add an influence slider to mesh cache.

release/scripts/startup/bl_ui/properties_data_modifier.py

@@ -167,6 +167,7 @@ class DATA_PT_modifiers(ModifierButtonsPanel, Panel):
         layout.prop(md, "filepath")
 
         layout.label(text="Evaluation:")
+        layout.prop(md, "factor", slider=True)
         layout.prop(md, "interpolation")
 
         layout.label(text="Time Mapping:")

source/blender/blenlib/BLI_math_vector.h

@@ -255,6 +255,7 @@ void sub_vn_vn(float *array_tar, const float *array_src, const int size);
 void sub_vn_vnvn(float *array_tar, const float *array_src_a, const float *array_src_b, const int size);
 void msub_vn_vn(float *array_tar, const float *array_src, const float f, const int size);
 void msub_vn_vnvn(float *array_tar, const float *array_src_a, const float *array_src_b, const float f, const int size);
+void interp_vn_vn(float *array_tar, const float *array_src, const float t, const int size);
 void fill_vn_i(int *array_tar, const int size, const int val);
 void fill_vn_ushort(unsigned short *array_tar, const int size, const unsigned short val);
 void fill_vn_fl(float *array_tar, const int size, const float val);

source/blender/blenlib/intern/math_vector.c

@@ -711,6 +711,19 @@ void msub_vn_vnvn(float *array_tar, const float *array_src_a, const float *array
 	}
 }
 
+void interp_vn_vn(float *array_tar, const float *array_src, const float t, const int size)
+{
+	const float s = 1.0f - t;
+	float *tar = array_tar + (size - 1);
+	const float *src = array_src + (size - 1);
+	int i = size;
+	while (i--) {
+		*(tar) = (s * *(tar)) + (t * *(src));
+		tar--;
+		src--;
+	}
+}
+
 void fill_vn_i(int *array_tar, const int size, const int val)
 {
 	int *tar = array_tar + (size - 1);

source/blender/makesdna/DNA_modifier_types.h

@@ -1174,7 +1174,7 @@ typedef struct MeshCacheModifierData {
 
 	char interp;
 
-	char pad[4];
+	float factor;
 
 	/* play_mode == MOD_MESHCACHE_PLAY_CFEA */
 	float frame_start;

source/blender/makesrna/intern/rna_modifier.c

@@ -3558,6 +3558,12 @@ static void rna_def_modifier_meshcache(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "File Path", "Path to external displacements file");
 	RNA_def_property_update(prop, 0, "rna_Modifier_update");
 
+	prop = RNA_def_property(srna, "factor", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_float_sdna(prop, NULL, "factor");
+	RNA_def_property_range(prop, 0.0f, 1.0f);
+	RNA_def_property_ui_text(prop, "Influence", "Influence of the deformation");
+	RNA_def_property_update(prop, 0, "rna_Modifier_update");
+
 	/* -------------------------------------------------------------------- */
 	/* Axis Conversion */
 	prop = RNA_def_property(srna, "forward_axis", PROP_ENUM, PROP_NONE);

source/blender/modifiers/intern/MOD_meshcache.c

@@ -34,12 +34,13 @@
 #include "BLI_path_util.h"
 #include "BLI_math.h"
 
-
 #include "BKE_DerivedMesh.h"
 #include "BKE_scene.h"
 #include "BKE_global.h"
 #include "BKE_main.h"
 
+#include "MEM_guardedalloc.h"
+
 #include "MOD_meshcache_util.h"  /* utility functions */
 
 #include "MOD_modifiertypes.h"
@@ -99,6 +100,8 @@ static void initData(ModifierData *md)
 	mcmd->interp = MOD_MESHCACHE_INTERP_LINEAR;
 	mcmd->frame_scale = 1.0f;
 
+	mcmd->factor = 1.0f;
+
 	/* (Y, Z). Blender default */
 	mcmd->forward_axis = 1;
 	mcmd->up_axis      = 2;
@@ -124,6 +127,8 @@ static void copyData(ModifierData *md, ModifierData *target)
 	tmcmd->frame_start = mcmd->frame_start;
 	tmcmd->frame_scale = mcmd->frame_scale;
 
+	tmcmd->factor = mcmd->factor;
+
 	tmcmd->eval_frame  = mcmd->eval_frame;
 	tmcmd->eval_time   = mcmd->eval_time;
 	tmcmd->eval_factor = mcmd->eval_factor;
@@ -142,14 +147,19 @@ static int isDisabled(ModifierData *md, int UNUSED(useRenderParams))
 	MeshCacheModifierData *mcmd = (MeshCacheModifierData *) md;
 
 	/* leave it up to the modifier to check the file is valid on calculation */
-	return (mcmd->filepath[0] == '\0');
+	return (mcmd->factor <= 0.0f) || (mcmd->filepath[0] == '\0');
 }
 
 
 static void meshcache_do(
         MeshCacheModifierData *mcmd, Object *ob, DerivedMesh *UNUSED(dm),
-        float (*vertexCos)[3], int numVerts)
+        float (*vertexCos_)[3], int numVerts)
 {
+	float (*vertexCos_Store)[3] = (mcmd->factor < 1.0f) ?
+	                              MEM_mallocN(sizeof(*vertexCos_Store) * numVerts, __func__) : NULL;
+	float (*vertexCos_Real)[3] = vertexCos_;
+	float (*vertexCos)[3] = vertexCos_Store ? vertexCos_Store : vertexCos_Real;
+
 	Scene *scene = mcmd->modifier.scene;
 	const float fps = FPS;
 
@@ -263,6 +273,14 @@ static void meshcache_do(
 			}
 		}
 	}
+
+	if (vertexCos_Store) {
+		if (ok) {
+			interp_vn_vn(*vertexCos_Real, *vertexCos_Store, mcmd->factor, numVerts * 3);
+		}
+
+		MEM_freeN(vertexCos_Store);
+	}
 }
 
 static void deformVerts(ModifierData *md, Object *ob,