SL-10276

SL-9851

Fix cloud shaders to ignore clouds when cloud_scale is 0.

Fix creation of heavenly body geo to avoid degenerate vector math
and not randomly flip orientation when crossing zenith.

Add sun_up_factor to eliminate sun glow around moon when sun is down.

5 files changed, 271 insertions, 256 deletions

diff --git a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsF.glsl b/indra/newview/app_settings/shaders/class2/windlight/atmosphericsF.glsl
index 2a629f4f42..5cf3cd1dd2 100644
--- a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsF.glsl
+++ b/indra/newview/app_settings/shaders/class2/windlight/atmosphericsF.glsl
@@ -42,6 +42,7 @@ uniform vec4 glow;
 uniform float scene_light_strength;
 uniform mat3 ssao_effect_mat;
 uniform int no_atmo;
+uniform float sun_up_factor;
 
 vec3 scaleSoftClipFrag(vec3 light);
 
@@ -117,6 +118,8 @@ void calcFragAtmospherics(vec3 inPositionEye, float ambFactor, out vec3 sunlit,
 
     //add "minimum anti-solar illumination"
     temp2.x += .25;
+
+    temp2.x *= sun_up_factor;
     
     //increase ambient when there are more clouds
     vec4 tmpAmbient = ambient + (vec4(1.) - ambient) * cloud_shadow * 0.5;
diff --git a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsV.glsl b/indra/newview/app_settings/shaders/class2/windlight/atmosphericsV.glsl
index 7a6bcd53a1..8c1a7c6281 100644
--- a/indra/newview/app_settings/shaders/class2/windlight/atmosphericsV.glsl
+++ b/indra/newview/app_settings/shaders/class2/windlight/atmosphericsV.glsl
@@ -54,110 +54,112 @@ uniform float density_multiplier;
 uniform float distance_multiplier;
 uniform float max_y;
 uniform vec4 glow;
+uniform float sun_up_factor;
 
 void calcAtmospherics(vec3 inPositionEye) {
 
-	vec3 P = inPositionEye;
-	setPositionEye(P);
-	
-	//(TERRAIN) limit altitude
-	if (P.y > max_y) P *= (max_y / P.y);
-	if (P.y < -max_y) P *= (-max_y / P.y);
-
-	vec3 tmpLightnorm = lightnorm.xyz;
-
-	vec3 Pn = normalize(P);
-	float  Plen = length(P);
-
-	vec4 temp1 = vec4(0);
-	vec3 temp2 = vec3(0);
-	vec4 blue_weight;
-	vec4 haze_weight;
-	vec4 sunlight = sunlight_color;
-	vec4 light_atten;
-
-	//sunlight attenuation effect (hue and brightness) due to atmosphere
-	//this is used later for sunlight modulation at various altitudes
-	light_atten = (blue_density + vec4(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
-
-	temp1 = blue_density + vec4(haze_density);
-	blue_weight = blue_density / temp1;
-	haze_weight = vec4(haze_density) / temp1;
-
-	//(TERRAIN) compute sunlight from lightnorm only (for short rays like terrain)
-	temp2.y = max(0.0, tmpLightnorm.y);
-	temp2.y = 1. / temp2.y;
-	sunlight *= exp( - light_atten * temp2.y);
-
-	// main atmospheric scattering line integral
-	temp2.z = Plen * density_multiplier;
-
-	// Transparency (-> temp1)
-	// ATI Bugfix -- can't store temp1*temp2.z*distance_multiplier in a variable because the ati
-	// compiler gets confused.
-	temp1 = exp(-temp1 * temp2.z * distance_multiplier);
-
-	//final atmosphere attenuation factor
-	setAtmosAttenuation(temp1.rgb);
-	//vary_AtmosAttenuation = distance_multiplier / 10000.;
-	//vary_AtmosAttenuation = density_multiplier * 100.;
-	//vary_AtmosAttenuation = vec4(Plen / 100000., 0., 0., 1.);
-
-	//compute haze glow
-	//(can use temp2.x as temp because we haven't used it yet)
-	temp2.x = dot(Pn, tmpLightnorm.xyz);
-	temp2.x = 1. - temp2.x;
-		//temp2.x is 0 at the sun and increases away from sun
-	temp2.x = max(temp2.x, .03);	//was glow.y
-		//set a minimum "angle" (smaller glow.y allows tighter, brighter hotspot)
-	temp2.x *= glow.x;
-		//higher glow.x gives dimmer glow (because next step is 1 / "angle")
-	temp2.x = pow(temp2.x, glow.z);
-		//glow.z should be negative, so we're doing a sort of (1 / "angle") function
-
-	//add "minimum anti-solar illumination"
-	temp2.x += .25;
-
-
-	//increase ambient when there are more clouds
-	vec4 tmpAmbient = ambient + (vec4(1.) - ambient) * cloud_shadow * 0.5;
-
-    vec3 additive =	
-		vec3(blue_horizon * blue_weight * (sunlight*(1.-cloud_shadow) + tmpAmbient)
-	  + (haze_horizon * haze_weight) * (sunlight*(1.-cloud_shadow) * temp2.x
-		  + tmpAmbient));
+    vec3 P = inPositionEye;
+    setPositionEye(P);
+    
+    //(TERRAIN) limit altitude
+    if (P.y > max_y) P *= (max_y / P.y);
+    if (P.y < -max_y) P *= (-max_y / P.y);
+
+    vec3 tmpLightnorm = lightnorm.xyz;
+
+    vec3 Pn = normalize(P);
+    float  Plen = length(P);
+
+    vec4 temp1 = vec4(0);
+    vec3 temp2 = vec3(0);
+    vec4 blue_weight;
+    vec4 haze_weight;
+    vec4 sunlight = sunlight_color;
+    vec4 light_atten;
+
+    //sunlight attenuation effect (hue and brightness) due to atmosphere
+    //this is used later for sunlight modulation at various altitudes
+    light_atten = (blue_density + vec4(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
+
+    temp1 = blue_density + vec4(haze_density);
+    blue_weight = blue_density / temp1;
+    haze_weight = vec4(haze_density) / temp1;
+
+    //(TERRAIN) compute sunlight from lightnorm only (for short rays like terrain)
+    temp2.y = max(0.0, tmpLightnorm.y);
+    temp2.y = 1. / temp2.y;
+    sunlight *= exp( - light_atten * temp2.y);
+
+    // main atmospheric scattering line integral
+    temp2.z = Plen * density_multiplier;
+
+    // Transparency (-> temp1)
+    // ATI Bugfix -- can't store temp1*temp2.z*distance_multiplier in a variable because the ati
+    // compiler gets confused.
+    temp1 = exp(-temp1 * temp2.z * distance_multiplier);
+
+    //final atmosphere attenuation factor
+    setAtmosAttenuation(temp1.rgb);
+    //vary_AtmosAttenuation = distance_multiplier / 10000.;
+    //vary_AtmosAttenuation = density_multiplier * 100.;
+    //vary_AtmosAttenuation = vec4(Plen / 100000., 0., 0., 1.);
+
+    //compute haze glow
+    //(can use temp2.x as temp because we haven't used it yet)
+    temp2.x = dot(Pn, tmpLightnorm.xyz);
+    temp2.x = 1. - temp2.x;
+        //temp2.x is 0 at the sun and increases away from sun
+    temp2.x = max(temp2.x, .03);    //was glow.y
+        //set a minimum "angle" (smaller glow.y allows tighter, brighter hotspot)
+    temp2.x *= glow.x;
+        //higher glow.x gives dimmer glow (because next step is 1 / "angle")
+    temp2.x = pow(temp2.x, glow.z);
+        //glow.z should be negative, so we're doing a sort of (1 / "angle") function
+
+        temp2.x *= sun_up_factor;
+
+    //add "minimum anti-solar illumination"
+    temp2.x += .25;
+
+    //increase ambient when there are more clouds
+    vec4 tmpAmbient = ambient + (vec4(1.) - ambient) * cloud_shadow * 0.5;
+
+    vec3 additive = 
+        vec3(blue_horizon * blue_weight * (sunlight*(1.-cloud_shadow) + tmpAmbient)
+      + (haze_horizon * haze_weight) * (sunlight*(1.-cloud_shadow) * temp2.x
+          + tmpAmbient));
     additive = normalize(additive);
 
-	//haze color
-	//setAdditiveColor(
-	//	vec3(blue_horizon * blue_weight * (sunlight*(1.-cloud_shadow) + tmpAmbient)
-	//  + (haze_horizon * haze_weight) * (sunlight*(1.-cloud_shadow) * temp2.x
-	//	  + tmpAmbient)));
-	
-	//brightness of surface both sunlight and ambient
-	setSunlitColor(vec3(sunlight * .5));
-	setAmblitColor(vec3(tmpAmbient * .25));
-	setAdditiveColor(additive * vec3(1.0 - exp(-temp2.z * distance_multiplier)) * 0.5);
-
-	// vary_SunlitColor = vec3(0);
-	// vary_AmblitColor = vec3(0);
-	// vary_AdditiveColor = vec4(Pn, 1.0);
-
-	/*
-	const float cloudShadowScale = 100.;
-	// Get cloud uvs for shadowing
-	vec3 cloudPos = inPositionEye + camPosWorld - cloudShadowScale / 2.;
-	vary_CloudUVs.xy = cloudPos.xz / cloudShadowScale;
-
-	// We can take uv1 and multiply it by (TerrainSpan / CloudSpan)
-//	cloudUVs *= (((worldMaxZ - worldMinZ) * 20) /40000.);
-	vary_CloudUVs *= (10000./40000.);
-
-	// Offset by sun vector * (CloudAltitude / CloudSpan)
-	vary_CloudUVs.x += tmpLightnorm.x / tmpLightnorm.y * (3000./40000.);
-	vary_CloudUVs.y += tmpLightnorm.z / tmpLightnorm.y * (3000./40000.);
-	*/
+    //haze color
+    //setAdditiveColor(
+    //  vec3(blue_horizon * blue_weight * (sunlight*(1.-cloud_shadow) + tmpAmbient)
+    //  + (haze_horizon * haze_weight) * (sunlight*(1.-cloud_shadow) * temp2.x
+    //    + tmpAmbient)));
+    
+    //brightness of surface both sunlight and ambient
+    setSunlitColor(vec3(sunlight * .5));
+    setAmblitColor(vec3(tmpAmbient * .25));
+    setAdditiveColor(additive * vec3(1.0 - exp(-temp2.z * distance_multiplier)) * 0.5);
+
+    // vary_SunlitColor = vec3(0);
+    // vary_AmblitColor = vec3(0);
+    // vary_AdditiveColor = vec4(Pn, 1.0);
+
+    /*
+    const float cloudShadowScale = 100.;
+    // Get cloud uvs for shadowing
+    vec3 cloudPos = inPositionEye + camPosWorld - cloudShadowScale / 2.;
+    vary_CloudUVs.xy = cloudPos.xz / cloudShadowScale;
+
+    // We can take uv1 and multiply it by (TerrainSpan / CloudSpan)
+//  cloudUVs *= (((worldMaxZ - worldMinZ) * 20) /40000.);
+    vary_CloudUVs *= (10000./40000.);
+
+    // Offset by sun vector * (CloudAltitude / CloudSpan)
+    vary_CloudUVs.x += tmpLightnorm.x / tmpLightnorm.y * (3000./40000.);
+    vary_CloudUVs.y += tmpLightnorm.z / tmpLightnorm.y * (3000./40000.);
+    */
 }
 
diff --git a/indra/newview/app_settings/shaders/class2/windlight/cloudsF.glsl b/indra/newview/app_settings/shaders/class2/windlight/cloudsF.glsl
index e3fa431ddf..93024bf4e7 100644
--- a/indra/newview/app_settings/shaders/class2/windlight/cloudsF.glsl
+++ b/indra/newview/app_settings/shaders/class2/windlight/cloudsF.glsl
@@ -66,60 +66,65 @@ vec4 cloudNoise(vec2 uv)
 
 void main()
 {
-	// Set variables
-	vec2 uv1 = vary_texcoord0.xy;
-	vec2 uv2 = vary_texcoord1.xy;
+    // Set variables
+    vec2 uv1 = vary_texcoord0.xy;
+    vec2 uv2 = vary_texcoord1.xy;
 
-	vec4 cloudColorSun = vary_CloudColorSun;
-	vec4 cloudColorAmbient = vary_CloudColorAmbient;
-	float cloudDensity = vary_CloudDensity;
-	vec2 uv3 = vary_texcoord2.xy;
-	vec2 uv4 = vary_texcoord3.xy;
+    vec4 cloudColorSun = vary_CloudColorSun;
+    vec4 cloudColorAmbient = vary_CloudColorAmbient;
+    float cloudDensity = vary_CloudDensity;
+    vec2 uv3 = vary_texcoord2.xy;
+    vec2 uv4 = vary_texcoord3.xy;
+
+    if (cloud_scale < 0.001)
+    {
+        discard;
+    }
 
     vec2 disturbance  = vec2(cloudNoise(uv1 / 8.0f).x, cloudNoise((uv3 + uv1) / 16.0f).x) * cloud_variance * (1.0f - cloud_scale * 0.25f);
     vec2 disturbance2 = vec2(cloudNoise((uv1 + uv3) / 4.0f).x, cloudNoise((uv4 + uv2) / 8.0f).x) * cloud_variance * (1.0f - cloud_scale * 0.25f);
 
-	// Offset texture coords
-	uv1 += cloud_pos_density1.xy + (disturbance * 0.02);	//large texture, visible density
-	uv2 += cloud_pos_density1.xy;	//large texture, self shadow
-	uv3 += cloud_pos_density2.xy;	//small texture, visible density
-	uv4 += cloud_pos_density2.xy;	//small texture, self shadow
+    // Offset texture coords
+    uv1 += cloud_pos_density1.xy + (disturbance * 0.02);    //large texture, visible density
+    uv2 += cloud_pos_density1.xy;   //large texture, self shadow
+    uv3 += cloud_pos_density2.xy;   //small texture, visible density
+    uv4 += cloud_pos_density2.xy;   //small texture, self shadow
 
     float density_variance = min(1.0, (disturbance.x* 2.0 + disturbance.y* 2.0 + disturbance2.x + disturbance2.y));
 
     cloudDensity *= 1.0 - (density_variance * density_variance);
 
-	// Compute alpha1, the main cloud opacity
+    // Compute alpha1, the main cloud opacity
 
-	float alpha1 = (cloudNoise(uv1).x - 0.5) + (cloudNoise(uv3).x - 0.5) * cloud_pos_density2.z;
-	alpha1 = min(max(alpha1 + cloudDensity, 0.) * 10 * cloud_pos_density1.z, 1.);
+    float alpha1 = (cloudNoise(uv1).x - 0.5) + (cloudNoise(uv3).x - 0.5) * cloud_pos_density2.z;
+    alpha1 = min(max(alpha1 + cloudDensity, 0.) * 10 * cloud_pos_density1.z, 1.);
 
-	// And smooth
-	alpha1 = 1. - alpha1 * alpha1;
-	alpha1 = 1. - alpha1 * alpha1;	
+    // And smooth
+    alpha1 = 1. - alpha1 * alpha1;
+    alpha1 = 1. - alpha1 * alpha1;  
 
     if (alpha1 < 0.001f)
     {
         discard;
     }
 
-	// Compute alpha2, for self shadowing effect
-	// (1 - alpha2) will later be used as percentage of incoming sunlight
-	float alpha2 = (cloudNoise(uv2).x - 0.5);
-	alpha2 = min(max(alpha2 + cloudDensity, 0.) * 2.5 * cloud_pos_density1.z, 1.);
+    // Compute alpha2, for self shadowing effect
+    // (1 - alpha2) will later be used as percentage of incoming sunlight
+    float alpha2 = (cloudNoise(uv2).x - 0.5);
+    alpha2 = min(max(alpha2 + cloudDensity, 0.) * 2.5 * cloud_pos_density1.z, 1.);
 
-	// And smooth
-	alpha2 = 1. - alpha2;
-	alpha2 = 1. - alpha2 * alpha2;	
+    // And smooth
+    alpha2 = 1. - alpha2;
+    alpha2 = 1. - alpha2 * alpha2;  
 
-	// Combine
-	vec4 color;
-	color = (cloudColorSun*(1.-alpha2) + cloudColorAmbient);
-	color *= 2.;
+    // Combine
+    vec4 color;
+    color = (cloudColorSun*(1.-alpha2) + cloudColorAmbient);
+    color *= 2.;
 
-	/// Gamma correct for WL (soft clip effect).
-	frag_data[0] = vec4(scaleSoftClip(color.rgb), alpha1);
-	frag_data[1] = vec4(0.0,0.0,0.0,0.0);
-	frag_data[2] = vec4(0,0,1,0);
+    /// Gamma correct for WL (soft clip effect).
+    frag_data[0] = vec4(scaleSoftClip(color.rgb), alpha1);
+    frag_data[1] = vec4(0.0,0.0,0.0,0.0);
+    frag_data[2] = vec4(0,0,1,0);
 }
 
diff --git a/indra/newview/app_settings/shaders/class2/windlight/cloudsV.glsl b/indra/newview/app_settings/shaders/class2/windlight/cloudsV.glsl
index c1dd45cd67..644cd5a35b 100644
--- a/indra/newview/app_settings/shaders/class2/windlight/cloudsV.glsl
+++ b/indra/newview/app_settings/shaders/class2/windlight/cloudsV.glsl
@@ -57,6 +57,7 @@ uniform float density_multiplier;
 uniform float max_y;
 
 uniform vec4 glow;
+uniform float sun_up_factor;
 
 uniform vec4 cloud_color;
 
@@ -65,126 +66,128 @@ uniform float cloud_scale;
 void main()
 {
 
-	// World / view / projection
-	gl_Position = modelview_projection_matrix * vec4(position.xyz, 1.0);
-
-	vary_texcoord0 = texcoord0;
-
-	// Get relative position
-	vec3 P = position.xyz - camPosLocal.xyz + vec3(0,50,0);
-
-	// Set altitude
-	if (P.y > 0.)
-	{
-		P *= (max_y / P.y);
-	}
-	else
-	{
-		P *= (-32000. / P.y);
-	}
-
-	// Can normalize then
-	vec3 Pn = normalize(P);
-	float  Plen = length(P);
-
-	// Initialize temp variables
-	vec4 temp1 = vec4(0.);
-	vec4 temp2 = vec4(0.);
-	vec4 blue_weight;
-	vec4 haze_weight;
-	vec4 sunlight = sunlight_color;
-	vec4 light_atten;
-
-
-	// Sunlight attenuation effect (hue and brightness) due to atmosphere
-	// this is used later for sunlight modulation at various altitudes
-	light_atten = (blue_density + vec4(haze_density * 0.25)) * (density_multiplier * max_y);
-
-	// Calculate relative weights
-	temp1 = blue_density + haze_density;
-	blue_weight = blue_density / temp1;
-	haze_weight = haze_density / temp1;
-
-	// Compute sunlight from P & lightnorm (for long rays like sky)
-	temp2.y = max(0., max(0., Pn.y) * 1.0 + lightnorm.y );
-	temp2.y = 1. / temp2.y;
-	sunlight *= exp( - light_atten * temp2.y);
-
-	// Distance
-	temp2.z = Plen * density_multiplier;
-
-	// Transparency (-> temp1)
-	// ATI Bugfix -- can't store temp1*temp2.z in a variable because the ati
-	// compiler gets confused.
-	temp1 = exp(-temp1 * temp2.z);
-
-
-	// Compute haze glow
-	temp2.x = dot(Pn, lightnorm.xyz);
-	temp2.x = 1. - temp2.x;
-		// temp2.x is 0 at the sun and increases away from sun
-	temp2.x = max(temp2.x, .001);	
-		// Set a minimum "angle" (smaller glow.y allows tighter, brighter hotspot)
-	temp2.x *= glow.x;
-		// Higher glow.x gives dimmer glow (because next step is 1 / "angle")
-	temp2.x = pow(temp2.x, glow.z);
-		// glow.z should be negative, so we're doing a sort of (1 / "angle") function
-
-	// Add "minimum anti-solar illumination"
-	temp2.x += .25;
-
-	// Increase ambient when there are more clouds
-	vec4 tmpAmbient = ambient;
-	tmpAmbient += (1. - tmpAmbient) * cloud_shadow * 0.5; 
-
-	// Dim sunlight by cloud shadow percentage
-	sunlight *= (1. - cloud_shadow);
-
-	// Haze color below cloud
-	vec4 additiveColorBelowCloud = (	  blue_horizon * blue_weight * (sunlight + tmpAmbient)
-				+ (haze_horizon * haze_weight) * (sunlight * temp2.x + tmpAmbient)
-			 );	
-
-	// CLOUDS
-
-	sunlight = sunlight_color;
-	temp2.y = max(0., lightnorm.y * 2.);
-	temp2.y = 1. / temp2.y;
-	sunlight *= exp( - light_atten * temp2.y);
-
-	// Cloud color out
-	vary_CloudColorSun = (sunlight * temp2.x) * cloud_color;
-	vary_CloudColorAmbient = tmpAmbient * cloud_color;
-	
-	// Attenuate cloud color by atmosphere
-	temp1 = sqrt(temp1);	//less atmos opacity (more transparency) below clouds
-	vary_CloudColorSun *= temp1;
-	vary_CloudColorAmbient *= temp1;
-	vec4 oHazeColorBelowCloud = additiveColorBelowCloud * (1. - temp1);
-
-	// Make a nice cloud density based on the cloud_shadow value that was passed in.
-	vary_CloudDensity = 2. * (cloud_shadow - 0.25);
-
-
-	// Texture coords
-	vary_texcoord0 = texcoord0;
-	vary_texcoord0.xy -= 0.5;
-	vary_texcoord0.xy /= cloud_scale;
-	vary_texcoord0.xy += 0.5;
-
-	vary_texcoord1 = vary_texcoord0;
-	vary_texcoord1.x += lightnorm.x * 0.0125;
-	vary_texcoord1.y += lightnorm.z * 0.0125;
-
-	vary_texcoord2 = vary_texcoord0 * 16.;
-	vary_texcoord3 = vary_texcoord1 * 16.;
-
-	// Combine these to minimize register use
-	vary_CloudColorAmbient += oHazeColorBelowCloud;
-
-	// needs this to compile on mac
-	//vary_AtmosAttenuation = vec3(0.0,0.0,0.0);
-
-	// END CLOUDS
+    // World / view / projection
+    gl_Position = modelview_projection_matrix * vec4(position.xyz, 1.0);
+
+    vary_texcoord0 = texcoord0;
+
+    // Get relative position
+    vec3 P = position.xyz - camPosLocal.xyz + vec3(0,50,0);
+
+    // Set altitude
+    if (P.y > 0.)
+    {
+        P *= (max_y / P.y);
+    }
+    else
+    {
+        P *= (-32000. / P.y);
+    }
+
+    // Can normalize then
+    vec3 Pn = normalize(P);
+    float  Plen = length(P);
+
+    // Initialize temp variables
+    vec4 temp1 = vec4(0.);
+    vec4 temp2 = vec4(0.);
+    vec4 blue_weight;
+    vec4 haze_weight;
+    vec4 sunlight = sunlight_color;
+    vec4 light_atten;
+
+
+    // Sunlight attenuation effect (hue and brightness) due to atmosphere
+    // this is used later for sunlight modulation at various altitudes
+    light_atten = (blue_density + vec4(haze_density * 0.25)) * (density_multiplier * max_y);
+
+    // Calculate relative weights
+    temp1 = blue_density + haze_density;
+    blue_weight = blue_density / temp1;
+    haze_weight = haze_density / temp1;
+
+    // Compute sunlight from P & lightnorm (for long rays like sky)
+    temp2.y = max(0., max(0., Pn.y) * 1.0 + lightnorm.y );
+    temp2.y = 1. / temp2.y;
+    sunlight *= exp( - light_atten * temp2.y);
+
+    // Distance
+    temp2.z = Plen * density_multiplier;
+
+    // Transparency (-> temp1)
+    // ATI Bugfix -- can't store temp1*temp2.z in a variable because the ati
+    // compiler gets confused.
+    temp1 = exp(-temp1 * temp2.z);
+
+
+    // Compute haze glow
+    temp2.x = dot(Pn, lightnorm.xyz);
+    temp2.x = 1. - temp2.x;
+        // temp2.x is 0 at the sun and increases away from sun
+    temp2.x = max(temp2.x, .001);   
+        // Set a minimum "angle" (smaller glow.y allows tighter, brighter hotspot)
+    temp2.x *= glow.x;
+        // Higher glow.x gives dimmer glow (because next step is 1 / "angle")
+    temp2.x = pow(temp2.x, glow.z);
+        // glow.z should be negative, so we're doing a sort of (1 / "angle") function
+
+    temp2.x *= sun_up_factor;
+
+    // Add "minimum anti-solar illumination"
+    temp2.x += .25;
+
+    // Increase ambient when there are more clouds
+    vec4 tmpAmbient = ambient;
+    tmpAmbient += (1. - tmpAmbient) * cloud_shadow * 0.5; 
+
+    // Dim sunlight by cloud shadow percentage
+    sunlight *= (1. - cloud_shadow);
+
+    // Haze color below cloud
+    vec4 additiveColorBelowCloud = (      blue_horizon * blue_weight * (sunlight + tmpAmbient)
+                + (haze_horizon * haze_weight) * (sunlight * temp2.x + tmpAmbient)
+             ); 
+
+    // CLOUDS
+
+    sunlight = sunlight_color;
+    temp2.y = max(0., lightnorm.y * 2.);
+    temp2.y = 1. / temp2.y;
+    sunlight *= exp( - light_atten * temp2.y);
+
+    // Cloud color out
+    vary_CloudColorSun = (sunlight * temp2.x) * cloud_color;
+    vary_CloudColorAmbient = tmpAmbient * cloud_color;
+    
+    // Attenuate cloud color by atmosphere
+    temp1 = sqrt(temp1);    //less atmos opacity (more transparency) below clouds
+    vary_CloudColorSun *= temp1;
+    vary_CloudColorAmbient *= temp1;
+    vec4 oHazeColorBelowCloud = additiveColorBelowCloud * (1. - temp1);
+
+    // Make a nice cloud density based on the cloud_shadow value that was passed in.
+    vary_CloudDensity = 2. * (cloud_shadow - 0.25);
+
+
+    // Texture coords
+    vary_texcoord0 = texcoord0;
+    vary_texcoord0.xy -= 0.5;
+    vary_texcoord0.xy /= max(0.001, cloud_scale);
+    vary_texcoord0.xy += 0.5;
+
+    vary_texcoord1 = vary_texcoord0;
+    vary_texcoord1.x += lightnorm.x * 0.0125;
+    vary_texcoord1.y += lightnorm.z * 0.0125;
+
+    vary_texcoord2 = vary_texcoord0 * 16.;
+    vary_texcoord3 = vary_texcoord1 * 16.;
+
+    // Combine these to minimize register use
+    vary_CloudColorAmbient += oHazeColorBelowCloud;
+
+    // needs this to compile on mac
+    //vary_AtmosAttenuation = vec3(0.0,0.0,0.0);
+
+    // END CLOUDS
 }
 
diff --git a/indra/newview/app_settings/shaders/class2/windlight/skyV.glsl b/indra/newview/app_settings/shaders/class2/windlight/skyV.glsl
index 3788ddaf2d..04cf4052b8 100644
--- a/indra/newview/app_settings/shaders/class2/windlight/skyV.glsl
+++ b/indra/newview/app_settings/shaders/class2/windlight/skyV.glsl
@@ -50,7 +50,7 @@ uniform float density_multiplier;
 uniform float max_y;
 
 uniform vec4 glow;
-
+uniform float sun_up_factor;
 uniform vec4 cloud_color;
 
 void main()
@@ -119,6 +119,8 @@ void main()
 	temp2.x = pow(temp2.x, glow.z);
 		// glow.z should be negative, so we're doing a sort of (1 / "angle") function
 
+        temp2.x *= sun_up_factor;
+
 	// Add "minimum anti-solar illumination"
 	temp2.x += .25;