/*******************************************************************************
 *
 * Simple GLSL FX file
 *
 *******************************************************************************/

#pragma language GLSL

// un-tweakables



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

uniform float sparkScale = 16.0;

varying vec3 eyeNormal;
varying vec3 eyeView;
varying vec2 texCoord;

void mainVS()
{ 

	//	Must write gl_Position for rasterization to be defined....
	//
	gl_Position = ftransform(); 

	//	Transform to shading space (we are going to shade in eyespace)
	//
	//
	eyeNormal = gl_NormalMatrix * gl_Normal;

	eyeView = -vec3(gl_ModelViewMatrix * gl_Vertex);

    texCoord = gl_MultiTexCoord0.st * sparkScale;

}

//sparkles texture to perturb the normals
uniform sampler2D sparkleTex;

//cubic environment map
uniform samplerCube envMap;

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

//how strong the spaks are at bending the normals, 0.0625 looks fairly good
uniform float sparkStrength = 0.625;

//ambient lighting
uniform vec3 ambient = vec3( 0.2, 0.2, 0.2);

uniform vec3 lightDir = vec3( 0.57735, 0.57735, 0.57735);
uniform vec3 lightColor = vec3( 1.0, 1.0, 1.0);




uniform vec3 carColor = vec3(0.0, 0.5, -0.70);

/*
//candy apple green
uniform vec3 carColor0 = vec3(0.0, 0.2, 0.70);
uniform vec3 carColor1 = vec3(0.0, 0.5, -0.70);
uniform vec3 carColor2 = vec3(0.1, 0.0, -0.1);
uniform vec3 sparkleColor = vec3(0.7, 0.2, 0.0);
*/
  
/*
//orange to red
const vec3 carColor0 = vec3(0.40, 0.4, -0.40);
const vec3 carColor1 = vec3(0.0, -0.43, 0.40);
const vec3 carColor2 = vec3(1.0, 0.05, 0.18);
const vec3 sparkleColor = vec3(-0.4, 0.5, -0.70);
  */  


/*
// cool gold
const vec3 carColor0 = vec3(0.70, -0.09, 0.00);
const vec3 carColor1 = vec3(0.20, 0.23, 0.00);
const vec3 carColor2 = vec3(0.20, 0.75, 0.08);
const vec3 sparkleColor = vec3(-0.2, 0.2, 0.20);
*/    

/*
//intense copper
const vec3 carColor0 = vec3(0.40, 0.0, 0.00);
const vec3 carColor1 = vec3(0.60, 0.1, 0.00);
const vec3 carColor2 = vec3(-0.5, 0.15, -0.35);
const vec3 sparkleColor = vec3(0.2, 0.3, 0.5);
*/


uniform float clearCoatShininess = 32.0;
uniform float paintShininess = 2.0;

void mainPS()
{
  
  vec3 light = normalize( lightDir);

  vec3 normal = normalize(eyeNormal);
  
  //fetch the sparkle texture
  vec4 sparkle1 = texture2D(sparkleTex, texCoord);

  //normalize the view vector
  vec3 view=normalize(eyeView);

  //compute the reflection vector
  vec3 reflection = -reflect( view, normal);

  float nDotV = clamp(dot(view,normal), 0.0, 1.0);

  vec3 sparkNorm = normalize( normal + vec3( sparkle1*2.0 - 1.0) * sparkStrength);
  vec3 sparkRefl = -reflect( view, sparkNorm);

  //compute the illumination, this is a sumation of two specular lobes 
  vec3 color = vec3(pow(max(0.0,dot(sparkRefl,light)), clearCoatShininess))*lightColor.rgb;
  color += carColor * (vec3(pow(max(0.0,dot(sparkRefl,light)), paintShininess)*pow(nDotV,reflFalloff))*lightColor.rgb+ambient.rgb);
  

  //apply the clearcoat with a fresnel term
  color = vec3(textureCube(envMap,reflection))*(1.0-pow(nDotV,reflFalloff))+color;//*nDotV;



  gl_FragColor = vec4(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();
	}
}