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);

src/animations/Rain.h

@@ -0,0 +1,48 @@
+#pragma once
+#include <Figments.h>
+
+class RainAnimation: public Figment {
+private:
+  struct Raindrop {
+    int size = 20;
+    int x = random(255);
+    int y = random(255);
+    CHSV fg{180, 255, 255};
+    CHSV nextColor{180, 255, 255};
+
+    void render(Display* dpy) const {
+      Surface sfc{dpy, {x - size, y - size}, {x + size, y + size}};
+      paint(sfc);
+    }
+
+    void paint(Surface& sfc) const {
+      sfc.paintShader([=](CRGB& pixel, const VirtualCoordinates& coords, const PhysicalCoordinates, const VirtualCoordinates& surfaceCoords) {
+        int distance = 255 - (min(128, abs(128 - surfaceCoords.x)) + min(128, abs(128 - surfaceCoords.y)));
+        pixel += CHSV{fg.h, fg.s, scale8_video(fg.v, distance)};
+      });
+    }
+
+    void update() {
+      if (random(255) >= 100) {
+        y++;
+        if (y >= 255) {
+          y = 0;
+          x += 13;
+          x %= 255;
+          fg = nextColor;
+        }
+      }
+    }
+  };
+
+  SpriteList<Raindrop, 10> m_drops;
+  uint16_t m_noiseOffset;
+  CHSV m_curColor{180, 255, 255};
+  AnimatedNumber m_hue;
+public:
+  RainAnimation();
+  //void handleEvent(const InputEvent& evt) override;
+  void loop() override;
+  void render(Display* dpy) const override;
+  void handleEvent(const InputEvent& evt) override;
+};