typed primitive buffers + macro for creation

src/render/primitive.rs

@@ -1,27 +1,93 @@
-use crate::Color;
-
-pub use super::data::PrimitiveInstance;
+use crate::{
+    Color, UiRegion,
+    render::{ArrBuf, data::PrimitiveInstance},
+};
+use bytemuck::Pod;
+use wgpu::*;
 
 #[derive(Default)]
 pub struct Primitives {
-    pub instances: Vec<PrimitiveInstance>,
-    pub data: Vec<u32>,
+    pub(super) instances: Vec<PrimitiveInstance>,
+    pub(super) data: PrimitiveData,
 }
 
-/// NOTE: Self must have at least u32 alignment
-pub trait PrimitiveData: bytemuck::Pod {
-    const DISCRIM: u32;
+pub trait Primitive: Pod {
+    const BINDING: u32;
+    fn vec(data: &mut PrimitiveData) -> &mut Vec<Self>;
+}
+
+macro_rules! primitives {
+    ($($name:ident: $ty:ty => $binding:expr,)*) => {
+        #[derive(Default)]
+        pub struct PrimitiveData {
+            $($name: Vec<$ty>,)*
+        }
+
+        pub struct PrimitiveBuffers {
+            $($name: ArrBuf<$ty>,)*
+        }
+
+        impl PrimitiveBuffers {
+            pub fn update(&mut self, device: &Device, queue: &Queue, data: &PrimitiveData) {
+                $(self.$name.update(device, queue, &data.$name);)*
+            }
+        }
+
+        impl PrimitiveBuffers {
+            pub const LEN: usize = primitives!(@count $($name)*);
+            pub fn buffers(&self) -> [&Buffer; Self::LEN] {
+                [
+                    $(&self.$name.buffer)*
+                ]
+            }
+            pub fn new(device: &Device) -> Self {
+                Self {
+                    $($name: ArrBuf::new(
+                        device,
+                        BufferUsages::STORAGE | BufferUsages::COPY_DST,
+                        stringify!($name),
+                    ))*
+                }
+            }
+        }
+
+        $(
+            unsafe impl bytemuck::Pod for $ty {}
+            unsafe impl bytemuck::Zeroable for $ty {}
+            impl Primitive for $ty {
+                const BINDING: u32 = $binding;
+                fn vec(data: &mut PrimitiveData) -> &mut Vec<Self> {
+                    &mut data.$name
+                }
+            }
+        )*
+    };
+    (@count $t1:tt, $($t:tt),+) => { 1 + gen!(@count $($t),+) };
+    (@count $t:tt) => { 1 };
+}
+
+primitives!(
+    rects: RoundedRectData => 0,
+);
+
+impl Primitives {
+    pub fn write<P: Primitive>(&mut self, data: P, region: UiRegion) {
+        let vec = P::vec(&mut self.data);
+        let i = vec.len() as u32;
+        self.instances.push(PrimitiveInstance {
+            region,
+            idx: i,
+            binding: P::BINDING,
+        });
+        vec.push(data);
+    }
 }
 
 #[repr(C)]
-#[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
+#[derive(Copy, Clone)]
 pub struct RoundedRectData {
     pub color: Color<u8>,
     pub radius: f32,
     pub thickness: f32,
     pub inner_radius: f32,
 }
-
-impl PrimitiveData for RoundedRectData {
-    const DISCRIM: u32 = 0;
-}