shader3/res/shader/test.fs

uniform vec3 U_EyePos;

varying vec3 V_Normal;
varying vec3 V_WorldPos;

void main()
{

	vec3 N = normalize(V_Normal);
	vec3 L = normalize(U_EyePos - V_WorldPos);

	float cosThta = dot(N,L);
	float alpha = 0.0;

	if(cosThta > 0.0){
		alpha = 1 - cosThta;
	}

	gl_FragColor = vec4(0.6) * alpha;
}