bevy_pbr2: Remove depth prepass

many_cubes_pipelined performance takes a big hit from doing a depth prepass.

Author: superdump

pipelined/bevy_core_pipeline/src/main_pass_3d.rs

@@ -81,10 +81,10 @@ impl Node for MainPass3dNode {
                 }],
                 depth_stencil_attachment: Some(RenderPassDepthStencilAttachment {
                     view: &depth.view,
-                    // NOTE: The opaque pass loads the depth prepass and does not store
+                    // NOTE: The opaque main pass clears and writes to the depth buffer.
                     depth_ops: Some(Operations {
-                        load: LoadOp::Load,
-                        store: false,
+                        load: LoadOp::Clear(0.0),
+                        store: true,
                     }),
                     stencil_ops: None,
                 }),
@@ -127,10 +127,10 @@ impl Node for MainPass3dNode {
                 }],
                 depth_stencil_attachment: Some(RenderPassDepthStencilAttachment {
                     view: &depth.view,
-                    // NOTE: The alpha mask pass loads the depth prepass and does not store
+                    // NOTE: The alpha mask pass loads the depth buffer and possibly overwrites it
                     depth_ops: Some(Operations {
                         load: LoadOp::Load,
-                        store: false,
+                        store: true,
                     }),
                     stencil_ops: None,
                 }),

pipelined/bevy_pbr2/src/lib.rs

@@ -27,13 +27,10 @@ use bevy_transform::TransformSystem;
 
 pub mod draw_3d_graph {
     pub mod node {
-        pub const DEPTH_PREPASS: &str = "depth_prepass";
         pub const SHADOW_PASS: &str = "shadow_pass";
     }
 }
 
-pub const DEPTH_PREPASS_SHADER_HANDLE: HandleUntyped =
-    HandleUntyped::weak_from_u64(Shader::TYPE_UUID, 18081189618302456913);
 pub const PBR_SHADER_HANDLE: HandleUntyped =
     HandleUntyped::weak_from_u64(Shader::TYPE_UUID, 4805239651767701046);
 pub const SHADOW_SHADER_HANDLE: HandleUntyped =
@@ -45,8 +42,6 @@ pub struct PbrPlugin;
 impl Plugin for PbrPlugin {
     fn build(&self, app: &mut App) {
         let mut shaders = app.world.get_resource_mut::<Assets<Shader>>().unwrap();
-        let depth_prepass_shader = Shader::from_wgsl(include_str!("render/depth_prepass.wgsl"));
-        shaders.set_untracked(DEPTH_PREPASS_SHADER_HANDLE, depth_prepass_shader);
         let pbr_shader = Shader::from_wgsl(include_str!("render/pbr.wgsl"));
         shaders.set_untracked(PBR_SHADER_HANDLE, pbr_shader);
         let shadow_shader = Shader::from_wgsl(include_str!("render/depth.wgsl"));
@@ -146,6 +141,5 @@ impl Plugin for PbrPlugin {
                 )
                 .unwrap();
         }
-        app.add_plugin(DepthPrepassPlugin);
     }
 }