From 2fb1a1dc7c6daae4c24572d2ca3f7f0205f24070 Mon Sep 17 00:00:00 2001
From: Florian RICHER <florian.richer@unova.fr>
Date: Wed, 15 Jun 2022 14:04:10 +0200
Subject: [PATCH] [REFACTOR] Begin refactor mesh

---
 src/render/mesh.rs | 63 ++++++++++++++++++++++++++++++++++++++++++++++
 src/render/mod.rs  | 11 +++++++-
 2 files changed, 73 insertions(+), 1 deletion(-)
 create mode 100644 src/render/mesh.rs

diff --git a/src/render/mesh.rs b/src/render/mesh.rs
new file mode 100644
index 0000000..4ca81fa
--- /dev/null
+++ b/src/render/mesh.rs
@@ -0,0 +1,63 @@
+use wgpu::{Device, util::DeviceExt, Queue};
+
+use super::{Vertex, Renderable, Instance};
+
+pub struct Mesh {
+    vertex_array: Vec<Vertex>,
+    index_array: Vec<u16>,
+    num_indices: u32,
+    instance_array: Vec<Instance>,
+    texture_bind_group: Option<wgpu::BindGroup>,
+    vertex_buffer: Option<wgpu::Buffer>,
+    index_buffer: Option<wgpu::Buffer>,
+    instance_buffer: Option<wgpu::Buffer>,
+}
+
+impl Renderable for Mesh {
+    fn prepare(&mut self, device: &Device) {
+        self.vertex_buffer = Some(device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
+            label: Some("Vertex Buffer"),
+            contents: bytemuck::cast_slice(&self.vertex_array),
+            usage: wgpu::BufferUsages::VERTEX,
+        }));
+
+        self.index_buffer = Some(device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
+            label: Some("Index Buffer"),
+            contents: bytemuck::cast_slice(&self.index_array),
+            usage: wgpu::BufferUsages::INDEX,
+        }));
+        self.num_indices = self.index_array.len() as u32;
+
+        let instance_data = self.instance_array
+            .iter()
+            .map(Instance::to_raw)
+            .collect::<Vec<_>>();
+        self.instance_buffer = Some(device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
+            label: Some("Instance Buffer"),
+            contents: bytemuck::cast_slice(&instance_data),
+            usage: wgpu::BufferUsages::VERTEX | wgpu::BufferUsages::COPY_DST,
+        }));
+    }
+
+    fn update_instances(&mut self, queue: &Queue) {
+        let instance_data = self
+            .instance_array
+            .iter()
+            .map(Instance::to_raw)
+            .collect::<Vec<_>>();
+        queue.write_buffer(
+            &self.instance_buffer.as_ref().unwrap(),
+            0,
+            bytemuck::cast_slice(&instance_data),
+        );
+    }
+
+    fn render<'a>(&'a self, render_pass: &mut wgpu::RenderPass<'a>) {
+        render_pass.set_bind_group(0, &self.texture_bind_group.as_ref().unwrap(), &[]);
+        render_pass.set_vertex_buffer(0, self.vertex_buffer.as_ref().unwrap().slice(..).clone());
+        render_pass.set_vertex_buffer(1, self.instance_buffer.as_ref().unwrap().slice(..));
+        render_pass.set_index_buffer(self.index_buffer.as_ref().unwrap().slice(..), wgpu::IndexFormat::Uint16);
+
+        render_pass.draw_indexed(0..self.index_array.len() as _, 0, 0..self.num_indices);
+    }
+}
\ No newline at end of file
diff --git a/src/render/mod.rs b/src/render/mod.rs
index c46f5e7..b9e59d4 100644
--- a/src/render/mod.rs
+++ b/src/render/mod.rs
@@ -12,4 +12,13 @@ pub use texture::Texture;
 mod instance;
 pub use instance::{
   Instance, InstanceRaw
-};
\ No newline at end of file
+};
+use wgpu::{Device, Queue};
+
+mod mesh;
+
+pub trait Renderable {
+  fn prepare(&mut self, device: &Device);
+  fn update_instances(&mut self, device: &Queue);
+  fn render<'a>(&'a self, render_pass: &mut wgpu::RenderPass<'a>);
+}
\ No newline at end of file