add callback OnLineChange when line changes its vertices or vertex positions

docs/sdk/definition/script.xml

@@ -193,6 +193,11 @@
           <col>int cause</col>
           <col>When a line object is broken. cause: 0 by movement, 1 because of a missing or incomplete target object.</col>
         </row>
+        <row id="OnLineChange">
+          <literal_col>OnLineChange</literal_col>
+          <col>int cause</col>
+          <col>When a line object is changed, that is when one of it vertices changed its position.</col>
+        </row>
         <row id="BuildNeedsMaterial">
           <literal_col>BuildNeedsMaterial</literal_col>
           <col>id material_definition, int amount</col>

src/game/C4GameScript.h

@@ -73,6 +73,7 @@ bool C4ValueToMatrix(const C4ValueArray& array, StdMeshMatrix* matrix);
 #define PSF_Stuck               "~Stuck"
 #define PSF_GrabLost            "~GrabLost"
 #define PSF_OnLineBreak         "~OnLineBreak" // iCause
+#define PSF_OnLineChange        "~OnLineChange" // current_length
 #define PSF_BuildNeedsMaterial  "~BuildNeedsMaterial" // idMat1, iAmount1, idMat2, iAmount2...
 #define PSF_ControlTransfer     "~ControlTransfer" // C4Object* pObj, int iTx, int iTy
 #define PSF_OnSynchronized       "~OnSynchronized"

src/object/C4Object.cpp

@@ -3999,6 +3999,7 @@ void C4Object::ExecAction()
 	case DFA_CONNECT:
 		{
 			bool fBroke=false;
+			bool fLineChange = false;
 
 			// Line destruction check: Target missing or incomplete
 			if (!Action.Target || (Action.Target->Con<FullCon)) fBroke=true;
@@ -4032,6 +4033,8 @@ void C4Object::ExecAction()
 				// No-intersection line
 				if (Def->LineIntersect == 1)
 					{ Shape.VtxX[0]=iConnectX1; Shape.VtxY[0]=iConnectY1; }
+					
+				fLineChange = true;
 			}
 
 			// Movement by Target2
@@ -4055,6 +4058,8 @@ void C4Object::ExecAction()
 				// No-intersection line
 				if (Def->LineIntersect == 1)
 					{ Shape.VtxX[Shape.VtxNum-1]=iConnectX2; Shape.VtxY[Shape.VtxNum-1]=iConnectY2; }
+					
+				fLineChange = true;
 			}
 
 			// Check max length
@@ -4063,7 +4068,9 @@ void C4Object::ExecAction()
 			if (max_dist)
 			{
 				int32_t dist_x = iConnectX2 - iConnectX1, dist_y = iConnectY2 - iConnectY1;
-				int64_t dist_x2 = int64_t(dist_x)*dist_x, dist_y2 = int64_t(dist_y)*dist_y, max_dist2 = int64_t(max_dist)*max_dist;
+				int64_t dist_x2 = int64_t(dist_x)*dist_x;
+				int64_t dist_y2 = int64_t(dist_y)*dist_y;
+				int64_t max_dist2 = int64_t(max_dist)*max_dist;
 				if (dist_x2+dist_y2 > max_dist2) fBroke = true;
 			}
 
@@ -4077,7 +4084,12 @@ void C4Object::ExecAction()
 
 			// Reduce line segments
 			if (!::Game.iTick35)
-				ReduceLineSegments(Shape, !::Game.iTick2);
+				if (ReduceLineSegments(Shape, !::Game.iTick2))
+					fLineChange = true;
+					
+			// Line change callback
+			if (fLineChange)
+				Call(PSF_OnLineChange);
 		}
 		break;
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