I am trying to make emissive lights on a transparent background that could have uses
for example for emissive HUD or for lighting up roads or runways during night without using computationally intensive pointlights or spotlights.
I followed the following formating rule for dds files
albedo: DXT1 format
normal: DXT5 format
roughness: BC4 / ATI1 format
opacity: BC4 / ATI1 format
reflectance: BC4 / ATI1 format
and set up a mat file for an emissive texture. It indeed turns out to be emissive but of course does not have a transparent background. I made the dds files from black&white jpg images converted to dds according to the above rules.
Unfortunately all trials to get a transparent background destroyed the emissive behaviour.
{
"version" : 512,
"mats" : [
{
"name" : "ground-light-material",
"color" : "1.0,0.0,0.0,1",
"f0" : "0.0",
"roughness" : "1",
"no_light" : false,
"alpha_masked" : false,
"emissive" : true,
"emissive_color" : "1.0,0.0,0.0,1",
"tex_albedo" : "ground-light-image-red.dds",
"tex_normal" : "",
"tex_roughness" : "",
"tex_opacity" : "",
"tex_reflectance" : "",
"tex_environment" : "",
"tex_emissive" : "ground-light-image-red.dds"
}]}
One of the failed trials to get an emissive texture on a transparent background was the following
{
"version" : 512,
"mats" : [
{
"name" : "ground-light-material",
"color" : "1.0,1.0,1.0,1.0",
"f0" : "0.0",
"roughness" : "1",
"no_light" : false,
"alpha_masked" : true,
"emissive" : true,
"emissive_color" : "1.0,1.0,1.0,1.0",
"tex_albedo" : "",
"tex_normal" : "",
"tex_roughness" : "",
"tex_opacity" : "ground-light-image-op.dds",
"tex_reflectance" : "",
"tex_environment" : "",
"tex_emissive" : "ground-light-image.dds",
}]}
Any suggestion how to achieve this ?