//pref
Ambient|float|0|0.25|1
Diffuse|float|0|0.7|1
Specular|float|0|0.7|1
DiffuseRough|float|0|1|5
SpecularRough|float|0.001|0.1|1
Sharpness|float|0|0.0|1
Edge|float|0|0|1.0
LightBackfaces|bool|false
Blinn-Phong shading. Adapted from Fluxus Library, Copyright 2007 Dave Griffiths, GPLv2.|note
//vert
#version 330
layout(location = 0) in vec3 Vert;
layout(location = 3) in vec3 Norm;
layout(location = 6) in vec4 Clr;
out vec3 vN, vL, vV;
out vec4 vClr, vP;
uniform mat4 ModelViewProjectionMatrix;
uniform mat4 ModelViewMatrix;
uniform mat3 NormalMatrix;
uniform vec3 LightPos = vec3(0.0, 20.0, 30.0); //LR, -DU+, -FN+
void main() {
    vN = normalize((NormalMatrix * Norm));
    vP = vec4(Vert, 1.0);
    gl_Position = ModelViewProjectionMatrix * vec4(Vert, 1.0);
    vL = normalize(LightPos);
    vV = -vec3(ModelViewMatrix*vec4(Vert,1.0));
    vClr = Clr;
}
//frag
#version 330
uniform float Ambient, Diffuse, Specular, SpecularRough, DiffuseRough, Edge, Sharpness;
uniform bool LightBackfaces;
uniform vec4 ClipPlane;
in vec3 vN, vV, vL;
in vec4 vP, vClr;
out vec4 color;

vec3 desaturate(vec3 color, float amount) {
    vec3 gray = vec3(dot(vec3(0.2126,0.7152,0.0722), color));
    return vec3(mix(color, gray, amount));
}

const float backscatter = 0.25;
const float edginess = 4.0;
const float sheen = 0.7;

void main() {
	if ((ClipPlane[0] < 1.5) && (dot( ClipPlane, vP) > 0.0)) discard;
	vec3 l = normalize(vL);
	vec3 n = normalize(vN);
	vec3 v = normalize(vV);
	vec3 h = normalize(l+v);
	vec3 a = vClr.rgb;
	vec3 d = a * Diffuse;
	a *= Ambient;
	vec3 backcolor = desaturate(0.75 * a + 0.75 * d *  abs(dot(n,l)), 0.5);
	float backface = 1.0 - step(0.0, n.z); //1=backface
	n = mix(n, -n, backface * float(LightBackfaces)); //reverse normal if backface AND two-sided lighting
	
	d = vClr.rgb;
	
	float diffuse = clamp(dot(l, n), 0.0, 1.0);

	float cosine = clamp(dot(l, v), 0.0, 1.0);
	float shiny = sheen * pow(cosine, 16.0) * backscatter;

	cosine = clamp(dot(n, v), 0.0, 1.0);
	float sine = sqrt(1.0 - cosine);
	shiny = shiny + sheen * pow(sine, edginess) * diffuse;
	//vec3 frontcolor = a + d +  s;
	vec3 frontcolor = a + (Diffuse*diffuse)*d + (Specular*shiny);
	//vec3 frontcolor = a + 0.8*(Diffuse*diffuse_f)*d + 0.2*(Diffuse*diffuse_b)*d + (Specular*specular);
	frontcolor *= min((max(dot(n,normalize(v)), 0.0) - 0.5) * Edge, 0.0) + 1.0;
	backface = 1.0 - step(0.0, n.z); //1=backface
	//backcolor = vec3(1.0,0.0,0.0);
	color = vec4(mix(frontcolor,backcolor,   backface), 1.0);
}
// Copyright (C) 2007 Dave Griffiths
// Fluxus Shader Library
// ---------------------
// Glossy Specular Reflection Shader
// A more controllable version of blinn shading,
// Useful for ceramic or fluids - from Advanced
// Renderman, thanks to Larry Gritz
// http://www.pawfal.org/fluxus/
// https://github.com/danomatika/fluxus/blob/master/LICENCE