[Bf-blender-cvs] SVN commit: /data/svn/bf-blender [53724] trunk/blender/source/blender: Changing units of stiffness parameter in classical (new) SPH solver: used to be speed of sound squared; now just speed of sound.

[Alex Fraser]

Revision: 53724
          http://projects.blender.org/scm/viewvc.php?view=rev&root=bf-blender&revision=53724
Author:   z0r
Date:     2013-01-11 03:06:10 +0000 (Fri, 11 Jan 2013)
Log Message:
-----------
Changing units of stiffness parameter in classical (new) SPH solver: used to be speed of sound squared; now just speed of sound.

The classical SPH solver was not in 2.65, so this change is unlikely to affect many users. But beta users who have been trying it out will need to change the stiffness parameter to sqrt(old value).

Modified Paths:
--------------
    trunk/blender/source/blender/blenkernel/intern/particle_system.c
    trunk/blender/source/blender/makesrna/intern/rna_particle.c

Modified: trunk/blender/source/blender/blenkernel/intern/particle_system.c
===================================================================
--- trunk/blender/source/blender/blenkernel/intern/particle_system.c	2013-01-11 02:03:22 UTC (rev 53723)
+++ trunk/blender/source/blender/blenkernel/intern/particle_system.c	2013-01-11 03:06:10 UTC (rev 53724)
@@ -2697,7 +2697,8 @@
 	/* 4.77 is an experimentally determined density factor */
 	float rest_density = fluid->rest_density * (fluid->flag & SPH_FAC_DENSITY ? 4.77f : 1.0f);
 
-	float stiffness = fluid->stiffness_k;
+	// Use speed of sound squared
+	float stiffness = pow2(fluid->stiffness_k);
 
 	ParticleData *npa;
 	float vec[3];

Modified: trunk/blender/source/blender/makesrna/intern/rna_particle.c
===================================================================
--- trunk/blender/source/blender/makesrna/intern/rna_particle.c	2013-01-11 02:03:22 UTC (rev 53723)
+++ trunk/blender/source/blender/makesrna/intern/rna_particle.c	2013-01-11 03:06:10 UTC (rev 53724)
@@ -1545,9 +1545,9 @@
 	/* Double density relaxation */
 	prop = RNA_def_property(srna, "stiffness", PROP_FLOAT, PROP_NONE);
 	RNA_def_property_float_sdna(prop, NULL, "stiffness_k");
-	RNA_def_property_range(prop, 0.0f, 100000.0f);
+	RNA_def_property_range(prop, 0.0f, 1000.0f);
 	RNA_def_property_ui_range(prop, 0.0f, 10.0f, 1, 3);
-	RNA_def_property_ui_text(prop, "Stiffness", "How incompressible the fluid is");
+	RNA_def_property_ui_text(prop, "Stiffness", "How incompressible the fluid is (speed of sound)");
 	RNA_def_property_update(prop, 0, "rna_Particle_reset");
 
 	prop = RNA_def_property(srna, "repulsion", PROP_FLOAT, PROP_NONE);