NORSPEC-285 NORSPEC-311 fix gamma correction of diffuse-only objects not...

NORSPEC-285 NORSPEC-311 fix gamma correction of diffuse-only objects not matching the rest of the sRGB herd

indra/newview/app_settings/shaders/class1/deferred/diffuseIndexedF.glsl

@@ -39,15 +39,34 @@ vec2 encode_normal(vec3 n)
 	return n.xy / f + 0.5;
 }
 
+vec3 srgb_to_linear(vec3 cs)
+{
+	
+/*        {  cs / 12.92,                 cs <= 0.04045
+    cl = {
+        {  ((cs + 0.055)/1.055)^2.4,   cs >  0.04045*/
+
+	return pow((cs+vec3(0.055))/vec3(1.055), vec3(2.4));
+}
+
+vec3 linear_to_srgb(vec3 cl)
+{
+	    /*{  0.0,                          0         <= cl
+            {  12.92 * c,                    0         <  cl < 0.0031308
+    cs = {  1.055 * cl^0.41666 - 0.055,   0.0031308 <= cl < 1
+            {  1.0,                                       cl >= 1*/
+
+	return 1.055 * pow(cl, vec3(0.41666)) - 0.055;
+}
 
 void main() 
 {
-	vec3 col = vertex_color.rgb * diffuseLookup(vary_texcoord0.xy).rgb;
+	vec3 col = vertex_color.rgb * srgb_to_linear(diffuseLookup(vary_texcoord0.xy).rgb);
 	
 	vec3 spec;
 	spec.rgb = vec3(vertex_color.a);
 
-	frag_data[0] = vec4(col, 0.0);
+	frag_data[0] = vec4(linear_to_srgb(col), 0.0);
 	frag_data[1] = vec4(spec, vertex_color.a); // spec
 	vec3 nvn = normalize(vary_normal);
 	frag_data[2] = vec4(encode_normal(nvn.xyz), vertex_color.a, 0.0);