#version 400 compatibility
#extension GL_EXT_gpu_shader4: enable
#extension GL_EXT_geometry_shader4: enable

layout( triangles )  in;
layout( triangle_strip, max_vertices=200 )  out;

uniform float uShrink;
uniform float uLightX, uLightY, uLightZ;
in vec3 teNormal[3];
out float gLightIntensity;

vec3 LightPos = vec3( uLightX, uLightY, uLightZ );

vec3 V[3];
vec3 CG;

void
ProduceVertex( int v )
{
	gLightIntensity  = abs(  dot( normalize(LightPos - V[v]), teNormal[v] )  );

	gl_Position = uProjectionMatrix * vec4( CG + uShrink * ( V[v] - CG ), 1. );
	EmitVertex( );
}



void
main( )
{
	V[0]  =   gl_PositionIn[0].xyz;
	V[1]  =   gl_PositionIn[1].xyz;
	V[2]  =   gl_PositionIn[2].xyz;

	CG = 0.33333 * ( V[0] + V[1] + V[2] );

	ProduceVertex( 0 );
	ProduceVertex( 1 );
	ProduceVertex( 2 );
}