Cycles: add colorspace manager class and utilities based on OpenColorIO

This is the groundwork for supporting loading image textures with arbitrary
color spaces through OpenColorIO.

Initial patch by Lukas, completed by Brecht.

Differential Revision: https://developer.blender.org/D3491

1 files changed, 65 insertions, 0 deletions

diff --git a/intern/cycles/render/colorspace.h b/intern/cycles/render/colorspace.h
new file mode 100644
index 00000000000..e7c7f943c2d
--- /dev/null
+++ b/intern/cycles/render/colorspace.h
@@ -0,0 +1,65 @@
+/*
+ * Copyright 2011-2013 Blender Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __COLORSPACE_H__
+#define __COLORSPACE_H__
+
+#include "util/util_map.h"
+#include "util/util_param.h"
+
+CCL_NAMESPACE_BEGIN
+
+extern ustring u_colorspace_auto;
+extern ustring u_colorspace_raw;
+extern ustring u_colorspace_srgb;
+
+class ColorSpaceProcessor;
+
+class ColorSpaceManager {
+ public:
+  /* Convert used specified colorspace to a colorspace that we are able to
+   * convert to and from. If the colorspace is u_colorspace_auto, we auto
+   * detect a colospace. */
+  static ustring detect_known_colorspace(ustring colorspace,
+                                         const char *file_format,
+                                         bool is_float);
+
+  /* Convert pixels in the specified colorspace to scene linear color for
+   * rendering. Must be a colorspace returned from detect_known_colorspace. */
+  template<typename T>
+  static void to_scene_linear(ustring colorspace,
+                              T *pixels,
+                              size_t width,
+                              size_t height,
+                              size_t depth,
+                              bool compress_as_srgb);
+
+  /* Efficiently convert pixels to scene linear colorspace at render time,
+   * for OSL where the image texture cache contains original pixels. The
+   * handle is valid for the lifetime of the application. */
+  static ColorSpaceProcessor *get_processor(ustring colorspace);
+  static void to_scene_linear(ColorSpaceProcessor *processor, float *pixel, int channels);
+
+  /* Clear memory when the application exits. Invalidates all processors. */
+  static void free_memory();
+
+ private:
+  static void is_builtin_colorspace(ustring colorspace, bool &is_no_op, bool &is_srgb);
+};
+
+CCL_NAMESPACE_END
+
+#endif /* __COLORSPACE_H__ */