Strand Render Simplification

============================

- Strand render now has options to remove child strands as
  the object's faces becomes smaller, in the Simplification
  particle panel.
- "Reference Size" is the approximate size of the object on
  screen, after which simplification starts.
- "Rate" is how fast strands are removed.
- "Transition" is the percentage of strands being faded out as
  they are removed.

- Another "Viewport" option removes strands on faces that are
  outside of the viewport. "Rate" again controls how fast these
  are removed.

- Strand render in Blender Units now has an adjustable minimum
  width. Below this minimum width, strands start fading out
  instead of getting smaller.

2 files changed, 63 insertions, 15 deletions

diff --git a/source/blender/src/buttons_object.c b/source/blender/src/buttons_object.c
index 3c2969e77bf..e5bb4dd8a10 100644
--- a/source/blender/src/buttons_object.c
+++ b/source/blender/src/buttons_object.c
@@ -3610,8 +3610,8 @@ static void object_panel_particle_children(Object *ob)
 	if(part==NULL) return;
 		
 	block= uiNewBlock(&curarea->uiblocks, "object_panel_particle_child", UI_EMBOSS, UI_HELV, curarea->win);
-	uiNewPanelTabbed("Extras", "Particle");
 	if(uiNewPanel(curarea, block, "Children", "Particle", 1300, 0, 318, 204)==0) return;
+	uiNewPanelTabbed("Extras", "Particle");
 
 	uiDefButS(block, MENU, B_PART_ALLOC_CHILD, "Children from:%t|Faces%x2|Particles%x1|None%x0", butx,buty,butw,buth, &part->childtype, 14.0, 0.0, 0, 0, "Create child particles");
 
@@ -3957,6 +3957,47 @@ static void object_panel_particle_visual(Object *ob)
 	}
 	uiBlockEndAlign(block);
 }
+static void object_panel_particle_simplification(Object *ob)
+{
+	uiBlock *block;
+	ParticleSystem *psys=psys_get_current(ob);
+	ParticleSettings *part;
+	short butx=0, buty=160, butw=150, buth=20;
+
+	if (psys==NULL) return;
+	part=psys->part;
+	if(part==NULL) return;
+
+	if(part->draw_as!=PART_DRAW_PATH || !(part->draw & PART_DRAW_REN_STRAND))
+		return;
+	if(part->childtype!=PART_CHILD_FACES)
+		return;
+	
+	block= uiNewBlock(&curarea->uiblocks, "object_panel_particle_simplification", UI_EMBOSS, UI_HELV, curarea->win);
+	uiNewPanelTabbed("Visualization", "Particle");
+	if(uiNewPanel(curarea, block, "Simplification", "Particle", 640, 0, 318, 204)==0) return;
+
+	uiBlockBeginAlign(block);
+	uiDefButBitS(block, TOG, PART_SIMPLIFY_ENABLE, B_PART_REDRAW, "Child Simplification", butx,buty-=buth,butw,buth, &part->simplify_flag, 0, 0, 0, 0, "Remove child strands as the object becomes smaller on the screen");
+	uiBlockEndAlign(block);
+	if(part->simplify_flag & PART_SIMPLIFY_ENABLE) {
+		buty -= 10;
+
+		uiBlockBeginAlign(block);
+		uiDefButS(block, NUM, B_NOP, "Reference Size:", butx,(buty-=buth),butw,buth, &part->simplify_refsize, 1.0, 32768.0, 0, 0, "Reference size size in pixels, after which simplification begins");
+		uiDefButF(block, NUM, B_NOP, "Rate:", butx,(buty-=buth),butw,buth, &part->simplify_rate, 0.0, 1.0, 0, 0, "Speed of simplification");
+		uiDefButF(block, NUM, B_NOP, "Transition:", butx,(buty-=buth),butw,buth, &part->simplify_transition, 0.0, 1.0, 0, 0, "Transition period for fading out strands");
+		uiBlockEndAlign(block);
+
+		buty -= 10;
+
+		uiBlockBeginAlign(block);
+		uiDefButBitS(block, TOG, PART_SIMPLIFY_VIEWPORT, B_PART_REDRAW, "Viewport", butx,buty-=buth,butw,buth, &part->simplify_flag, 0, 0, 0, 0, "Remove child strands as the object goes outside the viewport");
+		uiDefButF(block, NUM, B_NOP, "Rate:", butx,(buty-=buth),butw,buth, &part->simplify_viewport, 0.0, 0.999, 0, 0, "Speed of simplification");
+		uiBlockEndAlign(block);
+	}
+	uiBlockEndAlign(block);
+}
 static void boidrule_moveDown(void *part_v, void *rule_v)
 {
 	ParticleSettings *part = part_v;
@@ -4700,6 +4741,7 @@ void particle_panels()
 		if(psys){
 			object_panel_particle_physics(ob);
 			object_panel_particle_visual(ob);
+			object_panel_particle_simplification(ob);
 			object_panel_particle_extra(ob);
 			object_panel_particle_children(ob);
 		}
diff --git a/source/blender/src/buttons_shading.c b/source/blender/src/buttons_shading.c
index dafd156524f..ad1afcc0608 100644
--- a/source/blender/src/buttons_shading.c
+++ b/source/blender/src/buttons_shading.c
@@ -3852,31 +3852,37 @@ static uiBlock *strand_menu(void *mat_v)
 {
 	Material *ma= mat_v;
 	uiBlock *block;
+	int buth=20, butw=230, butx=10, buty=160;
 
 	block= uiNewBlock(&curarea->uiblocks, "strand menu", UI_EMBOSS, UI_HELV, curarea->win);
-	
+	 
+  	if(ma->mode & MA_STR_B_UNITS)
+		buty += buth;
+
 	/* use this for a fake extra empy space around the buttons */
-	uiDefBut(block, LABEL, 0, "", 0, 0, 250, 170, NULL,  0, 0, 0, 0, "");
+	uiDefBut(block, LABEL, 0, "", 0, 0, butw+20, buty+10, NULL,  0, 0, 0, 0, "");
+  					/* event return 0, to prevent menu to close */
   	
   	uiBlockBeginAlign(block);
-  					/* event return 0, to prevent menu to close */
- 
-	uiDefButBitI(block, TOG, MA_TANGENT_STR, 0,	"Use Tangent Shading",	10,140,230,20, &(ma->mode), 0, 0, 0, 0, "Uses direction of strands as normal for tangent-shading");
-	uiDefButBitI(block, TOG, MA_STR_SURFDIFF, 0, "Surface Diffuse",	10,120,115,20, &(ma->mode), 0, 0, 0, 0, "Make diffuse shading more similar to shading the surface");
-	uiDefButF(block, NUM, 0, "Dist", 125,120,115,20, &ma->strand_surfnor, 0.0f, 10.0f, 2, 0, "Distance in Blender units over which to blend in the surface normal");
+	uiDefButBitI(block, TOG, MA_TANGENT_STR, 0,	"Use Tangent Shading",	butx,buty-=buth,butw,buth, &(ma->mode), 0, 0, 0, 0, "Uses direction of strands as normal for tangent-shading");
+	uiDefButBitI(block, TOG, MA_STR_SURFDIFF, 0, "Surface Diffuse",	butx,buty-=buth,butw/2,buth, &(ma->mode), 0, 0, 0, 0, "Make diffuse shading more similar to shading the surface");
+	uiDefButF(block, NUM, 0, "Dist", butx+butw/2,buty,butw/2,buth, &ma->strand_surfnor, 0.0f, 10.0f, 2, 0, "Distance in Blender units over which to blend in the surface normal");
+
+	buty -= 5;
  
 	uiBlockBeginAlign(block);
-	uiDefButBitI(block, TOG, MA_STR_B_UNITS, 0,	"Use Blender Units", 10,95,230,20, &(ma->mode), 0, 0, 0, 0, "Use actual Blender units for widths instead of pixels");
+	uiDefButBitI(block, TOG, MA_STR_B_UNITS, 0,	"Use Blender Units", butx,buty-=buth,butw,buth, &(ma->mode), 0, 0, 0, 0, "Use actual Blender units for widths instead of pixels");
   	if(ma->mode & MA_STR_B_UNITS){
-		uiDefButF(block, NUMSLI, 0, "Start ",	10, 75, 230,20,   &ma->strand_sta, 0.0001, 2.0, 2, 0, "Start size of strands in Blender units");
-		uiDefButF(block, NUMSLI, 0, "End ",		10, 55, 230,20,  &ma->strand_end, 0.0001, 1.0, 2, 0, "End size of strands in Blender units");
+		uiDefButF(block, NUMSLI, 0, "Start ",	butx,buty-=buth, butw,buth,   &ma->strand_sta, 0.0001, 2.0, 2, 0, "Start size of strands in Blender units");
+		uiDefButF(block, NUMSLI, 0, "End ",		butx,buty-=buth, butw,buth,  &ma->strand_end, 0.0001, 1.0, 2, 0, "End size of strands in Blender units");
+		uiDefButF(block, NUMSLI, 0, "Minimum ",		butx,buty-=buth, butw,buth,  &ma->strand_min, 0.001, 10.0, 0, 0, "Minimum size of strands in pixels");
   	}
   	else{
-		uiDefButF(block, NUMSLI, 0, "Start ",	10, 75, 230,20,   &ma->strand_sta, 0.25, 20.0, 2, 0, "Start size of strands in pixels");
-		uiDefButF(block, NUMSLI, 0, "End ",		10, 55, 230,20,  &ma->strand_end, 0.25, 10.0, 2, 0, "End size of strands in pixels");
+		uiDefButF(block, NUMSLI, 0, "Start ",	butx,buty-=buth, butw,buth,   &ma->strand_sta, 0.25, 20.0, 2, 0, "Start size of strands in pixels");
+		uiDefButF(block, NUMSLI, 0, "End ",		butx,buty-=buth, butw,buth,  &ma->strand_end, 0.25, 10.0, 2, 0, "End size of strands in pixels");
   	}
-	uiDefButF(block, NUMSLI, 0, "Shape ",	10, 35, 230,20,  &ma->strand_ease, -0.9, 0.9, 2, 0, "Shape of strands, positive value makes it rounder, negative makes it spiky");
-	uiDefBut(block, TEX, B_MATPRV, "UV:", 10,10,230,20, ma->strand_uvname, 0, 31, 0, 0, "Set name of UV layer to override");
+	uiDefButF(block, NUMSLI, 0, "Shape ",	butx,buty-=buth, butw,buth,  &ma->strand_ease, -0.9, 0.9, 2, 0, "Shape of strands, positive value makes it rounder, negative makes it spiky");
+	uiDefBut(block, TEX, B_MATPRV, "UV:", butx,buty-=buth,butw,buth, ma->strand_uvname, 0, 31, 0, 0, "Set name of UV layer to override");
 
 	uiBlockSetDirection(block, UI_TOP);
 	BIF_preview_changed(ID_MA);