Animate items emerging from building output ports

src/ui/GameWorldView.cpp

@@ -402,6 +402,10 @@ void GameWorldView::paintGL()
     painter.setRenderHint(QPainter::Antialiasing, false);
 
     drawTiles(painter);
+    // Emerging items are drawn before the buildings so the building body occludes
+    // the portion still inside the footprint, making items appear to slide out of
+    // the output port rather than pop into existence (REQ-MAT-OUTPUT-EMERGE).
+    drawEmergingItems(painter);
     drawBuildings(painter);
     drawCopyConfigFeedback(painter);
     drawStations(painter);
@@ -1153,6 +1157,29 @@ void GameWorldView::drawCopyConfigFeedback(QPainter& painter)
     }
 }
 
+void GameWorldView::drawEmergingItems(QPainter& painter)
+{
+    const float halfPx = tilePx() * 0.5f * 0.5f;
+
+    m_sim->buildings().forEachEmergingItem(
+        [&](const ItemType& type, QPointF worldPos)
+    {
+        const std::map<std::string, ItemVisuals>::const_iterator it =
+            m_visuals->items.find(type.id);
+        if (it == m_visuals->items.end()) { return; }
+
+        const QPointF center = worldToWidget(
+            QVector2D(static_cast<float>(worldPos.x()),
+                      static_cast<float>(worldPos.y())));
+        const QRectF rect(center.x() - halfPx, center.y() - halfPx,
+                          halfPx * 2, halfPx * 2);
+        painter.fillRect(rect, it->second.fill);
+        painter.setPen(QPen(it->second.outline, 1));
+        painter.setBrush(Qt::NoBrush);
+        painter.drawRect(rect);
+    });
+}
+
 void GameWorldView::drawBeltItems(QPainter& painter)
 {
     const float halfPx = tilePx() * 0.5f * 0.5f;