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

#pragma language GLSL

// un-tweakables



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

varying vec3 eyeNormal;
varying vec4 eyePos;
varying vec3 eyeView;

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);	
}

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

uniform vec3 warmColor = vec3( 0.3, 0.3, 0.0);
uniform vec3 coolColor = vec3( 0.0, 0.3, 0.6);
uniform vec3 baseColor = vec3( 0.8, 0.8, 0.8);
uniform float alpha = 0.25;
uniform float beta = 0.5;
uniform float factor = 0.6;

void mainPS()
{

  vec3 norm;
  vec4 SurfColor;
  vec3 Cool;
  vec3 Warm;
  float Intensity;
  vec3 hvec;
  

   vec3 lightDirection = normalize(lightDir);
  
  //
  //	Since the EyeNormal is getting interpolated, we
  //	have to first restore it by normalizing it.
  //
  norm = normalize( eyeNormal );
  vec3 view = normalize(eyeView);

  
  //
  //	Per fragment gooch lighting

  Intensity = dot ( norm, lightDirection );  //  Gooch maps Intensity from (-1,1) to (0,1)
  Intensity = Intensity * 0.5 + 0.5;
    
  Cool = alpha * baseColor + coolColor;
  Warm = beta * baseColor + warmColor;
  SurfColor.rgb = factor * mix( Cool, Warm, Intensity);
  
    
  //
  //	Now, specular light....
  
  hvec = normalize(lightDirection + view);
  Intensity = dot ( norm, hvec );
  Intensity = max ( Intensity, 0.0 );
  Intensity = pow ( Intensity, 32.0 );
  
  SurfColor += 0.8* Intensity;		

  
  SurfColor.a = 1.0;
	
  gl_FragColor = SurfColor;

}


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

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

		PixelShader = compile ps_2_0 mainPS();
	}
}

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

		PixelShader = compile ps_2_0 mainPS();
	}
}