Glow effect for ALS space shader, converting a temperature into surface blackbody radiation color

Effects/space-combined.eff

@@ -4,7 +4,7 @@
   <name>Effects/space-combined</name>
   <inherits-from>Effects/model-combined</inherits-from>
 
-<!--<parameters>
+<parameters>
 	<geo_light_r type="float">0.0</geo_light_r>
 	<geo_light_g type="float">0.0</geo_light_g>
 	<geo_light_b type="float">0.0</geo_light_b>
@@ -13,13 +13,15 @@
 	<geo_light_z type="float">0.0</geo_light_z>
 	<geo_light_radius type="float">0.0</geo_light_radius>
 	<geo_ambience type="float">0.0</geo_ambience>
-</parameters> -->
+	<use_geo_light type="int">0</use_geo_light>
+</parameters> 
 
 <technique n="4">
  <pass>
  <program>
         <vertex-shader n="0">Shaders/space-ALS-ultra.vert</vertex-shader>
         <fragment-shader n="0">Shaders/space-ALS-ultra.frag</fragment-shader>
+	<fragment-shader n="6">Shaders/color_temperature.frag</fragment-shader>
   </program>
 
 			   <uniform>
@@ -816,6 +818,11 @@
 	<type>float</type>
 	<value><use>geo_ambience</use></value>
   </uniform>
+  <uniform>
+	<name>use_geo_light</name>
+	<type>int</type>
+	<value><use>use_geo_light</use></value>
+  </uniform>
   </pass>
  </technique>
 

Shaders/color_temperature.frag

@@ -0,0 +1,51 @@
+// -*-C++-*-
+#version 120
+
+
+vec4 color_temperature (in float T)
+{
+T *=0.01;
+
+float red;
+float green;
+float blue;
+float alpha;
+
+red = 1.0;
+
+if (T<66.0)
+	{
+	red = 255.0;
+	green = T;
+	green = 99.4708025 * log(green) - 161.11956;
+
+	if (T <=19) 
+		{blue = 0.0;}
+	else
+		{
+		blue = T-10;
+		blue = 138.517731 * log(blue) - 305.044792;
+		}
+
+	
+	}
+else
+	{
+	red = T - 60.0;
+	red = 329.6987 * pow(red, -0.1332047);
+	
+	green = T - 60.0;
+	green = 288.122169 * pow(green, -0.075514);	
+
+	blue = 255.0;
+	}
+
+alpha = 0.8 * smoothstep(5.0, 15.0, T);
+
+vec3 color = vec3 (red, green, blue);
+color /= 255.0;
+
+color = clamp(color, 0.0, 1.0);
+
+return vec4 (color, alpha);
+}

Shaders/space-ALS-ultra.frag

@@ -41,6 +41,7 @@ uniform int cloud_shadow_flag;
 uniform int use_searchlight;
 uniform int use_landing_light;
 uniform int use_alt_landing_light;
+uniform int use_geo_light;
 
 uniform float amb_correction;
 uniform float dirt_b_factor;
@@ -59,6 +60,7 @@ uniform float grain_magnification;
 uniform float wetness;
 uniform float rain_norm;
 uniform float darkmap_factor;
+uniform float delta_T;
 
 uniform float avisibility;
 uniform float cloud_self_shading;
@@ -116,7 +118,7 @@ vec3 get_hazeColor(in float lightArg);
 vec3 searchlight();
 vec3 landing_light(in float offset, in float offsetv);
 vec3 addLights(in vec3 color1, in vec3 color2);
-
+vec4 color_temperature (in float T);
 
 float light_func (in float x, in float a, in float b, in float c, in float d, in float e)
     {
@@ -346,12 +348,14 @@ void main (void)
     //Diffuse.rgb += secondary_light * light_distance_fading(dist) + geo_light;
 
     Diffuse.rgb = addLights(Diffuse.rgb, secondary_light * light_distance_fading(dist));
-    Diffuse.rgb = addLights(Diffuse.rgb, geo_light * diffuse_reduction );
+    //if (use_geo_light == 1)
+    {Diffuse.rgb = addLights(Diffuse.rgb, geo_light * diffuse_reduction );}	
 	
     vec4 Specular = gl_FrontMaterial.specular * light_diffuse * pf + gl_FrontMaterial.specular * light_ambient * pf1;
     Specular+=  gl_FrontMaterial.specular * pow(max(0.0,-dot(N,normalize(vertVec))),gl_FrontMaterial.shininess) * vec4(secondary_light,1.0);
 
     vec4 color = gl_Color * light_ambient + gl_FrontMaterial.emission;
+
     color = color + Diffuse * gl_FrontMaterial.diffuse;
     color = clamp( color, 0.0, 1.0 );
 
@@ -444,6 +448,8 @@ void main (void)
 
     ambient_Correction = vec4 (0.0, 0.0, 0.0, 1.0);
 
+
+
     color.a = texel.a * alpha;
     vec4 fragColor = vec4(color.rgb * mixedcolor + ambient_Correction.rgb, color.a);
 
@@ -479,6 +485,24 @@ void main (void)
     // END lightmap
     /////////////////////////////////////////////////////////////////////
 
+    /// BEGIN glow
+
+    float temperature = delta_T;
+
+    if (darkmap_enabled == 2)
+	{
+	temperature *=  (1.0 - darkmap_factor * lightmapTexel.a);
+	}
+
+    vec4 glow = color_temperature(temperature);
+    float glowFactor = 0.3  + 0.6 * (1.0 - length(texel.rgb)/1.73);
+    glowFactor *= glow.a;
+    fragColor.rgb = mix(fragColor.rgb, glow.rgb, glowFactor);
+
+    //////////////////////////////////////////////////////////////////////
+    // END glow
+    /////////////////////////////////////////////////////////////////////
+
 
     /// BEGIN fog amount
 
@@ -616,8 +640,11 @@ void main (void)
 	hazeColor *= eqColorFactor * fog_earthShade;
 	hazeColor.rgb = max(hazeColor.rgb, minLight.rgb);
 
+	
 
       fragColor.rgb = mix(hazeColor +secondary_light * fog_backscatter(mvisibility), fragColor.rgb,transmission);
+
+
     gl_FragColor = fragColor;