import msp_interface;

layout(set=1) uniform AlphaCutoff
{
	float alpha_cutoff;
};

layout(set=1) uniform sampler2D alpha_map;

layout(constant_id=auto) const bool use_alpha_cutoff = false;
layout(constant_id=auto) const bool use_instancing = false;

#pragma MSP stage(vertex)
virtual vec4 get_vertex_position()
{
	return vertex;
}

virtual mat4 get_vertex_transform()
{
	if(use_instancing)
		return transpose(mat4(instance_transform[0], instance_transform[1], instance_transform[2], vec4(0.0, 0.0, 0.0, 1.0)));
	else
		return world_obj_matrix;
}

virtual void clipping(vec3 eye_vertex)
{
}

void main()
{
	vec4 eye_vertex = eye_world_matrix*get_vertex_transform()*get_vertex_position();
	clipping(eye_vertex.xyz);
	gl_Position = clip_eye_matrix*eye_vertex;
	passthrough;
}

#pragma MSP stage(fragment)
layout(location=0) out vec4 frag_color;

void main()
{
	if(use_alpha_cutoff)
	{
		float alpha = texture(alpha_map, texcoord.xy).a;
		if(alpha<alpha_cutoff)
			discard;
		frag_color = vec4(1.0);
	}
}