blender/intern/cycles/kernel/svm/svm_hsv.h

/*
 * 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.
 */

#ifndef __SVM_HSV_H__
#define __SVM_HSV_H__

CCL_NAMESPACE_BEGIN

ccl_device void svm_node_hsv(
    KernelGlobals *kg, ShaderData *sd, float *stack, uint4 node, int *offset)
{
  uint in_color_offset, fac_offset, out_color_offset;
  uint hue_offset, sat_offset, val_offset;
  decode_node_uchar4(node.y, &in_color_offset, &fac_offset, &out_color_offset, NULL);
  decode_node_uchar4(node.z, &hue_offset, &sat_offset, &val_offset, NULL);

  float fac = stack_load_float(stack, fac_offset);
  float3 in_color = stack_load_float3(stack, in_color_offset);
  float3 color = in_color;

  float hue = stack_load_float(stack, hue_offset);
  float sat = stack_load_float(stack, sat_offset);
  float val = stack_load_float(stack, val_offset);

  color = rgb_to_hsv(color);

  /* remember: fmod doesn't work for negative numbers here */
  color.x = fmodf(color.x + hue + 0.5f, 1.0f);
  color.y = saturate(color.y * sat);
  color.z *= val;

  color = hsv_to_rgb(color);

  color.x = fac * color.x + (1.0f - fac) * in_color.x;
  color.y = fac * color.y + (1.0f - fac) * in_color.y;
  color.z = fac * color.z + (1.0f - fac) * in_color.z;

  /* Clamp color to prevent negative values caused by oversaturation. */
  color.x = max(color.x, 0.0f);
  color.y = max(color.y, 0.0f);
  color.z = max(color.z, 0.0f);

  if (stack_valid(out_color_offset))
    stack_store_float3(stack, out_color_offset, color);
}

CCL_NAMESPACE_END

#endif /* __SVM_HSV_H__ */