From d516a27dc6a3a8ddf09c2c259dbe99d6235ce3a9 Mon Sep 17 00:00:00 2001
From: IceSentry <IceSentry@users.noreply.github.com>
Date: Mon, 4 Sep 2023 11:26:05 -0400
Subject: [PATCH] Cache depth texture based on usage (#9565)

# Objective

- Currently, the depth textures are cached based on the target. If
multiple camera have the same target but a different
`depth_texture_usage` bevy will just use the same texture and ignore
that setting.

## Solution

- Add the usage as a cache key
---
 crates/bevy_core_pipeline/src/core_3d/mod.rs | 27 ++++++++++++++------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/crates/bevy_core_pipeline/src/core_3d/mod.rs b/crates/bevy_core_pipeline/src/core_3d/mod.rs
index f415751cde719..04f4f0973998f 100644
--- a/crates/bevy_core_pipeline/src/core_3d/mod.rs
+++ b/crates/bevy_core_pipeline/src/core_3d/mod.rs
@@ -340,8 +340,22 @@ pub fn prepare_core_3d_depth_textures(
         ),
     >,
 ) {
+    let mut render_target_usage = HashMap::default();
+    for (_, camera, depth_prepass, camera_3d) in &views_3d {
+        // Default usage required to write to the depth texture
+        let mut usage: TextureUsages = camera_3d.depth_texture_usages.into();
+        if depth_prepass.is_some() {
+            // Required to read the output of the prepass
+            usage |= TextureUsages::COPY_SRC;
+        }
+        render_target_usage
+            .entry(camera.target.clone())
+            .and_modify(|u| *u |= usage)
+            .or_insert_with(|| usage);
+    }
+
     let mut textures = HashMap::default();
-    for (entity, camera, depth_prepass, camera_3d) in &views_3d {
+    for (entity, camera, _, _) in &views_3d {
         let Some(physical_target_size) = camera.physical_target_size else {
             continue;
         };
@@ -349,13 +363,6 @@ pub fn prepare_core_3d_depth_textures(
         let cached_texture = textures
             .entry(camera.target.clone())
             .or_insert_with(|| {
-                // Default usage required to write to the depth texture
-                let mut usage = camera_3d.depth_texture_usages.into();
-                if depth_prepass.is_some() {
-                    // Required to read the output of the prepass
-                    usage |= TextureUsages::COPY_SRC;
-                }
-
                 // The size of the depth texture
                 let size = Extent3d {
                     depth_or_array_layers: 1,
@@ -363,6 +370,10 @@ pub fn prepare_core_3d_depth_textures(
                     height: physical_target_size.y,
                 };
 
+                let usage = *render_target_usage
+                    .get(&camera.target.clone())
+                    .expect("The depth texture usage should already exist for this target");
+
                 let descriptor = TextureDescriptor {
                     label: Some("view_depth_texture"),
                     size,