Merge pull request #42548 from pezcode/lights-metallic

Add METALLIC to light() built-ins

servers/rendering/shader_types.cpp

@@ -149,6 +149,7 @@ ShaderTypes::ShaderTypes() {
 	shader_modes[RS::SHADER_SPATIAL].functions["light"].built_ins["SHADOW_ATTENUATION"] = constt(ShaderLanguage::TYPE_VEC3);
 	shader_modes[RS::SHADER_SPATIAL].functions["light"].built_ins["ALBEDO"] = constt(ShaderLanguage::TYPE_VEC3);
 	shader_modes[RS::SHADER_SPATIAL].functions["light"].built_ins["BACKLIGHT"] = constt(ShaderLanguage::TYPE_VEC3);
+	shader_modes[RS::SHADER_SPATIAL].functions["light"].built_ins["METALLIC"] = constt(ShaderLanguage::TYPE_FLOAT);
 	shader_modes[RS::SHADER_SPATIAL].functions["light"].built_ins["ROUGHNESS"] = constt(ShaderLanguage::TYPE_FLOAT);
 	shader_modes[RS::SHADER_SPATIAL].functions["light"].built_ins["DIFFUSE_LIGHT"] = ShaderLanguage::TYPE_VEC3;
 	shader_modes[RS::SHADER_SPATIAL].functions["light"].built_ins["SPECULAR_LIGHT"] = ShaderLanguage::TYPE_VEC3;