#version 330

in vec2 pass_textureCoords;

out vec4 out_colour;

uniform vec3 colour;
uniform sampler2D fontAtlas;

const float width = 0;
const float edge = 1.0;

uniform float borderWidth;
uniform float borderEdge;

uniform vec2 offset;

uniform vec3 outlineColour;

void main(void){

	float distance = 1.0 - texture(fontAtlas, pass_textureCoords).a;
	float alpha = 1.0 - smoothstep(width, width + edge, distance);

	float distance2 = 1.0 - texture(fontAtlas, pass_textureCoords + offset).a;
	float outlineAlpha = 1.0 - smoothstep(borderWidth, borderWidth + borderEdge, distance2);

	float overallAlpha = alpha + (1.0 - alpha) * outlineAlpha;
	vec3 overallColour = mix(outlineColour, colour, alpha / overallAlpha);

	out_colour = vec4(overallColour, overallAlpha);

}