instancing

1 files changed, 21 insertions, 3 deletions

diff --git a/src/renderer.rs b/src/renderer.rs
index dc8ecb2..75e6d1e 100644
--- a/src/renderer.rs
+++ b/src/renderer.rs
@@ -1,6 +1,6 @@
 use std::convert::TryInto;
 
-use crate::{vertex::SQUARE, RenderWindowConfig, Vertex};
+use crate::{vertex::SQUARE, Instance, RenderWindowConfig, Vertex};
 use pollster::FutureExt;
 use thiserror::Error;
 use wgpu::{include_wgsl, util::DeviceExt};
@@ -44,6 +44,7 @@ pub struct Renderer {
 	render_pipeline: wgpu::RenderPipeline,
 	square_vertex_buffer: wgpu::Buffer,
 	square_vertices: u32,
+	instances: Vec<Instance>,
 	window: Window,
 }
 
@@ -128,7 +129,7 @@ impl Renderer {
 			vertex: wgpu::VertexState {
 				module: &shader,
 				entry_point: "vs_main",
-				buffers: &[Vertex::desc()],
+				buffers: &[Vertex::desc(), Instance::desc()],
 			},
 			// information about the fragment shader
 			fragment: Some(wgpu::FragmentState {
@@ -171,6 +172,8 @@ impl Renderer {
 			usage: wgpu::BufferUsages::VERTEX,
 		});
 
+		let instances = Vec::new();
+
 		Ok(Self {
 			surface,
 			device,
@@ -179,6 +182,7 @@ impl Renderer {
 			render_pipeline,
 			square_vertex_buffer,
 			square_vertices,
+			instances,
 			window,
 		})
 	}
@@ -216,6 +220,19 @@ impl Renderer {
 				label: Some("Render Encoder"),
 			});
 
+		let num_instances = self
+			.instances
+			.len()
+			.try_into()
+			.expect("expected less than 3 billion instances");
+		let instance_buffer = self
+			.device
+			.create_buffer_init(&wgpu::util::BufferInitDescriptor {
+				label: Some("Sprite Instance Buffer"),
+				contents: bytemuck::cast_slice(&self.instances),
+				usage: wgpu::BufferUsages::VERTEX,
+			});
+
 		{
 			let mut render_pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
 				label: Some("Render Pass"),
@@ -232,7 +249,8 @@ impl Renderer {
 
 			render_pass.set_pipeline(&self.render_pipeline);
 			render_pass.set_vertex_buffer(0, self.square_vertex_buffer.slice(..));
-			render_pass.draw(0..self.square_vertices, 0..1);
+			render_pass.set_vertex_buffer(1, instance_buffer.slice(..));
+			render_pass.draw(0..self.square_vertices, 0..num_instances);
 		}
 		// the encoder can't finish building the command buffer until the
 		// render pass is dropped