// Taken from the godot-demo-projects repo.
//                              GODOT ENGINE
//                      http://www.godotengine.org
//
// ************************************************************************
//
// Copyright (c) 2007-2016 Juan Linietsky, Ariel Manzur.
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
//************************************************************************

light_mode unshaded;
//shader_type canvas_item;
uniform float outline_width = 2.0;
// TODO: implement that hint_color thingy.
//uniform vec4 outline_color: hint_color;
uniform vec4 outline_color=vec4(1,0,0,0.33);

void fragment() {
	vec4 col = texture(TEXTURE, UV);
	vec2 ps = TEXTURE_PIXEL_SIZE;
	float a;
	float maxa = col.a;
	float mina = col.a;

	a = texture(TEXTURE, UV + vec2(0, -outline_width)*ps).a;
	maxa = max(a, maxa);
	mina = min(a, mina);

    a = texture(TEXTURE, UV + vec2(-outline_width, -outline_width)*ps).a;
    maxa = max(a, maxa);
    mina = min(a, mina);

	a = texture(TEXTURE, UV + vec2(0, outline_width)*ps).a;
	maxa = max(a, maxa);
	mina = min(a, mina);

    a = texture(TEXTURE, UV + vec2(outline_width, -outline_width)*ps).a;
    maxa = max(a, maxa);
    mina = min(a, mina);

	a = texture(TEXTURE, UV + vec2(-outline_width,0)*ps).a;
	maxa = max(a, maxa);
	mina = min(a, mina);

    a = texture(TEXTURE, UV + vec2(-outline_width, outline_width)*ps).a;
    maxa = max(a, maxa);
    mina = min(a, mina);

	a = texture(TEXTURE, UV + vec2(outline_width, 0)*ps).a;
	maxa = max(a, maxa);
	mina = min(a, mina);

    a = texture(TEXTURE, UV + vec2(outline_width, outline_width)*ps).a;
    maxa = max(a, maxa);
    mina = min(a, mina);

	COLOR = mix(col, outline_color, maxa-col.a);
}