animations: implement a rain animation for weather

src/animations/Rain.cpp

@@ -0,0 +1,45 @@
+#include "Rain.h"
+#include "../Static.h"
+
+RainAnimation::RainAnimation() : Figment("Rain")
+{
+}
+
+void
+RainAnimation::render(Display* dpy) const
+{
+  Surface sfc = Surface(dpy, {0, 0}, {255, 255});
+  uint8_t noiseY = sin8(m_noiseOffset % 255);
+  uint8_t noiseX = cos8(m_noiseOffset % 255);
+  sfc.paintShader([=](CRGB& pixel, const VirtualCoordinates& coords, const PhysicalCoordinates, const VirtualCoordinates& surfaceCoords) {
+      pixel = CHSV(m_hue, inoise8(noiseX + coords.x, coords.y), inoise8(m_noiseOffset + coords.x, noiseY + coords.y));
+  });
+  m_drops.render(dpy);
+}
+
+void
+RainAnimation::loop()
+{
+  EVERY_N_MILLISECONDS(250) {
+    m_drops.update();
+  }
+  EVERY_N_MILLISECONDS(60) {
+    m_hue.update(1);
+    m_curColor.h = m_hue;
+  }
+  m_noiseOffset += 1;
+}
+
+void
+RainAnimation::handleEvent(const InputEvent& evt) {
+  if (evt.intent == InputEvent::SetColor) {
+    CHSV next = rgb2hsv_approximate(evt.asRGB());
+    m_hue.set(next.h);
+    m_drops.forEach([=](Raindrop& drop) {
+      drop.nextColor = next;
+    });
+  }
+}
+
+STATIC_ALLOC(RainAnimation);
+STATIC_TASK(RainAnimation);