intern/cycles/kernel/osl/shaders/node_light_falloff.osl


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/*
 * Copyright 2011-2013 Blender Foundation
 *
 * 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.
 */

#include "stdcycles.h"

shader node_light_falloff(float Strength = 0.0,
                          float Smooth = 0.0,
                          output float Quadratic = 0.0,
                          output float Linear = 0.0,
                          output float Constant = 0.0)
{
  float ray_length = 0.0;
  float strength = Strength;
  getattribute("path:ray_length", ray_length);

  if (Smooth > 0.0) {
    float squared = ray_length * ray_length;
    strength *= squared / (Smooth + squared);
  }

  /* Quadratic */
  Quadratic = strength;

  /* Linear */
  Linear = (strength * ray_length);

  /* Constant */
  Constant = (strength * ray_length * ray_length);
}