Hook modifier

@@ -0,0 +123,4 @@
+};
+
+/* Calculate the factor of falloff. */
+static float gpencil_hook_falloff(const GreasePencilHookData_cb *tData, const float len_sq)

@@ -0,0 +134,4 @@
+
+    if (tData->falloff_type == MOD_GREASE_PENCIL_HOOK_Falloff_Const) {
+      fac = 1.0f;
+      goto finally;

@@ -0,0 +139,4 @@
+    else if (tData->falloff_type == MOD_GREASE_PENCIL_HOOK_Falloff_InvSquare) {
+      /* avoid sqrt below */
+      fac = 1.0f - (len_sq / tData->falloff_sq);
+      goto finally;

@@ -0,0 +142,4 @@
+      goto finally;
+    }
+
+    fac = 1.0f - (math::sqrt(len_sq) / tData->falloff);

@@ -0,0 +146,4 @@
+
+    switch (tData->falloff_type) {
+      case MOD_GREASE_PENCIL_HOOK_Falloff_Curve:
+        fac = BKE_curvemapping_evaluateF(tData->curfalloff, 0, fac);

@@ -0,0 +167,4 @@
+        break;
+    }
+
+  finally:

@@ -0,0 +170,4 @@
+  finally:
+    return fac * tData->fac_orig;
+  }
+  else {

@@ -0,0 +176,4 @@
+}
+
+/* apply point deformation */
+static void gpencil_hook_co_apply(GreasePencilHookData_cb *tData, float weight, float3 &position)

@@ -0,0 +116,4 @@
+  if (len_sq > falloff_sq) {
+    return 0.0f;
+  }
+  if (len_sq > 0.0f) {

@@ -0,0 +136,4 @@
+        return (3.0f * fac * fac - 2.0f * fac * fac * fac) * fac_orig;
+      case MOD_GREASE_PENCIL_HOOK_Falloff_Root:
+        return math::sqrt(fac) * fac_orig;
+        ;

@@ -0,0 +140,4 @@
+        break;
+      case MOD_GREASE_PENCIL_HOOK_Falloff_Sphere:
+        return math::sqrt(2 * fac - fac * fac) * fac_orig;
+      case MOD_GREASE_PENCIL_HOOK_Falloff_Linear: /* Pass. */

@@ -0,0 +171,4 @@
+  const float falloff = (mmd.falloff_type == eHook_Falloff_None) ? 0.0f : mmd.falloff;
+  const float falloff_sq = square_f(falloff);
+  const float fac_orig = mmd.force;
+  bool use_falloff = falloff_sq != 0.0f;

@@ -0,0 +172,4 @@
+  const float falloff_sq = square_f(falloff);
+  const float fac_orig = mmd.force;
+  bool use_falloff = falloff_sq != 0.0f;
+  bool use_uniform = (mmd.flag & MOD_GRAESE_PENCIL_HOOK_UNIFORM_SPACE) != 0;

@@ -0,0 +239,4 @@
+        fac = fac_orig;
+      }
+
+      if (fac) {

@@ -0,0 +240,4 @@
+      }
+
+      if (fac) {
+        float3 co_tmp = math::transform_point(use_mat, positions[point]);

@@ -0,0 +174,4 @@
+  const bool use_falloff = falloff_sq != 0.0f;
+  const bool use_uniform = (mmd.flag & MOD_GRAESE_PENCIL_HOOK_UNIFORM_SPACE) != 0;
+
+  float3x3 mat_uniform;

@@ -0,0 +191,4 @@
+    /* Just object target. */
+    dmat = mmd.object->object_to_world();
+  }
+  ob.runtime->world_to_object = math::invert(ob.object_to_world());

@@ -0,0 +77,4 @@
+{
+  auto *mmd = reinterpret_cast<GreasePencilHookModifierData *>(md);
+  if (mmd->object != nullptr) {
+    DEG_add_object_relation(ctx->node, mmd->object, DEG_OB_COMP_GEOMETRY, "Hook Modifier");

@@ -0,0 +327,4 @@
+
+ModifierTypeInfo modifierType_GreasePencilHook = {
+    /*idname*/ "GreasePencilHookModifier",
+    /*name*/ N_("Hoook"),