GLSL Fog library for jmonkeyengine

Fog.glsllib

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// @see: http://in2gpu.com/2014/07/22/create-fog-shader/
// @see: https://hub.jmonkeyengine.org/t/fog-glsl-library-for-materials/40943

// Float FogDensity: 0.05
// Float FogDensity: 0.003
// Float FogStart = 20.0
// Float FogEnd = 80.0

// .vert: varying float dist;
// .vert: dist = distance(g_CameraPosition, (g_WorldViewMatrix * modelSpacePos).xyz);

// pick one...
// .frag: vec4 fogResult = getFogLinear(gl_FragColor, fogColor, start, end, dist);
// .frag: vec4 fogResult = getFogExp(gl_FragColor, fogColor, m_FogDensity, dist);
// .frag: vec4 fogResult = getFogExpSquare(gl_FragColor, fogColor, m_FogDensity, dist);

vec4 getFogLinear(in vec4 diffuseColor, in vec4 fogColor, in float start, in float end, in float distance) {

    float fogFactor = (end - distance) / (end - start);
    fogFactor = clamp(fogFactor, 0.0, 1.0);

    return mix(fogColor, diffuseColor, fogFactor);
}

vec4 getFogExp(in vec4 diffuseColor, in vec4 fogColor, in float fogDensity, in float distance) {

    float fogFactor = 1.0 / exp(distance * fogDensity);
    fogFactor = clamp( fogFactor, 0.0, 1.0 );

    return mix(fogColor, diffuseColor, fogFactor);
}

vec4 getFogExpSquare(in vec4 diffuseColor, in vec4 fogColor, in float fogDensity, in float distance) {

    float fogFactor = 1.0 / exp( (distance * fogDensity) * (distance * fogDensity));
    fogFactor = clamp( fogFactor, 0.0, 1.0 );

    vec4 finalColor = mix(fogColor, diffuseColor, fogFactor);
    return finalColor;
}