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

/* SPDX-License-Identifier: Apache-2.0
 * Copyright 2011-2022 Blender Foundation */

#pragma once

CCL_NAMESPACE_BEGIN

/* TODO(sergey): Think of making it more generic volume-type attribute
 * sampler.
 */
ccl_device_noinline int svm_node_tex_voxel(
    KernelGlobals kg, ccl_private ShaderData *sd, ccl_private float *stack, uint4 node, int offset)
{
  uint co_offset, density_out_offset, color_out_offset, space;
  svm_unpack_node_uchar4(node.z, &co_offset, &density_out_offset, &color_out_offset, &space);
#ifdef __VOLUME__
  int id = node.y;
  float3 co = stack_load_float3(stack, co_offset);
  if (space == NODE_TEX_VOXEL_SPACE_OBJECT) {
    co = volume_normalized_position(kg, sd, co);
  }
  else {
    kernel_assert(space == NODE_TEX_VOXEL_SPACE_WORLD);
    Transform tfm;
    tfm.x = read_node_float(kg, &offset);
    tfm.y = read_node_float(kg, &offset);
    tfm.z = read_node_float(kg, &offset);
    co = transform_point(&tfm, co);
  }

  float4 r = kernel_tex_image_interp_3d(kg, id, co, INTERPOLATION_NONE);
#else
  float4 r = zero_float4();
#endif
  if (stack_valid(density_out_offset))
    stack_store_float(stack, density_out_offset, r.w);
  if (stack_valid(color_out_offset))
    stack_store_float3(stack, color_out_offset, make_float3(r.x, r.y, r.z));
  return offset;
}

CCL_NAMESPACE_END