From c2c3e4fd468023f1726718b915594f7fd3635b22 Mon Sep 17 00:00:00 2001
From: Florian RICHER <florian.richer@unova.fr>
Date: Tue, 14 Jun 2022 13:24:33 +0200
Subject: [PATCH] [DEPTH] From tutorial

---
 engine_core/src/state.rs   | 24 +++++++++++++++++++++---
 engine_core/src/texture.rs | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+), 3 deletions(-)

diff --git a/engine_core/src/state.rs b/engine_core/src/state.rs
index a7c53ca..c378b35 100644
--- a/engine_core/src/state.rs
+++ b/engine_core/src/state.rs
@@ -62,6 +62,7 @@ pub struct State {
     diffuse_bind_group: wgpu::BindGroup,
     #[allow(dead_code)]
     diffuse_texture: super::texture::Texture,
+    depth_texture: super::texture::Texture,
     toggle: bool
 }
 
@@ -316,6 +317,8 @@ impl State {
             usage: wgpu::BufferUsages::VERTEX | wgpu::BufferUsages::COPY_DST,
         });
 
+        let depth_texture = super::texture::Texture::create_depth_texture(&device, &config, "depth_texture");
+
         let render_pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
             label: Some("Render Pipeline"),
             layout: Some(&render_pipeline_layout),
@@ -345,7 +348,13 @@ impl State {
                 // Requires Features::CONSERVATIVE_RASTERIZATION
                 conservative: false,
             },
-            depth_stencil: None,
+            depth_stencil: Some(wgpu::DepthStencilState {
+                format: super::texture::Texture::DEPTH_FORMAT,
+                depth_write_enabled: true,
+                depth_compare: wgpu::CompareFunction::Less, // 1.
+                stencil: wgpu::StencilState::default(), // 2.
+                bias: wgpu::DepthBiasState::default(),
+            }),
             multisample: wgpu::MultisampleState {
                 count: 1,
                 mask: !0,
@@ -376,7 +385,8 @@ impl State {
             diffuse_texture_pikachu,
             instances,
             instance_buffer,
-            toggle: false
+            toggle: false,
+            depth_texture,
         }
     }
 
@@ -387,6 +397,7 @@ impl State {
             self.config.height = new_size.height;
             self.surface.configure(&self.device, &self.config);
         }
+        self.depth_texture = super::texture::Texture::create_depth_texture(&self.device, &self.config, "depth_texture");
     }
 
     pub fn input(&mut self, event: &WindowEvent) -> bool {
@@ -469,7 +480,14 @@ impl State {
                         },
                     },
                 ],
-                depth_stencil_attachment: None,
+                depth_stencil_attachment: Some(wgpu::RenderPassDepthStencilAttachment {
+                    view: &self.depth_texture.view,
+                    depth_ops: Some(wgpu::Operations {
+                        load: wgpu::LoadOp::Clear(1.0),
+                        store: true,
+                    }),
+                    stencil_ops: None,
+                })
             });
 
             render_pass.set_pipeline(&self.render_pipeline);
diff --git a/engine_core/src/texture.rs b/engine_core/src/texture.rs
index 076a297..a6f9165 100644
--- a/engine_core/src/texture.rs
+++ b/engine_core/src/texture.rs
@@ -8,6 +8,7 @@ pub struct Texture {
 }
 
 impl Texture {
+    pub const DEPTH_FORMAT: wgpu::TextureFormat = wgpu::TextureFormat::Depth32Float;
     pub fn from_bytes(
         device: &wgpu::Device,
         queue: &wgpu::Queue,
@@ -75,4 +76,41 @@ impl Texture {
             sampler,
         })
     }
+    
+    pub fn create_depth_texture(device: &wgpu::Device, config: &wgpu::SurfaceConfiguration, label: &str) -> Self {
+        let size = wgpu::Extent3d {
+            width: config.width,
+            height: config.height,
+            depth_or_array_layers: 1,
+        };
+        let desc = wgpu::TextureDescriptor {
+            label: Some(label),
+            size,
+            mip_level_count: 1,
+            sample_count: 1,
+            dimension: wgpu::TextureDimension::D2,
+            format: Self::DEPTH_FORMAT,
+            usage: wgpu::TextureUsages::RENDER_ATTACHMENT
+                | wgpu::TextureUsages::TEXTURE_BINDING,
+        };
+        let texture = device.create_texture(&desc);
+
+        let view = texture.create_view(&wgpu::TextureViewDescriptor::default());
+        let sampler = device.create_sampler(
+            &wgpu::SamplerDescriptor {
+                address_mode_u: wgpu::AddressMode::ClampToEdge,
+                address_mode_v: wgpu::AddressMode::ClampToEdge,
+                address_mode_w: wgpu::AddressMode::ClampToEdge,
+                mag_filter: wgpu::FilterMode::Linear,
+                min_filter: wgpu::FilterMode::Linear,
+                mipmap_filter: wgpu::FilterMode::Nearest,
+                compare: Some(wgpu::CompareFunction::LessEqual),
+                lod_min_clamp: -100.0,
+                lod_max_clamp: 100.0,
+                ..Default::default()
+            }
+        );
+
+        Self { texture, view, sampler }
+    }
 }