1 files changed, 59 insertions, 37 deletions
diff --git a/indra/newview/app_settings/shaders/class1/windlight/atmosphericsFuncs.glsl b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsFuncs.glsl
index ea2690ba09..a1da4b1f9a 100644
--- a/indra/newview/app_settings/shaders/class1/windlight/atmosphericsFuncs.glsl
+++ b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsFuncs.glsl
@@ -1,9 +1,9 @@
 /**
- * @file class1\windlight\atmosphericsFuncs.glsl
+ * @file class2\windlight\atmosphericsFuncs.glsl
  *
- * $LicenseInfo:firstyear=2005&license=viewerlgpl$
+ * $LicenseInfo:firstyear=2022&license=viewerlgpl$
  * Second Life Viewer Source Code
- * Copyright (C) 2019, Linden Research, Inc.
+ * Copyright (C) 2022, Linden Research, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -22,29 +22,33 @@
  * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
  * $/LicenseInfo$
  */
-uniform vec4  lightnorm;
-uniform vec4  sunlight_color;
-uniform vec4  moonlight_color;
+
+uniform vec3  lightnorm;
+uniform vec3  sunlight_color;
+uniform vec3  moonlight_color;
 uniform int   sun_up_factor;
-uniform vec4  ambient_color;
-uniform vec4  blue_horizon;
-uniform vec4  blue_density;
+uniform vec3  ambient_color;
+uniform vec3  blue_horizon;
+uniform vec3  blue_density;
 uniform float haze_horizon;
 uniform float haze_density;
 uniform float cloud_shadow;
 uniform float density_multiplier;
 uniform float distance_multiplier;
 uniform float max_y;
-uniform vec4  glow;
+uniform vec3  glow;
 uniform float scene_light_strength;
-uniform mat3  ssao_effect_mat;
-uniform int   no_atmo;
 uniform float sun_moon_glow_factor;
+uniform float sky_sunlight_scale;
+uniform float sky_ambient_scale;
 
 float getAmbientClamp() { return 1.0f; }
 
+vec3 srgb_to_linear(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;
 
@@ -53,17 +57,18 @@ void calcAtmosphericVars(vec3 inPositionEye, vec3 light_dir, float ambFactor, ou
 
     vec3  rel_pos_norm = normalize(rel_pos);
     float rel_pos_len  = length(rel_pos);
-    vec4  sunlight     = (sun_up_factor == 1) ? sunlight_color : moonlight_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
-    vec4 light_atten = (blue_density + vec4(haze_density * 0.25)) * (density_multiplier * max_y);
+    vec3 light_atten = (blue_density + vec3(haze_density * 0.25)) * (density_multiplier * max_y);
     // I had thought blue_density and haze_density should have equal weighting,
     // but attenuation due to haze_density tends to seem too strong
 
-    vec4 combined_haze = blue_density + vec4(haze_density);
-    vec4 blue_weight   = blue_density / combined_haze;
-    vec4 haze_weight   = vec4(haze_density) / combined_haze;
+    vec3 combined_haze = blue_density + vec3(haze_density);
+    vec3 blue_weight   = blue_density / combined_haze;
+    vec3 haze_weight   = vec3(haze_density) / combined_haze;
 
     //(TERRAIN) compute sunlight from lightnorm y component. Factor is roughly cosecant(sun elevation) (for short rays like terrain)
     float above_horizon_factor = 1.0 / max(1e-6, lightnorm.y);
@@ -101,24 +106,10 @@ void calcAtmosphericVars(vec3 inPositionEye, vec3 light_dir, float ambFactor, ou
 
     haze_glow *= sun_moon_glow_factor;
 
-    vec4 amb_color = ambient_color;
+    vec3 amb_color = ambient_color;
 
     // increase ambient when there are more clouds
-    vec4 tmpAmbient = amb_color + (vec4(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 = vec4(mix(ssao_effect_mat * tmpAmbient.rgb, tmpAmbient.rgb, ambFactor), tmpAmbient.a);
-    }
+    vec3 tmpAmbient = amb_color + (vec3(1.) - amb_color) * cloud_shadow * 0.5;
 
     // Similar/Shared Algorithms:
     //     indra\llinventory\llsettingssky.cpp                                        -- LLSettingsSky::calculateLightSettings()
@@ -128,7 +119,38 @@ void calcAtmosphericVars(vec3 inPositionEye, vec3 light_dir, float ambFactor, ou
     additive = (blue_horizon.rgb * blue_weight.rgb) * (cs + tmpAmbient.rgb) + (haze_horizon * haze_weight.rgb) * (cs * haze_glow + tmpAmbient.rgb);
 
     // brightness of surface both sunlight and ambient
-    sunlit = sunlight.rgb * 0.5;
-    amblit = tmpAmbient.rgb * .25;
+    
+    sunlit = sunlight.rgb;
+    amblit = tmpAmbient;
+
     additive *= vec3(1.0 - combined_haze);
 }
+
+vec3 srgb_to_linear(vec3 col);
+
+// provide a touch of lighting in the opposite direction of the sun light 
+    // so areas in shadow don't lose all detail
+float ambientLighting(vec3 norm, vec3 light_dir)
+{
+    float ambient = min(abs(dot(norm.xyz, light_dir.xyz)), 1.0);
+    ambient *= 0.5;
+    ambient *= ambient;
+    ambient = (1.0 - ambient);
+    return ambient;
+}
+
+
+// return lit amblit in linear space, leave sunlit and additive in sRGB space
+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);
+
+    // 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 *= sky_sunlight_scale;
+    amblit *= sky_ambient_scale;
+    
+    amblit = srgb_to_linear(amblit);
+    amblit *= ambientLighting(norm, light_dir);
+}