ImBuf: Make luminance calculation inlined

Title actually tells it all, it is rather simple function which totally makes
sense to be inlined.

This gives up to 5% of speedup when updating scopes for a large image.

Reviewers: campbellbarton

Differential Revision: https://developer.blender.org/D1310

5 files changed, 82 insertions, 32 deletions

diff --git a/source/blender/imbuf/CMakeLists.txt b/source/blender/imbuf/CMakeLists.txt
index c95f0abf3ca..abbc5a09040 100644
--- a/source/blender/imbuf/CMakeLists.txt
+++ b/source/blender/imbuf/CMakeLists.txt
@@ -46,6 +46,7 @@ set(SRC
 	intern/bmp.c
 	intern/cache.c
 	intern/colormanagement.c
+	intern/colormanagement_inline.c
 	intern/divers.c
 	intern/filetype.c
 	intern/filter.c
@@ -187,4 +188,10 @@ if(WIN32)
 	)
 endif()
 
+# no need to compile object files for inline headers.
+set_source_files_properties(
+	intern/colormanagement_inline.c
+	PROPERTIES HEADER_FILE_ONLY TRUE
+)
+
 blender_add_lib(bf_imbuf "${SRC}" "${INC}" "${INC_SYS}")
diff --git a/source/blender/imbuf/IMB_colormanagement.h b/source/blender/imbuf/IMB_colormanagement.h
index 59df8334099..ab822f1cd55 100644
--- a/source/blender/imbuf/IMB_colormanagement.h
+++ b/source/blender/imbuf/IMB_colormanagement.h
@@ -36,9 +36,11 @@
  */
 
 #include "BLI_sys_types.h"
+#include "BLI_compiler_compat.h"
 
 #define BCM_CONFIG_FILE "config.ocio"
 
+
 struct bContext;
 struct ColorManagedColorspaceSettings;
 struct ColorManagedDisplaySettings;
@@ -67,8 +69,8 @@ void IMB_colormanagement_assign_rect_colorspace(struct ImBuf *ibuf, const char *
 const char *IMB_colormanagement_get_float_colorspace(struct ImBuf *ibuf);
 const char *IMB_colormanagement_get_rect_colorspace(struct ImBuf *ibuf);
 
-float IMB_colormanagement_get_luminance(const float rgb[3]);
-unsigned char IMB_colormanagement_get_luminance_byte(const unsigned char[3]);
+BLI_INLINE float IMB_colormanagement_get_luminance(const float rgb[3]);
+BLI_INLINE unsigned char IMB_colormanagement_get_luminance_byte(const unsigned char[3]);
 
 /* ** Color space transformation functions ** */
 void IMB_colormanagement_transform(float *buffer, int width, int height, int channels,
@@ -206,4 +208,6 @@ enum {
 	COLOR_ROLE_DEFAULT_FLOAT,
 };
 
+#include "intern/colormanagement_inline.c"
+
 #endif  /* __IMB_COLORMANAGEMENT_H__ */
diff --git a/source/blender/imbuf/intern/IMB_colormanagement_intern.h b/source/blender/imbuf/intern/IMB_colormanagement_intern.h
index 710e70937e6..b75f12b239d 100644
--- a/source/blender/imbuf/intern/IMB_colormanagement_intern.h
+++ b/source/blender/imbuf/intern/IMB_colormanagement_intern.h
@@ -41,6 +41,8 @@
 struct OCIO_ConstProcessorRcPtr;
 struct ImBuf;
 
+extern float imbuf_luma_coefficients[3];
+
 #define MAX_COLORSPACE_NAME          64
 #define MAX_COLORSPACE_DESCRIPTION  512
 
diff --git a/source/blender/imbuf/intern/colormanagement.c b/source/blender/imbuf/intern/colormanagement.c
index 5a3d9b4c653..e4e93d3c4da 100644
--- a/source/blender/imbuf/intern/colormanagement.c
+++ b/source/blender/imbuf/intern/colormanagement.c
@@ -93,7 +93,7 @@ static int global_tot_looks = 0;
 /* Set to ITU-BT.709 / sRGB primaries weight. Brute force stupid, but only
  * option with no colormanagement in place.
  */
-static float luma_coefficients[3] = { 0.2126f, 0.7152f, 0.0722f };
+float imbuf_luma_coefficients[3] = { 0.2126f, 0.7152f, 0.0722f };
 
 /* lock used by pre-cached processors getters, so processor wouldn't
  * be created several times
@@ -552,7 +552,7 @@ static void colormanage_load_config(OCIO_ConstConfigRcPtr *config)
 	}
 
 	/* Load luminance coefficients. */
-	OCIO_configGetDefaultLumaCoefs(config, luma_coefficients);
+	OCIO_configGetDefaultLumaCoefs(config, imbuf_luma_coefficients);
 }
 
 static void colormanage_free_config(void)
@@ -1230,34 +1230,6 @@ const char *IMB_colormanagement_get_rect_colorspace(ImBuf *ibuf)
 	return ibuf->rect_colorspace->name;
 }
 
-/* Convert a float RGB triplet to the correct luminance weighted average.
- *
- * Grayscale, or Luma is a distillation of RGB data values down to a weighted average
- * based on the luminance positions of the red, green, and blue primaries.
- * Given that the internal reference space may be arbitrarily set, any
- * effort to glean the luminance coefficients must be aware of the reference
- * space primaries.
- *
- * See http://wiki.blender.org/index.php/User:Nazg-gul/ColorManagement#Luminance
- */
-
-float IMB_colormanagement_get_luminance(const float rgb[3])
-{
-	return dot_v3v3(luma_coefficients, rgb);
-}
-
-/* Byte equivalent of IMB_colormanagement_get_luminance(). */
-unsigned char IMB_colormanagement_get_luminance_byte(const unsigned char rgb[3])
-{
-	float rgbf[3];
-	float val;
-
-	rgb_uchar_to_float(rgbf, rgb);
-	val = dot_v3v3(luma_coefficients, rgbf);
-
-	return FTOCHAR(val);
-}
-
 /*********************** Threaded display buffer transform routines *************************/
 
 typedef struct DisplayBufferThread {
diff --git a/source/blender/imbuf/intern/colormanagement_inline.c b/source/blender/imbuf/intern/colormanagement_inline.c
new file mode 100644
index 00000000000..8382e2a9bfa
--- /dev/null
+++ b/source/blender/imbuf/intern/colormanagement_inline.c
@@ -0,0 +1,65 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * 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) 2015 by Blender Foundation.
+ * All rights reserved.
+ *
+ * Contributor(s): Sergey Sharybin
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ *
+ */
+
+/** \file blender/imbuf/intern/colormanagement_inline.c
+ *  \ingroup imbuf
+ */
+
+#ifndef __IMB_COLORMANAGEMENT_INLINE_C__
+#define __IMB_COLORMANAGEMENT_INLINE_C__
+
+#include "IMB_colormanagement_intern.h"
+#include "BLI_math_vector.h"
+
+/* Convert a float RGB triplet to the correct luminance weighted average.
+ *
+ * Grayscale, or Luma is a distillation of RGB data values down to a weighted average
+ * based on the luminance positions of the red, green, and blue primaries.
+ * Given that the internal reference space may be arbitrarily set, any
+ * effort to glean the luminance coefficients must be aware of the reference
+ * space primaries.
+ *
+ * See http://wiki.blender.org/index.php/User:Nazg-gul/ColorManagement#Luminance
+ */
+
+float IMB_colormanagement_get_luminance(const float rgb[3])
+{
+	return dot_v3v3(imbuf_luma_coefficients, rgb);
+}
+
+/* Byte equivalent of IMB_colormanagement_get_luminance(). */
+unsigned char IMB_colormanagement_get_luminance_byte(const unsigned char rgb[3])
+{
+	float rgbf[3];
+	float val;
+
+	rgb_uchar_to_float(rgbf, rgb);
+	val = dot_v3v3(imbuf_luma_coefficients, rgbf);
+
+	return FTOCHAR(val);
+}
+
+#endif  /* __IMB_COLORMANAGEMENT_INLINE_H__ */