src/engine/particle.c

@@ -556,11 +556,16 @@ void particle_emit_atmosphere_dust(Vec2 cam_pos, Vec2 vp) {
      * Two sub-layers for depth: large slow "far" motes and small quick
      * "near" specks. Wind carries them; gravity_scale controls how much
      * environmental forces (wind + gravity) affect each particle.
-     * Particles spawn along the upwind viewport edge and drift inward;
+     * When wind is strong, particles spawn along the upwind viewport edge
-     * occasional interior spawns prevent a visible edge seam. */
+     * and drift inward. When wind is calm, particles spawn across the
+     * full viewport to avoid clustering on one side. */
     float wind      = physics_get_wind();
     float margin    = 32.0f;
-    float dir    = (wind >= 0.0f) ? 1.0f : -1.0f; /* velocity sign */
+    float abs_wind  = (wind >= 0.0f) ? wind : -wind;
+    int   has_wind  = abs_wind > 5.0f; /* threshold for edge-spawning */
+
+    if (has_wind) {
+        float dir = (wind >= 0.0f) ? 1.0f : -1.0f;
 
         /* Upwind edge X for the two edge-spawned layers */
         float edge_far  = (wind >= 0.0f) ? cam_pos.x - margin
@@ -582,7 +587,7 @@ void particle_emit_atmosphere_dust(Vec2 cam_pos, Vec2 vp) {
             2.5f, 5.0f, 0.8f, 1.5f, 0.2f, 0.12f,
             200, 160, 120, 20);
 
-    /* Occasional interior spawn — prevents edge seam on calm wind */
+        /* Occasional interior spawn — prevents edge seam */
         if (rand() % 3 == 0) {
             spawn_dust_mote(
                 vec2(cam_pos.x + randf() * vp.x, cam_pos.y + randf() * vp.y),
@@ -590,4 +595,30 @@ void particle_emit_atmosphere_dust(Vec2 cam_pos, Vec2 vp) {
                 3.0f, 6.0f, 1.0f, 2.5f, 0.4f, 0.06f,
                 160, 130, 95, 25);
         }
+    } else {
+        /* Calm wind — spawn across the full viewport to distribute evenly */
+
+        /* Far dust motes — large, slow, translucent (1/frame) */
+        spawn_dust_mote(
+            vec2(cam_pos.x + randf() * vp.x, cam_pos.y + randf() * vp.y),
+            vec2(randf_range(-10.0f, 10.0f), randf_range(-6.0f, 6.0f)),
+            4.0f, 7.0f, 1.5f, 3.0f, 0.3f, 0.08f,
+            180, 140, 100, 25);
+
+        /* Near dust specks — small, quicker, brighter (1/frame) */
+        spawn_dust_mote(
+            vec2(cam_pos.x + randf() * vp.x, cam_pos.y + randf() * vp.y),
+            vec2(randf_range(-15.0f, 15.0f), randf_range(-10.0f, 10.0f)),
+            2.5f, 5.0f, 0.8f, 1.5f, 0.2f, 0.12f,
+            200, 160, 120, 20);
+
+        /* Extra interior mote for density parity with windy path */
+        if (rand() % 3 == 0) {
+            spawn_dust_mote(
+                vec2(cam_pos.x + randf() * vp.x, cam_pos.y + randf() * vp.y),
+                vec2(randf_range(-5.0f, 5.0f), randf_range(-8.0f, 3.0f)),
+                3.0f, 6.0f, 1.0f, 2.5f, 0.4f, 0.06f,
+                160, 130, 95, 25);
+        }
+    }
 }