<!
//  ForwardBufferWrite.slh
//  libraries/render-utils/src
//
//  Created by Gabriel Calero & Cristian Duarte on 31/07/17.
//  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 FORWARD_BUFFER_WRITE_SLH@>
<@def FORWARD_BUFFER_WRITE_SLH@>

<@include ForwardBuffer.slh@>


layout(location = 0) out vec4 _fragColor0;

// the alpha threshold
const float alphaThreshold = 0.5;
float evalOpaqueFinalAlpha(float alpha, float mapAlpha) {
    return mix(alpha, 1.0 - alpha, step(mapAlpha, alphaThreshold));
}

const float DEFAULT_ROUGHNESS = 0.9;
const float DEFAULT_SHININESS = 10.0;
const float DEFAULT_METALLIC = 0.0;
const vec3 DEFAULT_SPECULAR = vec3(0.1);
const vec3 DEFAULT_EMISSIVE = vec3(0.0);
const float DEFAULT_OCCLUSION = 1.0;
const float DEFAULT_SCATTERING = 0.0;
const vec3 DEFAULT_FRESNEL = DEFAULT_EMISSIVE;

void packForwardFragment(vec3 normal, float alpha, vec3 albedo, float roughness, float metallic, vec3 emissive, float occlusion, float scattering) {
    if (alpha != 1.0) {
        discard;
    }
    _fragColor0 = vec4(albedo, ((scattering > 0.0) ? packScatteringMetallic(metallic) : packShadedMetallic(metallic)));
}

void packForwardFragmentLightmap(vec3 normal, float alpha, vec3 albedo, float roughness, float metallic, vec3 fresnel, vec3 lightmap) {
    if (alpha != 1.0) {
        discard;
    }

    _fragColor0 = vec4(albedo, packLightmappedMetallic(metallic));
}

void packForwardFragmentUnlit(vec3 normal, float alpha, vec3 color) {
    if (alpha != 1.0) {
        discard;
    }
    _fragColor0 = vec4(color, packUnlit());
}

void packForwardFragmentTranslucent(vec3 normal, float alpha, vec3 albedo, vec3 fresnel, float roughness) {
    if (alpha <= 0.0) {
        discard;
    }
    _fragColor0 = vec4(albedo.rgb, alpha);
}

<@endif@>