<!
//  DeferredBuffer.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_SLH@>
<@def DEFERRED_BUFFER_SLH@>

// the diffuse texture
uniform sampler2D diffuseMap;

// the normal texture
uniform sampler2D normalMap;

// the specular texture
uniform sampler2D specularMap;

// the depth texture
uniform sampler2D depthMap;

// the distance to the near clip plane
uniform float near;

// scale factor for depth: (far - near) / far
uniform float depthScale;

// offset for depth texture coordinates
uniform vec2 depthTexCoordOffset;

// scale for depth texture coordinates
uniform vec2 depthTexCoordScale;

struct DeferredFragment {
    float depthVal;
    vec4 normalVal;
    vec4 diffuseVal;
    vec4 specularVal;
    vec4 position;
    vec3 normal;
};

DeferredFragment unpackDeferredFragment(vec2 texcoord) {
    DeferredFragment frag;
    frag.depthVal = texture2D(depthMap, texcoord).r;
    frag.normalVal = texture2D(normalMap, texcoord);
    frag.diffuseVal = texture2D(diffuseMap, texcoord);
    frag.specularVal = texture2D(specularMap, texcoord);

    // compute the view space position using the depth
    float z = near / (frag.depthVal * depthScale - 1.0);
    frag.position = vec4((depthTexCoordOffset + texcoord * depthTexCoordScale) * z, z, 1.0);

   // Unpack the normal from the map
    frag.normal = normalize(frag.normalVal.xyz * 2.0 - vec3(1.0));

    return frag;
}

<@endif@>