A bunch of fun stuff now possible because of new pointcache code:

* Baked normal particles can now use the "Path" visualization.
* Path "max length" & "abs length" are now history:
	- New option to set path start & end times + random variation to length.
	- Much more flexible (and calculated better) than previous options.
	- This works with parents, children, hair & normal particles unlike old length option.
	- Only known issue for now is that children from faces don't get calculated correctly when using path start time.
* New option "trails" for "halo", "line" and "billboard" visualizations:
	- Draws user controllable number of particle instances along particles path backwards from current position.
	- Works with children too for cool/weird visualizations that weren't possible before.
* Normal particle children's velocities are now approximated better when needed so that "line" visualization trails will look nice.
* New particle instance modifier options:
	- "path"-option works better and has controllable (max)position along path (with random variation possible).
	- "keep shape"-option for hair, keyed, or baked particles allows to place the instances to a single point (with random variation possible) along particle path.
	- "axis" option to make rotation handling better (still not perfect, but will have to do for now).

Some fixes & cleanup done along the way:
* Random path length didn't work for non-child particles.
* Cached & unborn particles weren't reset to emit locations.
* Particle numbers weren't drawn in the correct place.
* Setting proper render & draw visualizations was lost somewhere when initializing new particle settings.
* Changing child mode wasn't working correctly.
* Some cleanup & modularization of particle child effector code and particle drawing & rendering code.
* Object & group visualizations didn't work.
* Child simplification didn't work.

2 files changed, 86 insertions, 17 deletions

diff --git a/source/blender/makesrna/intern/rna_modifier.c b/source/blender/makesrna/intern/rna_modifier.c
index 48bfdf70171..f4c14a51b13 100644
--- a/source/blender/makesrna/intern/rna_modifier.c
+++ b/source/blender/makesrna/intern/rna_modifier.c
@@ -1300,6 +1300,13 @@ static void rna_def_modifier_particleinstance(BlenderRNA *brna)
 	StructRNA *srna;
 	PropertyRNA *prop;
 
+	static EnumPropertyItem particleinstance_axis[] = {
+		{0, "X", 0, "X", ""},
+		{1, "Y", 0, "Y", ""},
+		{2, "Z", 0, "Z", ""},
+		{0, NULL, 0, NULL, NULL}
+	};
+
 	srna= RNA_def_struct(brna, "ParticleInstanceModifier", "Modifier");
 	RNA_def_struct_ui_text(srna, "ParticleInstance Modifier", "Particle system instancing modifier.");
 	RNA_def_struct_sdna(srna, "ParticleInstanceModifierData");
@@ -1316,6 +1323,12 @@ static void rna_def_modifier_particleinstance(BlenderRNA *brna)
 	RNA_def_property_range(prop, 1, 10);
 	RNA_def_property_ui_text(prop, "Particle System Number", "");
 	RNA_def_property_update(prop, NC_OBJECT|ND_MODIFIER, "rna_Modifier_update");
+
+	prop= RNA_def_property(srna, "axis", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_sdna(prop, NULL, "axis");
+	RNA_def_property_enum_items(prop, particleinstance_axis);
+	RNA_def_property_ui_text(prop, "Axis", "Pole axis for rotation");
+	RNA_def_property_update(prop, NC_OBJECT|ND_MODIFIER, "rna_Modifier_update");
 	
 	prop= RNA_def_property(srna, "normal", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "flag", eParticleInstanceFlag_Parents);
@@ -1346,6 +1359,23 @@ static void rna_def_modifier_particleinstance(BlenderRNA *brna)
 	RNA_def_property_boolean_sdna(prop, NULL, "flag", eParticleInstanceFlag_Dead);
 	RNA_def_property_ui_text(prop, "Dead", "Show instances when particles are dead.");
 	RNA_def_property_update(prop, NC_OBJECT|ND_MODIFIER, "rna_Modifier_update");
+
+	prop= RNA_def_property(srna, "keep_shape", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "flag", eParticleInstanceFlag_KeepShape);
+	RNA_def_property_ui_text(prop, "Keep Shape", "Don't stretch the object.");
+	RNA_def_property_update(prop, NC_OBJECT|ND_MODIFIER, "rna_Modifier_update");
+
+	prop= RNA_def_property(srna, "position", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_float_sdna(prop, NULL, "position");
+	RNA_def_property_range(prop, 0.0, 1.0);
+	RNA_def_property_ui_text(prop, "Position", "Position along path.");
+	RNA_def_property_update(prop, NC_OBJECT|ND_MODIFIER, "rna_Modifier_update");
+
+	prop= RNA_def_property(srna, "random_position", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_float_sdna(prop, NULL, "random_position");
+	RNA_def_property_range(prop, 0.0, 1.0);
+	RNA_def_property_ui_text(prop, "Random Position", "Randomize position along path.");
+	RNA_def_property_update(prop, NC_OBJECT|ND_MODIFIER, "rna_Modifier_update");
 }
 
 static void rna_def_modifier_explode(BlenderRNA *brna)
diff --git a/source/blender/makesrna/intern/rna_particle.c b/source/blender/makesrna/intern/rna_particle.c
index d60a215b498..5c94c81da1f 100644
--- a/source/blender/makesrna/intern/rna_particle.c
+++ b/source/blender/makesrna/intern/rna_particle.c
@@ -151,6 +151,20 @@ static void rna_particle_settings_set(PointerRNA *ptr, PointerRNA value)
 	if(psys->part)
 		psys->part->id.us++;
 }
+static void rna_Particle_abspathtime_update(bContext *C, PointerRNA *ptr)
+{
+	ParticleSettings *settings = (ParticleSettings*)ptr->data;
+	float delta = settings->end + settings->lifetime - settings->sta;
+	if(settings->draw & PART_ABS_PATH_TIME) {
+		settings->path_start = settings->sta + settings->path_start * delta;
+		settings->path_end = settings->sta + settings->path_end * delta;
+	}
+	else {
+		settings->path_start = (settings->path_start - settings->sta)/delta;
+		settings->path_end = (settings->path_end - settings->sta)/delta;
+	}
+	rna_Particle_redo(C, ptr);
+}
 static void rna_PartSettings_start_set(struct PointerRNA *ptr, float value)
 {
 	ParticleSettings *settings = (ParticleSettings*)ptr->data;
@@ -189,7 +203,19 @@ static float rna_PartSetting_linelentail_get(struct PointerRNA *ptr)
 	ParticleSettings *settings = (ParticleSettings*)ptr->data;
 	return settings->draw_line[0];
 }
+static void rna_PartSetting_pathstartend_range(PointerRNA *ptr, float *min, float *max)
+{
+	ParticleSettings *settings = (ParticleSettings*)ptr->data;
 
+	if(settings->type==PART_HAIR) {
+		*min = 0.0f;
+		*max = (settings->draw & PART_ABS_PATH_TIME) ? 100.0f : 1.0;
+	}
+	else {
+		*min = (settings->draw & PART_ABS_PATH_TIME) ? settings->sta : 0.0f;
+		*max= (settings->draw & PART_ABS_PATH_TIME) ? MAXFRAMEF : 1.0f;
+	}
+}
 static void rna_PartSetting_linelenhead_set(struct PointerRNA *ptr, float value)
 {
 	ParticleSettings *settings = (ParticleSettings*)ptr->data;
@@ -702,15 +728,15 @@ static void rna_def_particle_settings(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Abs Length", "Use maximum length for children");
 	RNA_def_property_update(prop, NC_OBJECT|ND_PARTICLE, "rna_Particle_redo");
 
-	prop= RNA_def_property(srna, "absolute_time", PROP_BOOLEAN, PROP_NONE);
-	RNA_def_property_boolean_sdna(prop, NULL, "flag", PART_ABS_TIME);
-	RNA_def_property_ui_text(prop, "Absolute Time", "Set all ipos that work on particles to be calculated in absolute/relative time.");
-	RNA_def_property_update(prop, NC_OBJECT|ND_PARTICLE, "rna_Particle_reset");
+	//prop= RNA_def_property(srna, "absolute_time", PROP_BOOLEAN, PROP_NONE);
+	//RNA_def_property_boolean_sdna(prop, NULL, "flag", PART_ABS_TIME);
+	//RNA_def_property_ui_text(prop, "Absolute Time", "Set all ipos that work on particles to be calculated in absolute/relative time.");
+	//RNA_def_property_update(prop, NC_OBJECT|ND_PARTICLE, "rna_Particle_reset");
 
-	prop= RNA_def_property(srna, "global_time", PROP_BOOLEAN, PROP_NONE);
-	RNA_def_property_boolean_sdna(prop, NULL, "flag", PART_GLOB_TIME);
-	RNA_def_property_ui_text(prop, "Global Time", "Set all ipos that work on particles to be calculated in global/object time.");
-	RNA_def_property_update(prop, NC_OBJECT|ND_PARTICLE, "rna_Particle_reset");
+	//prop= RNA_def_property(srna, "global_time", PROP_BOOLEAN, PROP_NONE);
+	//RNA_def_property_boolean_sdna(prop, NULL, "flag", PART_GLOB_TIME);
+	//RNA_def_property_ui_text(prop, "Global Time", "Set all ipos that work on particles to be calculated in global/object time.");
+	//RNA_def_property_update(prop, NC_OBJECT|ND_PARTICLE, "rna_Particle_reset");
 
 	prop= RNA_def_property(srna, "boids_2d", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "flag", PART_BOIDS_2D);
@@ -836,15 +862,10 @@ static void rna_def_particle_settings(BlenderRNA *brna)
 	//RNA_def_property_ui_text(prop, "Health", "Draw boid health");
 	//RNA_def_property_update(prop, NC_OBJECT|ND_PARTICLE, "rna_Particle_redo");
 
-	//prop= RNA_def_property(srna, "timed_path", PROP_BOOLEAN, PROP_NONE);
-	//RNA_def_property_boolean_sdna(prop, NULL, "draw", PART_DRAW_TIMED_PATH);
-	//RNA_def_property_ui_text(prop, "Clip with time", "Clip path based on time");
-	//RNA_def_property_update(prop, NC_OBJECT|ND_PARTICLE, "rna_Particle_redo");
-
-	//prop= RNA_def_property(srna, "draw_cached_path", PROP_BOOLEAN, PROP_NONE);
-	//RNA_def_property_boolean_sdna(prop, NULL, "draw", PART_DRAW_CACHED_PATH);
-	//RNA_def_property_ui_text(prop, "Path", "Draw particle path if the path is baked");
-	//RNA_def_property_update(prop, NC_OBJECT|ND_PARTICLE, "rna_Particle_redo");
+	prop= RNA_def_property(srna, "abs_path_time", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "draw", PART_ABS_PATH_TIME);
+	RNA_def_property_ui_text(prop, "Absolute Path Time", "Path timing is in absolute frames");
+	RNA_def_property_update(prop, NC_OBJECT|ND_PARTICLE, "rna_Particle_abspathtime_update");
 
 	prop= RNA_def_property(srna, "billboard_lock", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "draw", PART_DRAW_BB_LOCK);
@@ -1410,6 +1431,24 @@ static void rna_def_particle_settings(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Head", "Length of the line's head");
 	RNA_def_property_update(prop, NC_OBJECT|ND_PARTICLE, "rna_Particle_redo");
 
+	prop= RNA_def_property(srna, "path_start", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_float_sdna(prop, NULL, "path_start");
+	RNA_def_property_float_funcs(prop, NULL, NULL, "rna_PartSetting_pathstartend_range");
+	RNA_def_property_ui_text(prop, "Path Start", "Starting time of drawn path.");
+	RNA_def_property_update(prop, NC_OBJECT|ND_PARTICLE, "rna_Particle_redo");
+
+	prop= RNA_def_property(srna, "path_end", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_float_sdna(prop, NULL, "path_end");
+	RNA_def_property_float_funcs(prop, NULL, NULL, "rna_PartSetting_pathstartend_range");
+	RNA_def_property_ui_text(prop, "Path End", "End time of drawn path.");
+	RNA_def_property_update(prop, NC_OBJECT|ND_PARTICLE, "rna_Particle_redo");
+
+	prop= RNA_def_property(srna, "trail_count", PROP_INT, PROP_NONE);
+	RNA_def_property_int_sdna(prop, NULL, "trail_count");
+	RNA_def_property_range(prop, 1.0f, 100.0f);
+	RNA_def_property_ui_text(prop, "Trail Count", "Number of trail particles.");
+	RNA_def_property_update(prop, NC_OBJECT|ND_PARTICLE, "rna_Particle_redo");
+	
 	/* boids */
 	prop= RNA_def_property(srna, "max_velocity", PROP_FLOAT, PROP_NONE);
 	RNA_def_property_float_sdna(prop, NULL, "max_vel");