<@include gpu/Config.slh@>
<$VERSION_HEADER$>
//  Generated on <$_SCRIBE_DATE$>
//
//  Haze.frag
//
//  Created by Nissim Hadar on 9/5/2107.
//  Copyright 2016 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
//

<@include DeferredTransform.slh@>
<$declareDeferredFrameTransform()$>

<@include graphics/Light.slh@>

<@include LightingModel.slh@>
<$declareLightBuffer()$>

<@include Haze.slh@>

layout(binding=RENDER_UTILS_TEXTURE_HAZE_LINEAR_DEPTH) uniform sampler2D linearDepthMap;

vec4 unpackPositionFromZeye(vec2 texcoord) {
    float Zeye = -texture(linearDepthMap, texcoord).x;
    int side = 0;
    if (isStereo()) {
        if (texcoord.x > 0.5) {
            texcoord.x -= 0.5;
            side = 1;
        }
        texcoord.x *= 2.0;
    }
    return vec4(evalEyePositionFromZeye(side, Zeye, texcoord), 1.0);
}

layout(location=0) in vec2 varTexCoord0;
layout(location=0) out vec4 outFragColor;

void main(void) {
    if ((isHazeEnabled() == 0.0) || (hazeParams.hazeMode & HAZE_MODE_IS_ACTIVE) != HAZE_MODE_IS_ACTIVE) {
        discard;
    }

    vec4 fragPositionES = unpackPositionFromZeye(varTexCoord0);

    mat4 viewInverse = getViewInverse();
    vec4 fragPositionWS = viewInverse * fragPositionES;
    vec4 eyePositionWS = viewInverse[3];

    Light light = getKeyLight();
    vec3 lightDirectionWS = getLightDirection(light);

    outFragColor = computeHazeColor(fragPositionES.xyz, fragPositionWS.xyz, eyePositionWS.xyz, lightDirectionWS);
    if (outFragColor.a < 1e-4) {
        discard;
    }
}