/**
* \brief Godrays.cg is a CG (C for Graphics) shader collection to imitate the effects of lightray scattering through post-processing approaches.
*
* \author Markus Wegmann
**/

/*

% Description of my shader.
% Second line of description for my shader.

keywords: material classic

date: 20110410

*/

void sun_shader(
    float4 position : POSITION,
	float4 normal: NORMAL,

    out float4 oPosition : POSITION,
    out float4 oColor : COLOR,

    uniform float4x4 modelViewProj,
    uniform float4 sunColor)
{
    oPosition = mul(modelViewProj, position);
    oColor    = 2 * normalize(sunColor);
}


void black_shader(
    float4 position : POSITION,

    out float4 oPosition : POSITION,
	out float4 oColor: COLOR0,

    uniform float4x4 modelViewProj)
{
    oPosition = mul(modelViewProj, position);
    oColor    = float4 (0, 0, 0, 1);
}


//// Variables ////
/////////////////////////////////////////////////////////////////////////////////////

float4 SunLightColor : Specular <
    string UIName =  "Lamp 0 Color";
    string Object = "Pointlight0";
    string UIWidget = "Color";
> = {0.3, 0.42, 1, 1};

//// UN-TWEAKABLES - AUTOMATICALLY-TRACKED TRANSFORMS ////

float4x4 WorldITXf : WorldInverseTranspose < string UIWidget="None"; >;
float4x4 WvpXf : WorldViewProjection < string UIWidget="None"; >;
float4x4 VpXf : ViewProjection < string UIWidget="None"; >;
float4x4 WorldXf : World < string UIWidget="None"; >;
float4x4 ViewIXf : ViewInverse < string UIWidget="None"; >;


//// Techniques ////
technique SunShader
{
	pass p0 <
	string Script = "Draw=geometry;";
> 	{
		DepthTestEnable = true;
		DepthMask = true;
		BlendEnable = true;
		CullFaceEnable = true;
			
		VertexProgram = compile vp30 sun_shader(WvpXf, SunLightColor);  	
  	}
}

technique BlackShader
{
		pass p0 <
		string Script = "Draw=geometry;";
> 		{
			DepthTestEnable = true;
			DepthMask = true;
			BlendEnable = true;
			CullFaceEnable = true;
		
			VertexProgram = compile vp30 black_shader(WvpXf);
  		}
}