1 files changed, 116 insertions, 0 deletions
diff --git a/indra/newview/app_settings/shaders/class1/windlight/atmosphericsFuncs.glsl b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsFuncs.glsl
new file mode 100644
index 0000000000..2854fb8139
--- /dev/null
+++ b/indra/newview/app_settings/shaders/class1/windlight/atmosphericsFuncs.glsl
@@ -0,0 +1,116 @@
+uniform vec4 gamma;
+uniform vec4 lightnorm;
+uniform vec4 sunlight_color;
+uniform vec4 moonlight_color;
+uniform int sun_up_factor;
+uniform vec4 ambient;
+uniform vec4 blue_horizon;
+uniform vec4 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 float scene_light_strength;
+uniform mat3 ssao_effect_mat;
+uniform int no_atmo;
+uniform float sun_moon_glow_factor;
+
+vec3 nothing() {
+    return vec3(0, 0, 0);
+}
+
+void calcAtmosphericVars(vec3 inPositionEye, float ambFactor, out vec3 sunlit, out vec3 amblit, out vec3 additive, out vec3 atten) {
+
+    vec3 P = inPositionEye;
+   
+    //(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 = (sun_up_factor == 1) ? sunlight_color : moonlight_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);
+    if (temp2.y > 0.001f)
+    {
+        temp2.y = 1. / temp2.y;
+    }
+    temp2.y = max(0.001f, 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
+    atten = temp1.rgb;
+    
+    //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;
+
+    temp2.x *= sun_moon_glow_factor;
+    
+    //increase ambient when there are more clouds
+    vec4 tmpAmbient = ambient + (vec4(1.) - ambient) * 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);
+     */
+    tmpAmbient = vec4(mix(ssao_effect_mat * tmpAmbient.rgb, tmpAmbient.rgb, ambFactor), tmpAmbient.a);
+
+    //haze color
+        additive =
+        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
+    sunlit = vec3(sunlight.rgb);
+    amblit = vec3(tmpAmbient * .25);
+    additive  = normalize(additive);
+    additive *= vec3(1.0 - exp(-temp2.z * distance_multiplier)) * 0.5;
+}
+\ No newline at end of file