Cycles: merge of cycles-x branch, a major update to the renderer

This includes much improved GPU rendering performance, viewport interactivity,
new shadow catcher, revamped sampling settings, subsurface scattering anisotropy,
new GPU volume sampling, improved PMJ sampling pattern, and more.

Some features have also been removed or changed, breaking backwards compatibility.
Including the removal of the OpenCL backend, for which alternatives are under
development.

Release notes and code docs:
https://wiki.blender.org/wiki/Reference/Release_Notes/3.0/Cycles
https://wiki.blender.org/wiki/Source/Render/Cycles

Credits:
* Sergey Sharybin
* Brecht Van Lommel
* Patrick Mours (OptiX backend)
* Christophe Hery (subsurface scattering anisotropy)
* William Leeson (PMJ sampling pattern)
* Alaska (various fixes and tweaks)
* Thomas Dinges (various fixes)

For the full commit history, see the cycles-x branch. This squashes together
all the changes since intermediate changes would often fail building or tests.

Ref T87839, T87837, T87836
Fixes T90734, T89353, T80267, T80267, T77185, T69800

1 files changed, 12 insertions, 172 deletions

diff --git a/intern/cycles/util/util_path.cpp b/intern/cycles/util/util_path.cpp
index 8905c8bc7f0..c78f4615013 100644
--- a/intern/cycles/util/util_path.cpp
+++ b/intern/cycles/util/util_path.cpp
@@ -66,6 +66,7 @@ typedef struct stat path_stat_t;
 
 static string cached_path = "";
 static string cached_user_path = "";
+static string cached_temp_path = "";
 static string cached_xdg_cache_path = "";
 
 namespace {
@@ -335,10 +336,11 @@ static string path_xdg_cache_get()
 }
 #endif
 
-void path_init(const string &path, const string &user_path)
+void path_init(const string &path, const string &user_path, const string &temp_path)
 {
   cached_path = path;
   cached_user_path = user_path;
+  cached_temp_path = temp_path;
 
 #ifdef _MSC_VER
   // workaround for https://svn.boost.org/trac/boost/ticket/6320
@@ -382,6 +384,15 @@ string path_cache_get(const string &sub)
 #endif
 }
 
+string path_temp_get(const string &sub)
+{
+  if (cached_temp_path == "") {
+    cached_temp_path = Filesystem::temp_directory_path();
+  }
+
+  return path_join(cached_temp_path, sub);
+}
+
 #if defined(__linux__) || defined(__APPLE__)
 string path_xdg_home_get(const string &sub = "");
 #endif
@@ -739,177 +750,6 @@ bool path_remove(const string &path)
   return remove(path.c_str()) == 0;
 }
 
-struct SourceReplaceState {
-  typedef map<string, string> ProcessedMapping;
-  /* Base director for all relative include headers. */
-  string base;
-  /* Result of processed files. */
-  ProcessedMapping processed_files;
-  /* Set of files which are considered "precompiled" and which are replaced
-   * with and empty string on a subsequent occurrence in include statement.
-   */
-  set<string> precompiled_headers;
-};
-
-static string path_source_replace_includes_recursive(const string &source,
-                                                     const string &source_filepath,
-                                                     SourceReplaceState *state);
-
-static string line_directive(const SourceReplaceState &state, const string &path, const int line)
-{
-  string unescaped_path = path;
-  /* First we make path relative. */
-  if (string_startswith(unescaped_path, state.base.c_str())) {
-    const string base_file = path_filename(state.base);
-    const size_t base_len = state.base.length();
-    unescaped_path = base_file +
-                     unescaped_path.substr(base_len, unescaped_path.length() - base_len);
-  }
-  /* Second, we replace all unsafe characters. */
-  const size_t length = unescaped_path.length();
-  string escaped_path = "";
-  for (size_t i = 0; i < length; ++i) {
-    const char ch = unescaped_path[i];
-    if (strchr("\"\'\?\\", ch) != NULL) {
-      escaped_path += "\\";
-    }
-    escaped_path += ch;
-  }
-  /* TODO(sergey): Check whether using std::to_string combined with several
-   * concatenation operations is any faster.
-   */
-  return string_printf("#line %d \"%s\"", line, escaped_path.c_str());
-}
-
-static string path_source_handle_preprocessor(const string &preprocessor_line,
-                                              const string &source_filepath,
-                                              const size_t line_number,
-                                              SourceReplaceState *state)
-{
-  string result = preprocessor_line;
-  string token = string_strip(preprocessor_line.substr(1, preprocessor_line.size() - 1));
-  if (string_startswith(token, "include")) {
-    token = string_strip(token.substr(7, token.size() - 7));
-    if (token[0] == '"') {
-      const size_t n_start = 1;
-      const size_t n_end = token.find("\"", n_start);
-      const string filename = token.substr(n_start, n_end - n_start);
-      const bool is_precompiled = string_endswith(token, "// PRECOMPILED");
-      string filepath = path_join(state->base, filename);
-      if (!path_exists(filepath)) {
-        filepath = path_join(path_dirname(source_filepath), filename);
-      }
-      if (is_precompiled) {
-        state->precompiled_headers.insert(filepath);
-      }
-      string text;
-      if (path_read_text(filepath, text)) {
-        text = path_source_replace_includes_recursive(text, filepath, state);
-        /* Use line directives for better error messages. */
-        result = line_directive(*state, filepath, 1) + "\n" + text + "\n" +
-                 line_directive(*state, source_filepath, line_number + 1);
-      }
-    }
-  }
-  return result;
-}
-
-/* Our own little c preprocessor that replaces #includes with the file
- * contents, to work around issue of OpenCL drivers not supporting
- * include paths with spaces in them.
- */
-static string path_source_replace_includes_recursive(const string &source,
-                                                     const string &source_filepath,
-                                                     SourceReplaceState *state)
-{
-  /* Try to re-use processed file without spending time on replacing all
-   * include directives again.
-   */
-  SourceReplaceState::ProcessedMapping::iterator replaced_file = state->processed_files.find(
-      source_filepath);
-  if (replaced_file != state->processed_files.end()) {
-    if (state->precompiled_headers.find(source_filepath) != state->precompiled_headers.end()) {
-      return "";
-    }
-    return replaced_file->second;
-  }
-  /* Perform full file processing. */
-  string result = "";
-  const size_t source_length = source.length();
-  size_t index = 0;
-  /* Information about where we are in the source. */
-  size_t line_number = 0, column_number = 1;
-  /* Currently gathered non-preprocessor token.
-   * Store as start/length rather than token itself to avoid overhead of
-   * memory re-allocations on each character concatenation.
-   */
-  size_t token_start = 0, token_length = 0;
-  /* Denotes whether we're inside of preprocessor line, together with
-   * preprocessor line itself.
-   *
-   * TODO(sergey): Investigate whether using token start/end position
-   * gives measurable speedup.
-   */
-  bool inside_preprocessor = false;
-  string preprocessor_line = "";
-  /* Actual loop over the whole source. */
-  while (index < source_length) {
-    const char ch = source[index];
-    if (ch == '\n') {
-      if (inside_preprocessor) {
-        result += path_source_handle_preprocessor(
-            preprocessor_line, source_filepath, line_number, state);
-        /* Start gathering net part of the token. */
-        token_start = index;
-        token_length = 0;
-      }
-      inside_preprocessor = false;
-      preprocessor_line = "";
-      column_number = 0;
-      ++line_number;
-    }
-    else if (ch == '#' && column_number == 1 && !inside_preprocessor) {
-      /* Append all possible non-preprocessor token to the result. */
-      if (token_length != 0) {
-        result.append(source, token_start, token_length);
-        token_start = index;
-        token_length = 0;
-      }
-      inside_preprocessor = true;
-    }
-    if (inside_preprocessor) {
-      preprocessor_line += ch;
-    }
-    else {
-      ++token_length;
-    }
-    ++index;
-    ++column_number;
-  }
-  /* Append possible tokens which happened before special events handled
-   * above.
-   */
-  if (token_length != 0) {
-    result.append(source, token_start, token_length);
-  }
-  if (inside_preprocessor) {
-    result += path_source_handle_preprocessor(
-        preprocessor_line, source_filepath, line_number, state);
-  }
-  /* Store result for further reuse. */
-  state->processed_files[source_filepath] = result;
-  return result;
-}
-
-string path_source_replace_includes(const string &source,
-                                    const string &path,
-                                    const string &source_filename)
-{
-  SourceReplaceState state;
-  state.base = path;
-  return path_source_replace_includes_recursive(source, path_join(path, source_filename), &state);
-}
-
 FILE *path_fopen(const string &path, const string &mode)
 {
 #ifdef _WIN32