/*******************************************************************************
 *
 * Simple HLSL FX file
 *
 *******************************************************************************/


// un-tweakables



// structures and shaders /////////////////////

float4x4 wvIT : WorldViewInverseTranspose;
float4x4 wvp : WorldViewProjection;
float4x4 wv : WorldView;

float sparkScale = 16.0;

void mainVS( float4 vertex : POSITION0,
             float3 normal : NORMAL0,
             float4 tex : TEXCOORD0,
             out float4 position: POSITION0, out float3 eyeNormal : TEXCOORD0, 
             out float3 eyeView : TEXCOORD1, out float2 texCoord : TEXCOORD2)
{ 

	//	Must write gl_Position for rasterization to be defined....
	//
	position = mul( vertex, wvp);

	//	Transform to shading space (we are going to shade in eyespace)
	//
	//
    eyeNormal = mul( normal, float3x3(wvIT));

	eyeView = -mul( vertex, wv).xyz;
    texCoord = tex.xy  * sparkScale;
}

//sparkles texture to perturb the normals
sampler2D sparkleTex;

//cubic environment map
samplerCUBE envMap;

//parameter to control the reflection falloff, 0.33 typically looks pretty good
float reflFalloff = 0.33;

//how strong the spaks are at bending the normals, 0.0625 looks fairly good
float sparkStrength = 0.125;

//ambient lighting
float3 ambient = float3( 0.2, 0.2, 0.2);

float3 lightDir = float3( 0.57735, 0.57735, 0.57735);
float3 lightColor = float3( 1.0, 1.0, 1.0);




float3 carColor = float3(0.0, 0.5, -0.70);

/*
//candy apple green
float3 carColor0 = float3(0.0, 0.2, 0.70);
float3 carColor1 = float3(0.0, 0.5, -0.70);
float3 carColor2 = float3(0.1, 0.0, -0.1);
float3 sparkleColor = float3(0.7, 0.2, 0.0);
*/
  
/*
//orange to red
const float3 carColor0 = float3(0.40, 0.4, -0.40);
const float3 carColor1 = float3(0.0, -0.43, 0.40);
const float3 carColor2 = float3(1.0, 0.05, 0.18);
const float3 sparkleColor = float3(-0.4, 0.5, -0.70);
  */  


/*
// cool gold
const float3 carColor0 = float3(0.70, -0.09, 0.00);
const float3 carColor1 = float3(0.20, 0.23, 0.00);
const float3 carColor2 = float3(0.20, 0.75, 0.08);
const float3 sparkleColor = float3(-0.2, 0.2, 0.20);
*/    

/*
//intense copper
const float3 carColor0 = float3(0.40, 0.0, 0.00);
const float3 carColor1 = float3(0.60, 0.1, 0.00);
const float3 carColor2 = float3(-0.5, 0.15, -0.35);
const float3 sparkleColor = float3(0.2, 0.3, 0.5);
*/


float clearCoatShininess = 32.0;
float paintShininess = 2.0;

float4 mainPS( float3 eyeNormal : TEXCOORD0, float3 eyeView : TEXCOORD1,
                float2 texCoord : TEXCOORD2) : COLOR0
{
  
  float3 light = normalize( lightDir);

  float3 normal = normalize(eyeNormal);
  
  //fetch the sparkle texture
  float4 sparkle1 = tex2D(sparkleTex, texCoord);

  //normalize the view vector
  float3 view=normalize(eyeView);

  //compute the reflection vector
  float3 reflection = -reflect( view, normal);

  float nDotV = saturate(dot(view,normal));

  float3 sparkNorm = normalize( normal + float3( sparkle1*2.0 - 1.0) * sparkStrength);
  float3 sparkRefl = -reflect( view, sparkNorm);

  //compute the illumination, this is a sumation of two specular lobes 
  float3 color = float3(pow(max(0.0,dot(sparkRefl,light)), clearCoatShininess))*lightColor.rgb;
  color += carColor * (float3(pow(max(0.0,dot(sparkRefl,light)), paintShininess)*pow(nDotV,reflFalloff))*lightColor.rgb+ambient.rgb);
  

  //apply the clearcoat with a fresnel term
  color = float3(texCUBE(envMap,reflection))*(1.0-pow(nDotV,reflFalloff))+color;//*nDotV;



  return float4(color,1.0);


}


//////// techniques ////////////////////////////

technique blinn
{
	pass p0
	{
		VertexShader = compile vs_2_0 mainVS();
		
		ZEnable = true;
		ZWriteEnable = true;
        ZFunc = LEqual;
		CullMode = Back;

		PixelShader = compile ps_2_0 mainPS();
	}
}