Implement event_whenbackropswitchesto

Author: adazem009

src/dev/blocks/eventblocks.cpp

@@ -27,6 +27,7 @@ void EventBlocks::registerBlocks(IEngine *engine)
     engine->addCompileFunction(this, "event_whenthisspriteclicked", &compileWhenThisSpriteClicked);
     engine->addCompileFunction(this, "event_whenstageclicked", &compileWhenStageClicked);
     engine->addCompileFunction(this, "event_whenbroadcastreceived", &compileWhenBroadcastReceived);
+    engine->addCompileFunction(this, "event_whenbackdropswitchesto", &compileWhenBackdropSwitchesTo);
 }
 
 CompilerValue *EventBlocks::compileWhenTouchingObject(Compiler *compiler)
@@ -65,3 +66,14 @@ CompilerValue *EventBlocks::compileWhenBroadcastReceived(Compiler *compiler)
 
     return nullptr;
 }
+
+CompilerValue *EventBlocks::compileWhenBackdropSwitchesTo(Compiler *compiler)
+{
+    auto block = compiler->block();
+    Field *field = compiler->field("BACKDROP");
+
+    if (field)
+        compiler->engine()->addBackdropChangeScript(block, field);
+
+    return nullptr;
+}

src/dev/blocks/eventblocks.h

@@ -21,6 +21,7 @@ class EventBlocks : public IExtension
         static CompilerValue *compileWhenThisSpriteClicked(Compiler *compiler);
         static CompilerValue *compileWhenStageClicked(Compiler *compiler);
         static CompilerValue *compileWhenBroadcastReceived(Compiler *compiler);
+        static CompilerValue *compileWhenBackdropSwitchesTo(Compiler *compiler);
 };
 
 } // namespace libscratchcpp

test/dev/blocks/event_blocks_test.cpp

@@ -99,3 +99,17 @@ TEST_F(EventBlocksTest, WhenBroadcastReceived)
     EXPECT_CALL(m_engineMock, addBroadcastScript(block, block->fieldAt(0).get(), broadcast.get()));
     compiler.compile(block);
 }
+
+TEST_F(EventBlocksTest, WhenBackdropSwitchesTo)
+{
+    auto target = std::make_shared<Sprite>();
+    ScriptBuilder builder(m_extension.get(), m_engine, target);
+
+    builder.addBlock("event_whenbackdropswitchesto");
+    builder.addDropdownField("BACKDROP", "backdrop2");
+    auto block = builder.currentBlock();
+
+    Compiler compiler(&m_engineMock, target.get());
+    EXPECT_CALL(m_engineMock, addBackdropChangeScript(block, block->fieldAt(0).get()));
+    compiler.compile(block);
+}