#ifndef __PBR_INC
#define __PBR_INC

#include "filamented.cginc"
#include "globals.cginc"
#include "interpolators.cginc"
#include "texture_utils.cginc"

struct Pbr {
  float4 albedo;
  float3 normal;
  float3x3 tbn;
  float smoothness;
  float roughness_perceptual;
  float roughness;
  float metallic;
#if defined(_CLEARCOAT)
  float cc_roughness;
  float cc_strength;
#endif
#if defined(_CLOTH_SHEEN)
  float cl_strength;
  float3 cl_color;
#endif
};

#define MIN_PERCEPTUAL_ROUGHNESS 5e-2f
#define MIN_ROUGHNESS 5e-3f

// TODO consider normal filtering like filamented
void propagateSmoothness(inout Pbr pbr) {
  pbr.roughness_perceptual = max(MIN_PERCEPTUAL_ROUGHNESS, 1.0f - pbr.smoothness);
  pbr.roughness = max(MIN_ROUGHNESS, pbr.roughness_perceptual * pbr.roughness_perceptual);
#if defined(_CLEARCOAT)
  pbr.cc_roughness = max(MIN_ROUGHNESS, pbr.cc_roughness * pbr.cc_roughness);
#endif
}

void apply_marble(float3 world_pos, inout float3 albedo) {
#if defined(_MARBLE)
  float3 uvw = world_pos * _Marble_Scale;
  float noise_r = sin_noise_3d_fbm(uvw + _Time[0],     _Marble_Octaves, 2.0f, _Marble_Strength);
  float noise_g = sin_noise_3d_fbm(uvw+3.1 + _Time[0], _Marble_Octaves, 2.0f, _Marble_Strength);
  float noise_b = sin_noise_3d_fbm(uvw+3.7 + _Time[0], _Marble_Octaves, 2.0f, _Marble_Strength);

  float3 r = _Marble_U_Ramp.Sample(linear_repeat_s, float2(noise_r, 0));
  float3 g = _Marble_V_Ramp.Sample(linear_repeat_s, float2(noise_g, 0));
  float3 b = _Marble_W_Ramp.Sample(linear_repeat_s, float2(noise_b, 0));

  albedo = r + g + b;
#endif
}

Pbr getPbr(v2f i) {
  Pbr pbr = (Pbr) 0;

#if defined(_UV_SCROLL)
  i.uv01.xy += getTime() * _UV_Scroll_Speed;
#endif  // _UV_SCROLL

  pbr.albedo = _MainTex.Sample(aniso16_trilinear_repeat_s, i.uv01.xy * _MainTex_ST.xy + _MainTex_ST.zw);
  pbr.albedo *= _Color;
  apply_marble(i.worldPos, pbr.albedo.xyz);

  float3 normal_tangent = UnpackNormal(_BumpMap.Sample(aniso16_trilinear_repeat_s, i.uv01.xy * _BumpMap_ST.xy));
  normal_tangent.xy *= _BumpScale;

#if defined(_DETAILS)
  float2 detail_uv = get_uv_by_channel(i, _Details_UV_Channel);
  float3 detail_normal = UnpackNormal(_DetailNormalMap.Sample(aniso16_trilinear_repeat_s, detail_uv * _DetailNormalMap_ST.xy));
  detail_normal.xy *= _DetailNormalMapScale;
  float detail_mask = _DetailMask.Sample(aniso16_trilinear_repeat_s, detail_uv * _DetailMask_ST.xy).r;
  detail_normal.xy *= detail_mask;
  normal_tangent = blendNormalsHill12(normal_tangent, detail_normal);
#endif

  // Map from tangent space to world space.
  float3 bitangent = cross(i.normal, i.tangent.xyz) * i.tangent.w;
  pbr.tbn = float3x3(i.tangent.xyz, bitangent, i.normal);
  pbr.normal = normalize(mul(normal_tangent, pbr.tbn));

  float4 metallic_gloss = _MetallicGlossMap.Sample(aniso16_trilinear_repeat_s, i.uv01.xy * _MetallicGlossMap_ST.xy);
  pbr.smoothness = metallic_gloss.a * _Glossiness;
  pbr.metallic = metallic_gloss.r * _Metallic;
#if defined(_CLEARCOAT)
  pbr.cc_roughness = _Clearcoat_Roughness;
  pbr.cc_strength = _Clearcoat_Strength;
#endif
#if defined(_CLOTH_SHEEN)
  pbr.cl_strength = _Cloth_Sheen_Strength;
  pbr.cl_color = _Cloth_Sheen_Color;
#endif
  propagateSmoothness(pbr);

  return pbr;
}

#endif  // __PBR_INC