Some advanced particle rotation modes and reorganization of the rotation panel:

- More angular velocity modes to support creative effects.
- Renamed "Initial Rotation" to "Initial Orientation" to better reflect the functionality
- Renamed "Spin" angular velocity mode to "Velocity".
- Organized the rotation panel a bit better.
- Also some better names and tooltips for the different rotation values.

6 files changed, 93 insertions, 51 deletions

diff --git a/release/scripts/startup/bl_ui/properties_particle.py b/release/scripts/startup/bl_ui/properties_particle.py
index c987ceb2562..78038e2c663 100644
--- a/release/scripts/startup/bl_ui/properties_particle.py
+++ b/release/scripts/startup/bl_ui/properties_particle.py
@@ -415,12 +415,7 @@ class PARTICLE_PT_rotation(ParticleButtonsPanel, Panel):
 
         layout.enabled = particle_panel_enabled(context, psys) and part.use_rotations
 
-        layout.prop(part, "use_dynamic_rotation")
-
-        if part.use_dynamic_rotation:
-            layout.label(text="Initial Rotation Axis:")
-        else:
-            layout.label(text="Rotation Axis:")
+        layout.label(text="Initial Orientation:")
 
         split = layout.split()
 
@@ -433,16 +428,17 @@ class PARTICLE_PT_rotation(ParticleButtonsPanel, Panel):
         col.prop(part, "phase_factor_random", text="Random", slider=True)
 
         if part.type != 'HAIR':
-            col = layout.column()
-            if part.use_dynamic_rotation:
-                col.label(text="Initial Angular Velocity:")
-            else:
-                col.label(text="Angular Velocity:")
-            sub = col.row(align=True)
-            sub.prop(part, "angular_velocity_mode", text="")
-            subsub = sub.column()
-            subsub.active = part.angular_velocity_mode != 'NONE'
-            subsub.prop(part, "angular_velocity_factor", text="")
+            layout.label(text="Angular Velocity:")
+
+            split = layout.split()
+            col = split.column(align=True)
+            col.prop(part, "angular_velocity_mode", text="")
+            sub = col.column()
+            sub.active = part.angular_velocity_mode != 'NONE'
+            sub.prop(part, "angular_velocity_factor", text="")
+
+            col = split.column()
+            col.prop(part, "use_dynamic_rotation")
 
 
 class PARTICLE_PT_physics(ParticleButtonsPanel, Panel):
diff --git a/source/blender/blenkernel/intern/particle.c b/source/blender/blenkernel/intern/particle.c
index 21dfe437ba0..8228a9da67f 100644
--- a/source/blender/blenkernel/intern/particle.c
+++ b/source/blender/blenkernel/intern/particle.c
@@ -3557,7 +3557,7 @@ static void default_particle_settings(ParticleSettings *part)
 	part->childsize=1.0;
 
 	part->rotmode = PART_ROT_VEL;
-	part->avemode = PART_AVE_SPIN;
+	part->avemode = PART_AVE_VELOCITY;
 
 	part->child_nbr=10;
 	part->ren_child_nbr=100;
diff --git a/source/blender/blenkernel/intern/particle_system.c b/source/blender/blenkernel/intern/particle_system.c
index 50c960d6c56..a0668d621e8 100644
--- a/source/blender/blenkernel/intern/particle_system.c
+++ b/source/blender/blenkernel/intern/particle_system.c
@@ -1570,6 +1570,45 @@ static void initialize_all_particles(ParticleSimulationData *sim)
 		}
 	}
 }
+
+static void get_angular_velocity_vector(short avemode, ParticleKey *state, float *vec)
+{
+	switch(avemode) {
+		case PART_AVE_VELOCITY:
+			copy_v3_v3(vec, state->vel);
+			break;	
+		case PART_AVE_HORIZONTAL:
+		{
+			float zvec[3];
+			zvec[0] = zvec[1] = 0;
+			zvec[2] = 1.f;
+			cross_v3_v3v3(vec, state->vel, zvec);
+			break;
+		}
+		case PART_AVE_VERTICAL:
+		{
+			float zvec[3], temp[3];
+			zvec[0] = zvec[1] = 0;
+			zvec[2] = 1.f;
+			cross_v3_v3v3(temp, state->vel, zvec);
+			cross_v3_v3v3(vec, temp, state->vel);
+			break;
+		}
+		case PART_AVE_GLOBAL_X:
+			vec[0] = 1.f;
+			vec[1] = vec[2] = 0;
+			break;
+		case PART_AVE_GLOBAL_Y:
+			vec[1] = 1.f;
+			vec[0] = vec[2] = 0;
+			break;
+		case PART_AVE_GLOBAL_Z:
+			vec[2] = 1.f;
+			vec[0] = vec[1] = 0;
+			break;
+	}
+}
+
 void psys_get_birth_coordinates(ParticleSimulationData *sim, ParticleData *pa, ParticleKey *state, float dtime, float cfra)
 {
 	Object *ob = sim->ob;
@@ -1782,14 +1821,11 @@ void psys_get_birth_coordinates(ParticleSimulationData *sim, ParticleData *pa, P
 		zero_v3(state->ave);
 
 		if(part->avemode) {
-			switch(part->avemode) {
-				case PART_AVE_SPIN:
-					copy_v3_v3(state->ave, vel);
-					break;
-				case PART_AVE_RAND:
-					copy_v3_v3(state->ave, r_ave);
-					break;
-			}
+			if(part->avemode == PART_AVE_RAND)
+				copy_v3_v3(state->ave, r_ave);
+			else
+				get_angular_velocity_vector(part->avemode, state, state->ave);
+
 			normalize_v3(state->ave);
 			mul_v3_fl(state->ave, part->avefac);
 		}
@@ -2692,26 +2728,26 @@ static void basic_rotate(ParticleSettings *part, ParticleData *pa, float dfra, f
 		return;
 	}
 
-	if((part->flag & PART_ROT_DYN)==0) {
-		if(part->avemode==PART_AVE_SPIN) {
-			float angle;
-			float len1 = len_v3(pa->prev_state.vel);
-			float len2 = len_v3(pa->state.vel);
-
-			if(len1==0.0f || len2==0.0f)
-				pa->state.ave[0]=pa->state.ave[1]=pa->state.ave[2]=0.0f;
-			else{
-				cross_v3_v3v3(pa->state.ave,pa->prev_state.vel,pa->state.vel);
-				normalize_v3(pa->state.ave);
-				angle=dot_v3v3(pa->prev_state.vel,pa->state.vel)/(len1*len2);
-				mul_v3_fl(pa->state.ave,saacos(angle)/dtime);
-			}
+	if((part->flag & PART_ROT_DYN)==0 && ELEM3(part->avemode, PART_AVE_VELOCITY, PART_AVE_HORIZONTAL, PART_AVE_VERTICAL)) {
+		float angle;
+		float len1 = len_v3(pa->prev_state.vel);
+		float len2 = len_v3(pa->state.vel);
+		float vec[3];
 
-			axis_angle_to_quat(rot2,pa->state.vel,dtime*part->avefac);
+		if(len1==0.0f || len2==0.0f)
+			pa->state.ave[0] = pa->state.ave[1] = pa->state.ave[2] = 0.0f;
+		else{
+			cross_v3_v3v3(pa->state.ave, pa->prev_state.vel, pa->state.vel);
+			normalize_v3(pa->state.ave);
+			angle = dot_v3v3(pa->prev_state.vel, pa->state.vel) / (len1 * len2);
+			mul_v3_fl(pa->state.ave, saacos(angle) / dtime);
 		}
+
+		get_angular_velocity_vector(part->avemode, &pa->state, vec);
+		axis_angle_to_quat(rot2, vec, dtime*part->avefac);
 	}
 
-	rotfac=len_v3(pa->state.ave);
+	rotfac = len_v3(pa->state.ave);
 	if(rotfac == 0.0f) { /* unit_qt(in VecRotToQuat) doesn't give unit quat [1,0,0,0]?? */
 		rot1[0]=1.0f;
 		rot1[1]=rot1[2]=rot1[3]=0;
diff --git a/source/blender/blenkernel/intern/pointcache.c b/source/blender/blenkernel/intern/pointcache.c
index 622c3ebe119..69e96c7a698 100644
--- a/source/blender/blenkernel/intern/pointcache.c
+++ b/source/blender/blenkernel/intern/pointcache.c
@@ -820,7 +820,7 @@ void BKE_ptcache_id_from_particles(PTCacheID *pid, Object *ob, ParticleSystem *p
 		pid->data_types|= (1<<BPHYS_DATA_ROTATION);
 
 		if(psys->part->rotmode!=PART_ROT_VEL
-			|| psys->part->avemode!=PART_AVE_SPIN || psys->part->avefac!=0.0f)
+			|| psys->part->avemode==PART_AVE_RAND || psys->part->avefac!=0.0f)
 			pid->data_types|= (1<<BPHYS_DATA_AVELOCITY);
 	}
 
diff --git a/source/blender/makesdna/DNA_particle_types.h b/source/blender/makesdna/DNA_particle_types.h
index 547a91e7852..63c4806028a 100644
--- a/source/blender/makesdna/DNA_particle_types.h
+++ b/source/blender/makesdna/DNA_particle_types.h
@@ -463,8 +463,13 @@ typedef struct ParticleSystem
 #define PART_ROT_OB_Z		8
 
 /* part->avemode */
-#define PART_AVE_SPIN		1
+#define PART_AVE_VELOCITY	1
 #define PART_AVE_RAND		2
+#define PART_AVE_HORIZONTAL	3
+#define PART_AVE_VERTICAL	4
+#define PART_AVE_GLOBAL_X	5
+#define PART_AVE_GLOBAL_Y	6
+#define PART_AVE_GLOBAL_Z	7
 
 /* part->reactevent */
 #define PART_EVENT_DEATH	0
diff --git a/source/blender/makesrna/intern/rna_particle.c b/source/blender/makesrna/intern/rna_particle.c
index 35b5ca571cb..b10639443c0 100644
--- a/source/blender/makesrna/intern/rna_particle.c
+++ b/source/blender/makesrna/intern/rna_particle.c
@@ -1510,7 +1510,12 @@ static void rna_def_particle_settings(BlenderRNA *brna)
 
 	static EnumPropertyItem ave_mode_items[] = {
 		{0, "NONE", 0, "None", ""},
-		{PART_AVE_SPIN, "SPIN", 0, "Spin", ""},
+		{PART_AVE_VELOCITY, "VELOCITY", 0, "Velocity", ""},
+		{PART_AVE_HORIZONTAL, "HORIZONTAL", 0, "Horizontal", ""},
+		{PART_AVE_VERTICAL, "VERTICAL", 0, "Vertical", ""},
+		{PART_AVE_GLOBAL_X, "GLOBAL_X", 0, "Global X", ""},
+		{PART_AVE_GLOBAL_Y, "GLOBAL_Y", 0, "Global Y", ""},
+		{PART_AVE_GLOBAL_Z, "GLOBAL_Z", 0, "Global Z", ""},
 		{PART_AVE_RAND, "RAND", 0, "Random", ""} ,
 		{0, NULL, 0, NULL, NULL}
 	};
@@ -1670,7 +1675,7 @@ static void rna_def_particle_settings(BlenderRNA *brna)
 	prop = RNA_def_property(srna, "use_dynamic_rotation", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "flag", PART_ROT_DYN);
 	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
-	RNA_def_property_ui_text(prop, "Dynamic", "Set rotation to dynamic/constant");
+	RNA_def_property_ui_text(prop, "Dynamic", "Particle rotations are effected by collisions and effectors");
 	RNA_def_property_update(prop, 0, "rna_Particle_reset");
 
 	prop = RNA_def_property(srna, "use_multiply_size_mass", PROP_BOOLEAN, PROP_NONE);
@@ -1761,14 +1766,14 @@ static void rna_def_particle_settings(BlenderRNA *brna)
 	RNA_def_property_enum_sdna(prop, NULL, "rotmode");
 	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
 	RNA_def_property_enum_items(prop, rot_mode_items);
-	RNA_def_property_ui_text(prop, "Rotation", "Particle rotation axis");
+	RNA_def_property_ui_text(prop, "Orientation axis", "Particle orientation axis (does not effect eplode modifier results)");
 	RNA_def_property_update(prop, 0, "rna_Particle_reset");
 
 	prop = RNA_def_property(srna, "angular_velocity_mode", PROP_ENUM, PROP_NONE);
 	RNA_def_property_enum_sdna(prop, NULL, "avemode");
 	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
 	RNA_def_property_enum_items(prop, ave_mode_items);
-	RNA_def_property_ui_text(prop, "Angular Velocity Mode", "Particle angular velocity mode");
+	RNA_def_property_ui_text(prop, "Angular Velocity Axis", "What axis is used to change particle rotation with time");
 	RNA_def_property_update(prop, 0, "rna_Particle_reset");
 
 	prop = RNA_def_property(srna, "react_event", PROP_ENUM, PROP_NONE);
@@ -2238,25 +2243,25 @@ static void rna_def_particle_settings(BlenderRNA *brna)
 	RNA_def_property_float_sdna(prop, NULL, "avefac");
 	RNA_def_property_range(prop, -200.0f, 200.0f);
 	RNA_def_property_ui_range(prop, -100, 100, 10, 3);
-	RNA_def_property_ui_text(prop, "Angular Velocity", "Angular velocity amount");
+	RNA_def_property_ui_text(prop, "Angular Velocity", "Angular velocity amount (in radians per second)");
 	RNA_def_property_update(prop, 0, "rna_Particle_reset");
 
 	prop = RNA_def_property(srna, "phase_factor", PROP_FLOAT, PROP_NONE);
 	RNA_def_property_float_sdna(prop, NULL, "phasefac");
 	RNA_def_property_range(prop, -1.0f, 1.0f);
-	RNA_def_property_ui_text(prop, "Phase", "Initial rotation phase");
+	RNA_def_property_ui_text(prop, "Phase", "Rotation around the chosen orientation axis");
 	RNA_def_property_update(prop, 0, "rna_Particle_reset");
 
 	prop = RNA_def_property(srna, "rotation_factor_random", PROP_FLOAT, PROP_NONE);
 	RNA_def_property_float_sdna(prop, NULL, "randrotfac");
 	RNA_def_property_range(prop, 0.0f, 1.0f);
-	RNA_def_property_ui_text(prop, "Random Rotation", "Randomize rotation");
+	RNA_def_property_ui_text(prop, "Random Orientation", "Randomize particle orientation");
 	RNA_def_property_update(prop, 0, "rna_Particle_reset");
 
 	prop = RNA_def_property(srna, "phase_factor_random", PROP_FLOAT, PROP_NONE);
 	RNA_def_property_float_sdna(prop, NULL, "randphasefac");
 	RNA_def_property_range(prop, 0.0f, 1.0f);
-	RNA_def_property_ui_text(prop, "Random Phase", "Randomize rotation phase");
+	RNA_def_property_ui_text(prop, "Random Phase", "Randomize rotation around the chosen orientation axis");
 	RNA_def_property_update(prop, 0, "rna_Particle_reset");
 
 	prop = RNA_def_property(srna, "hair_length", PROP_FLOAT, PROP_NONE);