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, 10 insertions, 2 deletions

diff --git a/intern/cycles/util/util_string.h b/intern/cycles/util/util_string.h
index f2272819b2f..55462cfd8b8 100644
--- a/intern/cycles/util/util_string.h
+++ b/intern/cycles/util/util_string.h
@@ -21,6 +21,11 @@
 #include <string.h>
 #include <string>
 
+/* Use string view implementation from OIIO.
+ * Ideally, need to switch to `std::string_view`, but this first requires getting rid of using
+ * namespace OIIO as it causes symbol collision. */
+#include <OpenImageIO/string_view.h>
+
 #include "util/util_vector.h"
 
 CCL_NAMESPACE_BEGIN
@@ -31,6 +36,8 @@ using std::string;
 using std::stringstream;
 using std::to_string;
 
+using OIIO::string_view;
+
 #ifdef __GNUC__
 #  define PRINTF_ATTRIBUTE __attribute__((format(printf, 1, 2)))
 #else
@@ -45,12 +52,13 @@ void string_split(vector<string> &tokens,
                   const string &separators = "\t ",
                   bool skip_empty_tokens = true);
 void string_replace(string &haystack, const string &needle, const string &other);
-bool string_startswith(const string &s, const char *start);
-bool string_endswith(const string &s, const string &end);
+bool string_startswith(string_view s, string_view start);
+bool string_endswith(string_view s, string_view end);
 string string_strip(const string &s);
 string string_remove_trademark(const string &s);
 string string_from_bool(const bool var);
 string to_string(const char *str);
+string string_to_lower(const string &s);
 
 /* Wide char strings are only used on Windows to deal with non-ASCII
  * characters in file names and such. No reason to use such strings