fix state machine advanceAndApply

this almost fixes the issue with ios. but somehow this ends up returning false sometimes still... it seem to stop in a similar position each time, a little nudge being enough to get it moving again for a longer while

also

```
- (bool)advanceBy:(double)elapsedSeconds
{
    return instance->advanceAndApply(elapsedSeconds);
}
```

note the intervals at which we call this function are somewhat laughable,

![CleanShot 2024-05-01 at 16 07 05](https://github.com/rive-app/rive/assets/1216025/694e61bf-8d0c-465e-9676-af221d6be174)

Diffs=
8db7cac50 fix state machine advanceAndApply (#7183)

Co-authored-by: Maxwell Talbot <talbot.maxwell@gmail.com>

.rive_head

@@ -1 +1 @@
-a55f1ffb6cabe9b918fa0b8fd1ad11b4d656ae1c
+8db7cac50c53ab10838da0cd80c869917c51c72a

include/rive/animation/nested_remap_animation.hpp

@@ -8,7 +8,7 @@ class NestedRemapAnimation : public NestedRemapAnimationBase
 {
 public:
     void timeChanged() override;
-    void advance(float elapsedSeconds) override;
+    bool advance(float elapsedSeconds) override;
     void initializeAnimation(ArtboardInstance*) override;
 };
 } // namespace rive

include/rive/animation/nested_simple_animation.hpp

@@ -7,7 +7,7 @@ namespace rive
 class NestedSimpleAnimation : public NestedSimpleAnimationBase
 {
 public:
-    void advance(float elapsedSeconds) override;
+    bool advance(float elapsedSeconds) override;
 };
 } // namespace rive
 

include/rive/animation/nested_state_machine.hpp

@@ -20,7 +20,7 @@ class NestedStateMachine : public NestedStateMachineBase
 public:
     NestedStateMachine();
     ~NestedStateMachine() override;
-    void advance(float elapsedSeconds) override;
+    bool advance(float elapsedSeconds) override;
     void initializeAnimation(ArtboardInstance*) override;
     StateMachineInstance* stateMachineInstance();
 

include/rive/nested_animation.hpp

@@ -12,7 +12,7 @@ class NestedAnimation : public NestedAnimationBase
     StatusCode onAddedDirty(CoreContext* context) override;
 
     // Advance animations and apply them to the artboard.
-    virtual void advance(float elapsedSeconds) = 0;
+    virtual bool advance(float elapsedSeconds) = 0;
 
     // Initialize the animation (make instances as necessary) from the
     // source artboard.

src/animation/nested_remap_animation.cpp

@@ -18,10 +18,13 @@ void NestedRemapAnimation::initializeAnimation(ArtboardInstance* artboard)
     timeChanged();
 }
 
-void NestedRemapAnimation::advance(float elapsedSeconds)
+bool NestedRemapAnimation::advance(float elapsedSeconds)
 {
+    bool keepGoing = false;
     if (m_AnimationInstance != nullptr && mix() != 0.0f)
     {
         m_AnimationInstance->apply(mix());
+        keepGoing = true;
     }
+    return keepGoing;
 }

src/animation/nested_simple_animation.cpp

@@ -3,17 +3,19 @@
 
 using namespace rive;
 
-void NestedSimpleAnimation::advance(float elapsedSeconds)
+bool NestedSimpleAnimation::advance(float elapsedSeconds)
 {
+    bool keepGoing = false;
     if (m_AnimationInstance != nullptr)
     {
         if (isPlaying())
         {
-            m_AnimationInstance->advance(elapsedSeconds * speed());
+            keepGoing = m_AnimationInstance->advance(elapsedSeconds * speed());
         }
         if (mix() != 0.0f)
         {
             m_AnimationInstance->apply(mix());
         }
     }
+    return keepGoing;
 }

src/animation/nested_state_machine.cpp

@@ -10,12 +10,14 @@ using namespace rive;
 NestedStateMachine::NestedStateMachine() {}
 NestedStateMachine::~NestedStateMachine() {}
 
-void NestedStateMachine::advance(float elapsedSeconds)
+bool NestedStateMachine::advance(float elapsedSeconds)
 {
+    bool keepGoing = false;
     if (m_StateMachineInstance != nullptr)
     {
-        m_StateMachineInstance->advance(elapsedSeconds);
+        keepGoing = m_StateMachineInstance->advance(elapsedSeconds);
     }
+    return keepGoing;
 }
 
 void NestedStateMachine::initializeAnimation(ArtboardInstance* artboard)

src/animation/state_machine_instance.cpp

@@ -744,9 +744,9 @@ bool StateMachineInstance::advance(float seconds)
 
 bool StateMachineInstance::advanceAndApply(float seconds)
 {
-    bool more = this->advance(seconds);
-    m_artboardInstance->advance(seconds);
-    return more;
+    bool keepGoing = this->advance(seconds);
+    keepGoing = m_artboardInstance->advance(seconds) || keepGoing;
+    return keepGoing;
 }
 
 void StateMachineInstance::markNeedsAdvance() { m_needsAdvance = true; }

src/nested_artboard.cpp

@@ -129,15 +129,16 @@ StatusCode NestedArtboard::onAddedClean(CoreContext* context)
 
 bool NestedArtboard::advance(float elapsedSeconds)
 {
+    bool keepGoing = false;
     if (m_Artboard == nullptr || isCollapsed())
     {
-        return false;
+        return keepGoing;
     }
     for (auto animation : m_NestedAnimations)
     {
-        animation->advance(elapsedSeconds);
+        keepGoing = keepGoing || animation->advance(elapsedSeconds);
     }
-    return m_Artboard->advance(elapsedSeconds);
+    return m_Artboard->advance(elapsedSeconds) || keepGoing;
 }
 
 void NestedArtboard::update(ComponentDirt value)

test/nested_artboard.cpp

@@ -37,4 +37,30 @@ TEST_CASE("collapsed nested artboards do not advance", "[solo]")
     auto greenMovingShapes = greenNestedArtboardArtboard->find<rive::Shape>();
     auto greenRect = greenMovingShapes.at(0);
     REQUIRE(greenRect->x() == 50);
+}
+
+TEST_CASE("nested artboards with looping animations will keep main advanceAndApply advancing",
+          "[nested]")
+{
+    auto file = ReadRiveFile("../../test/assets/ball_test.riv");
+    auto artboard = file->artboard("Artboard")->instance();
+    artboard->advance(0.0f);
+    auto stateMachine = artboard->stateMachineAt(0);
+    REQUIRE(stateMachine->advanceAndApply(0.0f) == true);
+    REQUIRE(stateMachine->advanceAndApply(1.0f) == true);
+    REQUIRE(stateMachine->advanceAndApply(1.0f) == true);
+}
+TEST_CASE("nested artboards with one shot animations will not main advanceAndApply advancing",
+          "[nested]")
+{
+
+    auto file = ReadRiveFile("../../test/assets/ball_test.riv");
+    auto artboard = file->artboard("Artboard 2")->instance();
+    artboard->advance(0.0f);
+    auto stateMachine = artboard->stateMachineAt(0);
+    REQUIRE(stateMachine->advanceAndApply(0.0f) == true);
+    REQUIRE(stateMachine->advanceAndApply(0.9f) == true);
+    REQUIRE(stateMachine->advanceAndApply(0.1f) == true);
+    // nested artboards animation is 1s long
+    REQUIRE(stateMachine->advanceAndApply(0.1f) == false);
 }