stylized 1-bit rendering

src/systems/render.rs

@@ -1,5 +1,9 @@
+use crate::mesh::InstanceRaw;
 use crate::render::DrawCall;
 use crate::world::World;
+use bytemuck::cast_slice;
+use glam::Mat4;
+use wgpu::util::DeviceExt;
 
 pub fn render_system(world: &World) -> Vec<DrawCall>
 {
@@ -11,12 +15,38 @@ pub fn render_system(world: &World) -> Vec<DrawCall>
             let transform = world.transforms.get(entity)?;
             let mesh_component = world.meshes.get(entity)?;
 
+            let model_matrix = transform.to_matrix();
+
+            let (instance_buffer, num_instances) = if let Some(ref buffer) =
+                mesh_component.instance_buffer
+            {
+                (Some(buffer.clone()), mesh_component.num_instances)
+            }
+            else
+            {
+                let instance_data = InstanceRaw {
+                    model: model_matrix.to_cols_array_2d(),
+                };
+
+                let buffer = crate::render::with_device(|device| {
+                    device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
+                        label: Some("Instance Buffer"),
+                        contents: cast_slice(&[instance_data]),
+                        usage: wgpu::BufferUsages::VERTEX,
+                    })
+                });
+
+                (Some(buffer), 1)
+            };
+
             Some(DrawCall {
                 vertex_buffer: mesh_component.mesh.vertex_buffer.clone(),
                 index_buffer: mesh_component.mesh.index_buffer.clone(),
                 num_indices: mesh_component.mesh.num_indices,
-                model: transform.to_matrix(),
+                model: model_matrix,
                 pipeline: mesh_component.pipeline,
+                instance_buffer,
+                num_instances,
             })
         })
         .collect()