Implemented time stepping

src/engine.py

@@ -45,7 +45,6 @@ class Engine:
 
     def next(self, step_size: Decimal):
         """Calculate light values for next step in time. Step size in seconds."""
-        prev_time = self.render_time
         self.render_time += step_size
 
         for t in self.tracks:
@@ -53,9 +52,8 @@ class Engine:
                 continue
 
             # Move keyframes forward
-            while step_size > 0:
+            t.step(step_size)
-                # TODO
+            # TODO: Interpolate values
-                pass
 
     def propagate(self):
         """Forward new fixture states to APIs."""

src/models.py

@@ -104,17 +104,17 @@ class EngineFixture:
         """Set value of fixture based on parameter."""
         match parameter:
             case Parameter.ON:
-                self.on = value
+                self.on = value  # type: ignore
             case Parameter.HUE:
-                self.hue = value
+                self.hue = value  # type: ignore
             case Parameter.BRIGHTNESS:
-                self.brightness = value
+                self.brightness = value  # type: ignore
             case Parameter.SATURATION:
-                self.saturation = value
+                self.saturation = value  # type: ignore
             case Parameter.TEMPERATURE:
-                self.temperature = value
+                self.temperature = value  # type: ignore
             case Parameter.TOPIC:
-                self.topic = value
+                self.topic = value  # type: ignore
             case _:
                 logging.warning(
                     f"Unknown parameter [{parameter}] with value [{value}] for fixture id [{self.fixture.id}]."
@@ -234,6 +234,16 @@ class EngineTrack:
                     prev_time = curr_time
                     curr_time = next.time
 
+    def step(self, step_size: Decimal):
+        """Step keyframes forward by given step."""
+        while self.next and step_size > 0:
+            self.next.delta -= step_size
+            if self.next.delta >= 0:
+                return
+
+            self.previous = self.keyframes.pop(0)
+            step_size = self.previous.delta.copy_abs()
+
 
 @dataclass_json
 @dataclass