path: root/source/blender/blenkernel/intern/cryptomatte.cc

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2020 Blender Foundation.
 * All rights reserved.
 */

/** \file
 * \ingroup bke
 */

#include "BKE_cryptomatte.h"
#include "BKE_cryptomatte.hh"
#include "BKE_image.h"
#include "BKE_main.h"

#include "DNA_layer_types.h"
#include "DNA_material_types.h"
#include "DNA_node_types.h"
#include "DNA_object_types.h"

#include "BLI_compiler_attrs.h"
#include "BLI_dynstr.h"
#include "BLI_hash_mm3.h"
#include "BLI_listbase.h"
#include "BLI_string.h"

#include "MEM_guardedalloc.h"

#include <cctype>
#include <cstring>
#include <iomanip>
#include <sstream>
#include <string>
#include <string_view>

struct CryptomatteSession {
  blender::bke::cryptomatte::CryptomatteLayer objects;
  blender::bke::cryptomatte::CryptomatteLayer assets;
  blender::bke::cryptomatte::CryptomatteLayer materials;

  CryptomatteSession();
  CryptomatteSession(const Main *bmain);

  std::optional<std::string> operator[](float encoded_hash) const;

#ifdef WITH_CXX_GUARDEDALLOC
  MEM_CXX_CLASS_ALLOC_FUNCS("cryptomatte:CryptomatteSession")
#endif
};

CryptomatteSession::CryptomatteSession()
{
}

CryptomatteSession::CryptomatteSession(const Main *bmain)
{
  LISTBASE_FOREACH (ID *, id, &bmain->objects) {
    objects.add_ID(*id);
  }
  LISTBASE_FOREACH (ID *, id, &bmain->materials) {
    materials.add_ID(*id);
  }
}

std::optional<std::string> CryptomatteSession::operator[](float encoded_hash) const
{
  std::optional<std::string> result = objects[encoded_hash];
  if (result) {
    return result;
  }
  return materials[encoded_hash];
}

CryptomatteSession *BKE_cryptomatte_init(void)
{
  CryptomatteSession *session = new CryptomatteSession();
  return session;
}

void BKE_cryptomatte_free(CryptomatteSession *session)
{
  BLI_assert(session != nullptr);
  delete session;
}

uint32_t BKE_cryptomatte_hash(const char *name, const int name_len)
{
  blender::bke::cryptomatte::CryptomatteHash hash(name, name_len);
  return hash.hash;
}

uint32_t BKE_cryptomatte_object_hash(CryptomatteSession *session, const Object *object)
{
  return session->objects.add_ID(object->id);
}

uint32_t BKE_cryptomatte_material_hash(CryptomatteSession *session, const Material *material)
{
  if (material == nullptr) {
    return 0.0f;
  }
  return session->materials.add_ID(material->id);
}

uint32_t BKE_cryptomatte_asset_hash(CryptomatteSession *session, const Object *object)
{
  const Object *asset_object = object;
  while (asset_object->parent != nullptr) {
    asset_object = asset_object->parent;
  }
  return session->assets.add_ID(asset_object->id);
}

float BKE_cryptomatte_hash_to_float(uint32_t cryptomatte_hash)
{
  return blender::bke::cryptomatte::CryptomatteHash(cryptomatte_hash).float_encoded();
}

char *BKE_cryptomatte_entries_to_matte_id(NodeCryptomatte *node_storage)
{
  DynStr *matte_id = BLI_dynstr_new();
  bool first = true;
  LISTBASE_FOREACH (CryptomatteEntry *, entry, &node_storage->entries) {
    if (!first) {
      BLI_dynstr_append(matte_id, ",");
    }
    if (BLI_strnlen(entry->name, sizeof(entry->name)) != 0) {
      BLI_dynstr_nappend(matte_id, entry->name, sizeof(entry->name));
    }
    else {
      BLI_dynstr_appendf(matte_id, "<%.9g>", entry->encoded_hash);
    }
    first = false;
  }
  char *result = BLI_dynstr_get_cstring(matte_id);
  BLI_dynstr_free(matte_id);
  return result;
}

void BKE_cryptomatte_matte_id_to_entries(NodeCryptomatte *node_storage, const char *matte_id)
{
  BLI_freelistN(&node_storage->entries);
  std::optional<CryptomatteSession> session = std::nullopt;

  std::istringstream ss(matte_id);
  while (ss.good()) {
    CryptomatteEntry *entry = nullptr;
    std::string token;
    getline(ss, token, ',');
    /* Ignore empty tokens. */
    if (token.length() > 0) {
      size_t first = token.find_first_not_of(' ');
      size_t last = token.find_last_not_of(' ');
      if (first == std::string::npos || last == std::string::npos) {
        break;
      }
      token = token.substr(first, (last - first + 1));
      if (*token.begin() == '<' && *(--token.end()) == '>') {
        float encoded_hash = atof(token.substr(1, token.length() - 2).c_str());
        entry = (CryptomatteEntry *)MEM_callocN(sizeof(CryptomatteEntry), __func__);
        entry->encoded_hash = encoded_hash;
      }
      else {
        const char *name = token.c_str();
        int name_len = token.length();
        entry = (CryptomatteEntry *)MEM_callocN(sizeof(CryptomatteEntry), __func__);
        STRNCPY(entry->name, name);
        uint32_t hash = BKE_cryptomatte_hash(name, name_len);
        entry->encoded_hash = BKE_cryptomatte_hash_to_float(hash);
      }
    }
    if (entry != nullptr) {
      BLI_addtail(&node_storage->entries, entry);
    }
  }
}

static std::string cryptomatte_determine_name(const ViewLayer *view_layer,
                                              const blender::StringRefNull cryptomatte_layer_name)
{
  std::stringstream stream;
  const size_t view_layer_name_len = BLI_strnlen(view_layer->name, sizeof(view_layer->name));
  stream << std::string(view_layer->name, view_layer_name_len) << "." << cryptomatte_layer_name;
  return stream.str();
}

static uint32_t cryptomatte_determine_identifier(const blender::StringRef name)
{
  return BLI_hash_mm3(reinterpret_cast<const unsigned char *>(name.data()), name.size(), 0);
}

static void add_render_result_meta_data(RenderResult *render_result,
                                        const blender::StringRef layer_name,
                                        const blender::StringRefNull key_name,
                                        const blender::StringRefNull value)
{
  BKE_render_result_stamp_data(
      render_result,
      blender::bke::cryptomatte::BKE_cryptomatte_meta_data_key(layer_name, key_name).c_str(),
      value.data());
}

void BKE_cryptomatte_store_metadata(struct CryptomatteSession *session,
                                    RenderResult *render_result,
                                    const ViewLayer *view_layer,
                                    eViewLayerCryptomatteFlags cryptomatte_layer,
                                    const char *cryptomatte_layer_name)
{
  /* Create Manifest. */
  blender::bke::cryptomatte::CryptomatteLayer *layer = nullptr;
  switch (cryptomatte_layer) {
    case VIEW_LAYER_CRYPTOMATTE_OBJECT:
      layer = &session->objects;
      break;
    case VIEW_LAYER_CRYPTOMATTE_MATERIAL:
      layer = &session->materials;
      break;
    case VIEW_LAYER_CRYPTOMATTE_ASSET:
      layer = &session->assets;
      break;
    default:
      BLI_assert(!"Incorrect cryptomatte layer");
      break;
  }

  const std::string manifest = layer->manifest();
  const std::string name = cryptomatte_determine_name(view_layer, cryptomatte_layer_name);

  /* Store the meta data into the render result. */
  add_render_result_meta_data(render_result, name, "name", name);
  add_render_result_meta_data(render_result, name, "hash", "MurmurHash3_32");
  add_render_result_meta_data(render_result, name, "conversion", "uint32_to_float32");
  add_render_result_meta_data(render_result, name, "manifest", manifest);
}

namespace blender::bke::cryptomatte {
namespace manifest {
constexpr StringRef WHITESPACES = " \t\n\v\f\r";

static constexpr blender::StringRef skip_whitespaces_(blender::StringRef ref)
{
  size_t skip = ref.find_first_not_of(WHITESPACES);
  if (skip == blender::StringRef::not_found) {
    return ref;
  }
  return ref.drop_prefix(skip);
}

static constexpr int quoted_string_len_(blender::StringRef ref)
{
  int len = 1;
  bool skip_next = false;
  while (len < ref.size()) {
    char current_char = ref[len];
    if (skip_next) {
      skip_next = false;
    }
    else {
      if (current_char == '\\') {
        skip_next = true;
      }
      if (current_char == '\"') {
        len += 1;
        break;
      }
    }
    len += 1;
  }
  return len;
}

static std::string unquote_(const blender::StringRef ref)
{
  std::ostringstream stream;
  for (char c : ref) {
    if (c != '\\') {
      stream << c;
    }
  }
  return stream.str();
}

static bool from_manifest(CryptomatteLayer &layer, blender::StringRefNull manifest)
{
  StringRef ref = manifest;
  ref = skip_whitespaces_(ref);
  if (ref.is_empty() || ref.front() != '{') {
    return false;
  }
  ref = ref.drop_prefix(1);
  while (!ref.is_empty()) {
    char front = ref.front();

    if (front == '\"') {
      const int quoted_name_len = quoted_string_len_(ref);
      const int name_len = quoted_name_len - 2;
      std::string name = unquote_(ref.substr(1, name_len));
      ref = ref.drop_prefix(quoted_name_len);
      ref = skip_whitespaces_(ref);

      char colon = ref.front();
      if (colon != ':') {
        return false;
      }
      ref = ref.drop_prefix(1);
      ref = skip_whitespaces_(ref);

      if (ref.front() != '\"') {
        return false;
      }

      const int quoted_hash_len = quoted_string_len_(ref);
      const int hash_len = quoted_hash_len - 2;
      CryptomatteHash hash = CryptomatteHash::from_hex_encoded(ref.substr(1, hash_len));
      ref = ref.drop_prefix(quoted_hash_len);
      layer.add_hash(name, hash);
    }
    else if (front == ',') {
      ref = ref.drop_prefix(1);
    }
    else if (front == '}') {
      ref = ref.drop_prefix(1);
      ref = skip_whitespaces_(ref);
      break;
    }
    ref = skip_whitespaces_(ref);
  }

  if (!ref.is_empty()) {
    return false;
  }

  return true;
}

static std::string to_manifest(const CryptomatteLayer *layer)
{
  std::stringstream manifest;

  bool is_first = true;
  const blender::Map<std::string, CryptomatteHash> &const_map = layer->hashes;
  manifest << "{";
  for (blender::Map<std::string, CryptomatteHash>::Item item : const_map.items()) {
    if (is_first) {
      is_first = false;
    }
    else {
      manifest << ",";
    }
    manifest << quoted(item.key) << ":\"" << (item.value.hex_encoded()) << "\"";
  }
  manifest << "}";
  return manifest.str();
}

}  // namespace manifest

/* Return the hash of the given cryptomatte layer name.
 *
 * The cryptomatte specification limits the hash to 7 characters.
 * The 7 position limitation solves issues when using cryptomatte together with OpenEXR.
 * The specification suggests to use the first 7 chars of the hashed layer_name.
 */
static std::string cryptomatte_layer_name_hash(const StringRef layer_name)
{
  std::stringstream stream;
  const uint32_t render_pass_identifier = cryptomatte_determine_identifier(layer_name);
  stream << std::setfill('0') << std::setw(sizeof(uint32_t) * 2) << std::hex
         << render_pass_identifier;
  return stream.str().substr(0, 7);
}

std::string BKE_cryptomatte_meta_data_key(const StringRef layer_name, const StringRefNull key_name)
{
  return "cryptomatte/" + cryptomatte_layer_name_hash(layer_name) + "/" + key_name;
}

/* Extracts the cryptomatte name from a render pass name.
 *
 * Example: A render pass could be named `CryptoObject00`. This
 *   function would remove the trailing digits and return `CryptoObject`. */
StringRef BKE_cryptomatte_extract_layer_name(const StringRef render_pass_name)
{
  int64_t last_token = render_pass_name.size();
  while (last_token > 0 && std::isdigit(render_pass_name[last_token - 1])) {
    last_token -= 1;
  }
  return render_pass_name.substr(0, last_token);
}

CryptomatteHash::CryptomatteHash(uint32_t hash) : hash(hash)
{
}

CryptomatteHash::CryptomatteHash(const char *name, const int name_len)
{
  hash = BLI_hash_mm3((const unsigned char *)name, name_len, 0);
}

CryptomatteHash CryptomatteHash::from_hex_encoded(blender::StringRef hex_encoded)
{
  CryptomatteHash result(0);
  std::istringstream(hex_encoded) >> std::hex >> result.hash;
  return result;
}

std::string CryptomatteHash::hex_encoded() const
{
  std::stringstream encoded;
  encoded << std::setfill('0') << std::setw(sizeof(uint32_t) * 2) << std::hex << hash;
  return encoded.str();
}

/* Convert a cryptomatte hash to a float.
 *
 * Cryptomatte hashes are stored in float textures and images. The conversion is taken from the
 * cryptomatte specification. See Floating point conversion section in
 * https://github.com/Psyop/Cryptomatte/blob/master/specification/cryptomatte_specification.pdf.
 *
 * The conversion uses as many 32 bit floating point values as possible to minimize hash
 * collisions. Unfortunately not all 32 bits can be used as NaN and Inf can be problematic.
 *
 * Note that this conversion assumes to be running on a L-endian system. */
float CryptomatteHash::float_encoded() const
{
  uint32_t mantissa = hash & ((1 << 23) - 1);
  uint32_t exponent = (hash >> 23) & ((1 << 8) - 1);
  exponent = MAX2(exponent, (uint32_t)1);
  exponent = MIN2(exponent, (uint32_t)254);
  exponent = exponent << 23;
  uint32_t sign = (hash >> 31);
  sign = sign << 31;
  uint32_t float_bits = sign | exponent | mantissa;
  float f;
  memcpy(&f, &float_bits, sizeof(uint32_t));
  return f;
}

std::unique_ptr<CryptomatteLayer> CryptomatteLayer::read_from_manifest(
    blender::StringRefNull manifest)
{
  std::unique_ptr<CryptomatteLayer> layer = std::make_unique<CryptomatteLayer>();
  blender::bke::cryptomatte::manifest::from_manifest(*layer.get(), manifest);
  return layer;
}

uint32_t CryptomatteLayer::add_ID(const ID &id)
{
  const char *name = &id.name[2];
  const int name_len = BLI_strnlen(name, MAX_NAME - 2);
  uint32_t cryptohash_int = BKE_cryptomatte_hash(name, name_len);

  add_hash(blender::StringRef(name, name_len), cryptohash_int);

  return cryptohash_int;
}

void CryptomatteLayer::add_hash(blender::StringRef name, CryptomatteHash cryptomatte_hash)
{
  hashes.add_overwrite(name, cryptomatte_hash);
}

std::optional<std::string> CryptomatteLayer::operator[](float encoded_hash) const
{
  const blender::Map<std::string, CryptomatteHash> &const_map = hashes;
  for (blender::Map<std::string, CryptomatteHash>::Item item : const_map.items()) {
    if (BKE_cryptomatte_hash_to_float(item.value.hash) == encoded_hash) {
      return std::make_optional(item.key);
    }
  }
  return std::nullopt;
}

std::string CryptomatteLayer::manifest() const
{
  return blender::bke::cryptomatte::manifest::to_manifest(this);
}

}  // namespace blender::bke::cryptomatte