/*
 * Copyright (c) 2019-2021, NVIDIA CORPORATION.  All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * SPDX-FileCopyrightText: Copyright (c) 2019-2021 NVIDIA CORPORATION
 * SPDX-License-Identifier: Apache-2.0
 */

#version 460 core
#extension GL_EXT_ray_tracing : enable
#extension GL_GOOGLE_include_directive : enable
#extension GL_EXT_shader_explicit_arithmetic_types_int64 : require

#include "raycommon.glsl"
#include "host_device.h"

layout(location = 3) callableDataInEXT rayLight cLight;

layout(push_constant) uniform _PushConstantRay
{
  PushConstantRay pcRay;
};

void main()
{
  vec3 lDir               = pcRay.lightPosition - cLight.inHitPosition;
  cLight.outLightDistance = length(lDir);
  cLight.outIntensity     = pcRay.lightIntensity / (cLight.outLightDistance * cLight.outLightDistance);
  cLight.outLightDir      = normalize(lDir);
  float theta             = dot(cLight.outLightDir, normalize(-pcRay.lightDirection));
  float epsilon           = pcRay.lightSpotCutoff - pcRay.lightSpotOuterCutoff;
  float spotIntensity     = clamp((theta - pcRay.lightSpotOuterCutoff) / epsilon, 0.0, 1.0);
  cLight.outIntensity *= spotIntensity;
}