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, 30 insertions, 14 deletions

diff --git a/release/ui/buttons_data_modifier.py b/release/ui/buttons_data_modifier.py
index 2400461b623..477be27e820 100644
--- a/release/ui/buttons_data_modifier.py
+++ b/release/ui/buttons_data_modifier.py
@@ -300,9 +300,18 @@ class DATA_PT_modifiers(DataButtonsPanel):
 		col.itemR(md, "normal")
 		col.itemR(md, "children")
 		col.itemR(md, "path")
+		if md.path:
+			col.itemR(md, "keep_shape")
 		col.itemR(md, "unborn")
 		col.itemR(md, "alive")
 		col.itemR(md, "dead")
+		if md.path:
+			col.itemR(md, "axis", text="")
+		
+		if md.path:
+			row = layout.row()
+			row.itemR(md, "position", slider=True)
+			row.itemR(md, "random_position", text = "Random", slider=True)
 		
 	def particlesystem(self, layout, ob, md):
 		layout.itemL(text="See Particle panel.")
diff --git a/release/ui/buttons_particle.py b/release/ui/buttons_particle.py
index 49ceaf6aae1..93ce9c5c745 100644
--- a/release/ui/buttons_particle.py
+++ b/release/ui/buttons_particle.py
@@ -353,19 +353,14 @@ class PARTICLE_PT_render(ParticleButtonsPanel):
 			colsub.itemR(part, "adaptive_pix")
 			sub.itemR(part, "hair_bspline")
 			sub.itemR(part, "render_step", text="Steps")
-			sub = split.column()
-			sub.itemL(text="Length:")
-			sub.itemR(part, "abs_length", text="Absolute")
-			sub.itemR(part, "absolute_length", text="Maximum")
+			sub = split.column()	
+
+			sub.itemL(text="Timing:")
+			sub.itemR(part, "abs_path_time")
+			sub.itemR(part, "path_start", text="Start", slider= not part.abs_path_time)
+			sub.itemR(part, "path_end", text="End", slider= not part.abs_path_time)		
 			sub.itemR(part, "random_length", text="Random", slider=True)
 			
-			#row = layout.row()
-			#row.itemR(part, "timed_path")
-			#col = row.column(align=True)
-			#col.active = part.timed_path == True
-			#col.itemR(part, "line_length_tail", text="Start")
-			#col.itemR(part, "line_length_head", text="End")
-			
 			row = layout.row()
 			col = row.column()
 			
@@ -384,7 +379,6 @@ class PARTICLE_PT_render(ParticleButtonsPanel):
 			
 
 		elif part.ren_as == 'OBJECT':
-			#sub = split.column()
 			sub.itemR(part, "dupli_object")
 		elif part.ren_as == 'GROUP':
 			sub.itemR(part, "dupli_group")
@@ -428,7 +422,19 @@ class PARTICLE_PT_render(ParticleButtonsPanel):
 			row.itemR(part, "billboard_animation", expand=True)
 			row.itemL(text="Offset:")
 			row.itemR(part, "billboard_split_offset", expand=True)
-		
+		if part.ren_as == 'HALO' or part.ren_as == 'LINE' or part.ren_as=='BILLBOARD':
+			row = layout.row()
+			col = row.column()
+			col.itemR(part, "trail_count")
+			if part.trail_count > 1:
+				col.itemR(part, "abs_path_time", text="Length in frames")
+				col = row.column()
+				col.itemR(part, "path_end", text="Length", slider=not part.abs_path_time)
+				col.itemR(part, "random_length", text="Random", slider=True)
+			else:
+				col = row.column()
+				col.itemL(text="")
+				
 class PARTICLE_PT_draw(ParticleButtonsPanel):
 	__idname__= "PARTICLE_PT_draw"
 	__label__ = "Display"
@@ -475,11 +481,12 @@ class PARTICLE_PT_draw(ParticleButtonsPanel):
 			col.itemR(part, "draw_health")
 		
 		col = row.column()
+		col.itemR(part, "material_color", text="Use material color")
+		
 		if (path):
 			box = col.box()				
 			box.itemR(part, "draw_step")
 		else:
-			col.itemR(part, "material_color", text="Use material color")
 			subcol = col.column()
 			subcol.active = part.material_color==False
 			#subcol.itemL(text="color")