Add capability to render to a texture (bevyengine#3412)

# Objective Will fix bevyengine#3377 and bevyengine#3254 ## Solution Use an enum to represent either a `WindowId` or `Handle<Image>` in place of `Camera::window`. Co-authored-by: Carter Anderson <[email protected]>
jakobhellermann · Feb 24, 2022 · 81d57e1 · 81d57e1
1 parent ba6b74b
commit 81d57e1
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Showing 12 changed files with 500 additions and 120 deletions.
diff --git a/Cargo.toml b/Cargo.toml
@@ -212,6 +212,10 @@ path = "examples/3d/spherical_area_lights.rs"
 name = "texture"
 path = "examples/3d/texture.rs"
 
+[[example]]
+name = "render_to_texture"
+path = "examples/3d/render_to_texture.rs"
+
 [[example]]
 name = "update_gltf_scene"
 path = "examples/3d/update_gltf_scene.rs"

diff --git a/crates/bevy_core_pipeline/Cargo.toml b/crates/bevy_core_pipeline/Cargo.toml
@@ -19,4 +19,5 @@ bevy_asset = { path = "../bevy_asset", version = "0.6.0" }
 bevy_core = { path = "../bevy_core", version = "0.6.0" }
 bevy_ecs = { path = "../bevy_ecs", version = "0.6.0" }
 bevy_render = { path = "../bevy_render", version = "0.6.0" }
+bevy_utils = { path = "../bevy_utils", version = "0.6.0" }
 
diff --git a/crates/bevy_core_pipeline/src/clear_pass.rs b/crates/bevy_core_pipeline/src/clear_pass.rs
@@ -1,9 +1,11 @@
 use std::collections::HashSet;
 
-use crate::ClearColor;
+use crate::{ClearColor, RenderTargetClearColors};
 use bevy_ecs::prelude::*;
 use bevy_render::{
-    camera::ExtractedCamera,
+    camera::{ExtractedCamera, RenderTarget},
+    prelude::Image,
+    render_asset::RenderAssets,
     render_graph::{Node, NodeRunError, RenderGraphContext, SlotInfo},
     render_resource::{
         LoadOp, Operations, RenderPassColorAttachment, RenderPassDepthStencilAttachment,
@@ -47,21 +49,26 @@ impl Node for ClearPassNode {
         render_context: &mut RenderContext,
         world: &World,
     ) -> Result<(), NodeRunError> {
-        let mut cleared_windows = HashSet::new();
+        let mut cleared_targets = HashSet::new();
         let clear_color = world.get_resource::<ClearColor>().unwrap();
+        let render_target_clear_colors = world.get_resource::<RenderTargetClearColors>().unwrap();
 
         // This gets all ViewTargets and ViewDepthTextures and clears its attachments
         // TODO: This has the potential to clear the same target multiple times, if there
         // are multiple views drawing to the same target. This should be fixed when we make
         // clearing happen on "render targets" instead of "views" (see the TODO below for more context).
         for (target, depth, camera) in self.query.iter_manual(world) {
+            let mut color = &clear_color.0;
             if let Some(camera) = camera {
-                cleared_windows.insert(camera.window_id);
+                cleared_targets.insert(&camera.target);
+                if let Some(target_color) = render_target_clear_colors.get(&camera.target) {
+                    color = target_color;
+                }
             }
             let pass_descriptor = RenderPassDescriptor {
                 label: Some("clear_pass"),
                 color_attachments: &[target.get_color_attachment(Operations {
-                    load: LoadOp::Clear(clear_color.0.into()),
+                    load: LoadOp::Clear((*color).into()),
                     store: true,
                 })],
                 depth_stencil_attachment: depth.map(|depth| RenderPassDepthStencilAttachment {
@@ -83,18 +90,28 @@ impl Node for ClearPassNode {
         // which will cause panics. The real fix here is to clear "render targets" directly
         // instead of "views". This should be removed once full RenderTargets are implemented.
         let windows = world.get_resource::<ExtractedWindows>().unwrap();
-        for window in windows.values() {
+        let images = world.get_resource::<RenderAssets<Image>>().unwrap();
+        for target in render_target_clear_colors.colors.keys().cloned().chain(
+            windows
+                .values()
+                .map(|window| RenderTarget::Window(window.id)),
+        ) {
             // skip windows that have already been cleared
-            if cleared_windows.contains(&window.id) {
+            if cleared_targets.contains(&target) {
                 continue;
             }
             let pass_descriptor = RenderPassDescriptor {
                 label: Some("clear_pass"),
                 color_attachments: &[RenderPassColorAttachment {
-                    view: window.swap_chain_texture.as_ref().unwrap(),
+                    view: target.get_texture_view(windows, images).unwrap(),
                     resolve_target: None,
                     ops: Operations {
-                        load: LoadOp::Clear(clear_color.0.into()),
+                        load: LoadOp::Clear(
+                            (*render_target_clear_colors
+                                .get(&target)
+                                .unwrap_or(&clear_color.0))
+                            .into(),
+                        ),
                         store: true,
                     },
                 }],

diff --git a/crates/bevy_core_pipeline/src/lib.rs b/crates/bevy_core_pipeline/src/lib.rs
@@ -9,6 +9,8 @@ pub mod prelude {
     pub use crate::ClearColor;
 }
 
+use bevy_utils::HashMap;
+
 pub use clear_pass::*;
 pub use clear_pass_driver::*;
 pub use main_pass_2d::*;
@@ -21,7 +23,7 @@ use bevy_app::{App, Plugin};
 use bevy_core::FloatOrd;
 use bevy_ecs::prelude::*;
 use bevy_render::{
-    camera::{ActiveCameras, CameraPlugin},
+    camera::{ActiveCameras, CameraPlugin, RenderTarget},
     color::Color,
     render_graph::{EmptyNode, RenderGraph, SlotInfo, SlotType},
     render_phase::{
@@ -48,6 +50,20 @@ impl Default for ClearColor {
     }
 }
 
+#[derive(Clone, Debug, Default)]
+pub struct RenderTargetClearColors {
+    colors: HashMap<RenderTarget, Color>,
+}
+
+impl RenderTargetClearColors {
+    pub fn get(&self, target: &RenderTarget) -> Option<&Color> {
+        self.colors.get(target)
+    }
+    pub fn insert(&mut self, target: RenderTarget, color: Color) {
+        self.colors.insert(target, color);
+    }
+}
+
 // Plugins that contribute to the RenderGraph should use the following label conventions:
 // 1. Graph modules should have a NAME, input module, and node module (where relevant)
 // 2. The "top level" graph is the plugin module root. Just add things like `pub mod node` directly under the plugin module
@@ -96,7 +112,8 @@ pub enum CorePipelineRenderSystems {
 
 impl Plugin for CorePipelinePlugin {
     fn build(&self, app: &mut App) {
-        app.init_resource::<ClearColor>();
+        app.init_resource::<ClearColor>()
+            .init_resource::<RenderTargetClearColors>();
 
         let render_app = match app.get_sub_app_mut(RenderApp) {
             Ok(render_app) => render_app,
@@ -330,12 +347,22 @@ impl CachedPipelinePhaseItem for Transparent3d {
     }
 }
 
-pub fn extract_clear_color(clear_color: Res<ClearColor>, mut render_world: ResMut<RenderWorld>) {
+pub fn extract_clear_color(
+    clear_color: Res<ClearColor>,
+    clear_colors: Res<RenderTargetClearColors>,
+    mut render_world: ResMut<RenderWorld>,
+) {
     // If the clear color has changed
     if clear_color.is_changed() {
         // Update the clear color resource in the render world
         render_world.insert_resource(clear_color.clone());
     }
+
+    // If the clear color has changed
+    if clear_colors.is_changed() {
+        // Update the clear color resource in the render world
+        render_world.insert_resource(clear_colors.clone());
+    }
 }
 
 pub fn extract_core_pipeline_camera_phases(

diff --git a/crates/bevy_pbr/src/light.rs b/crates/bevy_pbr/src/light.rs
@@ -1,11 +1,13 @@
 use std::collections::HashSet;
 
+use bevy_asset::Assets;
 use bevy_ecs::prelude::*;
 use bevy_math::{Mat4, UVec2, UVec3, Vec2, Vec3, Vec3Swizzles, Vec4, Vec4Swizzles};
 use bevy_reflect::Reflect;
 use bevy_render::{
     camera::{Camera, CameraProjection, OrthographicProjection},
     color::Color,
+    prelude::Image,
     primitives::{Aabb, CubemapFrusta, Frustum, Sphere},
     view::{ComputedVisibility, RenderLayers, Visibility, VisibleEntities},
 };
@@ -354,62 +356,62 @@ const Z_SLICES: u32 = 24;
 pub fn add_clusters(
     mut commands: Commands,
     windows: Res<Windows>,
+    images: Res<Assets<Image>>,
     cameras: Query<(Entity, &Camera), Without<Clusters>>,
 ) {
     for (entity, camera) in cameras.iter() {
-        let window = match windows.get(camera.window) {
-            Some(window) => window,
-            None => continue,
-        };
-        let clusters = Clusters::from_screen_size_and_z_slices(
-            UVec2::new(window.physical_width(), window.physical_height()),
-            Z_SLICES,
-        );
-        commands.entity(entity).insert(clusters);
+        if let Some(size) = camera.target.get_physical_size(&windows, &images) {
+            let clusters = Clusters::from_screen_size_and_z_slices(size, Z_SLICES);
+            commands.entity(entity).insert(clusters);
+        }
     }
 }
 
-pub fn update_clusters(windows: Res<Windows>, mut views: Query<(&Camera, &mut Clusters)>) {
+pub fn update_clusters(
+    windows: Res<Windows>,
+    images: Res<Assets<Image>>,
+    mut views: Query<(&Camera, &mut Clusters)>,
+) {
     for (camera, mut clusters) in views.iter_mut() {
         let is_orthographic = camera.projection_matrix.w_axis.w == 1.0;
         let inverse_projection = camera.projection_matrix.inverse();
-        let window = windows.get(camera.window).unwrap();
-        let screen_size_u32 = UVec2::new(window.physical_width(), window.physical_height());
-        // Don't update clusters if screen size is 0.
-        if screen_size_u32.x == 0 || screen_size_u32.y == 0 {
-            continue;
-        }
-        *clusters =
-            Clusters::from_screen_size_and_z_slices(screen_size_u32, clusters.axis_slices.z);
-        let screen_size = screen_size_u32.as_vec2();
-        let tile_size_u32 = clusters.tile_size;
-        let tile_size = tile_size_u32.as_vec2();
-
-        // Calculate view space AABBs
-        // NOTE: It is important that these are iterated in a specific order
-        // so that we can calculate the cluster index in the fragment shader!
-        // I (Rob Swain) choose to scan along rows of tiles in x,y, and for each tile then scan
-        // along z
-        let mut aabbs = Vec::with_capacity(
-            (clusters.axis_slices.y * clusters.axis_slices.x * clusters.axis_slices.z) as usize,
-        );
-        for y in 0..clusters.axis_slices.y {
-            for x in 0..clusters.axis_slices.x {
-                for z in 0..clusters.axis_slices.z {
-                    aabbs.push(compute_aabb_for_cluster(
-                        clusters.near,
-                        camera.far,
-                        tile_size,
-                        screen_size,
-                        inverse_projection,
-                        is_orthographic,
-                        clusters.axis_slices,
-                        UVec3::new(x, y, z),
-                    ));
+        if let Some(screen_size_u32) = camera.target.get_physical_size(&windows, &images) {
+            // Don't update clusters if screen size is 0.
+            if screen_size_u32.x == 0 || screen_size_u32.y == 0 {
+                continue;
+            }
+            *clusters =
+                Clusters::from_screen_size_and_z_slices(screen_size_u32, clusters.axis_slices.z);
+            let screen_size = screen_size_u32.as_vec2();
+            let tile_size_u32 = clusters.tile_size;
+            let tile_size = tile_size_u32.as_vec2();
+
+            // Calculate view space AABBs
+            // NOTE: It is important that these are iterated in a specific order
+            // so that we can calculate the cluster index in the fragment shader!
+            // I (Rob Swain) choose to scan along rows of tiles in x,y, and for each tile then scan
+            // along z
+            let mut aabbs = Vec::with_capacity(
+                (clusters.axis_slices.y * clusters.axis_slices.x * clusters.axis_slices.z) as usize,
+            );
+            for y in 0..clusters.axis_slices.y {
+                for x in 0..clusters.axis_slices.x {
+                    for z in 0..clusters.axis_slices.z {
+                        aabbs.push(compute_aabb_for_cluster(
+                            clusters.near,
+                            camera.far,
+                            tile_size,
+                            screen_size,
+                            inverse_projection,
+                            is_orthographic,
+                            clusters.axis_slices,
+                            UVec3::new(x, y, z),
+                        ));
+                    }
                 }
             }
+            clusters.aabbs = aabbs;
         }
-        clusters.aabbs = aabbs;
     }
 }