shadow_catcher.h

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/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
 *
 * SPDX-License-Identifier: Apache-2.0 */
 
#pragma once
 
#include "kernel/integrator/state_flow.h"
 
CCL_NAMESPACE_BEGIN
 
/* Check whether current surface bounce is where path is to be split for the shadow catcher. */
ccl_device_inline bool kernel_shadow_catcher_is_path_split_bounce(KernelGlobals kg,
                                                                  IntegratorState state,
                                                                  const int object_flag)
{
#ifdef __SHADOW_CATCHER__
  if (!kernel_data.integrator.has_shadow_catcher) {
    return false;
  }
 
  /* Check the flag first, avoiding fetches form global memory. */
  if ((object_flag & SD_OBJECT_SHADOW_CATCHER) == 0) {
    return false;
  }
  if (object_flag & SD_OBJECT_HOLDOUT_MASK) {
    return false;
  }
 
  const uint32_t path_flag = INTEGRATOR_STATE(state, path, flag);
 
  if ((path_flag & PATH_RAY_TRANSPARENT_BACKGROUND) == 0) {
    /* Split only on primary rays, secondary bounces are to treat shadow catcher as a regular
     * object. */
    return false;
  }
 
  if (path_flag & PATH_RAY_SHADOW_CATCHER_HIT) {
    return false;
  }
 
  return true;
#else
  (void)object_flag;
  return false;
#endif
}
 
/* Check whether the current path can still split. */
ccl_device_inline bool kernel_shadow_catcher_path_can_split(KernelGlobals kg,
                                                            ConstIntegratorState state)
{
  if (integrator_path_is_terminated(state)) {
    return false;
  }
 
  const uint32_t path_flag = INTEGRATOR_STATE(state, path, flag);
 
  if (path_flag & PATH_RAY_SHADOW_CATCHER_HIT) {
    /* Shadow catcher was already hit and the state was split. No further split is allowed. */
    return false;
  }
 
  return (path_flag & PATH_RAY_TRANSPARENT_BACKGROUND) != 0;
}
 
#ifdef __SHADOW_CATCHER__
 
ccl_device_forceinline bool kernel_shadow_catcher_is_matte_path(const uint32_t path_flag)
{
  return (path_flag & PATH_RAY_SHADOW_CATCHER_HIT) == 0;
}
 
ccl_device_forceinline bool kernel_shadow_catcher_is_object_pass(const uint32_t path_flag)
{
  return path_flag & PATH_RAY_SHADOW_CATCHER_PASS;
}
 
#endif /* __SHADOW_CATCHER__ */
 
CCL_NAMESPACE_END