Units: add support for light power units in Watt. Use for Eevee lights.

This affects point, spot and area lights. Sun light strength remains without
a unit. This change does not affect .blend file compatibility in any way, as
with the rest of the unit system it's purely a display and editing feature.

Not used for Cycles yet, that will be done after unifying the settings with
Eevee.

9 files changed, 66 insertions, 20 deletions

diff --git a/source/blender/blenkernel/BKE_unit.h b/source/blender/blenkernel/BKE_unit.h
index 8fb7c41ad55..4a6f8a63d5d 100644
--- a/source/blender/blenkernel/BKE_unit.h
+++ b/source/blender/blenkernel/BKE_unit.h
@@ -77,7 +77,8 @@ enum {
 	B_UNIT_VELOCITY         = 7,
 	B_UNIT_ACCELERATION     = 8,
 	B_UNIT_CAMERA           = 9,
-	B_UNIT_TYPE_TOT         = 10,
+	B_UNIT_POWER            = 10,
+	B_UNIT_TYPE_TOT         = 11,
 };
 
 #ifdef __cplusplus
diff --git a/source/blender/blenkernel/intern/scene.c b/source/blender/blenkernel/intern/scene.c
index 432538f96ff..0ce17573caf 100644
--- a/source/blender/blenkernel/intern/scene.c
+++ b/source/blender/blenkernel/intern/scene.c
@@ -1801,6 +1801,7 @@ double BKE_scene_unit_scale(const UnitSettings *unit, const int unit_type, doubl
 		case B_UNIT_LENGTH:
 			return value * (double)unit->scale_length;
 		case B_UNIT_AREA:
+		case B_UNIT_POWER:
 			return value * pow(unit->scale_length, 2);
 		case B_UNIT_VOLUME:
 			return value * pow(unit->scale_length, 3);
diff --git a/source/blender/blenkernel/intern/unit.c b/source/blender/blenkernel/intern/unit.c
index 241a8327190..369bf2e1389 100644
--- a/source/blender/blenkernel/intern/unit.c
+++ b/source/blender/blenkernel/intern/unit.c
@@ -299,13 +299,25 @@ static struct bUnitDef buCameraLenDef[] = {
 };
 static struct bUnitCollection buCameraLenCollection = {buCameraLenDef, 3, 0, UNIT_COLLECTION_LENGTH(buCameraLenDef)};
 
+/* (Light) Power */
+static struct bUnitDef buPowerDef[] = {
+	{"gigawatt",  "gigawatts",  "GW", NULL, "Gigawatts",  NULL, 1e9f,  0.0, B_UNIT_DEF_NONE},
+	{"megawatt",  "megawatts",  "MW", NULL, "Megawatts",  NULL, 1e6f,  0.0, B_UNIT_DEF_NONE},
+	{"kilowatt",  "kilowatts",  "kW", NULL, "Kilowatts",  NULL, 1e3f,  0.0, B_UNIT_DEF_SUPPRESS},
+	{"watt",      "watts",      "W",  NULL, "Watts",      NULL, 1.0f,  0.0, B_UNIT_DEF_NONE},
+	{"milliwatt", "milliwatts", "mW", NULL, "Milliwatts", NULL, 1e-3f, 0.0, B_UNIT_DEF_NONE},
+	{"microwatt", "microwatts", "µW", "uW", "Microwatts", NULL, 1e-6f, 0.0, B_UNIT_DEF_NONE},
+	{"nanowatt",  "nanowatts",  "nW", NULL, "Nannowatts", NULL, 1e-9f, 0.0, B_UNIT_DEF_NONE},
+};
+static struct bUnitCollection buPowerCollection = {buPowerDef, 3, 0, UNIT_COLLECTION_LENGTH(buPowerDef)};
+
 
 #define UNIT_SYSTEM_TOT (((sizeof(bUnitSystems) / B_UNIT_TYPE_TOT) / sizeof(void *)) - 1)
 static const struct bUnitCollection *bUnitSystems[][B_UNIT_TYPE_TOT] = {
-	{NULL, NULL, NULL, NULL, NULL, &buNaturalRotCollection, &buNaturalTimeCollection, NULL, NULL, NULL},
-	{NULL, &buMetricLenCollection, &buMetricAreaCollection, &buMetricVolCollection, &buMetricMassCollection, &buNaturalRotCollection, &buNaturalTimeCollection, &buMetricVelCollection, &buMetricAclCollection, &buCameraLenCollection}, /* metric */
-	{NULL, &buImperialLenCollection, &buImperialAreaCollection, &buImperialVolCollection, &buImperialMassCollection, &buNaturalRotCollection, &buNaturalTimeCollection, &buImperialVelCollection, &buImperialAclCollection, &buCameraLenCollection}, /* imperial */
-	{NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
+	{NULL, NULL, NULL, NULL, NULL, &buNaturalRotCollection, &buNaturalTimeCollection, NULL, NULL, NULL, NULL},
+	{NULL, &buMetricLenCollection, &buMetricAreaCollection, &buMetricVolCollection, &buMetricMassCollection, &buNaturalRotCollection, &buNaturalTimeCollection, &buMetricVelCollection, &buMetricAclCollection, &buCameraLenCollection, &buPowerCollection}, /* metric */
+	{NULL, &buImperialLenCollection, &buImperialAreaCollection, &buImperialVolCollection, &buImperialMassCollection, &buNaturalRotCollection, &buNaturalTimeCollection, &buImperialVelCollection, &buImperialAclCollection, &buCameraLenCollection, &buPowerCollection}, /* imperial */
+	{NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL},
 };
 
 
@@ -570,7 +582,8 @@ static const char *unit_find_str(const char *str, const char *substr)
 {
 	if (substr && substr[0] != '\0') {
 		while (true) {
-			const char *str_found = strstr(str, substr);
+			/* Unit detection is case insensitive. */
+			const char *str_found = BLI_strcasestr(str, substr);
 
 			if (str_found) {
 				/* Previous char cannot be a letter. */
@@ -774,7 +787,7 @@ bool bUnit_ReplaceString(char *str, int len_max, const char *str_prev, double sc
 	char str_tmp[TEMP_STR_SIZE];
 	bool changed = false;
 
-	/* make lowercase */
+	/* Convert to lowercase, to make unit detection case insensitive. */
 	BLI_str_tolower_ascii(str, len_max);
 
 	/* Try to find a default unit from current or previous string. */
diff --git a/source/blender/makesrna/RNA_types.h b/source/blender/makesrna/RNA_types.h
index 1742e8b8795..a02bf644620 100644
--- a/source/blender/makesrna/RNA_types.h
+++ b/source/blender/makesrna/RNA_types.h
@@ -90,6 +90,7 @@ typedef enum PropertyUnit {
 	PROP_UNIT_VELOCITY     = (7 << 16),   /* m/s */
 	PROP_UNIT_ACCELERATION = (8 << 16),   /* m/(s^2) */
 	PROP_UNIT_CAMERA       = (9 << 16),   /* mm */
+	PROP_UNIT_POWER        = (10 << 16),  /* W */
 } PropertyUnit;
 
 #define RNA_SUBTYPE_UNIT(subtype)       ((subtype) &  0x00FF0000)
@@ -146,6 +147,9 @@ typedef enum PropertySubType {
 	/* booleans */
 	PROP_LAYER             = 40,
 	PROP_LAYER_MEMBER      = 41,
+
+	/* light */
+	PROP_POWER             = 42 | PROP_UNIT_POWER,
 } PropertySubType;
 
 /* Make sure enums are updated with these */
diff --git a/source/blender/makesrna/intern/makesrna.c b/source/blender/makesrna/intern/makesrna.c
index 7230b65738b..df8911f425c 100644
--- a/source/blender/makesrna/intern/makesrna.c
+++ b/source/blender/makesrna/intern/makesrna.c
@@ -2579,6 +2579,7 @@ static const char *rna_property_subtypename(PropertySubType type)
 		case PROP_LAYER: return "PROP_LAYER";
 		case PROP_LAYER_MEMBER: return "PROP_LAYER_MEMBER";
 		case PROP_PASSWORD: return "PROP_PASSWORD";
+		case PROP_POWER: return "PROP_POWER";
 		default:
 		{
 			/* in case we don't have a type preset that includes the subtype */
@@ -2605,6 +2606,7 @@ static const char *rna_property_subtype_unit(PropertySubType type)
 		case PROP_UNIT_VELOCITY:     return "PROP_UNIT_VELOCITY";
 		case PROP_UNIT_ACCELERATION: return "PROP_UNIT_ACCELERATION";
 		case PROP_UNIT_CAMERA:       return "PROP_UNIT_CAMERA";
+		case PROP_UNIT_POWER:        return "PROP_UNIT_POWER";
 		default:                     return "PROP_UNIT_UNKNOWN";
 	}
 }
diff --git a/source/blender/makesrna/intern/rna_lamp.c b/source/blender/makesrna/intern/rna_lamp.c
index dc82e8b28f8..c15186399e7 100644
--- a/source/blender/makesrna/intern/rna_lamp.c
+++ b/source/blender/makesrna/intern/rna_lamp.c
@@ -137,12 +137,6 @@ static void rna_def_light(BlenderRNA *brna)
 	                         "Falloff distance - the light is at half the original intensity at this point");
 	RNA_def_property_update(prop, 0, "rna_Light_draw_update");
 
-	prop = RNA_def_property(srna, "energy", PROP_FLOAT, PROP_NONE);
-	RNA_def_property_float_default(prop, 10.0f);
-	RNA_def_property_ui_range(prop, 0, 1000000.0f, 1, 3);
-	RNA_def_property_ui_text(prop, "Energy", "Amount of light emitted");
-	RNA_def_property_update(prop, 0, "rna_Light_draw_update");
-
 	prop = RNA_def_property(srna, "color", PROP_FLOAT, PROP_COLOR);
 	RNA_def_property_float_sdna(prop, NULL, "r");
 	RNA_def_property_array(prop, 3);
@@ -187,6 +181,30 @@ static void rna_def_light(BlenderRNA *brna)
 	rna_def_animdata_common(srna);
 }
 
+static void rna_def_light_energy(StructRNA *srna, bool distant)
+{
+	PropertyRNA *prop;
+
+	if(distant) {
+		/* Distant light strength has no unit defined, it's proportional to
+		 * Watt/m^2 and is not sensitive to scene unit scale. */
+		prop = RNA_def_property(srna, "energy", PROP_FLOAT, PROP_NONE);
+		RNA_def_property_float_default(prop, 10.0f);
+		RNA_def_property_ui_range(prop, 0.0f, 10.0f, 1, 3);
+		RNA_def_property_ui_text(prop, "Strength", "Amount of light emitted");
+		RNA_def_property_update(prop, 0, "rna_Light_draw_update");
+	}
+	else {
+		/* Lights with a location have power in Watt, which is sensitive to
+		 * scene unit scale. */
+		prop = RNA_def_property(srna, "energy", PROP_FLOAT, PROP_POWER);
+		RNA_def_property_float_default(prop, 10.0f);
+		RNA_def_property_ui_range(prop, 0.0f, 1000000.0f, 1, 5);
+		RNA_def_property_ui_text(prop, "Power", "Amount of light emitted");
+		RNA_def_property_update(prop, 0, "rna_Light_draw_update");
+	}
+}
+
 static void rna_def_light_falloff(StructRNA *srna)
 {
 	PropertyRNA *prop;
@@ -245,7 +263,7 @@ static void rna_def_light_falloff(StructRNA *srna)
 	RNA_def_property_update(prop, 0, "rna_Light_draw_update");
 }
 
-static void rna_def_light_shadow(StructRNA *srna, int sun)
+static void rna_def_light_shadow(StructRNA *srna, bool sun)
 {
 	PropertyRNA *prop;
 
@@ -405,8 +423,9 @@ static void rna_def_point_light(BlenderRNA *brna)
 	RNA_def_struct_ui_text(srna, "Point Light", "Omnidirectional point Light");
 	RNA_def_struct_ui_icon(srna, ICON_LIGHT_POINT);
 
+	rna_def_light_energy(srna, false);
 	rna_def_light_falloff(srna);
-	rna_def_light_shadow(srna, 0);
+	rna_def_light_shadow(srna, false);
 }
 
 static void rna_def_area_light(BlenderRNA *brna)
@@ -427,7 +446,8 @@ static void rna_def_area_light(BlenderRNA *brna)
 	RNA_def_struct_ui_text(srna, "Area Light", "Directional area Light");
 	RNA_def_struct_ui_icon(srna, ICON_LIGHT_AREA);
 
-	rna_def_light_shadow(srna, 0);
+	rna_def_light_energy(srna, false);
+	rna_def_light_shadow(srna, false);
 	rna_def_light_falloff(srna);
 
 	prop = RNA_def_property(srna, "shape", PROP_ENUM, PROP_NONE);
@@ -464,8 +484,9 @@ static void rna_def_spot_light(BlenderRNA *brna)
 	RNA_def_struct_ui_text(srna, "Spot Light", "Directional cone Light");
 	RNA_def_struct_ui_icon(srna, ICON_LIGHT_SPOT);
 
+	rna_def_light_energy(srna, false);
 	rna_def_light_falloff(srna);
-	rna_def_light_shadow(srna, 0);
+	rna_def_light_shadow(srna, false);
 
 	prop = RNA_def_property(srna, "use_square", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "mode", LA_SQUARE);
@@ -502,7 +523,8 @@ static void rna_def_sun_light(BlenderRNA *brna)
 	RNA_def_struct_ui_text(srna, "Sun Light", "Constant direction parallel ray Light");
 	RNA_def_struct_ui_icon(srna, ICON_LIGHT_SUN);
 
-	rna_def_light_shadow(srna, 1);
+	rna_def_light_energy(srna, true);
+	rna_def_light_shadow(srna, true);
 }
 
 void RNA_def_light(BlenderRNA *brna)
diff --git a/source/blender/makesrna/intern/rna_rna.c b/source/blender/makesrna/intern/rna_rna.c
index 594d947b996..6af3e30f1ab 100644
--- a/source/blender/makesrna/intern/rna_rna.c
+++ b/source/blender/makesrna/intern/rna_rna.c
@@ -116,6 +116,7 @@ const EnumPropertyItem rna_enum_property_unit_items[] = {
 	{PROP_UNIT_ACCELERATION, "ACCELERATION", 0, "Acceleration", ""},
 	{PROP_UNIT_MASS, "MASS", 0, "Mass", ""},
 	{PROP_UNIT_CAMERA, "CAMERA", 0, "Camera", ""},
+	{PROP_UNIT_POWER, "POWER", 0, "Power", ""},
 	{0, NULL, 0, NULL, NULL},
 };
 
diff --git a/source/blender/python/intern/bpy_props.c b/source/blender/python/intern/bpy_props.c
index 52354e7f740..f901572a423 100644
--- a/source/blender/python/intern/bpy_props.c
+++ b/source/blender/python/intern/bpy_props.c
@@ -131,6 +131,7 @@ static const EnumPropertyItem property_subtype_array_items[] = {
 	{PROP_COLOR_GAMMA, "COLOR_GAMMA", 0, "Color Gamma", ""},
 	{PROP_LAYER, "LAYER", 0, "Layer", ""},
 	{PROP_LAYER_MEMBER, "LAYER_MEMBER", 0, "Layer Member", ""},
+	{PROP_POWER, "Power", 0, "Power", ""},
 
 	{PROP_NONE, "NONE", 0, "None", ""},
 	{0, NULL, 0, NULL, NULL},
@@ -139,7 +140,7 @@ static const EnumPropertyItem property_subtype_array_items[] = {
 #define BPY_PROPDEF_SUBTYPE_ARRAY_DOC \
 "   :arg subtype: Enumerator in ['COLOR', 'TRANSLATION', 'DIRECTION', " \
                                 "'VELOCITY', 'ACCELERATION', 'MATRIX', 'EULER', 'QUATERNION', 'AXISANGLE', " \
-                                "'XYZ', 'COLOR_GAMMA', 'LAYER', 'LAYER_MEMBER', 'NONE'].\n" \
+                                "'XYZ', 'COLOR_GAMMA', 'LAYER', 'LAYER_MEMBER', 'POWER', 'NONE'].\n" \
 "   :type subtype: string\n"
 
 /* PyObject's */
@@ -1902,7 +1903,7 @@ static void bpy_prop_callback_assign_enum(struct PropertyRNA *prop, PyObject *ge
 "   :type description: string\n" \
 
 #define BPY_PROPDEF_UNIT_DOC \
-"   :arg unit: Enumerator in ['NONE', 'LENGTH', 'AREA', 'VOLUME', 'ROTATION', 'TIME', 'VELOCITY', 'ACCELERATION', 'MASS', 'CAMERA'].\n" \
+"   :arg unit: Enumerator in ['NONE', 'LENGTH', 'AREA', 'VOLUME', 'ROTATION', 'TIME', 'VELOCITY', 'ACCELERATION', 'MASS', 'CAMERA', 'POWER'].\n" \
 "   :type unit: string\n" \
 
 #define BPY_PROPDEF_NUM_MIN_DOC \
diff --git a/source/blender/python/intern/bpy_utils_units.c b/source/blender/python/intern/bpy_utils_units.c
index ca27212822a..3d890143720 100644
--- a/source/blender/python/intern/bpy_utils_units.c
+++ b/source/blender/python/intern/bpy_utils_units.c
@@ -59,6 +59,7 @@ static const char *bpyunits_ucategorie_items[] = {
 	"VELOCITY",
 	"ACCELERATION",
 	"CAMERA",
+	"POWER",
 	NULL,
 };