//
// Globals
//

texture Top;
texture Slope;
texture Bottom;
//texture Tex;

vector Ambient;
vector Sun_Direction;

float4x4 g_mWorldViewProjection;
float4x4 g_mWorldView;

float FarPlaneMinusNearPlane; // Distance of the far plane minus distance of the near plane.

//
// Sampler
//

sampler TopTex = sampler_state
{
	Texture   = (Top);
    MinFilter = LINEAR; 
    MagFilter = LINEAR; 
    MipFilter = LINEAR;
};

sampler SlopeTex = sampler_state
{
	Texture   = (Slope);
    MinFilter = LINEAR; 
    MagFilter = LINEAR; 
    MipFilter = LINEAR;
};

sampler BottomTex = sampler_state
{
	Texture   = (Bottom);
    MinFilter = LINEAR; 
    MagFilter = LINEAR; 
    MipFilter = LINEAR;
};

//
// Structures
//

struct VS_OUTPUT
{
    float4 pos : POSITION;
    float2 coord1 : TEXCOORD0;
    float3 Normal : TEXCOORD1;
    vector values : COLOR0;
	
};

struct VS_OUTPUT_RAY
{
    float4 pos : POSITION;
    float2 coord1 : TEXCOORD0;
    float3 Normal : TEXCOORD1;
    float3 pos2 : TEXCOORD2;
	vector values : COLOR0;
	
};

struct VS_OUTPUT_DEPTH 
{
    float4 HPosition : POSITION;
    float4 texCoord	: TEXCOORD0;
};

struct PS_OUTPUT
{
    float4 diffuse : COLOR0;
};

//
// VertexShader Main
//


VS_OUTPUT vs_main(float4 inPos: POSITION, float3 inNormal: NORMAL, float2 inCoord1: TEXCOORD0, vector inValues : COLOR0)
{
	VS_OUTPUT Out;
	
	Out.pos = mul(inPos, g_mWorldViewProjection );
	Out.coord1 = inCoord1;
	Out.Normal = inNormal;
	Out.values = inValues;
	return Out;
}

VS_OUTPUT_RAY vs_main_ray(float4 inPos: POSITION, float3 inNormal: NORMAL, float2 inCoord1: TEXCOORD0, vector inValues : COLOR0)
{
	VS_OUTPUT_RAY Out;
	
	Out.pos = mul(inPos, g_mWorldViewProjection );
	Out.coord1 = inCoord1;
	Out.Normal = inNormal;
	Out.values = inValues;
	Out.pos2 = mul(inPos, g_mWorldView );
	return Out;
}

VS_OUTPUT_DEPTH vs_main_depth(float4 position : POSITION, float4 texCoord1 : TEXCOORD0) 
{
    VS_OUTPUT_DEPTH OUT;
    float4 vertexpos = float4(position.xyz, 1.0);
	float4 eyespace = mul(vertexpos, g_mWorldViewProjection);
	OUT.HPosition = eyespace;
	float tempDepth = saturate(eyespace.z/FarPlaneMinusNearPlane);
	texCoord1.a = tempDepth;
	OUT.texCoord = texCoord1;
	return OUT;
}

//per pixel lighting function
float4 Light_PointDiffuse(vector LightDir, float3 Normal)
{
	// Compute suface/light angle based attenuation defined as dot(N,L)
	float AngleAttn = clamp(0, 1, dot(Normal, LightDir.xyz) );
	
	return AngleAttn;
}

//
// PixelShader Main
//

PS_OUTPUT ps_main(float2 coord1 : TEXCOORD0, float3 Normal : TEXCOORD1, vector values : COLOR0)
{
    // zero out members of output
    PS_OUTPUT output = (PS_OUTPUT)0;

    // sample appropriate textures
    vector t = tex2D(TopTex, coord1);
    vector s = tex2D(SlopeTex, coord1);
    vector b = tex2D(BottomTex, coord1);
    
    // combine texel colors
    vector c = t*values.x + s*values.y + b*values.z;
    
    // do per-pixel-lighting
    output.diffuse = c * Light_PointDiffuse(Sun_Direction,Normal) + 0.1;
    
    //return result
    return output;
}

PS_OUTPUT ps_main_ray(float2 coord1 : TEXCOORD0, float3 Normal : TEXCOORD1, float3 pos2 : TEXCOORD2, vector values : COLOR0)
{
    // zero out members of output
    PS_OUTPUT output = (PS_OUTPUT)0;

    // sample appropriate textures
    vector t = tex2D(TopTex, coord1);
    vector s = tex2D(SlopeTex, coord1);
    vector b = tex2D(BottomTex, coord1);
    
    // combine texel colors
    vector c = t*values.x + s*values.y + b*values.z;
    
    // do per-pixel-lighting
    output.diffuse = c * Light_PointDiffuse(Sun_Direction,Normal) + 0.1;
    
    // The distance
    output.diffuse.a = (float) ( length( pos2.xyz ) );
    
    //return result
    return output;
}

PS_OUTPUT ps_main_depth(VS_OUTPUT_DEPTH IN)
{
	PS_OUTPUT OUT;
	float depth = IN.texCoord.a;
	OUT.diffuse = float4(depth, depth, depth, depth);
	return OUT;
}

// 
// Effect
//

technique TerrainShader
{
	pass P0
	{
		//
        // Set Misc render states.
        vertexshader     = compile vs_2_0 vs_main();
        pixelshader      = compile ps_2_0 ps_main();
        fvf              = XYZ | Normal | Tex1;
        Lighting         = false;
        NormalizeNormals = false;
        SpecularEnable   = false;
	}
}

technique TerrainShaderRay
{
	pass P0
	{
		//
        // Set Misc render states.
        vertexshader     = compile vs_2_0 vs_main_ray();
        pixelshader      = compile ps_2_0 ps_main_ray();
        fvf              = XYZ | Normal | Tex1;
        Lighting         = false;
        NormalizeNormals = false;
        SpecularEnable   = false;
	}
}

technique TerrainShaderDepth
{
	pass P0
	{
		//
        // Set Misc render states.
        vertexshader     = compile vs_2_0 vs_main_depth();
        pixelshader      = compile ps_2_0 ps_main_depth();
        fvf              = XYZ | Normal | Tex1;
        Lighting         = false;
        NormalizeNormals = false;
        SpecularEnable   = false;
	}
}