Implementation of a target density feature for the hair simulation.

This allows setting a target density which the fluid simulation will
take into account as an additional term in the pressure Poisson
equation. Based on two papers
"Detail Preserving Continuum Simulation of Straight Hair" (McAdams et al. 2009)
and
"Two-way Coupled SPH and Particle Level Set Fluid Simulation" (Losasso et al. 2008)

Currently the target pressure is specified directly, but it will be
a lot more convenient to define this in terms of a geometric value such
as "number of hairs per area" (combined with hair "thickness").

Conflicts:
	source/blender/physics/intern/BPH_mass_spring.cpp

1 files changed, 2 insertions, 2 deletions

diff --git a/source/blender/makesdna/DNA_cloth_types.h b/source/blender/makesdna/DNA_cloth_types.h
index f4d8faa7958..3144dadb680 100644
--- a/source/blender/makesdna/DNA_cloth_types.h
+++ b/source/blender/makesdna/DNA_cloth_types.h
@@ -69,8 +69,8 @@ typedef struct ClothSimSettings {
 	float	goalspring;
 	float	goalfrict;
 	float	velocity_smooth; /* smoothing of velocities for hair */
-	float	pressure;			/* pressure factor from hair density */
-	float	pressure_threshold;	/* minimum density for hair pressure */
+	float	density_target;		/* minimum density for hair */
+	float	density_strength;	/* influence of hair density */
 	float	collider_friction; /* friction with colliders */
 	float	vel_damping; /* damp the velocity to speed up getting to the resting position */
 	float	shrink_min;  /* min amount to shrink cloth by 0.0f (no shrink) - 1.0f (shrink to nothing) */