[Bf-blender-cvs] [c9e8c87] hair_system: Use the actual gravity from the scene for the hair simulation.

[Lukas Tönne]

Commit: c9e8c875afe33e83f343f66f95e160f73eaeab56
Author: Lukas Tönne
Date:   Mon Jul 28 17:47:18 2014 +0200
Branches: hair_system
https://developer.blender.org/rBc9e8c875afe33e83f343f66f95e160f73eaeab56

Use the actual gravity from the scene for the hair simulation.

A new solver struct for forces has been added, this is supposed to
organize all the external influences in some consistent way.

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

M	source/blender/hair/HAIR_capi.cpp
M	source/blender/hair/HAIR_capi.h
M	source/blender/hair/intern/HAIR_solver.cpp
M	source/blender/hair/intern/HAIR_solver.h
M	source/blender/modifiers/intern/MOD_hair.c

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

diff --git a/source/blender/hair/HAIR_capi.cpp b/source/blender/hair/HAIR_capi.cpp
index 39e3017..5dd8cc2 100644
--- a/source/blender/hair/HAIR_capi.cpp
+++ b/source/blender/hair/HAIR_capi.cpp
@@ -29,6 +29,7 @@ extern "C" {
 
 #include "DNA_hair_types.h"
 #include "DNA_object_types.h"
+#include "DNA_scene_types.h"
 
 #include "BKE_hair.h"
 }
@@ -55,12 +56,14 @@ void HAIR_solver_free(struct HAIR_Solver *csolver)
 	delete solver;
 }
 
-void HAIR_solver_init(struct HAIR_Solver *csolver, Object *ob, HairSystem *hsys)
+void HAIR_solver_init(struct HAIR_Solver *csolver, Scene *scene, Object *ob, HairSystem *hsys)
 {
 	Solver *solver = (Solver *)csolver;
 	HairCurve *hair;
 	int i;
 	
+	solver->forces().gravity = float3(scene->physics_settings.gravity);
+	
 	Transform mat = Transform(ob->obmat);
 	
 	/* count points */
diff --git a/source/blender/hair/HAIR_capi.h b/source/blender/hair/HAIR_capi.h
index 87d121a..7de4374 100644
--- a/source/blender/hair/HAIR_capi.h
+++ b/source/blender/hair/HAIR_capi.h
@@ -28,6 +28,8 @@
 extern "C" {
 #endif
 
+struct Scene;
+struct Object;
 struct HairCurve;
 struct HairSystem;
 
@@ -36,7 +38,7 @@ struct HAIR_SmoothingIteratorFloat3;
 
 struct HAIR_Solver *HAIR_solver_new(const struct HairParams *params);
 void HAIR_solver_free(struct HAIR_Solver *solver);
-void HAIR_solver_init(struct HAIR_Solver *solver, struct Object *ob, struct HairSystem *hsys);
+void HAIR_solver_init(struct HAIR_Solver *solver, struct Scene *scene, struct Object *ob, struct HairSystem *hsys);
 void HAIR_solver_step(struct HAIR_Solver *solver, float timestep);
 void HAIR_solver_apply(struct HAIR_Solver *solver, struct Object *ob, struct HairSystem *hsys);
 
diff --git a/source/blender/hair/intern/HAIR_solver.cpp b/source/blender/hair/intern/HAIR_solver.cpp
index 111b2d3..797962a 100644
--- a/source/blender/hair/intern/HAIR_solver.cpp
+++ b/source/blender/hair/intern/HAIR_solver.cpp
@@ -61,6 +61,13 @@ SolverData::~SolverData()
 		delete[] points;
 }
 
+
+SolverForces::SolverForces()
+{
+	gravity = float3(0.0f, 0.0f, 0.0f);
+}
+
+
 Solver::Solver(const HairParams &params) :
     m_params(params),
     m_data(NULL)
@@ -107,7 +114,9 @@ float3 Solver::calc_stretch(Curve *curve, Point *point0, Point *point1, float ti
 
 float3 Solver::calc_acceleration(Curve *curve, Point *point, float time, float3 prev_stretch, float3 stretch, Point::State &state) const
 {
-	float3 acc = float3(0.0f, 0.0f, -0.01f);
+	float3 acc = float3(0.0f, 0.0f, 0.0f);
+	
+	acc = acc + m_forces.gravity;
 	
 	acc = acc - prev_stretch + stretch;
 	
diff --git a/source/blender/hair/intern/HAIR_solver.h b/source/blender/hair/intern/HAIR_solver.h
index 3cd0e45..09798e2 100644
--- a/source/blender/hair/intern/HAIR_solver.h
+++ b/source/blender/hair/intern/HAIR_solver.h
@@ -50,6 +50,12 @@ struct SolverData {
 	HAIR_CXX_CLASS_ALLOC(SolverData)
 };
 
+struct SolverForces {
+	SolverForces();
+	
+	float3 gravity;
+};
+
 class Solver
 {
 public:
@@ -58,6 +64,8 @@ public:
 	
 	const HairParams &params() const { return m_params; }
 	
+	SolverForces &forces() { return m_forces; }
+	
 	void init_data(int totcurves, int totpoints);
 	void free_data();
 	SolverData *data() const { return m_data; }
@@ -71,6 +79,7 @@ protected:
 	
 private:
 	HairParams m_params;
+	SolverForces m_forces;
 	SolverData *m_data;
 
 	HAIR_CXX_CLASS_ALLOC(Solver)
diff --git a/source/blender/modifiers/intern/MOD_hair.c b/source/blender/modifiers/intern/MOD_hair.c
index 7e80141..85afa16 100644
--- a/source/blender/modifiers/intern/MOD_hair.c
+++ b/source/blender/modifiers/intern/MOD_hair.c
@@ -93,7 +93,7 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob,
 		int s;
 		
 		solver = HAIR_solver_new(&hsys->params);
-		HAIR_solver_init(solver, ob, hsys);
+		HAIR_solver_init(solver, scene, ob, hsys);
 		
 		if (num_steps < 10000) {
 			for (s = 0; s < num_steps; ++s) {