Reintroduce support for custom primitives in `iced_wgpu`

1 files changed, 89 insertions, 14 deletions

diff --git a/wgpu/src/primitive.rs b/wgpu/src/primitive.rs
index 8e311d2b..4ba1ed9a 100644
--- a/wgpu/src/primitive.rs
+++ b/wgpu/src/primitive.rs
@@ -1,20 +1,95 @@
-//! Draw using different graphical primitives.
-pub mod pipeline;
+//! Draw custom primitives.
+use crate::core::{self, Rectangle};
+use crate::graphics::Viewport;
 
-pub use pipeline::Pipeline;
+use rustc_hash::FxHashMap;
+use std::any::{Any, TypeId};
+use std::fmt::Debug;
 
-use crate::graphics::Mesh;
+/// A batch of primitives.
+pub type Batch = Vec<Instance>;
 
-use std::fmt::Debug;
+/// A set of methods which allows a [`Primitive`] to be rendered.
+pub trait Primitive: Debug + Send + Sync + 'static {
+    /// Processes the [`Primitive`], allowing for GPU buffer allocation.
+    fn prepare(
+        &self,
+        device: &wgpu::Device,
+        queue: &wgpu::Queue,
+        format: wgpu::TextureFormat,
+        storage: &mut Storage,
+        bounds: &Rectangle,
+        viewport: &Viewport,
+    );
+
+    /// Renders the [`Primitive`].
+    fn render(
+        &self,
+        encoder: &mut wgpu::CommandEncoder,
+        storage: &Storage,
+        target: &wgpu::TextureView,
+        clip_bounds: &Rectangle<u32>,
+    );
+}
+
+#[derive(Debug)]
+/// An instance of a specific [`Primitive`].
+pub struct Instance {
+    /// The bounds of the [`Instance`].
+    pub bounds: Rectangle,
+
+    /// The [`Primitive`] to render.
+    pub primitive: Box<dyn Primitive>,
+}
+
+impl Instance {
+    /// Creates a new [`Pipeline`] with the given [`Primitive`].
+    pub fn new(bounds: Rectangle, primitive: impl Primitive) -> Self {
+        Instance {
+            bounds,
+            primitive: Box::new(primitive),
+        }
+    }
+}
+
+/// A renderer than can draw custom primitives.
+pub trait Renderer: core::Renderer {
+    /// Draws a custom primitive.
+    fn draw_primitive(&mut self, bounds: Rectangle, primitive: impl Primitive);
+}
+
+/// Stores custom, user-provided types.
+#[derive(Default, Debug)]
+pub struct Storage {
+    pipelines: FxHashMap<TypeId, Box<dyn Any + Send>>,
+}
+
+impl Storage {
+    /// Returns `true` if `Storage` contains a type `T`.
+    pub fn has<T: 'static>(&self) -> bool {
+        self.pipelines.get(&TypeId::of::<T>()).is_some()
+    }
+
+    /// Inserts the data `T` in to [`Storage`].
+    pub fn store<T: 'static + Send>(&mut self, data: T) {
+        let _ = self.pipelines.insert(TypeId::of::<T>(), Box::new(data));
+    }
 
-/// The graphical primitives supported by `iced_wgpu`.
-pub type Primitive = crate::graphics::Primitive<Custom>;
+    /// Returns a reference to the data with type `T` if it exists in [`Storage`].
+    pub fn get<T: 'static>(&self) -> Option<&T> {
+        self.pipelines.get(&TypeId::of::<T>()).map(|pipeline| {
+            pipeline
+                .downcast_ref::<T>()
+                .expect("Pipeline with this type does not exist in Storage.")
+        })
+    }
 
-/// The custom primitives supported by `iced_wgpu`.
-#[derive(Debug, Clone, PartialEq)]
-pub enum Custom {
-    /// A mesh primitive.
-    Mesh(Mesh),
-    /// A custom pipeline primitive.
-    Pipeline(Pipeline),
+    /// Returns a mutable reference to the data with type `T` if it exists in [`Storage`].
+    pub fn get_mut<T: 'static>(&mut self) -> Option<&mut T> {
+        self.pipelines.get_mut(&TypeId::of::<T>()).map(|pipeline| {
+            pipeline
+                .downcast_mut::<T>()
+                .expect("Pipeline with this type does not exist in Storage.")
+        })
+    }
 }