layout(triangles, invocations=3) in;
layout(line_strip, max_vertices=8) out;
out vec4 fcolor;
in vec4 fca[];

void main(){
	vec3 a = gl_in[2].gl_Position.xyz - gl_in[0].gl_Position.xyz;
	vec3 b = gl_in[1].gl_Position.xyz - gl_in[0].gl_Position.xyz;
	vec3 normal = normalize(cross(a,b));

	vec4 avg = vec4(0, 0, 0, 0);
	for(int i = 0; i < 3; i++){
		gl_Position = gl_in[i].gl_Position;
		fcolor = fca[i];
		EmitVertex();
		gl_Position = gl_in[i].gl_Position + vec4(normal, 0);
		fcolor = fca[i];
		EmitVertex();
		EndPrimitive();
		avg += gl_in[i].gl_Position;
	}
	gl_Position = avg;
	fcolor = vec4(0, 0, 0, 1);
	EmitVertex();
	gl_Position = avg + vec4(normal, 0) * 3;
	fcolor = vec4(0, 0, 0, 1);
	EmitVertex();
	EndPrimitive();
	
}