// Upgrade NOTE: replaced 'glstate_matrix_invtrans_modelview0' with 'UNITY_MATRIX_IT_MV'
// Upgrade NOTE: replaced 'glstate_matrix_modelview0' with 'UNITY_MATRIX_MV'
// Upgrade NOTE: replaced 'glstate_matrix_mvp' with 'UNITY_MATRIX_MVP'

// Example shader for a scriptable render loop that calculates multiple lights
// in a single forward-rendered shading pass. Uses same PBR shading model as the
// Standard shader.
//
// The parameters and inspector of the shader are the same as Standard shader,
// for easier experimentation.
Shader "RenderLoop/Batching/Standard8"
{
    // Properties is just a copy of Standard.shader. Our example shader does not use all of them,
    // but the inspector UI expects all these to exist.
	Properties
	{
//		_Color("Color", Color) = (1,1,1,1)
		myColor("Color", Color) = (1,1,1,1)
		myTexture1("Albedo1", 2D) = "white" {}
		myTexture2("Albedo2", 2D) = "white" {}
		myTexture3("Albedo3", 2D) = "white" {}
		myTexture4("Albedo4", 2D) = "white" {}
		myTexture5("Albedo5", 2D) = "white" {}
		myTexture6("Albedo6", 2D) = "white" {}
		myTexture7("Albedo7", 2D) = "white" {}
		myTexture8("Albedo8", 2D) = "white" {}
	//        [HideInInspector] _Mode("__mode", Float) = 0.0
 //       [HideInInspector] _SrcBlend("__src", Float) = 1.0
   //     [HideInInspector] _DstBlend("__dst", Float) = 0.0
     //   [HideInInspector] _ZWrite("__zw", Float) = 1.0
    }

    SubShader
    {
        Tags { "RenderType" = "Opaque" "PerformanceChecks" = "False" }
        LOD 300

        // Multiple lights at once pass, for our example Basic render loop.
        Pass
        {
            Tags { "LightMode" = "BasicPass" }

            // Use same blending / depth states as Standard shader
            Blend One Zero
            ZWrite On

CGPROGRAM
#pragma target 3.0
#pragma vertex vert
#pragma fragment frag
//#pragma shader_feature _METALLICGLOSSMAP
//#include "UnityCG.cginc"
#include "HLSLSupport.cginc"

//float4 _Color;

// Global lighting data (setup from C# code once per frame).

CBUFFER_START(GlobalLightData)
    // The variables are very similar to built-in unity_LightColor, unity_LightPosition,
    // unity_LightAtten, unity_SpotDirection as used by the VertexLit shaders, except here
    // we use world space positions instead of view space.
    half4 globalLightColor[8];
    float4 globalLightPos[8];
    float4 globalLightSpotDir[8];
    float4 globalLightAtten[8];
    int4  globalLightCount;
    // Global ambient/SH probe, similar to unity_SH* built-in variables.
    float4 globalSH[7];
CBUFFER_END


CBUFFER_START(simplebufferTest)
	float4 myColor;
CBUFFER_END


/*
CBUFFER_START(UnityPerDraw)			// 352 bytes, uploaded per object (even if just position change position )
	float4x4 UNITY_MATRIX_MVP;
	float4x4 UNITY_MATRIX_MV;
	float4x4 UNITY_MATRIX_IT_MV;

	float4x4 unity_ObjectToWorld;
	float4x4 unity_WorldToObject;
	float4 unity_LODFade; // x is the fade value ranging within [0,1]. y is x quantized into 16 levels
	float4 unity_WorldTransformParams; // w is usually 1.0, or -1.0 for odd-negative scale transforms
CBUFFER_END
*/


// Compute attenuation & illumination from one light
half3 EvaluateOneLight(int idx, float3 positionWS, half3 normalWS, float3 vAlbedo)
{
    // direction to light
    float3 dirToLight = globalLightPos[idx].xyz;
    dirToLight -= positionWS * globalLightPos[idx].w;
    // distance attenuation
    float att = 1.0;
    float distSqr = dot(dirToLight, dirToLight);
    att /= (1.0 + globalLightAtten[idx].z * distSqr);
    if (globalLightPos[idx].w != 0 && distSqr > globalLightAtten[idx].w) att = 0.0; // set to 0 if outside of range
    distSqr = max(distSqr, 0.000001); // don't produce NaNs if some vertex position overlaps with the light
    dirToLight *= rsqrt(distSqr);

	// spotlight angular attenuation
    // Fill in light & indirect structures, and evaluate Standard BRDF
    half3 light = globalLightColor[idx].rgb * att;
	half3 c = dot(dirToLight, normalWS) * light * vAlbedo;
    return c;
}

sampler2D myTexture1;
sampler2D myTexture2;
sampler2D myTexture3;
sampler2D myTexture4;
sampler2D myTexture5;
sampler2D myTexture6;
sampler2D myTexture7;
sampler2D myTexture8;


// Vertex shader
struct v2f			// vertex to fragment
{
    float2 uv : TEXCOORD0;
    float3 positionWS : TEXCOORD1;
    float3 normalWS : TEXCOORD2;
    float4 hpos : SV_POSITION;
};

struct s2v			// stream to vertex
{
	float4 vertex : POSITION;
	float3 normal : NORMAL;
	float4 texcoord : TEXCOORD0;
};


v2f vert(s2v v)
{
    v2f o;
	o.uv = v.texcoord.xy;
    o.hpos = mul(UNITY_MATRIX_MVP, v.vertex);
    o.positionWS = mul(unity_ObjectToWorld, v.vertex).xyz;
	o.normalWS = normalize(mul((float3x3)unity_WorldToObject, v.normal));
    return o;
}

// Fragment shader
half4 frag(v2f i) : SV_Target
{
    i.normalWS = normalize(i.normalWS);
	float4 color;

	float4 diffuseAlbedo = float4(0, 0, 0, 0);
	
	diffuseAlbedo += tex2D(myTexture1, i.uv);
	diffuseAlbedo += tex2D(myTexture2, i.uv);
	diffuseAlbedo += tex2D(myTexture3, i.uv);
	diffuseAlbedo += tex2D(myTexture4, i.uv);
	diffuseAlbedo += tex2D(myTexture5, i.uv);
	diffuseAlbedo += tex2D(myTexture6, i.uv);
	diffuseAlbedo += tex2D(myTexture7, i.uv);
	diffuseAlbedo += tex2D(myTexture8, i.uv);

	color = half4(EvaluateOneLight(0, i.positionWS, i.normalWS, diffuseAlbedo.rgb * myColor.rgb),1);
    return color;
}

ENDCG
		}
	}

//	CustomEditor "StandardShaderGUI"
}