Improve airflow particles

assets/voxygen/shaders/particle-vert.glsl

@@ -164,10 +164,24 @@ mat4 spin_in_axis(vec3 axis, float angle)
     float c = cos(angle);
     float oc = 1.0 - c;
 
-    return mat4(oc * axis.x * axis.x + c,  oc * axis.x * axis.y - axis.z * s, oc * axis.z * axis.x + axis.y * s, 0,
+    return mat4(
-        oc * axis.x * axis.y + axis.z * s, oc * axis.y * axis.y + c,          oc * axis.y * axis.z - axis.x * s, 0,
+        oc * axis.x * axis.x + c,
-        oc * axis.z * axis.x - axis.y * s, oc * axis.y * axis.z + axis.x * s, oc * axis.z * axis.z + c,          0,
+        oc * axis.x * axis.y - axis.z * s,
-        0,                                 0,                                 0,                                 1);
+        oc * axis.z * axis.x + axis.y * s,
+        0,
+
+        oc * axis.x * axis.y + axis.z * s,
+        oc * axis.y * axis.y + c,
+        oc * axis.y * axis.z - axis.x * s,
+        0,
+
+        oc * axis.z * axis.x - axis.y * s,
+        oc * axis.y * axis.z + axis.x * s,
+        oc * axis.z * axis.z + c,
+        0,
+
+        0, 0, 0, 1
+    );
 }
 
 mat4 identity() {
@@ -986,11 +1000,19 @@ void main() {
             );
             break;
         case AIRFLOW:
-            perp_axis = normalize(cross(inst_dir, vec3(0.0, 0.0, 1.0)));
+            perp_axis = normalize(cross(inst_dir, vec3(1.0, 0.0, 0.0)));
             attr = Attr(
+                // offsets
                 inst_dir * 0.2 * length(inst_dir) * percent() + inst_dir * percent() * 0.08,
-                vec3(0.03 * length(inst_dir), 0.03 * length(inst_dir), 20.0 * length(inst_dir) * percent() * (1 - percent())),
+                // scale
+                vec3(
+                    0.3 * length(inst_dir),
+                    0.3 * length(inst_dir),
+                    3.0 * length(inst_dir) * percent() * (1 - percent())
+                ),
+                // color
                 vec4(1.1, 1.1, 1.1, 0.3),
+                // rotation
                 spin_in_axis(perp_axis, asin(inst_dir.z / length(inst_dir)) + PI / 2.0)
             );
             break;
@@ -1018,7 +1040,14 @@ void main() {
 
     // First 3 normals are negative, next 3 are positive
     // TODO: Make particle normals match orientation
-    vec4 normals[6] = vec4[](vec4(-1,0,0,0), vec4(1,0,0,0), vec4(0,-1,0,0), vec4(0,1,0,0), vec4(0,0,-1,0), vec4(0,0,1,0));
+    vec4 normals[6] = vec4[](
+        vec4(-1,0,0,0),
+        vec4(1,0,0,0),
+        vec4(0,-1,0,0),
+        vec4(0,1,0,0),
+        vec4(0,0,-1,0),
+        vec4(0,0,1,0)
+    );
     f_norm =
         // inst_pos *
         normalize(((normals[(v_norm_ao >> 0) & 0x7u]) * attr.rot).xyz);

voxygen/anim/src/character/gliding.rs

@@ -26,7 +26,8 @@ impl Animation for GlidingAnimation {
     ) -> Self::Skeleton {
         let mut next = (*skeleton).clone();
 
-        next.glider_trails = true;
+        // TODO: remove glider trails completely
+        next.glider_trails = false;
 
         let speednorm = velocity.magnitude().min(50.0) / 50.0;
         let slow = (acc_vel * 0.1).sin();

voxygen/src/scene/particle.rs

@@ -1326,10 +1326,37 @@ impl ParticleMgr {
                         elevation: _,
                     }) = physics.in_fluid
                     {
-                        self.particles.resize_with(
+                        // Empirical observation is that air_vel is somewhere
-                            self.particles.len()
+                        // between 0.0 and 13.0, but we are extending to be sure
-                                + usize::from(self.scheduler.heartbeats(Duration::from_millis(10))), // scale with wind speed
+                        const MAX_AIR_VEL: f32 = 15.0;
-                            || {
+                        const MIN_AIR_VEL: f32 = -2.0;
+
+                        let minmax_norm = |val, min, max| (val - min) / (max - min);
+
+                        let wind_speed = air_vel.0.magnitude();
+
+                        // Less means more frequent particles
+                        let heartbeat = 200
+                            - Lerp::lerp(
+                                50u64,
+                                150,
+                                minmax_norm(wind_speed, MIN_AIR_VEL, MAX_AIR_VEL),
+                            );
+
+                        let new_count = self.particles.len()
+                            + usize::from(
+                                self.scheduler.heartbeats(Duration::from_millis(heartbeat)),
+                            );
+
+                        // More number, longer particles
+                        let duration = Lerp::lerp(
+                            0u64,
+                            1000,
+                            minmax_norm(wind_speed, MIN_AIR_VEL, MAX_AIR_VEL),
+                        );
+                        let duration = Duration::from_millis(duration);
+
+                        self.particles.resize_with(new_count, || {
                             let start_pos = interpolated.pos
                                 + Vec3::new(
                                     body.max_radius(),
@@ -1337,15 +1364,15 @@ impl ParticleMgr {
                                     body.height() / 2.0,
                                 )
                                 .map(|d| d * rng.gen_range(-10.0..10.0));
+
                             Particle::new_directed(
-                                    Duration::from_millis(300), // scale with wind speed
+                                duration,
                                 time,
                                 ParticleMode::Airflow,
                                 start_pos,
                                 start_pos + air_vel.0,
                             )
-                            },
+                        });
-                        );
                     }
                 },
                 _ => {},