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.

3 files changed, 6 insertions, 1 deletions

diff --git a/source/blender/render/intern/include/render_types.h b/source/blender/render/intern/include/render_types.h
index 4a731878ffb..7fbbd0f5abc 100644
--- a/source/blender/render/intern/include/render_types.h
+++ b/source/blender/render/intern/include/render_types.h
@@ -343,7 +343,7 @@ typedef struct StrandBuffer {
 	unsigned int lay;
 	int overrideuv;
 	int flag, maxdepth;
-	float adaptcos;
+	float adaptcos, minwidth;
 
 	float winmat[4][4];
 	int winx, winy;
diff --git a/source/blender/render/intern/include/renderdatabase.h b/source/blender/render/intern/include/renderdatabase.h
index 0346f2d6413..c919a54008e 100644
--- a/source/blender/render/intern/include/renderdatabase.h
+++ b/source/blender/render/intern/include/renderdatabase.h
@@ -69,6 +69,7 @@ typedef struct StrandTableNode {
 	struct StrandRen *strand;
 	float *winspeed;
 	float *surfnor;
+	float *simplify;
 	struct MCol *mcol;
 	float *uv;
 	int totuv, totmcol;
@@ -112,6 +113,7 @@ int RE_vlakren_get_normal(struct Render *re, struct ObjectInstanceRen *obi, stru
 float *RE_strandren_get_surfnor(struct ObjectRen *obr, struct StrandRen *strand, int verify);
 float *RE_strandren_get_uv(struct ObjectRen *obr, struct StrandRen *strand, int n, char **name, int verify);
 struct MCol *RE_strandren_get_mcol(struct ObjectRen *obr, struct StrandRen *strand, int n, char **name, int verify);
+float *RE_strandren_get_simplify(struct ObjectRen *obr, struct StrandRen *strand, int verify);
 float *RE_strandren_get_winspeed(struct ObjectInstanceRen *obi, struct StrandRen *strand, int verify);
 
 struct VertRen *RE_vertren_copy(struct ObjectRen *obr, struct VertRen *ver);
diff --git a/source/blender/render/intern/include/strand.h b/source/blender/render/intern/include/strand.h
index 7f37317d4d5..34a147c1933 100644
--- a/source/blender/render/intern/include/strand.h
+++ b/source/blender/render/intern/include/strand.h
@@ -68,6 +68,9 @@ typedef struct StrandPoint {
 	/* screen space */
 	float hoco[4];
 	float x, y;
+
+	/* simplification */
+	float alpha;
 } StrandPoint;
 
 typedef struct StrandSegment {