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| 1 | +use crate::blit::{BlitPipeline, BlitPipelineKey}; |
| 2 | +use bevy_app::{App, Plugin}; |
| 3 | +use bevy_ecs::prelude::*; |
| 4 | +use bevy_render::{ |
| 5 | + camera::ExtractedCamera, |
| 6 | + render_graph::{Node, NodeRunError, RenderGraph, RenderGraphContext, SlotInfo, SlotType}, |
| 7 | + renderer::RenderContext, |
| 8 | + view::{Msaa, ViewTarget}, |
| 9 | + RenderSet, |
| 10 | +}; |
| 11 | +use bevy_render::{render_resource::*, RenderApp}; |
| 12 | + |
| 13 | +/// This enables "msaa writeback" support for the `core_2d` and `core_3d` pipelines, which can be enabled on cameras |
| 14 | +/// using [`bevy_render::camera::Camera::msaa_writeback`]. See the docs on that field for more information. |
| 15 | +pub struct MsaaWritebackPlugin; |
| 16 | + |
| 17 | +impl Plugin for MsaaWritebackPlugin { |
| 18 | + fn build(&self, app: &mut App) { |
| 19 | + let Ok(render_app) = app.get_sub_app_mut(RenderApp) else { |
| 20 | + return |
| 21 | + }; |
| 22 | + |
| 23 | + render_app.add_system(queue_msaa_writeback_pipelines.in_set(RenderSet::Queue)); |
| 24 | + let msaa_writeback_2d = MsaaWritebackNode::new(&mut render_app.world); |
| 25 | + let msaa_writeback_3d = MsaaWritebackNode::new(&mut render_app.world); |
| 26 | + let mut graph = render_app.world.resource_mut::<RenderGraph>(); |
| 27 | + if let Some(core_2d) = graph.get_sub_graph_mut(crate::core_2d::graph::NAME) { |
| 28 | + let input_node = core_2d.input_node().id; |
| 29 | + core_2d.add_node( |
| 30 | + crate::core_2d::graph::node::MSAA_WRITEBACK, |
| 31 | + msaa_writeback_2d, |
| 32 | + ); |
| 33 | + core_2d.add_node_edge( |
| 34 | + crate::core_2d::graph::node::MSAA_WRITEBACK, |
| 35 | + crate::core_2d::graph::node::MAIN_PASS, |
| 36 | + ); |
| 37 | + core_2d.add_slot_edge( |
| 38 | + input_node, |
| 39 | + crate::core_2d::graph::input::VIEW_ENTITY, |
| 40 | + crate::core_2d::graph::node::MSAA_WRITEBACK, |
| 41 | + MsaaWritebackNode::IN_VIEW, |
| 42 | + ); |
| 43 | + } |
| 44 | + |
| 45 | + if let Some(core_3d) = graph.get_sub_graph_mut(crate::core_3d::graph::NAME) { |
| 46 | + let input_node = core_3d.input_node().id; |
| 47 | + core_3d.add_node( |
| 48 | + crate::core_3d::graph::node::MSAA_WRITEBACK, |
| 49 | + msaa_writeback_3d, |
| 50 | + ); |
| 51 | + core_3d.add_node_edge( |
| 52 | + crate::core_3d::graph::node::MSAA_WRITEBACK, |
| 53 | + crate::core_3d::graph::node::MAIN_PASS, |
| 54 | + ); |
| 55 | + core_3d.add_slot_edge( |
| 56 | + input_node, |
| 57 | + crate::core_3d::graph::input::VIEW_ENTITY, |
| 58 | + crate::core_3d::graph::node::MSAA_WRITEBACK, |
| 59 | + MsaaWritebackNode::IN_VIEW, |
| 60 | + ); |
| 61 | + } |
| 62 | + } |
| 63 | +} |
| 64 | + |
| 65 | +pub struct MsaaWritebackNode { |
| 66 | + cameras: QueryState<(&'static ViewTarget, &'static MsaaWritebackBlitPipeline)>, |
| 67 | +} |
| 68 | + |
| 69 | +impl MsaaWritebackNode { |
| 70 | + pub const IN_VIEW: &'static str = "view"; |
| 71 | + |
| 72 | + pub fn new(world: &mut World) -> Self { |
| 73 | + Self { |
| 74 | + cameras: world.query(), |
| 75 | + } |
| 76 | + } |
| 77 | +} |
| 78 | + |
| 79 | +impl Node for MsaaWritebackNode { |
| 80 | + fn input(&self) -> Vec<SlotInfo> { |
| 81 | + vec![SlotInfo::new(Self::IN_VIEW, SlotType::Entity)] |
| 82 | + } |
| 83 | + fn update(&mut self, world: &mut World) { |
| 84 | + self.cameras.update_archetypes(world); |
| 85 | + } |
| 86 | + fn run( |
| 87 | + &self, |
| 88 | + graph: &mut RenderGraphContext, |
| 89 | + render_context: &mut RenderContext, |
| 90 | + world: &World, |
| 91 | + ) -> Result<(), NodeRunError> { |
| 92 | + let view_entity = graph.get_input_entity(Self::IN_VIEW)?; |
| 93 | + if let Ok((target, blit_pipeline_id)) = self.cameras.get_manual(world, view_entity) { |
| 94 | + let blit_pipeline = world.resource::<BlitPipeline>(); |
| 95 | + let pipeline_cache = world.resource::<PipelineCache>(); |
| 96 | + let pipeline = pipeline_cache |
| 97 | + .get_render_pipeline(blit_pipeline_id.0) |
| 98 | + .unwrap(); |
| 99 | + |
| 100 | + // The current "main texture" needs to be bound as an input resource, and we need the "other" |
| 101 | + // unused target to be the "resolve target" for the MSAA write. Therefore this is the same |
| 102 | + // as a post process write! |
| 103 | + let post_process = target.post_process_write(); |
| 104 | + |
| 105 | + let pass_descriptor = RenderPassDescriptor { |
| 106 | + label: Some("msaa_writeback"), |
| 107 | + // The target's "resolve target" is the "destination" in post_process |
| 108 | + // We will indirectly write the results to the "destination" using |
| 109 | + // the MSAA resolve step. |
| 110 | + color_attachments: &[Some(target.get_color_attachment(Operations { |
| 111 | + load: LoadOp::Clear(Default::default()), |
| 112 | + store: true, |
| 113 | + }))], |
| 114 | + depth_stencil_attachment: None, |
| 115 | + }; |
| 116 | + |
| 117 | + let bind_group = |
| 118 | + render_context |
| 119 | + .render_device() |
| 120 | + .create_bind_group(&BindGroupDescriptor { |
| 121 | + label: None, |
| 122 | + layout: &blit_pipeline.texture_bind_group, |
| 123 | + entries: &[ |
| 124 | + BindGroupEntry { |
| 125 | + binding: 0, |
| 126 | + resource: BindingResource::TextureView(post_process.source), |
| 127 | + }, |
| 128 | + BindGroupEntry { |
| 129 | + binding: 1, |
| 130 | + resource: BindingResource::Sampler(&blit_pipeline.sampler), |
| 131 | + }, |
| 132 | + ], |
| 133 | + }); |
| 134 | + |
| 135 | + let mut render_pass = render_context |
| 136 | + .command_encoder() |
| 137 | + .begin_render_pass(&pass_descriptor); |
| 138 | + |
| 139 | + render_pass.set_pipeline(pipeline); |
| 140 | + render_pass.set_bind_group(0, &bind_group, &[]); |
| 141 | + render_pass.draw(0..3, 0..1); |
| 142 | + } |
| 143 | + Ok(()) |
| 144 | + } |
| 145 | +} |
| 146 | + |
| 147 | +#[derive(Component)] |
| 148 | +pub struct MsaaWritebackBlitPipeline(CachedRenderPipelineId); |
| 149 | + |
| 150 | +fn queue_msaa_writeback_pipelines( |
| 151 | + mut commands: Commands, |
| 152 | + pipeline_cache: Res<PipelineCache>, |
| 153 | + mut pipelines: ResMut<SpecializedRenderPipelines<BlitPipeline>>, |
| 154 | + blit_pipeline: Res<BlitPipeline>, |
| 155 | + view_targets: Query<(Entity, &ViewTarget, &ExtractedCamera)>, |
| 156 | + msaa: Res<Msaa>, |
| 157 | +) { |
| 158 | + for (entity, view_target, camera) in view_targets.iter() { |
| 159 | + // only do writeback if writeback is enabled for the camera and this isn't the first camera in the target, |
| 160 | + // as there is nothing to write back for the first camera. |
| 161 | + if msaa.samples() > 1 && camera.msaa_writeback && camera.sorted_camera_index_for_target > 0 |
| 162 | + { |
| 163 | + let key = BlitPipelineKey { |
| 164 | + texture_format: view_target.main_texture_format(), |
| 165 | + samples: msaa.samples(), |
| 166 | + blend_state: None, |
| 167 | + }; |
| 168 | + |
| 169 | + let pipeline = pipelines.specialize(&pipeline_cache, &blit_pipeline, key); |
| 170 | + commands |
| 171 | + .entity(entity) |
| 172 | + .insert(MsaaWritebackBlitPipeline(pipeline)); |
| 173 | + } else { |
| 174 | + // This isn't strictly necessary now, but if we move to retained render entity state I don't |
| 175 | + // want this to silently break |
| 176 | + commands |
| 177 | + .entity(entity) |
| 178 | + .remove::<MsaaWritebackBlitPipeline>(); |
| 179 | + } |
| 180 | + } |
| 181 | +} |
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