node_composite_brightness.cc

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/* SPDX-FileCopyrightText: 2006 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

 
#include <limits>
 
#include "BLI_math_color.h"
#include "BLI_math_vector_types.hh"
 
#include "FN_multi_function_builder.hh"
 
#include "NOD_multi_function.hh"
 
#include "UI_interface.hh"
#include "UI_resources.hh"
 
#include "GPU_material.hh"
 
#include "node_composite_util.hh"
 
/* **************** Brightness and Contrast  ******************** */
 
namespace blender::nodes::node_composite_brightness_cc {
 
static void cmp_node_brightcontrast_declare(NodeDeclarationBuilder &b)
{
  b.add_input<decl::Color>("Image").default_value({1.0f, 1.0f, 1.0f, 1.0f});
  b.add_input<decl::Float>("Bright").min(-100.0f).max(100.0f);
  b.add_input<decl::Float>("Contrast").min(-100.0f).max(100.0f);
  b.add_output<decl::Color>("Image");
}
 
using namespace blender::compositor;
 
static int node_gpu_material(GPUMaterial *material,
                             bNode *node,
                             bNodeExecData * /*execdata*/,
                             GPUNodeStack *inputs,
                             GPUNodeStack *outputs)
{
  return GPU_stack_link(material, node, "node_composite_bright_contrast", inputs, outputs);
}
 
/* The algorithm is by Werner D. Streidt, extracted of OpenCV `demhist.c`:
 *   http://visca.com/ffactory/archives/5-99/msg00021.html */
static float4 brightness_and_contrast(const float4 &color,
                                      const float brightness,
                                      const float contrast)
{
  float scaled_brightness = brightness / 100.0f;
  float delta = contrast / 200.0f;
 
  float multiplier, offset;
  if (contrast > 0.0f) {
    multiplier = 1.0f - delta * 2.0f;
    multiplier = 1.0f / math::max(multiplier, std::numeric_limits<float>::epsilon());
    offset = multiplier * (scaled_brightness - delta);
  }
  else {
    delta *= -1.0f;
    multiplier = math::max(1.0f - delta * 2.0f, 0.0f);
    offset = multiplier * scaled_brightness + delta;
  }
 
  return float4(color.xyz() * multiplier + offset, color.w);
}
 
static void node_build_multi_function(blender::nodes::NodeMultiFunctionBuilder &builder)
{
  static auto function = mf::build::SI3_SO<float4, float, float, float4>(
      "Bright And Contrast",
      [](const float4 &color, const float brightness, const float contrast) -> float4 {
        return brightness_and_contrast(color, brightness, contrast);
      },
      mf::build::exec_presets::SomeSpanOrSingle<0>());
  builder.set_matching_fn(function);
}
 
}  // namespace blender::nodes::node_composite_brightness_cc
 
static void register_node_type_cmp_brightcontrast()
{
  namespace file_ns = blender::nodes::node_composite_brightness_cc;
 
  static blender::bke::bNodeType ntype;
 
  cmp_node_type_base(&ntype, "CompositorNodeBrightContrast", CMP_NODE_BRIGHTCONTRAST);
  ntype.ui_name = "Brightness/Contrast";
  ntype.ui_description = "Adjust brightness and contrast";
  ntype.enum_name_legacy = "BRIGHTCONTRAST";
  ntype.nclass = NODE_CLASS_OP_COLOR;
  ntype.declare = file_ns::cmp_node_brightcontrast_declare;
  ntype.gpu_fn = file_ns::node_gpu_material;
  ntype.build_multi_function = file_ns::node_build_multi_function;
 
  blender::bke::node_register_type(ntype);
}
NOD_REGISTER_NODE(register_node_type_cmp_brightcontrast)