Workbench: StudioLight HDRI's

The Studio lights are now loaded from disk. The location is
`datafiles/studiolights` they need to be JPG for now. JPG cannot store
HDRI color range but they are clamped inside the Workbench
engine for speed reason. I didn't select JP2K as it might not be
enabled.

Users can add upto 20 HDRI files. This limitation is inside the
RNA_space.c Currently the icons are calculated when you first open the
selection box for the HDRI's. We could add them to a background
rendering later.

I added 2 test files a sky texture rendered in Cycles and an HDRI from
cloud.blender.org.

5 files changed, 387 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_icons.h b/source/blender/blenkernel/BKE_icons.h
index 766704b8f9c..e54531bdb0e 100644
--- a/source/blender/blenkernel/BKE_icons.h
+++ b/source/blender/blenkernel/BKE_icons.h
@@ -43,6 +43,7 @@ enum {
 	ICON_DATA_PREVIEW,
 	/** 2D triangles: obj is #Icon_Geom */
 	ICON_DATA_GEOM,
+	ICON_DATA_STUDIOLIGHT,
 };
 
 struct Icon {
@@ -77,6 +78,7 @@ typedef struct Icon Icon;
 struct ImBuf;
 struct PreviewImage;
 struct ID;
+struct StudioLight;
 
 enum eIconSizes;
 
@@ -158,6 +160,8 @@ struct ImBuf *BKE_icon_geom_rasterize(
         const struct Icon_Geom *geom,
         const unsigned int size_x, const unsigned int size_y);
 
+int BKE_icon_ensure_studio_light(struct StudioLight *sl);
+
 #define ICON_RENDER_DEFAULT_HEIGHT 32
 
 #endif /*  __BKE_ICONS_H__ */
diff --git a/source/blender/blenkernel/BKE_studiolight.h b/source/blender/blenkernel/BKE_studiolight.h
new file mode 100644
index 00000000000..c65e9050157
--- /dev/null
+++ b/source/blender/blenkernel/BKE_studiolight.h
@@ -0,0 +1,73 @@
+/*
+ * ***** 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) 2006-2007 Blender Foundation.
+ * All rights reserved.
+ *
+ * The Original Code is: all of this file.
+ *
+ * Contributor(s): none yet.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+#ifndef __BKE_STUDIOLIGHT_H__
+#define __BKE_STUDIOLIGHT_H__
+
+/** \file BKE_studiolight.h
+ *  \ingroup bke
+ *
+ * Studio lighting for the 3dview
+ */
+
+#include "BLI_sys_types.h"
+
+#include "DNA_space_types.h"
+
+#define STUDIOLIGHT_X_POS 0
+#define STUDIOLIGHT_X_NEG 1
+#define STUDIOLIGHT_Y_POS 2
+#define STUDIOLIGHT_Y_NEG 3
+#define STUDIOLIGHT_Z_POS 4
+#define STUDIOLIGHT_Z_NEG 5
+
+enum StudioLightFlag
+{
+	STUDIOLIGHT_DIFFUSE_LIGHT_CALCULATED = (1 << 0),
+	STUDIOLIGHT_EXTERNAL_FILE            = (1 << 1),
+} StudioLightFlag;
+
+typedef struct StudioLight
+{
+	struct StudioLight *next, *prev;
+	int flag;
+	char name[FILE_MAXFILE];
+	char path[FILE_MAX];
+	int icon_id;
+	int index;
+	float diffuse_light[6][3];
+} StudioLight;
+
+void BKE_studiolight_init(void);
+void BKE_studiolight_free(void);
+struct StudioLight *BKE_studiolight_find(const char* name);
+struct StudioLight *BKE_studiolight_findindex(int index);
+unsigned int *BKE_studiolight_preview(StudioLight *sl, int icon_size);
+const struct ListBase *BKE_studiolight_listbase(void);
+void BKE_studiolight_ensure_flag(StudioLight *sl, int flag);
+
+#endif /*  __BKE_STUDIOLIGHT_H__ */
diff --git a/source/blender/blenkernel/CMakeLists.txt b/source/blender/blenkernel/CMakeLists.txt
index 37e08cedb10..d5ce6f2f94d 100644
--- a/source/blender/blenkernel/CMakeLists.txt
+++ b/source/blender/blenkernel/CMakeLists.txt
@@ -185,6 +185,7 @@ set(SRC
 	intern/softbody.c
 	intern/sound.c
 	intern/speaker.c
+	intern/studiolight.c
 	intern/subsurf_ccg.c
 	intern/suggestions.c
 	intern/text.c
@@ -303,6 +304,7 @@ set(SRC
 	BKE_softbody.h
 	BKE_sound.h
 	BKE_speaker.h
+	BKE_studiolight.h
 	BKE_subsurf.h
 	BKE_suggestions.h
 	BKE_text.h
diff --git a/source/blender/blenkernel/intern/icons.c b/source/blender/blenkernel/intern/icons.c
index f1f343faac8..61c05c2500d 100644
--- a/source/blender/blenkernel/intern/icons.c
+++ b/source/blender/blenkernel/intern/icons.c
@@ -56,6 +56,7 @@
 
 #include "BKE_icons.h"
 #include "BKE_global.h" /* only for G.background test */
+#include "BKE_studiolight.h"
 
 #include "BLI_sys_types.h" // for intptr_t support
 
@@ -802,3 +803,13 @@ struct Icon_Geom *BKE_icon_geom_from_file(const char *filename)
 }
 
 /** \} */
+
+/** \name Studio Light Icon
+ * \{ */
+int BKE_icon_ensure_studio_light(struct StudioLight *sl) {
+	int icon_id = get_next_free_id();
+	icon_create(icon_id, ICON_DATA_STUDIOLIGHT, sl);
+	return icon_id;
+}
+/** \} */
+
diff --git a/source/blender/blenkernel/intern/studiolight.c b/source/blender/blenkernel/intern/studiolight.c
new file mode 100644
index 00000000000..9bc678a1820
--- /dev/null
+++ b/source/blender/blenkernel/intern/studiolight.c
@@ -0,0 +1,297 @@
+/*
+ * ***** 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) 2006-2007 Blender Foundation.
+ * All rights reserved.
+ *
+ * The Original Code is: all of this file.
+ *
+ * Contributor(s): none yet.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ *
+ */
+
+/** \file blender/blenkernel/intern/studiolight.c
+ *  \ingroup bke
+ */
+
+#include "BKE_studiolight.h"
+
+#include "BKE_appdir.h"
+#include "BKE_icons.h"
+
+#include "BLI_fileops.h"
+#include "BLI_fileops_types.h"
+#include "BLI_listbase.h"
+#include "BLI_math.h"
+#include "BLI_path_util.h"
+#include "BLI_string.h"
+
+#include "DNA_listBase.h"
+
+#include "IMB_imbuf.h"
+#include "IMB_imbuf_types.h"
+
+#include "MEM_guardedalloc.h"
+
+
+/* Statics */
+static ListBase studiolights;
+static const char *STUDIO_LIGHT_FOLDER = "studiolights/";
+
+/* FUNCTIONS */
+static void studiolight_free(struct StudioLight *sl)
+{
+	MEM_freeN(sl);
+}
+
+static struct StudioLight *studiolight_create(void)
+{
+	struct StudioLight *sl = MEM_callocN(sizeof(*sl), __func__);
+	sl->path[0] = 0x00;
+	sl->name[0] = 0x00;
+	sl->flag = 0;
+	sl->index = BLI_listbase_count(&studiolights);
+	sl->icon_id = BKE_icon_ensure_studio_light(sl);
+	return sl;
+}
+
+static void direction_to_equirectangular(float r[2], const float dir[3])
+{
+	r[0] = (atan2f(dir[1], dir[0]) - M_PI) / -(M_PI * 2);
+	r[1] = (acosf(dir[2] / 1.0) - M_PI) / -M_PI;
+}
+
+static void studiolight_calculate_directional_diffuse_light(ImBuf *ibuf, float color[4], const float start[3], const float v1[3], const float v2[3], int steps)
+{
+	float uv[2];
+	float dir[3];
+	float col[4];
+	float v11[3];
+	float v12[3];
+	float totcol[4];
+
+	zero_v4(totcol);
+	for (int x = 0; x < steps ; x++) {
+		float xf = (float)x / (float)steps;
+		mul_v3_v3fl(v11, v1, xf);
+		for (int y = 0; y < steps; y++) {
+			float yf = (float)y / (float)steps;
+			/* start + x/steps*v1 + y/steps*v2 */
+			mul_v3_v3fl(v12, v2, yf);
+			add_v3_v3v3(dir, start, v11);
+			add_v3_v3(dir, v12);
+			/* normalize */
+			normalize_v3(dir);
+
+			/* sample */
+			direction_to_equirectangular(uv, dir);
+			nearest_interpolation_color_wrap(ibuf, NULL, col, uv[0] * ibuf->x, uv[1] * ibuf->y);
+			add_v3_v3(totcol, col);
+		}
+	}
+	mul_v3_v3fl(color, totcol, 1.0/(steps*steps));
+}
+
+static void studiolight_calculate_diffuse_light(StudioLight *sl)
+{
+	const int steps = 16;
+	float start[3];
+	float v1[3];
+	float v2[3];
+
+	/* init light to black */
+	copy_v3_fl(sl->diffuse_light[STUDIOLIGHT_X_POS], 0.0f);
+	copy_v3_fl(sl->diffuse_light[STUDIOLIGHT_X_NEG], 0.0f);
+	copy_v3_fl(sl->diffuse_light[STUDIOLIGHT_Y_POS], 0.0f);
+	copy_v3_fl(sl->diffuse_light[STUDIOLIGHT_Y_NEG], 0.0f);
+	copy_v3_fl(sl->diffuse_light[STUDIOLIGHT_Z_POS], 0.0f);
+	copy_v3_fl(sl->diffuse_light[STUDIOLIGHT_Z_NEG], 0.0f);
+
+	if (sl->flag &= STUDIOLIGHT_EXTERNAL_FILE) {
+		ImBuf* ibuf = NULL;
+		ibuf = IMB_loadiffname(sl->path, 0, NULL);
+		if (ibuf) {
+			IMB_float_from_rect(ibuf);
+
+			copy_v3_fl3(start, -1.0f, -1.0f, -1.0f);
+			copy_v3_fl3(v1, 0.0f, 2.0f, 0.0f);
+			copy_v3_fl3(v2, 0.0f, 0.0f, 2.0f);
+			studiolight_calculate_directional_diffuse_light(ibuf, sl->diffuse_light[STUDIOLIGHT_Z_NEG], start, v1, v2, steps);
+			copy_v3_fl3(start, 1.0f, -1.0f, -1.0f);
+			studiolight_calculate_directional_diffuse_light(ibuf, sl->diffuse_light[STUDIOLIGHT_Z_POS], start, v1, v2, steps);
+
+			copy_v3_fl3(start, -1.0f, -1.0f, -1.0f);
+			copy_v3_fl3(v1, 2.0f, 0.0f, 0.0f);
+			copy_v3_fl3(v2, 0.0f, 0.0f, 2.0f);
+			studiolight_calculate_directional_diffuse_light(ibuf, sl->diffuse_light[STUDIOLIGHT_X_POS], start, v1, v2, steps);
+			copy_v3_fl3(start, -1.0f, 1.0f, -1.0f);
+			studiolight_calculate_directional_diffuse_light(ibuf, sl->diffuse_light[STUDIOLIGHT_X_NEG], start, v1, v2, steps);
+
+			copy_v3_fl3(start, -1.0f, -1.0f, -1.0f);
+			copy_v3_fl3(v1, 2.0f, 0.0f, 0.0f);
+			copy_v3_fl3(v2, 0.0f, 2.0f, 0.0f);
+			studiolight_calculate_directional_diffuse_light(ibuf, sl->diffuse_light[STUDIOLIGHT_Y_NEG], start, v1, v2, steps);
+			copy_v3_fl3(start, -1.0f, -1.0f, 1.0f);
+			studiolight_calculate_directional_diffuse_light(ibuf, sl->diffuse_light[STUDIOLIGHT_Y_POS], start, v1, v2, steps);
+
+			IMB_freeImBuf(ibuf);
+		}
+	}
+	sl->flag |= STUDIOLIGHT_DIFFUSE_LIGHT_CALCULATED;
+}
+
+
+/* API */
+void BKE_studiolight_init(void)
+{
+	StudioLight *sl;
+	/* go over the preset folder and add a studiolight for every image with its path */
+	/* order studio lights by name */
+	/* Also reserve icon space for it. */
+	/* Add default studio light */
+	sl = studiolight_create();
+	BLI_strncpy(sl->name, "INTERNAL_01\0", FILE_MAXFILE);
+	sl->flag = STUDIOLIGHT_DIFFUSE_LIGHT_CALCULATED;
+	copy_v3_fl(sl->diffuse_light[STUDIOLIGHT_X_POS], 0.0f);
+	copy_v3_fl(sl->diffuse_light[STUDIOLIGHT_X_NEG], 0.0f);
+	copy_v3_fl(sl->diffuse_light[STUDIOLIGHT_Y_POS], 0.0f);
+	copy_v3_fl(sl->diffuse_light[STUDIOLIGHT_Y_NEG], 0.0f);
+	copy_v3_fl(sl->diffuse_light[STUDIOLIGHT_Z_POS], 1.0f);
+	copy_v3_fl(sl->diffuse_light[STUDIOLIGHT_Z_NEG], 0.0f);
+	BLI_addtail(&studiolights, sl);
+
+	struct direntry *dir;
+	const char *folder = BKE_appdir_folder_id(BLENDER_DATAFILES, STUDIO_LIGHT_FOLDER);
+	unsigned int totfile = BLI_filelist_dir_contents(folder, &dir);
+	int i;
+	for (i = 0; i < totfile; i++) {
+		if ((dir[i].type & S_IFREG)) {
+			const char *filename = dir[i].relname;
+			const char *path = dir[i].path;
+			if (BLI_testextensie(filename, ".jpg")) {
+				sl = studiolight_create();
+				sl->flag = STUDIOLIGHT_EXTERNAL_FILE;
+				BLI_strncpy(sl->name, filename, FILE_MAXFILE);
+				BLI_strncpy(sl->path, path, FILE_MAXFILE);
+				BLI_addtail(&studiolights, sl);
+			}
+		}
+	}
+	BLI_filelist_free(dir, totfile);
+	dir = NULL;
+}
+
+void BKE_studiolight_free(void)
+{
+	struct StudioLight *sl;
+	while((sl = (StudioLight*)BLI_pophead(&studiolights)))
+	{
+		studiolight_free(sl);
+	}
+}
+
+struct StudioLight *BKE_studiolight_find(const char* name)
+{
+	LISTBASE_FOREACH(StudioLight *, sl, &studiolights) {
+		if (STREQLEN(sl->name, name, FILE_MAXFILE)) {
+			return sl;
+		}
+	}
+	/* When not found, use the default studio light */
+	return (StudioLight*)studiolights.first;
+}
+
+struct StudioLight *BKE_studiolight_findindex(int index)
+{
+	LISTBASE_FOREACH(StudioLight *, sl, &studiolights) {
+		if (sl->index == index) {
+			return sl;
+		}
+	}
+	/* When not found, use the default studio light */
+	return (StudioLight*)studiolights.first;
+}
+
+const struct ListBase *BKE_studiolight_listbase(void)
+{
+	return &studiolights;
+}
+
+unsigned int *BKE_studiolight_preview(StudioLight *sl, int icon_size)
+{
+	BKE_studiolight_ensure_flag(sl, STUDIOLIGHT_DIFFUSE_LIGHT_CALCULATED);
+
+	uint *rect = MEM_mallocN(icon_size * icon_size * sizeof(uint), __func__);
+	int icon_center = icon_size / 2;
+	float sphere_radius = icon_center * 0.9;
+
+	int offset = 0;
+	for (int y = 0; y < icon_size; y++) {
+		float dy = y - icon_center;
+		for (int x = 0; x < icon_size; x++) {
+			float dx = x - icon_center;
+			/* calculate aliasing */
+			float alias = 0;
+			const float alias_step = 0.333;
+			for (float ay = dy - 0.5; ay < dy + 0.5; ay += alias_step) {
+				for (float ax = dx - 0.5; ax < dx + 0.5; ax += alias_step) {
+					if (sqrt(ay * ay + ax * ax) < sphere_radius) {
+						alias += alias_step * alias_step;
+					}
+				}
+			}
+			uint pixelresult = 0x0;
+			uint alias_i = clamp_i(alias * 256, 0, 255);
+			if (alias_i != 0) {
+				/* calculate normal */
+				uint alias_mask = alias_i << 24;
+				float normal[3];
+				normal[0] = dx / sphere_radius;
+				normal[1] = dy / sphere_radius;
+				normal[2] = sqrt(-(normal[0] * normal[0]) - (normal[1] * normal[1]) + 1);
+				normalize_v3(normal);
+
+				float color[3];
+				mul_v3_v3fl(color, sl->diffuse_light[STUDIOLIGHT_X_POS], clamp_f(normal[0], 0.0, 1.0));
+				interp_v3_v3v3(color, color, sl->diffuse_light[STUDIOLIGHT_X_NEG], clamp_f(-normal[0], 0.0, 1.0));
+				interp_v3_v3v3(color, color, sl->diffuse_light[STUDIOLIGHT_Y_POS], clamp_f(normal[1], 0.0, 1.0));
+				interp_v3_v3v3(color, color, sl->diffuse_light[STUDIOLIGHT_Y_NEG], clamp_f(-normal[1], 0.0, 1.0));
+				interp_v3_v3v3(color, color, sl->diffuse_light[STUDIOLIGHT_Z_POS], clamp_f(normal[2], 0.0, 1.0));
+
+				pixelresult = rgb_to_cpack(
+				        linearrgb_to_srgb(color[0]),
+				        linearrgb_to_srgb(color[1]),
+				        linearrgb_to_srgb(color[2])) | alias_mask;
+			}
+			rect[offset++] = pixelresult;
+		}
+	}
+	return rect;
+}
+
+void BKE_studiolight_ensure_flag(StudioLight *sl, int flag)
+{
+	if (sl->flag & flag){
+		return;
+	}
+
+	if ((flag & STUDIOLIGHT_DIFFUSE_LIGHT_CALCULATED)) {
+		studiolight_calculate_diffuse_light(sl);
+	}
+}