<!
//  DeferredGlobalLight.slh
//  libraries/render-utils/src
//
//  Created by Sam Gateau on 2/5/15.
//  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_GLOBAL_LIGHT_SLH@>
<@def DEFERRED_GLOBAL_LIGHT_SLH@>

<@include model/Light.slh@>
<@include DeferredLighting.slh@>

<@func declareSkyboxMap()@>
// declareSkyboxMap
uniform samplerCube skyboxMap;

vec4 evalSkyboxLight(vec3 direction, float lod) {
    // textureQueryLevels is not available until #430, so we require explicit lod
    // float mipmapLevel = lod * textureQueryLevels(skyboxMap);
    return textureLod(skyboxMap, direction, lod);
}
<@endfunc@>

<@func prepareGlobalLight()@>
    // prepareGlobalLight

    // Transform directions to worldspace
    vec3 fragNormal = vec3(invViewMat * vec4(normal, 0.0));
  //  vec3 fragEyeVector = vec3(invViewMat * vec4(-position, 0.0));
    vec3 fragEyeVector = vec3(invViewMat * vec4(-normalize(position), 0.0));
    vec3 fragEyeDir = normalize(fragEyeVector);

    // Get light
    Light light = getLight();
    vec3 fresnel = vec3(0.03); // Default Di-electric fresnel value
    if (metallic > 0.5) {
        fresnel = albedo;
        metallic = 1.0;
    }
    vec4 shading = evalFragShading(fragNormal, -getLightDirection(light), fragEyeDir, metallic, fresnel, roughness);
    vec3 color = vec3(albedo * shading.w + shading.rgb) * min(shadowAttenuation, obscurance) * getLightColor(light) * getLightIntensity(light);
    color += emissive;
<@endfunc@>

<@func declareAmbientFresnel()@>
vec3 fresnelSchlickAmbient(vec3 fresnelColor, vec3 lightDir, vec3 halfDir, float gloss) {
    return fresnelColor + (max(vec3(gloss), fresnelColor) - fresnelColor) * pow(1.0 - clamp(dot(lightDir, halfDir), 0.0, 1.0), 5);
}
<@endfunc@>

<@func declareEvalAmbientGlobalColor()@>
vec3 evalAmbientGlobalColor(mat4 invViewMat, float shadowAttenuation, float obscurance, vec3 position, vec3 normal, vec3 albedo, float metallic, vec3 emissive, float roughness) {
    <$prepareGlobalLight()$>
    color += albedo * getLightColor(light) * obscurance * getLightAmbientIntensity(light);
    return color;
}
<@endfunc@>

<@func declareEvalAmbientSphereGlobalColor()@>
<$declareAmbientFresnel()$>

vec3 evalAmbientSphereGlobalColor(mat4 invViewMat, float shadowAttenuation, float obscurance, vec3 position, vec3 normal, vec3 albedo, float metallic, vec3 emissive, float roughness) {
    <$prepareGlobalLight()$>

    // Diffuse from ambient
    color += (1 - metallic) * albedo * evalSphericalLight(getLightAmbientSphere(light), fragNormal).xyz * obscurance * getLightAmbientIntensity(light);

    // Specular highlight from ambient
    vec3 direction = -reflect(fragEyeDir, fragNormal);
    vec3 skyboxLight = evalSphericalLight(getLightAmbientSphere(light), direction).xyz;
    vec3 ambientFresnel = fresnelSchlickAmbient(fresnel, fragEyeDir, fragNormal, 1 - roughness);
    color += ambientFresnel * skyboxLight.rgb * obscurance * getLightAmbientIntensity(light);

    return color;
}
<@endfunc@>

<@func declareEvalSkyboxGlobalColor()@>
<$declareSkyboxMap()$>
<$declareAmbientFresnel()$>

vec3 evalSkyboxGlobalColor(mat4 invViewMat, float shadowAttenuation, float obscurance, vec3 position, vec3 normal, vec3 albedo, float metallic, vec3 emissive, float roughness) {
    <$prepareGlobalLight()$>

    // Diffuse from ambient
    color += (1 - metallic) * albedo * evalSphericalLight(getLightAmbientSphere(light), fragNormal).xyz * obscurance * getLightAmbientIntensity(light);

    // Specular highlight from ambient
    //vec3 direction = -reflect(fragEyeDir, fragNormal);
  //  -normalize(position)
    vec3 direction = -reflect(-normalize(position), normal);
   // vec3 direction = normal;

  //  if (gl_FragCoord.x > 1000) {
        float angleY = fract(asin(direction.y)/ 0.314);
        float angleX = fract(acos(normalize(direction.xz).x)/ 0.314);
        float stripeY = step(0.05,abs(angleY));
        float stripeX = step(0.05,abs(angleX));
        float grid = max(stripeY, stripeX);
        return mix( 0.5 * direction + vec3(0.5), mix(vec3(0.0, 1.0, 0.0), vec3(1.0, 0.0, 0.0), stripeY), grid);
//    }

    float levels = getLightAmbientMapNumMips(light);
    float lod = min(floor((roughness) * levels), levels);
   // vec4 skyboxLight = evalSkyboxLight(direction, lod);
    vec4 skyboxLight = evalSkyboxLight(direction, levels * 0.5);
    
    return skyboxLight.xyz;


    //vec3 ambientFresnel = fresnelSchlickAmbient(fresnel, fragEyeDir, fragNormal, 1 - roughness);
    //color += ambientFresnel * skyboxLight.rgb * obscurance * getLightAmbientIntensity(light);

    //return color;
}
<@endfunc@>

<@func declareEvalLightmappedColor()@>
vec3 evalLightmappedColor(mat4 invViewMat, float shadowAttenuation, float obscurance, vec3 normal, vec3 albedo, vec3 lightmap) {
    Light light = getLight();

    // Catch normals perpendicular to the projection plane, hence the magic number for the threshold
    // It should be just 0, but we have inaccuracy so we overshoot
    const float PERPENDICULAR_THRESHOLD = -0.005;
    vec3 fragNormal = vec3(invViewMat * vec4(normal, 0.0)); // transform to worldspace
    float diffuseDot = dot(fragNormal, -getLightDirection(light));
    float facingLight = step(PERPENDICULAR_THRESHOLD, diffuseDot); 

    // Reevaluate the shadow attenuation for light facing fragments
    float lightAttenuation = (1 - facingLight) + facingLight * shadowAttenuation;

    // Diffuse light is the lightmap dimmed by shadow
    vec3 diffuseLight = lightAttenuation * lightmap;

    // Ambient light is the lightmap when in shadow
    vec3 ambientLight = (1 - lightAttenuation) * lightmap * getLightAmbientIntensity(light); 

    return  obscurance * albedo * (diffuseLight + ambientLight);
}
<@endfunc@>

<@endif@>