<@include gpu/Config.slh@>
<$VERSION_HEADER$>
//  Generated on <$_SCRIBE_DATE$>
//  lightClusters_drawClusterFromDepth.frag
//
//  Created by Sam Gateau on 9/8/2016.
//  Copyright 2015 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
//


// Everything about deferred buffer
<@include DeferredBufferRead.slh@>


<@include LightClusterGrid.slh@>

<@include gpu/Color.slh@>
<$declareColorWheel()$>


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

void main(void) {

    // Grab the fragment data from the uv
    vec2 texCoord = varTexCoord0.st;

    vec4 fragEyePos = unpackDeferredPositionFromZdb(texCoord);
    vec4 fragWorldPos = getViewInverse() * fragEyePos;
    
    // From frag world pos find the cluster
    vec4 clusterEyePos = frustumGrid_worldToEye(fragWorldPos);
    ivec3 clusterPos = frustumGrid_eyeToClusterPos(clusterEyePos.xyz);


    ivec3 cluster = clusterGrid_getCluster(frustumGrid_clusterToIndex(clusterPos));
    int numLights = cluster.x + cluster.y;
    float numLightsScale = clamp(float(numLights) * 0.05, 0.01, 1.0);


   ivec3 dims = frustumGrid.dims.xyz;
   dims.z +=1;
   ivec3 summedDims = ivec3(dims.x * dims.y, dims.x, 1);
   
   if (clusterPos.x < 0 || clusterPos.x >= dims.x) {
       _fragColor = vec4(0.0);
       return;
   }
   
   if (clusterPos.y < 0 || clusterPos.y >= dims.y) {
       _fragColor = vec4(0.0);
       return;
   }
   if (clusterPos.z < 0 || clusterPos.z > dims.z) {
       _fragColor = vec4(0.0);
       return;
   }
   
   float relClusterId = float(clusterPos.z * summedDims.x + clusterPos.y * summedDims.y + clusterPos.x) / float(frustumGrid_numClusters());
   
   _fragColor = mix(mix(vec4(colorWheel(fract(relClusterId)), float(numLights > 0) * (0.05 + 0.95 * numLightsScale)),
                        vec4(vec3(1.0), 0.2),
                        float(relClusterId >= 1.0)),
                    vec4(0.0),
                    float(relClusterId < 0.0));
}