FFPLib_Lighting.glsl

/*
-----------------------------------------------------------------------------
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(Object-oriented Graphics Rendering Engine)
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*/

//-----------------------------------------------------------------------------
// Program Name: FFPLib_Lighting
// Program Desc: Lighting functions of the FFP.
// Program Type: Vertex shader
// Language: GLSL
// Notes: Implements core functions for FFPLighting class.
// based on lighting engine. 
// See http://msdn.microsoft.com/en-us/library/bb147178.aspx
//-----------------------------------------------------------------------------


//-----------------------------------------------------------------------------
void FFP_Light_Directional_Diffuse(in mat4 mWorldViewIT, 
				   in vec3 vNormal,
				   in vec3 vNegLightDirView,
				   in vec3 vDiffuseColour, 
				   in vec3 vBaseColour, 
				   out vec3 vOut)
{
	vec3 vNormalView = normalize((mWorldViewIT * vec4(vNormal.xyz, 1.0)).xyz); 
	float nDotL = dot(vNormalView, vNegLightDirView);
	
	vOut = vBaseColour + vDiffuseColour * clamp(nDotL, 0.0, 1.0);
	vOut = clamp(vOut, 0.0, 1.0);
}


//-----------------------------------------------------------------------------
void FFP_Light_Directional_DiffuseSpecular(in mat4 mWorldView, 
					in vec4 vPos,
					in mat4 mWorldViewIT, 
					in vec3 vNormal,
					in vec3 vNegLightDirView,
					in vec3 vDiffuseColour, 
					in vec3 vSpecularColour, 
					in float fSpecularPower, 
					in vec3 vBaseDiffuseColour,
					in vec3 vBaseSpecularColour,					
					out vec3 vOutDiffuse,
					out vec3 vOutSpecular)
{
	vOutDiffuse  = vBaseDiffuseColour;
	vOutSpecular = vBaseSpecularColour;
	
	vec3 vNormalView = normalize((mWorldViewIT * vec4(vNormal.xyz, 1.0)).xyz); 	
	float nDotL		   = dot(vNormalView, vNegLightDirView);			
	vec3 vView       = -normalize((mWorldView* vPos).xyz);
	vec3 vHalfWay    = normalize(vView + vNegLightDirView);
	float nDotH        = dot(vNormalView, vHalfWay);
	
	if (nDotL > 0.0)
	{
		vOutDiffuse  += vDiffuseColour * nDotL;		
		vOutSpecular += vSpecularColour * pow(clamp(nDotH, 0.0, 1.0), fSpecularPower);						
	}
	vOutSpecular = clamp(vOutSpecular, 0.0, 1.0);
}


//-----------------------------------------------------------------------------
void FFP_Light_Point_Diffuse(in mat4 mWorldView, 
					in vec4 vPos,
					in mat4 mWorldViewIT, 
				    in vec3 vNormal,
				    in vec3 vLightPosView,
				    in vec4 vAttParams,
				    in vec3 vDiffuseColour, 
				    in vec3 vBaseColour, 
				    out vec3 vOut)
{
	vOut = vBaseColour;		

	vec3 vViewPos    = (mWorldView * vPos).xyz;
	vec3 vLightView  = vLightPosView - vViewPos;
	float fLightD      = length(vLightView);
	vec3 vNormalView = normalize((mWorldViewIT * vec4(vNormal.xyz, 1.0)).xyz); 
	float nDotL        = dot(vNormalView, normalize(vLightView));
	
	if (nDotL > 0.0 && fLightD <= vAttParams.x)
	{
		float fAtten	   = 1.0 / (vAttParams.y + vAttParams.z*fLightD + vAttParams.w*fLightD*fLightD);
			
		vOut += vDiffuseColour * nDotL * fAtten;
	}
	vOut = clamp(vOut, 0.0, 1.0);	
}

//-----------------------------------------------------------------------------
void FFP_Light_Point_DiffuseSpecular(in mat4 mWorldView, 
					in vec4 vPos,
					in mat4 mWorldViewIT, 
				    in vec3 vNormal,
				    in vec3 vLightPosView,
				    in vec4 vAttParams,
				    in vec3 vDiffuseColour, 
				    in vec3 vSpecularColour, 
					in float fSpecularPower, 
				    in vec3 vBaseDiffuseColour,
					in vec3 vBaseSpecularColour,					
					out vec3 vOutDiffuse,
					out vec3 vOutSpecular)
{
	vOutDiffuse  = vBaseDiffuseColour;
	vOutSpecular = vBaseSpecularColour;

	vec3 vViewPos    = (mWorldView * vPos).xyz;
	vec3 vLightView  = vLightPosView - vViewPos;
	float fLightD      = length(vLightView);
	
	vLightView		   = normalize(vLightView);	
	vec3 vNormalView = normalize((mWorldViewIT * vec4(vNormal.xyz, 1.0)).xyz); 
	float nDotL        = dot(vNormalView, vLightView);	
		
	if (nDotL > 0.0 && fLightD <= vAttParams.x)
	{					
		vec3 vView       = -normalize(vViewPos);			
		vec3 vHalfWay    = normalize(vView + vLightView);		
		float nDotH        = dot(vNormalView, vHalfWay);
		float fAtten	   = 1.0 / (vAttParams.y + vAttParams.z*fLightD + vAttParams.w*fLightD*fLightD);					
		
		vOutDiffuse  += vDiffuseColour * nDotL * fAtten;
		vOutSpecular += vSpecularColour * pow(clamp(nDotH, 0.0, 1.0), fSpecularPower) * fAtten;					
	}
	vOutSpecular = clamp(vOutSpecular, 0.0, 1.0);	
}

//-----------------------------------------------------------------------------
void FFP_Light_Spot_Diffuse(in mat4 mWorldView, 
					in vec4 vPos,
					in mat4 mWorldViewIT, 
				    in vec3 vNormal,
				    in vec3 vLightPosView,
				    in vec3 vNegLightDirView,
				    in vec4 vAttParams,
				    in vec3 vSpotParams,
				    in vec3 vDiffuseColour, 
				    in vec3 vBaseColour, 
				    out vec3 vOut)
{
	vOut = vBaseColour;		

	vec3 vViewPos    = (mWorldView * vPos).xyz;
	vec3 vLightView  = vLightPosView - vViewPos;
	float fLightD      = length(vLightView);
	vLightView		   = normalize(vLightView);
	vec3 vNormalView = normalize((mWorldViewIT * vec4(vNormal.xyz, 1.0)).xyz); 	
	float nDotL        = dot(vNormalView, vLightView);
	
	if (nDotL > 0.0 && fLightD <= vAttParams.x)
	{
		float fAtten	= 1.0 / (vAttParams.y + vAttParams.z*fLightD + vAttParams.w*fLightD*fLightD);
		float rho		= dot(vNegLightDirView, vLightView);						
		float fSpotE	= clamp((rho - vSpotParams.y) / (vSpotParams.x - vSpotParams.y), 0.0, 1.0);
		float fSpotT	= pow(fSpotE, vSpotParams.z);	
						
		vOut += vDiffuseColour * nDotL * fAtten * fSpotT;
	}
	
	vOut = clamp(vOut, 0.0, 1.0);
}

//-----------------------------------------------------------------------------
void FFP_Light_Spot_DiffuseSpecular(in mat4 mWorldView, 
					in vec4 vPos,
					in mat4 mWorldViewIT, 
				    in vec3 vNormal,
				    in vec3 vLightPosView,
				    in vec3 vNegLightDirView,
				    in vec4 vAttParams,
				    in vec3 vSpotParams,
				    in vec3 vDiffuseColour, 
				    in vec3 vSpecularColour, 
					in float fSpecularPower, 
				    in vec3 vBaseDiffuseColour,
					in vec3 vBaseSpecularColour,					
					out vec3 vOutDiffuse,
					out vec3 vOutSpecular)
{
	vOutDiffuse  = vBaseDiffuseColour;		
	vOutSpecular = vBaseSpecularColour;

	vec3 vViewPos    = (mWorldView * vPos).xyz;
	vec3 vLightView  = vLightPosView - vViewPos;
	float fLightD      = length(vLightView);
	vLightView		   = normalize(vLightView);
	vec3 vNormalView = normalize((mWorldViewIT * vec4(vNormal.xyz, 1.0)).xyz); 	
	float nDotL        = dot(vNormalView, vLightView);
	
	
	
	if (nDotL > 0.0 && fLightD <= vAttParams.x)
	{
		vec3 vView       = -normalize(vViewPos);	
		vec3 vHalfWay    = normalize(vView + vLightView);				
		float nDotH        = dot(vNormalView, vHalfWay);
		float fAtten	= 1.0 / (vAttParams.y + vAttParams.z*fLightD + vAttParams.w*fLightD*fLightD);
		float rho		= dot(vNegLightDirView, vLightView);						
		float fSpotE	= clamp((rho - vSpotParams.y) / (vSpotParams.x - vSpotParams.y), 0.0, 1.0);
		float fSpotT	= pow(fSpotE, vSpotParams.z);	
						
		vOutDiffuse  += vDiffuseColour * nDotL * fAtten * fSpotT;
		vOutSpecular += vSpecularColour * pow(clamp(nDotH, 0.0, 1.0), fSpecularPower) * fAtten * fSpotT;
	}
	
	vOutSpecular = clamp(vOutSpecular, 0.0, 1.0);
}