mdl 1.3;

import ::df::*;
import ::state::*;
import ::math::*;
import ::tex::*;
import ::anno::*;
import ::base::*;

using .::DrivesimPBR_Model import *;

float3 tangent_space_normal(
    float3 normal = float3(0.0,0.0,1.0),
    float3 tangent_u = state::texture_tangent_u(0),
	float3 tangent_v = state::texture_tangent_v(0)
)
[[
    anno::description("Interprets the vector in tangent space"),
    anno::noinline()
]]
{
    return math::normalize(
        tangent_u * normal.x +
        tangent_v * normal.y +
        state::normal() * (normal.z));
}

export material OmniUe4Base(
    float3 base_color = float3(0.0, 0.0, 0.0),
    float metallic = 0.0,
    float roughness = 0.5,
    float specular = 0.5,
    float3 normal = float3(0.0, 0.0, 1.0),
    uniform float clearcoat_weight = 0.0,
    uniform float clearcoat_roughness = 0.0,
    float3 clearcoat_normal = float3(0.0, 0.0, 1.0),
    //float3 emissive_color = float3(0.0, 0.0, 0.0),
    //float3 displacement = float3(0.0, 0.0, 0.0),
    uniform float opacity = 1.0,
    uniform bool is_tangent_space_normal = true,
    //uniform bool two_sided = false,
    uniform bool is_unlit = false
)
[[
	anno::author("NVIDIA CORPORATION"), 
	anno::key_words(string[]("omni", "UE4", "omniverse", "lit", "clearcoat", "generic"))
]]
= let {
    uniform bool enable_clearcoat = clearcoat_weight > 0.0 ? true : false;
    // bool enable_emission = (emissive_color.x > 0.0 || emissive_color.y > 0.0 || emissive_color.z > 0.0) ? true : false;
    uniform bool enable_opacity = opacity < 1.0 ? true : false;

    float3 final_normal = math::normalize(normal);
	float3 the_normal =  is_unlit ? state::normal() : 
							(is_tangent_space_normal ? tangent_space_normal(
                                            normal:         final_normal,
                                            tangent_u:      state::texture_tangent_u(0),
                                            tangent_v:      state::texture_tangent_v(0)
                            ) : final_normal);
} in DrivesimPBR_Model(
    diffuse_color: color(base_color),
    roughness: roughness,
    metallic: metallic,
    specular: specular,
    normal: the_normal,
    enable_clearcoat: enable_clearcoat,
    clearcoat_weight: clearcoat_weight,
    clearcoat_reflection_roughness: clearcoat_roughness,
    clearcoat_normal: clearcoat_normal,
    enable_emission: false, // xxxnsubtil: no emission in road_base.mdl
    enable_opacity: enable_opacity,
    alpha: opacity
);