node_shader_light_falloff.cc

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/* SPDX-FileCopyrightText: 2005 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#include "node_shader_util.hh"
 
namespace blender::nodes::node_shader_light_falloff_cc {
 
static void node_declare(NodeDeclarationBuilder &b)
{
  b.add_input<decl::Float>("Strength")
      .default_value(100.0f)
      .min(0.0f)
      .max(1000000.0f)
      .description("Light strength before applying falloff modification")
      .translation_context(BLT_I18NCONTEXT_AMOUNT);
 
  b.add_input<decl::Float>("Smooth").default_value(0.0f).min(0.0f).max(1000.0f).description(
      "Smooth intensity of light near light sources.\n"
      "This can avoid harsh highlights, and reduce global illumination noise. "
      "0.0 corresponds to no smoothing; higher values smooth more");
  b.add_output<decl::Float>("Quadratic");
  b.add_output<decl::Float>("Linear");
  b.add_output<decl::Float>("Constant");
}
 
static int node_shader_gpu_light_falloff(GPUMaterial *mat,
                                         bNode *node,
                                         bNodeExecData * /*execdata*/,
                                         GPUNodeStack *in,
                                         GPUNodeStack *out)
{
  return GPU_stack_link(mat, node, "node_light_falloff", in, out);
}
 
NODE_SHADER_MATERIALX_BEGIN
#ifdef WITH_MATERIALX
{
  NodeItem strength = get_input_value("Strength", NodeItem::Type::Float);
  NodeItem smooth = get_input_value("Smooth", NodeItem::Type::Float);
 
  /* This node isn't supported by MaterialX. This formula was given from OSL shader code in Cycles
   * node_light_falloff.osl. Considered ray_length=1.0f. */
  return strength / (smooth + val(1.0f));
}
#endif
NODE_SHADER_MATERIALX_END
 
}  // namespace blender::nodes::node_shader_light_falloff_cc
 
/* node type definition */
void register_node_type_sh_light_falloff()
{
  namespace file_ns = blender::nodes::node_shader_light_falloff_cc;
 
  static blender::bke::bNodeType ntype;
 
  sh_node_type_base(&ntype, "ShaderNodeLightFalloff", SH_NODE_LIGHT_FALLOFF);
  ntype.ui_name = "Light Falloff";
  ntype.ui_description =
      "Manipulate how light intensity decreases over distance. Typically used for "
      "non-physically-based effects; in reality light always falls off quadratically";
  ntype.enum_name_legacy = "LIGHT_FALLOFF";
  ntype.nclass = NODE_CLASS_OP_COLOR;
  ntype.declare = file_ns::node_declare;
  blender::bke::node_type_size_preset(ntype, blender::bke::eNodeSizePreset::Middle);
  ntype.gpu_fn = file_ns::node_shader_gpu_light_falloff;
  ntype.materialx_fn = file_ns::node_shader_materialx;
 
  blender::bke::node_register_type(ntype);
}