[rs] Add RenderEncoder

wgpu/CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ### unreleased
 - introduce `ShaderModuleDescriptor`
+- introduce `RenderEncoder`
 
 ### v0.6.2 (2020-11-24)
 - don't panic in the staging belt if the channel is dropped

wgpu/src/lib.rs

@@ -2575,6 +2575,183 @@ impl<'a> RenderBundleEncoder<'a> {
     }
 }
 
+/// Methods shared by `RenderPass` and `RenderBundleEncoder`
+pub trait RenderEncoder<'a> {
+    /// Sets the active bind group for a given bind group index. The bind group layout
+    /// in the active pipeline when any `draw()` function is called must match the layout of this bind group.
+    ///
+    /// If the bind group have dynamic offsets, provide them in order of their declaration.
+    fn set_bind_group(&mut self, index: u32, bind_group: &'a BindGroup, offsets: &[DynamicOffset]);
+
+    /// Sets the active render pipeline.
+    ///
+    /// Subsequent draw calls will exhibit the behavior defined by `pipeline`.
+    fn set_pipeline(&mut self, pipeline: &'a RenderPipeline);
+
+    /// Sets the active index buffer.
+    ///
+    /// Subsequent calls to [`draw_indexed`](RenderBundleEncoder::draw_indexed) on this [`RenderBundleEncoder`] will
+    /// use `buffer` as the source index buffer.
+    fn set_index_buffer(&mut self, buffer_slice: BufferSlice<'a>, index_format: IndexFormat);
+
+    /// Assign a vertex buffer to a slot.
+    ///
+    /// Subsequent calls to [`draw`] and [`draw_indexed`] on this
+    /// [`RenderBundleEncoder`] will use `buffer` as one of the source vertex buffers.
+    ///
+    /// The `slot` refers to the index of the matching descriptor in
+    /// [`VertexStateDescriptor::vertex_buffers`].
+    ///
+    /// [`draw`]: RenderBundleEncoder::draw
+    /// [`draw_indexed`]: RenderBundleEncoder::draw_indexed
+    fn set_vertex_buffer(&mut self, slot: u32, buffer_slice: BufferSlice<'a>);
+
+    /// Draws primitives from the active vertex buffer(s).
+    ///
+    /// The active vertex buffers can be set with [`RenderBundleEncoder::set_vertex_buffer`].
+    fn draw(&mut self, vertices: Range<u32>, instances: Range<u32>);
+
+    /// Draws indexed primitives using the active index buffer and the active vertex buffers.
+    ///
+    /// The active index buffer can be set with [`RenderBundleEncoder::set_index_buffer`], while the active
+    /// vertex buffers can be set with [`RenderBundleEncoder::set_vertex_buffer`].
+    fn draw_indexed(&mut self, indices: Range<u32>, base_vertex: i32, instances: Range<u32>);
+
+    /// Draws primitives from the active vertex buffer(s) based on the contents of the `indirect_buffer`.
+    ///
+    /// The active vertex buffers can be set with [`RenderBundleEncoder::set_vertex_buffer`].
+    ///
+    /// The structure expected in `indirect_buffer` is the following:
+    ///
+    /// ```rust
+    /// #[repr(C)]
+    /// struct DrawIndirect {
+    ///     vertex_count: u32, // The number of vertices to draw.
+    ///     instance_count: u32, // The number of instances to draw.
+    ///     base_vertex: u32, // The Index of the first vertex to draw.
+    ///     base_instance: u32, // The instance ID of the first instance to draw.
+    /// }
+    /// ```
+    fn draw_indirect(&mut self, indirect_buffer: &'a Buffer, indirect_offset: BufferAddress);
+
+    /// Draws indexed primitives using the active index buffer and the active vertex buffers,
+    /// based on the contents of the `indirect_buffer`.
+    ///
+    /// The active index buffer can be set with [`RenderBundleEncoder::set_index_buffer`], while the active
+    /// vertex buffers can be set with [`RenderBundleEncoder::set_vertex_buffer`].
+    ///
+    /// The structure expected in `indirect_buffer` is the following:
+    ///
+    /// ```rust
+    /// #[repr(C)]
+    /// struct DrawIndexedIndirect {
+    ///     vertex_count: u32, // The number of vertices to draw.
+    ///     instance_count: u32, // The number of instances to draw.
+    ///     base_index: u32, // The base index within the index buffer.
+    ///     vertex_offset: i32, // The value added to the vertex index before indexing into the vertex buffer.
+    ///     base_instance: u32, // The instance ID of the first instance to draw.
+    /// }
+    /// ```
+    fn draw_indexed_indirect(
+        &mut self,
+        indirect_buffer: &'a Buffer,
+        indirect_offset: BufferAddress,
+    );
+}
+
+impl<'a> RenderEncoder<'a> for RenderPass<'a> {
+    #[inline(always)]
+    fn set_bind_group(&mut self, index: u32, bind_group: &'a BindGroup, offsets: &[DynamicOffset]) {
+        (self as &mut RenderPass<'a>).set_bind_group(index, bind_group, offsets);
+    }
+
+    #[inline(always)]
+    fn set_pipeline(&mut self, pipeline: &'a RenderPipeline) {
+        (self as &mut RenderPass<'a>).set_pipeline(pipeline);
+    }
+
+    #[inline(always)]
+    fn set_index_buffer(&mut self, buffer_slice: BufferSlice<'a>, index_format: IndexFormat) {
+        (self as &mut RenderPass<'a>).set_index_buffer(buffer_slice, index_format);
+    }
+
+    #[inline(always)]
+    fn set_vertex_buffer(&mut self, slot: u32, buffer_slice: BufferSlice<'a>) {
+        (self as &mut RenderPass<'a>).set_vertex_buffer(slot, buffer_slice);
+    }
+
+    #[inline(always)]
+    fn draw(&mut self, vertices: Range<u32>, instances: Range<u32>) {
+        (self as &mut RenderPass<'a>).draw(vertices, instances);
+    }
+
+    #[inline(always)]
+    fn draw_indexed(&mut self, indices: Range<u32>, base_vertex: i32, instances: Range<u32>) {
+        (self as &mut RenderPass<'a>).draw_indexed(indices, base_vertex, instances);
+    }
+
+    #[inline(always)]
+    fn draw_indirect(&mut self, indirect_buffer: &'a Buffer, indirect_offset: BufferAddress) {
+        (self as &mut RenderPass<'a>).draw_indirect(indirect_buffer, indirect_offset);
+    }
+
+    #[inline(always)]
+    fn draw_indexed_indirect(
+        &mut self,
+        indirect_buffer: &'a Buffer,
+        indirect_offset: BufferAddress,
+    ) {
+        (self as &mut RenderPass<'a>).draw_indexed_indirect(indirect_buffer, indirect_offset);
+    }
+}
+
+impl<'a> RenderEncoder<'a> for RenderBundleEncoder<'a> {
+    #[inline(always)]
+    fn set_bind_group(&mut self, index: u32, bind_group: &'a BindGroup, offsets: &[DynamicOffset]) {
+        (self as &mut RenderBundleEncoder<'a>).set_bind_group(index, bind_group, offsets);
+    }
+
+    #[inline(always)]
+    fn set_pipeline(&mut self, pipeline: &'a RenderPipeline) {
+        (self as &mut RenderBundleEncoder<'a>).set_pipeline(pipeline);
+    }
+
+    #[inline(always)]
+    fn set_index_buffer(&mut self, buffer_slice: BufferSlice<'a>, index_format: IndexFormat) {
+        (self as &mut RenderBundleEncoder<'a>).set_index_buffer(buffer_slice, index_format);
+    }
+
+    #[inline(always)]
+    fn set_vertex_buffer(&mut self, slot: u32, buffer_slice: BufferSlice<'a>) {
+        (self as &mut RenderBundleEncoder<'a>).set_vertex_buffer(slot, buffer_slice);
+    }
+
+    #[inline(always)]
+    fn draw(&mut self, vertices: Range<u32>, instances: Range<u32>) {
+        (self as &mut RenderBundleEncoder<'a>).draw(vertices, instances);
+    }
+
+    #[inline(always)]
+    fn draw_indexed(&mut self, indices: Range<u32>, base_vertex: i32, instances: Range<u32>) {
+        (self as &mut RenderBundleEncoder<'a>).draw_indexed(indices, base_vertex, instances);
+    }
+
+    #[inline(always)]
+    fn draw_indirect(&mut self, indirect_buffer: &'a Buffer, indirect_offset: BufferAddress) {
+        (self as &mut RenderBundleEncoder<'a>).draw_indirect(indirect_buffer, indirect_offset);
+    }
+
+    #[inline(always)]
+    fn draw_indexed_indirect(
+        &mut self,
+        indirect_buffer: &'a Buffer,
+        indirect_offset: BufferAddress,
+    ) {
+        (self as &mut RenderBundleEncoder<'a>)
+            .draw_indexed_indirect(indirect_buffer, indirect_offset);
+    }
+}
+
 impl Queue {
     /// Schedule a data write into `buffer` starting at `offset`.
     ///