild<LLUICtrl>(FIELD_SKY_DENSITY_DROPLET_RADIUS)->setValue(droplet_radius);
     getChild<LLUICtrl>(FIELD_SKY_DENSITY_ICE_LEVEL)->setValue(ice_level);
     getChild<LLUICtrl>(FIELD_REFLECTION_PROBE_AMBIANCE)->setValue(rp_ambiance);
+
+    updateGammaLabel();
 }
 
 //-------------------------------------------------------------------------
@@ -321,11 +323,29 @@ void LLPanelSettingsSkyAtmosTab::onReflectionProbeAmbianceChanged()
 {
     if (!mSkySettings) return;
     F32 ambiance = getChild<LLUICtrl>(FIELD_REFLECTION_PROBE_AMBIANCE)->getValue().asReal();
+
     mSkySettings->setReflectionProbeAmbiance(ambiance);
     mSkySettings->update();
     setIsDirty();
+
+    updateGammaLabel();
 }
 
+
+void LLPanelSettingsSkyAtmosTab::updateGammaLabel()
+{
+    if (!mSkySettings) return;
+    F32 ambiance = mSkySettings->getReflectionProbeAmbiance();
+    if (ambiance != 0.f)
+    {
+        childSetValue("scene_gamma_label", getString("hdr_string"));
+    }
+    else
+    {
+        childSetValue("scene_gamma_label", getString("brightness_string"));
+    }
+
+}
 //==========================================================================
 LLPanelSettingsSkyCloudTab::LLPanelSettingsSkyCloudTab() :
     LLPanelSettingsSky()
diff --git a/indra/newview/llpaneleditsky.h b/indra/newview/llpaneleditsky.h
index cd89e02eea..33af667ab7 100644
--- a/indra/newview/llpaneleditsky.h
+++ b/indra/newview/llpaneleditsky.h
@@ -80,6 +80,7 @@ private:
     void                    onDropletRadiusChanged();
     void                    onIceLevelChanged();
     void                    onReflectionProbeAmbianceChanged();
+    void                    updateGammaLabel();
 
 };
 
diff --git a/indra/newview/llreflectionmapmanager.cpp b/indra/newview/llreflectionmapmanager.cpp
index 5dc93dbeb8..15d41c4161 100644
--- a/indra/newview/llreflectionmapmanager.cpp
+++ b/indra/newview/llreflectionmapmanager.cpp
@@ -915,7 +915,8 @@ void LLReflectionMapManager::updateUniforms()
     LLSettingsSky::ptr_t psky = environment.getCurrentSky();
 
     static LLCachedControl<F32> cloud_shadow_scale(gSavedSettings, "RenderCloudShadowAmbianceFactor", 0.125f);
-    F32 minimum_ambiance = psky->getTotalReflectionProbeAmbiance(cloud_shadow_scale);
+    static LLCachedControl<bool> should_auto_adjust(gSavedSettings, "RenderSkyAutoAdjustLegacy", true);
+    F32 minimum_ambiance = psky->getTotalReflectionProbeAmbiance(cloud_shadow_scale, should_auto_adjust);
 
     F32 ambscale = gCubeSnapshot && !isRadiancePass() ? 0.f : 1.f;
     F32 radscale = gCubeSnapshot && !isRadiancePass() ? 0.5f : 1.f;
diff --git a/indra/newview/llsettingsvo.cpp b/indra/newview/llsettingsvo.cpp
index de11f580a8..6321dbc085 100644
--- a/indra/newview/llsettingsvo.cpp
+++ b/indra/newview/llsettingsvo.cpp
@@ -718,45 +718,42 @@ void LLSettingsVOSky::applySpecial(void *ptarget, bool force)
 
     F32 g = getGamma();
 
+    static LLCachedControl<bool> should_auto_adjust(gSavedSettings, "RenderSkyAutoAdjustLegacy", true);
+
+    static LLCachedControl<F32> cloud_shadow_scale(gSavedSettings, "RenderCloudShadowAmbianceFactor", 0.125f);
+    F32 probe_ambiance = getTotalReflectionProbeAmbiance(cloud_shadow_scale);
+
     if (irradiance_pass)
     { // during an irradiance map update, disable ambient lighting (direct lighting only) and desaturate sky color (avoid tinting the world blue)
-        shader->uniform3fv(LLShaderMgr::AMBIENT_LINEAR, LLVector3::zero.mV);
         shader->uniform3fv(LLShaderMgr::AMBIENT, LLVector3::zero.mV);
     }
     else
     {
-        if (psky->getReflectionProbeAmbiance() == 0.f)
+        if (psky->getReflectionProbeAmbiance() != 0.f)
         {
-            LLVector3 ambcol(ambient.mV);
-            F32 cloud_shadow = psky->getCloudShadow();
-            LLVector3 tmpAmbient = ambcol + ((LLVector3::all_one - ambcol) * cloud_shadow * 0.5f);
-
-            shader->uniform3fv(LLShaderMgr::AMBIENT_LINEAR, linearColor3v(tmpAmbient));
-            shader->uniform3fv(LLShaderMgr::AMBIENT, tmpAmbient.mV);
+            shader->uniform3fv(LLShaderMgr::AMBIENT, getAmbientColor().mV);
+            shader->uniform1f(LLShaderMgr::SKY_HDR_SCALE, sqrtf(g)*2.0); // use a modifier here so 1.0 maps to the "most desirable" default and the maximum value doesn't go off the rails
+        }
+        else if (psky->canAutoAdjust() && should_auto_adjust)
+        { // auto-adjust legacy sky to take advantage of probe ambiance 
+            shader->uniform3fv(LLShaderMgr::AMBIENT, (ambient * 0.5f).mV);
+            shader->uniform1f(LLShaderMgr::SKY_HDR_SCALE, 2.f);
+            probe_ambiance = 1.f;
         }
         else
         {
-            shader->uniform3fv(LLShaderMgr::AMBIENT_LINEAR, linearColor3v(getAmbientColor() / 3.f)); // note magic number 3.f comes from SLIDER_SCALE_SUN_AMBIENT
+            shader->uniform1f(LLShaderMgr::SKY_HDR_SCALE, 1.f);
             shader->uniform3fv(LLShaderMgr::AMBIENT, LLVector3(ambient.mV));
         }
     }
 
-    shader->uniform3fv(LLShaderMgr::BLUE_HORIZON_LINEAR, linearColor3v(getBlueHorizon() / 2.f)); // note magic number of 2.f comes from SLIDER_SCALE_BLUE_HORIZON_DENSITY
-    shader->uniform3fv(LLShaderMgr::BLUE_DENSITY_LINEAR, linearColor3v(getBlueDensity() / 2.f));
-
-    shader->uniform3fv(LLShaderMgr::SUNLIGHT_LINEAR, linearColor3v(sunDiffuse));
-    shader->uniform3fv(LLShaderMgr::MOONLIGHT_LINEAR,linearColor3v(moonDiffuse));
-
-    static LLCachedControl<F32> cloud_shadow_scale(gSavedSettings, "RenderCloudShadowAmbianceFactor", 0.125f);
-    shader->uniform1f(LLShaderMgr::REFLECTION_PROBE_AMBIANCE, getTotalReflectionProbeAmbiance(cloud_shadow_scale));
+    shader->uniform1f(LLShaderMgr::REFLECTION_PROBE_AMBIANCE, probe_ambiance);
 
     shader->uniform1i(LLShaderMgr::SUN_UP_FACTOR, getIsSunUp() ? 1 : 0);
     shader->uniform1f(LLShaderMgr::SUN_MOON_GLOW_FACTOR, getSunMoonGlowFactor());
     shader->uniform1f(LLShaderMgr::DENSITY_MULTIPLIER, getDensityMultiplier());
     shader->uniform1f(LLShaderMgr::DISTANCE_MULTIPLIER, getDistanceMultiplier());
 
-    shader->uniform1f(LLShaderMgr::HAZE_DENSITY_LINEAR, sRGBtoLinear(getHazeDensity()));
-
     shader->uniform1f(LLShaderMgr::GAMMA, g);
 }
 
diff --git a/indra/newview/llviewermedia.cpp b/indra/newview/llviewermedia.cpp
index d0dd02426e..02108e861a 100644
--- a/indra/newview/llviewermedia.cpp
+++ b/indra/newview/llviewermedia.cpp
@@ -3014,7 +3014,7 @@ LLViewerMediaTexture* LLViewerMediaImpl::updateMediaImage()
         return nullptr; // not ready for updating
     }
 
-    llassert(!mTextureId.isNull());
+    //llassert(!mTextureId.isNull());
     // *TODO: Consider enabling mipmaps (they have been disabled for a long time). Likely has a significant performance impact for tiled/high texture repeat media. Mip generation in a shader may also be an option if necessary.
     LLViewerMediaTexture* media_tex = LLViewerTextureManager::getMediaTexture( mTextureId, USE_MIPMAPS );
  
diff --git a/indra/newview/llviewertexture.cpp b/indra/newview/llviewertexture.cpp
index f178ec9d8d..cb58588848 100644
--- a/indra/newview/llviewertexture.cpp
+++ b/indra/newview/llviewertexture.cpp
@@ -490,20 +490,6 @@ bool LLViewerTexture::isMemoryForTextureLow()
 }
 
 //static
-bool LLViewerTexture::isMemoryForTextureSuficientlyFree()
-{
-    LL_PROFILE_ZONE_SCOPED_CATEGORY_TEXTURE;
-    const S32Megabytes DESIRED_FREE_TEXTURE_MEMORY(50);
-    const S32Megabytes DESIRED_FREE_MAIN_MEMORY(200);
-
-    S32Megabytes gpu;
-    S32Megabytes physical;
-    getGPUMemoryForTextures(gpu, physical);
-
-    return (gpu > DESIRED_FREE_TEXTURE_MEMORY); // && (physical > DESIRED_FREE_MAIN_MEMORY);
-}
-
-//static
 void LLViewerTexture::getGPUMemoryForTextures(S32Megabytes &gpu, S32Megabytes &physical)
 {
     LL_PROFILE_ZONE_SCOPED_CATEGORY_TEXTURE;
diff --git a/indra/newview/llviewertexture.h b/indra/newview/llviewertexture.h
index 34118c86cd..35fb0a2237 100644
--- a/indra/newview/llviewertexture.h
+++ b/indra/newview/llviewertexture.h
@@ -186,7 +186,6 @@ private:
 
 	virtual void switchToCachedImage();
 	
-	static bool isMemoryForTextureSuficientlyFree();
 	static void getGPUMemoryForTextures(S32Megabytes &gpu, S32Megabytes &physical);
 
 public:
diff --git a/indra/newview/pipeline.cpp b/indra/newview/pipeline.cpp
index 9a8597e519..852845edf4 100644
--- a/indra/newview/pipeline.cpp
+++ b/indra/newview/pipeline.cpp
@@ -6751,22 +6751,25 @@ void LLPipeline::generateExposure(LLRenderTarget* src, LLRenderTarget* dst) {
 		static LLStaticHashedString noiseVec("noiseVec");
 		static LLStaticHashedString dynamic_exposure_params("dynamic_exposure_params");
 		static LLCachedControl<F32> dynamic_exposure_coefficient(gSavedSettings, "RenderDynamicExposureCoefficient", 0.175f);
-		static LLCachedControl<F32> dynamic_exposure_min(gSavedSettings, "RenderDynamicExposureMin", 0.125f);
-		static LLCachedControl<F32> dynamic_exposure_max(gSavedSettings, "RenderDynamicExposureMax", 1.3f);
-
-        F32 exposure_max = dynamic_exposure_max;
         LLSettingsSky::ptr_t sky = LLEnvironment::instance().getCurrentSky();
 
-        if (sky->getReflectionProbeAmbiance() > 0.f)
-        { //not a legacy sky, use gamma as a boost to max exposure
-            exposure_max = llmax(exposure_max - 1.f, 0.f);
-            exposure_max *= sky->getGamma();
-            exposure_max += 1.f;
-        }
+        F32 probe_ambiance = LLEnvironment::instance().getCurrentSky()->getReflectionProbeAmbiance();
+        F32 exp_min = 1.f;
+        F32 exp_max = 1.f;
+                
+        if (probe_ambiance > 0.f)
+        {
+            F32 hdr_scale = sqrtf(LLEnvironment::instance().getCurrentSky()->getGamma())*2.f;
 
+            if (hdr_scale > 1.f)
+            {
+                exp_min = 1.f / hdr_scale;
+                exp_max = hdr_scale;
+            }
+        }
 		gExposureProgram.uniform1f(dt, gFrameIntervalSeconds);
 		gExposureProgram.uniform2f(noiseVec, ll_frand() * 2.0 - 1.0, ll_frand() * 2.0 - 1.0);
-		gExposureProgram.uniform3f(dynamic_exposure_params, dynamic_exposure_coefficient, dynamic_exposure_min, exposure_max);
+		gExposureProgram.uniform3f(dynamic_exposure_params, dynamic_exposure_coefficient, exp_min, exp_max);
 
 		mScreenTriangleVB->setBuffer();
 		mScreenTriangleVB->drawArrays(LLRender::TRIANGLES, 0, 3);
@@ -6789,8 +6792,12 @@ void LLPipeline::gammaCorrect(LLRenderTarget* src, LLRenderTarget* dst) {
 
 		// Apply gamma correction to the frame here.
 
+        static LLCachedControl<bool> should_auto_adjust(gSavedSettings, "RenderSkyAutoAdjustLegacy", true);
+        
+        LLSettingsSky::ptr_t psky = LLEnvironment::instance().getCurrentSky();
+
         LLGLSLShader& shader = no_post && gFloaterTools->isAvailable() ? gNoPostGammaCorrectProgram : // no post (no gamma, no exposure, no tonemapping)
-            LLEnvironment::instance().getCurrentSky()->getReflectionProbeAmbiance() == 0.f ? gLegacyPostGammaCorrectProgram :
+            psky->getReflectionProbeAmbiance(should_auto_adjust) == 0.f ? gLegacyPostGammaCorrectProgram :
             gDeferredPostGammaCorrectProgram;
         
         shader.bind();
@@ -7846,14 +7853,18 @@ void LLPipeline::renderDeferredLighting()
             LL_PROFILE_GPU_ZONE("atmospherics");
             bindDeferredShader(soften_shader);
 
-            static LLCachedControl<F32> sky_scale(gSavedSettings, "RenderSkyHDRScale", 1.f);
-            static LLStaticHashedString sky_hdr_scale("sky_hdr_scale");
+            static LLCachedControl<F32> ssao_scale(gSavedSettings, "RenderSSAOIrradianceScale", 0.5f);
+            static LLCachedControl<F32> ssao_max(gSavedSettings, "RenderSSAOIrradianceMax", 0.25f);
+            static LLStaticHashedString ssao_scale_str("ssao_irradiance_scale");
+            static LLStaticHashedString ssao_max_str("ssao_irradiance_max");
+            
+            soften_shader.uniform1f(ssao_scale_str, ssao_scale);
+            soften_shader.uniform1f(ssao_max_str, ssao_max);
 
             LLEnvironment &environment = LLEnvironment::instance();
             soften_shader.uniform1i(LLShaderMgr::SUN_UP_FACTOR, environment.getIsSunUp() ? 1 : 0);
             soften_shader.uniform3fv(LLShaderMgr::LIGHTNORM, 1, environment.getClampedLightNorm().mV);
-            soften_shader.uniform1f(sky_hdr_scale, sky_scale);
-
+            
             soften_shader.uniform4fv(LLShaderMgr::WATER_WATERPLANE, 1, LLDrawPoolAlpha::sWaterPlane.mV);
 
             {
diff --git a/indra/newview/skins/default/xui/en/floater_adjust_environment.xml b/indra/newview/skins/default/xui/en/floater_adjust_environment.xml
index 5258bdbaf2..518a83f846 100644
--- a/indra/newview/skins/default/xui/en/floater_adjust_environment.xml
+++ b/indra/newview/skins/default/xui/en/floater_adjust_environment.xml
@@ -10,6 +10,8 @@
          min_height="275"
          single_instance="true"
          can_resize="false">
+  <string name="hdr_string">HDR Scale:</string>
+  <string name="brightness_string">Brightness:</string>
     <layout_stack name="outer_stack"
                   width="845"
                   height="275"
@@ -245,25 +247,6 @@
                             top_pad="5"
                             width="185"
                             can_edit_text="true"/>
-                    <text follows="left|top"
-                          name="scene_gamma_label"
-                          height="10"
-                          layout="topleft"
-                          left_delta="-5"
-                          top_pad="15"
-                          width="80">Brightness:</text>
-                    <slider decimal_digits="2"
-                            follows="left|top"
-                            height="16"
-                            increment="0.01"
-                            initial_value="0"
-                            layout="topleft"
-                            left_delta="5"
-                            max_val="20"
-                            name="scene_gamma"
-                            top_pad="5"
-                            width="185"
-                            can_edit_text="true"/>
                   <text follows="left|top"
                           height="10"
                           layout="topleft"
@@ -283,6 +266,25 @@
                           top_pad="5"
                           width="185"
                           can_edit_text="true"/>
+                    <text follows="left|top"
+                          name="scene_gamma_label"
+                          height="10"
+                          layout="topleft"
+                          left_delta="-5"
+                          top_pad="15"
+                          width="80">Brightness:</text>
+                    <slider decimal_digits="2"
+                            follows="left|top"
+                            height="16"
+                            increment="0.01"
+                            initial_value="0"
+                            layout="topleft"
+                            left_delta="5"
+                            max_val="20"
+                            name="scene_gamma"
+                            top_pad="5"
+                            width="185"
+                            can_edit_text="true"/>
                 </layout_panel>
                 <layout_panel border="false"
                               name="lp_3"
diff --git a/indra/newview/skins/default/xui/en/floater_preferences_graphics_advanced.xml b/indra/newview/skins/default/xui/en/floater_preferences_graphics_advanced.xml
index fd80673903..c1a94a2128 100644
--- a/indra/newview/skins/default/xui/en/floater_preferences_graphics_advanced.xml
+++ b/indra/newview/skins/default/xui/en/floater_preferences_graphics_advanced.xml
@@ -601,6 +601,20 @@
   </check_box>
 
   <check_box
+  control_name="RenderSkyAutoAdjustLegacy"
+  height="16"
+  initial_value="true"
+  label="Auto-adjust Legacy Sky"
+  layout="topleft"
+  left="420"
+  name="AutoAdjustLegacySky"
+  top_delta="16"
+  width="240">
+    <check_box.commit_callback
+      function="Pref.RenderOptionUpdate" />
+  </check_box>
+
+  <check_box
     control_name="RenderDepthOfField"
     height="16"
     initial_value="true"
diff --git a/indra/newview/skins/default/xui/en/panel_settings_sky_atmos.xml b/indra/newview/skins/default/xui/en/panel_settings_sky_atmos.xml
index 58d125a88e..36a485e498 100644
--- a/indra/newview/skins/default/xui/en/panel_settings_sky_atmos.xml
+++ b/indra/newview/skins/default/xui/en/panel_settings_sky_atmos.xml
@@ -7,6 +7,8 @@
         left="0"
         name="panel_settings_sky_atmos"
         top="0">
+  <string name="hdr_string">HDR Scale:</string>
+  <string name="brightness_string">Brightness:</string>
     <layout_stack
             name="main_ls"
             follows="all"
@@ -228,29 +230,6 @@
                             name="ice_level"
                             width="207"
                             can_edit_text="true"/>
-                    <text
-                            name="scene_gamma_label"
-                            follows="left|top"
-                            height="10"
-                            layout="topleft"
-                            left_delta="-5"
-                            top_delta="25"
-                            width="80">
-                        Brightness:
-                    </text>
-                    <slider
-                            decimal_digits="2"
-                            follows="left|top"
-                            height="16"
-                            increment="0.01"
-                            initial_value="0"
-                            layout="topleft"
-                            left_delta="5"
-                            max_val="20"
-                            name="scene_gamma"
-                            top_delta="20"
-                            width="207"
-                            can_edit_text="true"/>
                 </layout_panel>            
                 <layout_panel
                         name="right_lp"
@@ -338,8 +317,9 @@
                             layout="topleft"
                             left_delta="-5"
                             top_delta="25"
+                            tooltip="Irradiance control.  When not zero, enables HDR lighting model."
                             width="200">
-                    Reflection Probe Ambiance:
+                    Reflection Probe Ambiance (HDR):
                   </text>
                   <slider
                           decimal_digits="2"
@@ -355,6 +335,29 @@
                           top_delta="20"
                           width="219"
                           can_edit_text="true"/>
+                  <text
+                            name="scene_gamma_label"
+                            follows="left|top"
+                            height="10"
+                            layout="topleft"
+                            left_delta="-5"
+                            top_delta="25"
+                            width="80">
+                    Brightness:
+                  </text>
+                  <slider
+                          decimal_digits="2"
+                          follows="left|top"
+                          height="16"
+                          increment="0.01"
+                          initial_value="0"
+                          layout="topleft"
+                          left_delta="5"
+                          max_val="20"
+                          name="scene_gamma"
+                          top_delta="20"
+                          width="207"
+                          can_edit_text="true"/>
                 </layout_panel>            
             </layout_stack>                
         </layout_panel>