Cloth: Componentize forces

This separates cloth stiffness and damping forces into tension,
compression, and shearing components, allowing more control over the
cloth behaviour.

This also adds a bending model selector (although the new bending model
itself is not implemented in this commit). This is because some of the
features implemented here only make sense within the new bending model,
while the old model is kept for compatibility.

This commit makes non-breaking changes, and thus maintains full
compatibility with existing simulations.

Reviewed By: brecht

Differential Revision: http://developer.blender.org/D3655

1 files changed, 145 insertions, 34 deletions

diff --git a/source/blender/makesrna/intern/rna_cloth.c b/source/blender/makesrna/intern/rna_cloth.c
index 0958011a7f0..f46f6e96b62 100644
--- a/source/blender/makesrna/intern/rna_cloth.c
+++ b/source/blender/makesrna/intern/rna_cloth.c
@@ -97,26 +97,70 @@ static void rna_ClothSettings_max_bend_set(struct PointerRNA *ptr, float value)
 	settings->max_bend = value;
 }
 
-static void rna_ClothSettings_structural_set(struct PointerRNA *ptr, float value)
+static void rna_ClothSettings_tension_set(struct PointerRNA *ptr, float value)
 {
 	ClothSimSettings *settings = (ClothSimSettings *)ptr->data;
 
-	settings->structural = value;
+	settings->tension = value;
 
 	/* check for max clipping */
-	if (value > settings->max_struct)
-		settings->max_struct = value;
+	if (value > settings->max_tension)
+		settings->max_tension = value;
 }
 
-static void rna_ClothSettings_max_struct_set(struct PointerRNA *ptr, float value)
+static void rna_ClothSettings_max_tension_set(struct PointerRNA *ptr, float value)
 {
 	ClothSimSettings *settings = (ClothSimSettings *)ptr->data;
 
 	/* check for clipping */
-	if (value < settings->structural)
-		value = settings->structural;
+	if (value < settings->tension)
+		value = settings->tension;
 
-	settings->max_struct = value;
+	settings->max_tension = value;
+}
+
+static void rna_ClothSettings_compression_set(struct PointerRNA *ptr, float value)
+{
+	ClothSimSettings *settings = (ClothSimSettings *)ptr->data;
+
+	settings->compression = value;
+
+	/* check for max clipping */
+	if (value > settings->max_compression)
+		settings->max_compression = value;
+}
+
+static void rna_ClothSettings_max_compression_set(struct PointerRNA *ptr, float value)
+{
+	ClothSimSettings *settings = (ClothSimSettings *)ptr->data;
+
+	/* check for clipping */
+	if (value < settings->compression)
+		value = settings->compression;
+
+	settings->max_compression = value;
+}
+
+static void rna_ClothSettings_shear_set(struct PointerRNA *ptr, float value)
+{
+	ClothSimSettings *settings = (ClothSimSettings *)ptr->data;
+
+	settings->shear = value;
+
+	/* check for max clipping */
+	if (value > settings->max_shear)
+		settings->max_shear = value;
+}
+
+static void rna_ClothSettings_max_shear_set(struct PointerRNA *ptr, float value)
+{
+	ClothSimSettings *settings = (ClothSimSettings *)ptr->data;
+
+	/* check for clipping */
+	if (value < settings->shear)
+		value = settings->shear;
+
+	settings->max_shear = value;
 }
 
 static void rna_ClothSettings_max_sewing_set(struct PointerRNA *ptr, float value)
@@ -184,6 +228,24 @@ static void rna_ClothSettings_struct_vgroup_set(PointerRNA *ptr, const char *val
 	rna_object_vgroup_name_index_set(ptr, value, &sim->vgroup_struct);
 }
 
+static void rna_ClothSettings_shear_vgroup_get(PointerRNA *ptr, char *value)
+{
+	ClothSimSettings *sim = (ClothSimSettings *)ptr->data;
+	rna_object_vgroup_name_index_get(ptr, value, sim->vgroup_shear);
+}
+
+static int rna_ClothSettings_shear_vgroup_length(PointerRNA *ptr)
+{
+	ClothSimSettings *sim = (ClothSimSettings *)ptr->data;
+	return rna_object_vgroup_name_index_length(ptr, sim->vgroup_shear);
+}
+
+static void rna_ClothSettings_shear_vgroup_set(PointerRNA *ptr, const char *value)
+{
+	ClothSimSettings *sim = (ClothSimSettings *)ptr->data;
+	rna_object_vgroup_name_index_set(ptr, value, &sim->vgroup_shear);
+}
+
 static void rna_ClothSettings_bend_vgroup_get(PointerRNA *ptr, char *value)
 {
 	ClothSimSettings *sim = (ClothSimSettings *)ptr->data;
@@ -350,6 +412,12 @@ static void rna_def_cloth_sim_settings(BlenderRNA *brna)
 	StructRNA *srna;
 	PropertyRNA *prop;
 
+	static const EnumPropertyItem prop_bending_model_items[] = {
+		{CLOTH_BENDING_ANGULAR, "ANGULAR", 0, "Angular", "Cloth model with angular bending springs"},
+		{CLOTH_BENDING_LINEAR, "LINEAR", 0, "Linear", "Cloth model with linear bending springs (legacy)"},
+		{0, NULL, 0, NULL, NULL}
+	};
+
 	srna = RNA_def_struct(brna, "ClothSettings", NULL);
 	RNA_def_struct_ui_text(srna, "Cloth Settings", "Cloth simulation settings for an object");
 	RNA_def_struct_sdna(srna, "ClothSimSettings");
@@ -511,25 +579,67 @@ static void rna_def_cloth_sim_settings(BlenderRNA *brna)
 	RNA_def_property_update(prop, 0, "rna_cloth_update");
 	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
 
-	prop = RNA_def_property(srna, "spring_damping", PROP_FLOAT, PROP_NONE);
-	RNA_def_property_float_sdna(prop, NULL, "Cdis");
+	prop = RNA_def_property(srna, "tension_damping", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_float_sdna(prop, NULL, "tension_damp");
 	RNA_def_property_range(prop, 0.0f, 50.0f);
-	RNA_def_property_ui_text(prop, "Spring Damping",
-	                         "Damping of cloth velocity (higher = more smooth, less jiggling)");
+	RNA_def_property_ui_text(prop, "Tension Spring Damping",
+	                         "Damping of spring velocity (higher = more smooth, less jiggling)");
 	RNA_def_property_update(prop, 0, "rna_cloth_update");
 
-	prop = RNA_def_property(srna, "structural_stiffness", PROP_FLOAT, PROP_NONE);
-	RNA_def_property_float_sdna(prop, NULL, "structural");
+	prop = RNA_def_property(srna, "compression_damping", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_float_sdna(prop, NULL, "compression_damp");
+	RNA_def_property_range(prop, 0.0f, 50.0f);
+	RNA_def_property_ui_text(prop, "Compression Spring Damping",
+	                         "Damping of spring velocity (higher = more smooth, less jiggling)");
+	RNA_def_property_update(prop, 0, "rna_cloth_update");
+
+	prop = RNA_def_property(srna, "shear_damping", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_float_sdna(prop, NULL, "shear_damp");
+	RNA_def_property_range(prop, 0.0f, 50.0f);
+	RNA_def_property_ui_text(prop, "Shear Spring Damping",
+	                         "Damping of spring velocity (higher = more smooth, less jiggling)");
+	RNA_def_property_update(prop, 0, "rna_cloth_update");
+
+	prop = RNA_def_property(srna, "tension_stiffness", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_float_sdna(prop, NULL, "tension");
 	RNA_def_property_range(prop, 0.0f, 10000.0f);
-	RNA_def_property_float_funcs(prop, NULL, "rna_ClothSettings_structural_set", NULL);
-	RNA_def_property_ui_text(prop, "Structural Stiffness", "Overall stiffness of structure");
+	RNA_def_property_float_funcs(prop, NULL, "rna_ClothSettings_tension_set", NULL);
+	RNA_def_property_ui_text(prop, "Tension Stiffness", "Tension stiffness of structure");
+	RNA_def_property_update(prop, 0, "rna_cloth_update");
+
+	prop = RNA_def_property(srna, "tension_stiffness_max", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_float_sdna(prop, NULL, "max_tension");
+	RNA_def_property_range(prop, 0.0f, 10000.0f);
+	RNA_def_property_float_funcs(prop, NULL, "rna_ClothSettings_max_tension_set", NULL);
+	RNA_def_property_ui_text(prop, "Tension Stiffness Maximum", "Maximum tension stiffness value");
+	RNA_def_property_update(prop, 0, "rna_cloth_update");
+
+	prop = RNA_def_property(srna, "compression_stiffness", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_float_sdna(prop, NULL, "compression");
+	RNA_def_property_range(prop, 0.0f, 10000.0f);
+	RNA_def_property_float_funcs(prop, NULL, "rna_ClothSettings_compression_set", NULL);
+	RNA_def_property_ui_text(prop, "Compression Stiffness", "Compression stiffness of structure");
+	RNA_def_property_update(prop, 0, "rna_cloth_update");
+
+	prop = RNA_def_property(srna, "compression_stiffness_max", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_float_sdna(prop, NULL, "max_compression");
+	RNA_def_property_range(prop, 0.0f, 10000.0f);
+	RNA_def_property_float_funcs(prop, NULL, "rna_ClothSettings_max_compression_set", NULL);
+	RNA_def_property_ui_text(prop, "Compression Stiffness Maximum", "Maximum compression stiffness value");
+	RNA_def_property_update(prop, 0, "rna_cloth_update");
+
+	prop = RNA_def_property(srna, "shear_stiffness", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_float_sdna(prop, NULL, "shear");
+	RNA_def_property_range(prop, 0.0f, 10000.0f);
+	RNA_def_property_float_funcs(prop, NULL, "rna_ClothSettings_shear_set", NULL);
+	RNA_def_property_ui_text(prop, "Shear Stiffness", "Shear spring stiffness");
 	RNA_def_property_update(prop, 0, "rna_cloth_update");
 
-	prop = RNA_def_property(srna, "structural_stiffness_max", PROP_FLOAT, PROP_NONE);
-	RNA_def_property_float_sdna(prop, NULL, "max_struct");
+	prop = RNA_def_property(srna, "shear_stiffness_max", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_float_sdna(prop, NULL, "max_shear");
 	RNA_def_property_range(prop, 0.0f, 10000.0f);
-	RNA_def_property_float_funcs(prop, NULL, "rna_ClothSettings_max_struct_set", NULL);
-	RNA_def_property_ui_text(prop, "Structural Stiffness Maximum", "Maximum structural stiffness value");
+	RNA_def_property_float_funcs(prop, NULL, "rna_ClothSettings_max_shear_set", NULL);
+	RNA_def_property_ui_text(prop, "Shear Stiffness Maximum", "Maximum shear scaling value");
 	RNA_def_property_update(prop, 0, "rna_cloth_update");
 
 	prop = RNA_def_property(srna, "sewing_force_max", PROP_FLOAT, PROP_NONE);
@@ -547,6 +657,14 @@ static void rna_def_cloth_sim_settings(BlenderRNA *brna)
 	                         "Vertex group for fine control over structural stiffness");
 	RNA_def_property_update(prop, 0, "rna_cloth_update");
 
+	prop = RNA_def_property(srna, "vertex_group_shear_stiffness", PROP_STRING, PROP_NONE);
+	RNA_def_property_string_funcs(prop, "rna_ClothSettings_shear_vgroup_get",
+	                              "rna_ClothSettings_shear_vgroup_length",
+	                              "rna_ClothSettings_shear_vgroup_set");
+	RNA_def_property_ui_text(prop, "Shear Stiffness Vertex Group",
+	                         "Vertex group for fine control over shear stiffness");
+	RNA_def_property_update(prop, 0, "rna_cloth_update");
+
 	prop = RNA_def_property(srna, "bending_stiffness", PROP_FLOAT, PROP_NONE);
 	RNA_def_property_float_sdna(prop, NULL, "bending");
 	RNA_def_property_range(prop, 0.0f, 10000.0f);
@@ -601,24 +719,17 @@ static void rna_def_cloth_sim_settings(BlenderRNA *brna)
 	RNA_def_property_update(prop, 0, "rna_cloth_update");
 	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
 
+	prop = RNA_def_property(srna, "bending_model", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_sdna(prop, NULL, "bending_model");
+	RNA_def_property_enum_items(prop, prop_bending_model_items);
+	RNA_def_property_ui_text(prop, "Bending Model", "Physical model for simulating bending forces");
+	RNA_def_property_update(prop, 0, "rna_cloth_update");
+	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
+
 	/* unused */
 
 	/* unused still */
 #if 0
-	prop = RNA_def_property(srna, "shear_stiffness", PROP_FLOAT, PROP_NONE);
-	RNA_def_property_float_sdna(prop, NULL, "shear");
-	RNA_def_property_range(prop, 0.0f, 1000.0f);
-	RNA_def_property_ui_text(prop, "Shear Stiffness", "Shear spring stiffness");
-#endif
-	/* unused still */
-#if 0
-	prop = RNA_def_property(srna, "shear_stiffness_max", PROP_FLOAT, PROP_NONE);
-	RNA_def_property_float_sdna(prop, NULL, "max_shear");
-	RNA_def_property_range(prop, 0.0f, upperLimitf);
-	RNA_def_property_ui_text(prop, "Shear Stiffness Maximum", "Maximum shear scaling value");
-#endif
-	/* unused still */
-#if 0
 	prop = RNA_def_property(srna, "effector_force_scale", PROP_FLOAT, PROP_NONE);
 	RNA_def_property_float_sdna(prop, NULL, "eff_force_scale");
 	RNA_def_property_range(prop, 0.0f, 100.0f);