layout(triangles, invocations=1) in;
layout(triangle_strip, max_vertices=6) out;
out vec4 fcolor;
in vec4 fca[];
uniform mat4 mvp;
uniform int sw;
uniform float bulge;


vec4 n4_test(vec4 x){
	return vec4(normalize(x.xyz), 1);
}

void dt(vec4 a, vec4 b, vec4 c, vec4 ac, vec4 bc, vec4 cc){
	gl_Position = mvp * n4_test(a);
	fcolor = ac;
	EmitVertex();
	gl_Position = mvp * n4_test(b);
	fcolor = bc;
	EmitVertex();
	gl_Position = mvp * n4_test(c);
	fcolor = cc;
	EmitVertex();
	EndPrimitive();
}

void main(){
	vec3 av = gl_in[2].gl_Position.xyz - gl_in[0].gl_Position.xyz;
	vec3 bv = gl_in[1].gl_Position.xyz - gl_in[0].gl_Position.xyz;
	vec4 normal = vec4(normalize(cross(av,bv)), 0);

	vec4 a = gl_in[0].gl_Position;
	vec4 b = gl_in[1].gl_Position;
	vec4 c = gl_in[2].gl_Position;
	vec4 ac = fca[0];
	vec4 bc = fca[1];
	vec4 cc = fca[2];
//	if(sw < 1){
//		dt(a, b, c, ac, bc, cc);
//		return;
//	}

	float d_ab = distance(a, b);
	float d_bc = distance(b, c);
	float d_ca = distance(c, a);
	
	if(d_ab > d_bc && d_ab > d_ca){
		vec4 hc = (a + b) / 2 - normal * bulge;
		vec4 hcol = (ac + bc) / 2;
		dt(a, hc, c, ac, hcol, cc);
		dt(hc, b, c, hcol, bc, cc);
	}
	else if(d_bc > d_ca){
		vec4 hc = (b + c) / 2 - normal * bulge;
		vec4 hcol = (bc + cc) / 2;
		dt(a, b, hc, ac, bc, hcol);
		dt(a, hc, c, ac, hcol, cc);
	}
	else {
		vec4 hc = (c + a) / 2 - normal * bulge;
		vec4 hcol = (cc + ac) / 2;
		dt(a, b, hc, ac, bc, hcol);
		dt(hc, b, c, hcol, bc, cc);
	}
}