#if !defined(LIGHTING_INCLUDED)
#define LIGHTING_INCLUDED

#include "UnityPBSLighting.cginc"
#include "AutoLight.cginc"
#include "UnityCG.cginc"

float4 _Ambient;
sampler2D _MainTex;
sampler2D _NormalMap;
float4 _MainTex_ST;
float _ToonAmount;

struct VertexData
{
    float4 vertex: POSITION;
    float3 normal: NORMAL;
    float4 tangent: TANGENT;
    float2 uv: TEXCOORD0;
};

struct Interpolators
{
    float4 pos: SV_POSITION;
    float2 uv: TEXCOORD0;
    float3 normal: TEXCOORD1;
    float4 tangent: TEXCOORD2;
    float3 worldPos: TEXCOORD4;

    SHADOW_COORDS(5)

    #if defined(VERTEXLIGHT_ON)
        float3 vertexLightColor: TEXCOORD6;
    #endif
};

void ComputeVertexLightColor(inout Interpolators i)
{
    #if defined(VERTEXLIGHT_ON)
        i.vertexLightColor = Shade4PointLights(
            unity_4LightPosX0, unity_4LightPosY0, unity_4LightPosZ0,
            unity_LightColor[0].rgb, unity_LightColor[1].rgb,
            unity_LightColor[2].rgb, unity_LightColor[3].rgb,
            unity_4LightAtten0, i.worldPos, i.normal
        );
    #endif
}

Interpolators vert(VertexData v)
{
    Interpolators i;
	#if defined(MANUAL_BILLBOARD)
    i.pos = UnityObjectToClipPos(v.vertex);
    i.normal = UnityObjectToWorldNormal(v.normal);
    i.tangent = float4(UnityObjectToWorldDir(v.tangent.xyz), v.tangent.w);
    i.worldPos = mul(unity_ObjectToWorld, v.vertex);
	#else
    // i.pos = mul(UNITY_MATRIX_P,
    //           	mul(UNITY_MATRIX_MV, float4(0, 0, 0, 1))
    //           	+ float4(v.vertex.x, v.vertex.y, 0, 0));
    float4 world_origin = mul(UNITY_MATRIX_M, float4(0, 0, 0, 1));
    float4 view_origin = float4(UnityObjectToViewPos(float3(0, 0, 0)), 1);

    float4 world_pos = mul(UNITY_MATRIX_M, v.vertex);
    float4 view_pos = world_pos - world_origin + view_origin;
    float4 clip_pos = mul(UNITY_MATRIX_P, view_pos);

    i.pos = clip_pos;
    i.normal = -1 * normalize(unity_CameraToWorld._m02_m12_m22);
	//This tangent calculation uses (0, 1, 0) to generate the perpendicular value (tangent)
	//Could be modified to fit other vectors
    //I also don't know why w is negative but it works
    i.tangent = normalize(float4(i.normal.z * -1, 0, i.normal.x, -1));
	//i.worldPos = mul(unity_ObjectToWorld, mul(UNITY_MATRIX_MV, float4(0, 0, 0, 1)) + float4(v.vertex.x, v.vertex.y, 0, 0));
    //i.worldPos = mul(unity_ObjectToWorld, v.vertex);
    i.worldPos = view_pos;
    v.vertex = float4(0, 0, 0, 0);
	#endif

    i.uv = TRANSFORM_TEX(v.uv, _MainTex);

    // #if defined (SHADOWS_SCREEN)
    //     #if defined (UNITY_NO_SCREENSPACE_SHADOWS)
    //         i._ShadowCoord = mul( unity_WorldToShadow[0], world_pos );
    //     #else
    //         i._ShadowCoord = ComputeScreenPos(i.pos);
    //     #endif
    // #endif
    // #if defined (SHADOWS_DEPTH) && defined (SPOT)
    //     i._ShadowCoord = mul (unity_WorldToShadow[0], world_pos);
    // #endif
    // #if defined (SHADOWS_CUBED)
    //     i._ShadowCoord.xyz = world_pos.xyz - _LightPositionRange.xyz;
    // #endif

    TRANSFER_SHADOW(i)
    ComputeVertexLightColor(i);
    return i;
}
//ShadowsScreen && UNITY_NO_SCREENSPACE_SHADOWS
//#define TRANSFER_SHADOW(a) a._ShadowCoord = mul( unity_WorldToShadow[0], mul( unity_ObjectToWorld, v.vertex ) );
//ShadowsScreen && !UNITY_NO_SCREENSPACE_SHADOWS
//#define TRANSFER_SHADOW(a) a._ShadowCoord = ComputeScreenPos(a.pos);
//SpotLight && ShadowsDepth
//#define TRANSFER_SHADOW(a) a._ShadowCoord = mul (unity_WorldToShadow[0], mul(unity_ObjectToWorld,v.vertex));
//ShadowsCubed (Point Light)
//#define TRANSFER_SHADOW(a) a._ShadowCoord.xyz = mul(unity_ObjectToWorld, v.vertex).xyz - _LightPositionRange.xyz;

UnityLight CreateLight(Interpolators i)
{
    UnityLight light;

    #if defined(POINT) || defined(POINT_COOKIE) || defined(SPOT)
        light.dir = normalize(_WorldSpaceLightPos0.xyz - i.worldPos);
    #else
        light.dir = _WorldSpaceLightPos0.xyz;
    #endif
    UNITY_LIGHT_ATTENUATION(attenuation, i, i.worldPos);
    light.color = _LightColor0.rgb * attenuation;
    light.ndotl = DotClamped(i.normal, light.dir);
    return light;
}

void InitializeFragmentNormal(inout Interpolators i)
{
    float3 mainNormal = UnpackScaleNormal(tex2D(_NormalMap, i.uv), 1);

    float3 binormal = cross(i.normal, i.tangent.xyz) *
    (i.tangent.w * unity_WorldTransformParams.w);

    i.normal = normalize(
        mainNormal.x * i.tangent +
        mainNormal.y * binormal +
        mainNormal.z * i.normal
    );
}

float Toonify(float ndotl)
{
    return round(ndotl * _ToonAmount) / _ToonAmount;
}

float4 frag(Interpolators i): SV_TARGET
{
    InitializeFragmentNormal(i);
    float4 col = tex2D(_MainTex, i.uv);
    clip(col.a - 0.5);
    UnityLight light = CreateLight(i);
    UNITY_LIGHT_ATTENUATION(atten, i, i.worldPos.xyz);
    atten /= 2;
    atten += 0.5;
    return col * atten * float4(_LightColor0.rgb * Toonify(light.ndotl) + _Ambient.rgb, 1);
}

#endif