add gfx.weather library & add weather.set command

src/graphics/render/WorldRenderer.cpp

@@ -154,22 +154,6 @@ void WorldRenderer::renderLevel(
 ) {
     weather.update(delta);
 
-    if (timer > 1.0f && weather.b.fall.texture.empty() && timer < 2.0f) {
-        weather.b.deserialize(io::read_json("res:presets/weather/snow.json"));
-        weather.t = 0.0f;
-        weather.speed = 0.5f;
-        weather.update(delta);
-    }
-
-    if (timer > 15.0f && weather.a.fall.texture.empty()) {
-        std::swap(weather.a, weather.b);
-        weather.b = {};
-        weather.b.deserialize(io::read_json("res:presets/weather/fog.json"));
-        weather.t = 0.0f;
-        weather.speed = 0.1f;
-        weather.update(delta);
-    }
-
     texts->render(ctx, camera, settings, hudVisible, false);
 
     bool culling = engine.getSettings().graphics.frustumCulling.get();

src/graphics/render/WorldRenderer.hpp

@@ -47,6 +47,14 @@ struct Weather {
         a.intensity = 1.0f - t;
     }
 
+    void change(WeatherPreset preset, float time) {
+        std::swap(a, b);
+        b = std::move(preset);
+        t = 0.0f;
+        speed = 1.0f / glm::max(time, 1.e-5f);
+        update(0.0f);
+    }
+
     float fogOpacity() const {
         return b.fogOpacity * t + a.fogOpacity * (1.0f - t);
     }