Waterfall improvements

neothesia-core/src/render/waterfall/mod.rs

@@ -55,7 +55,7 @@ impl WaterfallRenderer {
     ) {
         let range_start = layout.range.start() as usize;
 
-        let mut instances = Vec::new();
+        self.notes_pipeline.clear();
 
         let mut longer_than_range = false;
         for note in self.notes.iter() {
@@ -78,7 +78,7 @@ impl WaterfallRenderer {
                     0.1
                 };
 
-                instances.push(NoteInstance {
+                self.notes_pipeline.instances().push(NoteInstance {
                     position: [key.x(), note.start.as_secs_f32()],
                     size: [key.width() - 1.0, h - 0.01], // h - 0.01 to make a litle gap bettwen successive notes
                     color: color.into_linear_rgb(),
@@ -96,7 +96,7 @@ impl WaterfallRenderer {
             );
         }
 
-        self.notes_pipeline.update_instance_buffer(queue, instances);
+        self.notes_pipeline.prepare(queue);
     }
 
     pub fn update(&mut self, queue: &wgpu::Queue, time: f32) {

neothesia-core/src/render/waterfall/pipeline/mod.rs

@@ -93,8 +93,15 @@ impl<'a> WaterfallPipeline {
         render_pass.draw_indexed(0..self.quad.indices_len, 0, 0..self.instances.len());
     }
 
-    pub fn update_instance_buffer(&mut self, queue: &wgpu::Queue, instances: Vec<NoteInstance>) {
-        self.instances.data = instances;
+    pub fn clear(&mut self) {
+        self.instances.data.clear();
+    }
+
+    pub fn instances(&mut self) -> &mut Vec<NoteInstance> {
+        &mut self.instances.data
+    }
+
+    pub fn prepare(&self, queue: &wgpu::Queue) {
         self.instances.update(queue);
     }
 

neothesia-core/src/render/waterfall/pipeline/shader.wgsl

@@ -39,10 +39,17 @@ struct VertexOutput {
 @vertex
 fn vs_main(vertex: Vertex, note: NoteInstance) -> VertexOutput {
     let speed = time_uniform.speed / view_uniform.scale;
-    let size = vec2<f32>(note.size.x, note.size.y * speed);
+    let size = vec2<f32>(note.size.x, note.size.y * abs(speed));
 
-    let y = view_uniform.size.y - view_uniform.size.y / 5.0 - size.y / 2.0;
-    let pos = vec2<f32>(note.n_position.x, y) - vec2<f32>(0.0, size.y / 2.0);
+    let keyboard_start_y = view_uniform.size.y - view_uniform.size.y / 5.0;
+    let y = keyboard_start_y - size.y / 2.0;
+    var pos = vec2<f32>(note.n_position.x, y) - vec2<f32>(0.0, size.y / 2.0);
+
+    // If notes are falling from down to top, we need to adjust the position,
+    // as their start is on top of the quad rather than down
+    if speed < 0.0 {
+        pos.y += size.y;
+    }
 
     let offset = vec2<f32>(0.0, -(note.n_position.y - time_uniform.time) * speed);
 

neothesia/src/scene/playing_scene/mod.rs

@@ -262,9 +262,16 @@ fn handle_settings_input(
 
             if key == NamedKey::PageUp {
                 target.config.animation_speed += amount;
+                // 0.0 is invalid speed, let's skip it and jump to positive
+                if target.config.animation_speed == 0.0 {
+                    target.config.animation_speed += amount;
+                }
             } else {
                 target.config.animation_speed -= amount;
-                target.config.animation_speed = target.config.animation_speed.max(100.0);
+                // 0.0 is invalid speed, let's skip it and jump to negative
+                if target.config.animation_speed == 0.0 {
+                    target.config.animation_speed -= amount;
+                }
             }
 
             waterfall