blender/intern/cycles/kernel/kernel_film.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.
 */

CCL_NAMESPACE_BEGIN

ccl_device float4 film_map(KernelGlobals *kg, float4 irradiance, float scale)
{
  float exposure = kernel_data.film.exposure;
  float4 result = irradiance * scale;

  /* conversion to srgb */
  result.x = color_linear_to_srgb(result.x * exposure);
  result.y = color_linear_to_srgb(result.y * exposure);
  result.z = color_linear_to_srgb(result.z * exposure);

  /* clamp since alpha might be > 1.0 due to russian roulette */
  result.w = saturate(result.w);

  return result;
}

ccl_device uchar4 film_float_to_byte(float4 color)
{
  uchar4 result;

  /* simple float to byte conversion */
  result.x = (uchar)(saturate(color.x) * 255.0f);
  result.y = (uchar)(saturate(color.y) * 255.0f);
  result.z = (uchar)(saturate(color.z) * 255.0f);
  result.w = (uchar)(saturate(color.w) * 255.0f);

  return result;
}

ccl_device void kernel_film_convert_to_byte(KernelGlobals *kg,
                                            ccl_global uchar4 *rgba,
                                            ccl_global float *buffer,
                                            float sample_scale,
                                            int x,
                                            int y,
                                            int offset,
                                            int stride)
{
  /* buffer offset */
  int index = offset + x + y * stride;

  rgba += index;
  buffer += index * kernel_data.film.pass_stride;

  /* map colors */
  float4 irradiance = *((ccl_global float4 *)buffer);
  float4 float_result = film_map(kg, irradiance, sample_scale);
  uchar4 byte_result = film_float_to_byte(float_result);

  *rgba = byte_result;
}

ccl_device void kernel_film_convert_to_half_float(KernelGlobals *kg,
                                                  ccl_global uchar4 *rgba,
                                                  ccl_global float *buffer,
                                                  float sample_scale,
                                                  int x,
                                                  int y,
                                                  int offset,
                                                  int stride)
{
  /* buffer offset */
  int index = offset + x + y * stride;

  ccl_global float4 *in = (ccl_global float4 *)(buffer + index * kernel_data.film.pass_stride);
  ccl_global half *out = (ccl_global half *)rgba + index * 4;

  float exposure = kernel_data.film.exposure;

  float4 rgba_in = *in;

  if (exposure != 1.0f) {
    rgba_in.x *= exposure;
    rgba_in.y *= exposure;
    rgba_in.z *= exposure;
  }

  float4_store_half(out, rgba_in, sample_scale);
}

CCL_NAMESPACE_END