Add FullscreenPassNode for post-processing

Cargo.toml

@@ -383,6 +383,10 @@ path = "examples/shader/animate_shader.rs"
 name = "array_texture"
 path = "examples/shader/array_texture.rs"
 
+[[example]]
+name = "fullscreen_pass"
+path = "examples/shader/fullscreen_pass.rs"
+
 [[example]]
 name = "hot_shader_reloading"
 path = "examples/shader/hot_shader_reloading.rs"

crates/bevy_render/src/render_graph/base.rs

@@ -128,6 +128,8 @@ pub(crate) fn add_base_graph(config: &BaseRenderGraphConfig, world: &mut World)
                                                           * bit depth for better performance */
                     usage: TextureUsage::OUTPUT_ATTACHMENT,
                 },
+                None,
+                None,
             ),
         );
     }
@@ -222,6 +224,8 @@ pub(crate) fn add_base_graph(config: &BaseRenderGraphConfig, world: &mut World)
                     format: TextureFormat::default(),
                     usage: TextureUsage::OUTPUT_ATTACHMENT,
                 },
+                None,
+                None,
             ),
         );
 

crates/bevy_render/src/render_graph/node_slot.rs

@@ -51,7 +51,7 @@ impl ResourceSlots {
 
     pub fn get(&self, label: impl Into<SlotLabel>) -> Option<RenderResourceId> {
         let slot = self.get_slot(label).unwrap();
-        slot.resource.clone()
+        slot.resource
     }
 
     pub fn get_slot(&self, label: impl Into<SlotLabel>) -> Result<&ResourceSlot, RenderGraphError> {

crates/bevy_render/src/render_graph/nodes/fullscreen_pass_node/fullscreen.vert

@@ -0,0 +1,11 @@
+#version 450
+
+layout(location=0) out vec2 v_Uv;
+
+void main() {
+    // Setup a single triangle
+    float x = float((gl_VertexIndex & 1) << 2);
+    float y = float((gl_VertexIndex & 2) << 1);
+    v_Uv = vec2(x * 0.5, 1.0-y * 0.5);
+    gl_Position = vec4(x - 1.0, y - 1.0, 0, 1);
+}

crates/bevy_render/src/render_graph/nodes/fullscreen_pass_node/mod.rs

@@ -0,0 +1,6 @@
+pub mod node;
+
+pub mod shaders {
+    pub const VERTEX_SHADER: &str = include_str!("fullscreen.vert");
+    pub const NOOP_SHADER: &str = include_str!("noop.frag");
+}