[#2874] Update Transform on Zone entity to outline's centroid on setPoints()

scripts/api/entity/zone.lua

@@ -19,15 +19,30 @@ end
 local Entity = getLuaEntityFunctionTable()
 --- Sets the corners of this Zone n-gon to x_1, y_1, x_2, y_2, ... x_n, y_n.
 --- Positive x coordinates are right/"east" of the origin, and positive y coordinates are down/"south" of the origin in space.
+--- This also moves the Zone's Transform coordinates to the new centroid via setPosition().
 --- Example: zone:setPoints(2000,0, 0,3000, -2000,0) -- defines a triangular zone
 function Entity:setPoints(...)
     if self.components.zone then
         local coords = {...}
         local points = {}
-        for n=1,#coords,2 do
-            table.insert(points, {coords[n], coords[n+1]})
+        local sum_x, sum_y, count = 0, 0, 0
+        for n = 1, #coords, 2 do
+            local x, y = coords[n], coords[n+1]
+            table.insert(points, {x, y})
+            sum_x = sum_x + x
+            sum_y = sum_y + y
+            count = count + 1
+        end
+        if count > 0 then
+            local center_x = sum_x / count
+            local center_y = sum_y / count
+            self:setPosition(center_x, center_y)
+            local relative_points = {}
+            for _, pt in ipairs(points) do
+                table.insert(relative_points, {pt[1] - center_x, pt[2] - center_y})
+            end
+            self.components.zone.points = relative_points
         end
-        self.components.zone.points = points
     end
     return self
 end

scripts/api/gm.lua

@@ -586,12 +586,17 @@ function __exportZone(entity)
             extras = extras .. ":setLocalSkybox('" .. z.skybox .. "')"
         end
     end
-    -- Outline points: z.points is {{x1,y1},{x2,y2},...}; setPoints takes a flat coord list
+    -- Outline points: z.points is {{x1,y1},{x2,y2},...} (relative to center); setPoints takes absolute coords
     if z.points and #z.points > 0 then
         local coords = {}
+        local tx, ty = 0, 0
+        if entity.components.transform and entity.components.transform.position then
+            tx = entity.components.transform.position[1] or 0
+            ty = entity.components.transform.position[2] or 0
+        end
         for _, pt in ipairs(z.points) do
-            coords[#coords+1] = string.format("%.0f", pt[1])
-            coords[#coords+1] = string.format("%.0f", pt[2])
+            coords[#coords+1] = string.format("%.0f", pt[1] + tx)
+            coords[#coords+1] = string.format("%.0f", pt[2] + ty)
         end
         extras = extras .. ":setPoints(" .. table.concat(coords, ", ") .. ")"
     end

src/components/zone.cpp

@@ -5,19 +5,23 @@
 
 void Zone::updateTriangles()
 {
-    if (outline.empty()) {
-        radius = 1;
-        triangles.clear();
-        return;
-    }
+    // Re-initalize the zone radius cache and shape.
+    radius = 1.0f;
+    triangles.clear();
+
+    // If there aren't any points, clear the shape.
+    if (outline.empty()) return;
 
+    // Place the label at the center of the outline.
     label_offset = centerOfMass(outline);
-    radius = 1;
-    for(auto p : outline) {
+
+    // Populate the shape and recalculate radius from outline points.
+    for (auto p : outline)
+    {
         p -= label_offset;
         radius = std::max(radius, glm::length(p));
     }
-    
-    triangles.clear();
+
+    // Re-triangulate the shape.
     Triangulate::process(outline, triangles);
-}
+}