improve verification for buffer_proto5

verify that different pieces of the sim are properly connected.

src/render.rs

@@ -494,9 +494,18 @@ impl<S: SampleableSim> Renderer<S> for Y4MRenderer {
 
 struct MultiRendererElement<S> {
     step_frequency: u64,
+    step_limit: Option<u64>,
     renderer: Box<dyn Renderer<S>>,
 }
 
+impl<S> MultiRendererElement<S> {
+    fn work_this_frame(&self, frame: u64) -> bool {
+        frame % self.step_frequency == 0 && match self.step_limit {
+            None => true,
+            Some(end) => frame < end,
+        }
+    }
+}
 
 pub struct MultiRenderer<S> {
     renderers: RwLock<Vec<MultiRendererElement<S>>>,
@@ -514,18 +523,19 @@ impl<S> MultiRenderer<S> {
     pub fn new() -> Self {
         Default::default()
     }
-    pub fn push<R: Renderer<S> + 'static>(&self, renderer: R, step_frequency: u64) {
+    pub fn push<R: Renderer<S> + 'static>(&self, renderer: R, step_frequency: u64, step_limit: Option<u64>) {
         self.renderers.write().unwrap().push(MultiRendererElement {
             step_frequency,
+            step_limit,
             renderer: Box::new(renderer),
         });
     }
-    pub fn with<R: Renderer<S> + 'static>(self, renderer: R, step_frequency: u64) -> Self {
-        self.push(renderer, step_frequency);
+    pub fn with<R: Renderer<S> + 'static>(self, renderer: R, step_frequency: u64, step_limit: Option<u64>) -> Self {
+        self.push(renderer, step_frequency, step_limit);
         self
     }
     pub fn any_work_for_frame(&self, frame: u64) -> bool {
-        self.renderers.read().unwrap().iter().any(|m| frame % m.step_frequency == 0)
+        self.renderers.read().unwrap().iter().any(|m| m.work_this_frame(frame))
     }
 }
 
@@ -541,7 +551,7 @@ impl<S: SampleableSim> Renderer<S> for MultiRenderer<S> {
 
     fn render_with_image(&self, state: &S, im: &RgbImage, measurements: &[Box<dyn AbstractMeasurement>], config: RenderConfig) {
         for r in &*self.renderers.read().unwrap() {
-            if state.step_no() % r.step_frequency == 0 {
+            if r.work_this_frame(state.step_no()) {
                 r.renderer.render_with_image(state, im, measurements, config);
             }
         }