<!
//  DeferredBufferWrite.slh
//  libraries/render-utils/src
//
//  Created by Sam Gateau on 1/12/15.
//  Copyright 2013 High Fidelity, Inc.
//
//  Distributed under the Apache License, Version 2.0.
//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
!>
<@if not DEFERRED_BUFFER_WRITE_SLH@>
<@def DEFERRED_BUFFER_WRITE_SLH@>

layout(location = 0) out vec4 _fragColor0;
layout(location = 1) out vec4 _fragColor1;
layout(location = 2) out vec4 _fragColor2;

// the glow intensity
uniform float glowIntensity;

// the alpha threshold
uniform float alphaThreshold;

uniform sampler2D normalFittingMap;

vec3 bestFitNormal(vec3 normal) {
    vec3 absNorm = abs(normal);
    float maxNAbs = max(absNorm.z, max(absNorm.x, absNorm.y));

    vec2 texcoord = (absNorm.z < maxNAbs ? 
                        (absNorm.y < maxNAbs ? absNorm.yz : absNorm.xz) :
                        absNorm.xy);
    texcoord = (texcoord.x < texcoord.y ? texcoord.yx : texcoord.xy);
    texcoord.y /= texcoord.x;
    vec3 cN = normal / maxNAbs;

    float fittingScale = texture(normalFittingMap, texcoord).a;
    cN *= fittingScale;
    return (cN * 0.5 + 0.5);
}

float evalOpaqueFinalAlpha(float alpha, float mapAlpha) {
    return mix(alpha * glowIntensity, 1.0 - alpha * glowIntensity, step(mapAlpha, alphaThreshold));
}

const vec3 DEFAULT_SPECULAR = vec3(0.1);
const float DEFAULT_SHININESS = 10;

void packDeferredFragment(vec3 normal, float alpha, vec3 diffuse, vec3 specular, float shininess) {
    if (alpha != glowIntensity) {
        discard;
    }

    _fragColor0 = vec4(diffuse.rgb, alpha);
    _fragColor1 = vec4(bestFitNormal(normal), 1.0);
    _fragColor2 = vec4(specular, shininess / 128.0);
}

void packDeferredFragmentLightmap(vec3 normal, float alpha, vec3 diffuse, vec3 specular, float shininess, vec3 emissive) {
    if (alpha != glowIntensity) {
        discard;
    }

    _fragColor0 = vec4(diffuse.rgb, alpha);
    //_fragColor1 = vec4(normal, 0.0) * 0.5 + vec4(0.5, 0.5, 0.5, 1.0);
    _fragColor1 = vec4(bestFitNormal(normal), 0.5);
    _fragColor2 = vec4(emissive, shininess / 128.0);
}

void packDeferredFragmentTranslucent(vec3 normal, float alpha, vec3 diffuse, vec3 specular, float shininess) {
    if (alpha <= alphaThreshold) {
        discard;
    } 

    _fragColor0 = vec4(diffuse.rgb, alpha);
  //  _fragColor1 = vec4(normal, 0.0) * 0.5 + vec4(0.5, 0.5, 0.5, 1.0);
  //  _fragColor2 = vec4(specular, shininess / 128.0);
}

<@endif@>