Eevee: Add SSS support in probes

Previously the lighting of SSS material was not present in reflection probe or irradiance grid.

This does not compute the SSS correctly but at least output the corresponding irradiance power to the correct output.

source/blender/draw/engines/eevee/shaders/bsdf_common_lib.glsl

@@ -656,6 +656,8 @@ Closure closure_add(Closure cl1, Closure cl2)
 	return cl;
 }
 
+uniform bool sssToggle;
+
 #if defined(MESH_SHADER) && !defined(USE_ALPHA_HASH) && !defined(USE_ALPHA_CLIP) && !defined(SHADOW_SHADER) && !defined(USE_MULTIPLY)
 layout(location = 0) out vec4 fragColor;
 #ifdef USE_SSS
@@ -701,6 +703,15 @@ void main()
 #ifdef USE_SSS_ALBEDO
 	sssAlbedo = cl.sss_albedo.rgbb;
 #endif
+#endif
+
+	/* For Probe capture */
+#ifdef USE_SSS
+#ifdef USE_SSS_ALBEDO
+	fragColor.rgb += cl.sss_data.rgb * cl.sss_albedo.rgb * float(!sssToggle);
+#else
+	fragColor.rgb += cl.sss_data.rgb * float(!sssToggle);
+#endif
 #endif
 }