From b01c606fbedcacb1e5002bb1958a38052ca99bc1 Mon Sep 17 00:00:00 2001
From: MinerSebas <scherthan_sebastian@web.de>
Date: Mon, 19 Apr 2021 21:38:42 +0200
Subject: [PATCH 1/2] Provide better error message when missing a render
 backend

---
 crates/bevy_render/src/lib.rs | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/crates/bevy_render/src/lib.rs b/crates/bevy_render/src/lib.rs
index 3f0ffe41efcbf..fbe6aaa8c7782 100644
--- a/crates/bevy_render/src/lib.rs
+++ b/crates/bevy_render/src/lib.rs
@@ -14,7 +14,7 @@ pub mod wireframe;
 
 use bevy_ecs::{
     schedule::{ParallelSystemDescriptorCoercion, SystemStage},
-    system::{IntoExclusiveSystem, IntoSystem},
+    system::{IntoExclusiveSystem, IntoSystem, Res},
 };
 use bevy_transform::TransformSystem;
 use draw::{OutsideFrustum, Visible};
@@ -52,7 +52,7 @@ use render_graph::{
     base::{self, BaseRenderGraphConfig, MainPass},
     RenderGraph,
 };
-use renderer::{AssetRenderResourceBindings, RenderResourceBindings};
+use renderer::{AssetRenderResourceBindings, RenderResourceBindings, RenderResourceContext};
 use shader::ShaderLoader;
 #[cfg(feature = "hdr")]
 use texture::HdrTextureLoader;
@@ -160,6 +160,10 @@ impl Plugin for RenderPlugin {
         .init_resource::<RenderResourceBindings>()
         .init_resource::<AssetRenderResourceBindings>()
         .init_resource::<ActiveCameras>()
+        .add_startup_system_to_stage(
+            StartupStage::PreStartup,
+            check_for_render_resource_context.system(),
+        )
         .add_system_to_stage(CoreStage::PreUpdate, draw::clear_draw_system.system())
         .add_system_to_stage(
             CoreStage::PostUpdate,
@@ -222,3 +226,9 @@ impl Plugin for RenderPlugin {
         }
     }
 }
+
+fn check_for_render_resource_context(context: Option<Res<Box<dyn RenderResourceContext>>>) {
+    if context.is_none() {
+        panic!("bevy_render couldn't find a render backend. Try adding bevy_wgpu!")
+    }
+}

From e86cb6c80db4dbd959de0f31ec526e6c0ec85419 Mon Sep 17 00:00:00 2001
From: MinerSebas <scherthan_sebastian@web.de>
Date: Mon, 19 Apr 2021 23:17:25 +0200
Subject: [PATCH 2/2] Mention the bevy_wgpu plugin

---
 crates/bevy_render/src/lib.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/crates/bevy_render/src/lib.rs b/crates/bevy_render/src/lib.rs
index fbe6aaa8c7782..1a9b293b95d9c 100644
--- a/crates/bevy_render/src/lib.rs
+++ b/crates/bevy_render/src/lib.rs
@@ -229,6 +229,8 @@ impl Plugin for RenderPlugin {
 
 fn check_for_render_resource_context(context: Option<Res<Box<dyn RenderResourceContext>>>) {
     if context.is_none() {
-        panic!("bevy_render couldn't find a render backend. Try adding bevy_wgpu!")
+        panic!(
+            "bevy_render couldn't find a render backend. Perhaps try adding the bevy_wgpu plugin!"
+        )
     }
 }