render: start moving to a shadow map atlas texture and expose the resources as slots

lyra-game/src/render/graph/passes/shadows.rs

@@ -8,9 +8,12 @@ use tracing::{debug, warn};
 use wgpu::util::DeviceExt;
 
 use crate::render::{
-    graph::{Node, NodeDesc, NodeType},
+    graph::{Node, NodeDesc, NodeType, SlotAttribute, SlotValue},
     light::directional::DirectionalLight,
-    resource::{FragmentState, PipelineDescriptor, RenderPipeline, RenderPipelineDescriptor, Shader, VertexState},
+    resource::{
+        FragmentState, PipelineDescriptor, RenderPipeline, RenderPipelineDescriptor, Shader,
+        VertexState,
+    },
     transform_buffer_storage::TransformBuffers,
     vertex::Vertex,
 };
@@ -19,14 +22,18 @@ use super::{MeshBufferStorage, RenderAssets, RenderMeshes};
 
 const SHADOW_SIZE: glam::UVec2 = glam::UVec2::new(1024, 1024);
 
+#[derive(Debug, Clone, Hash, PartialEq, RenderGraphLabel)]
+pub enum ShadowMapsPassSlots {
+    ShadowAtlasTexture,
+    ShadowAtlasTextureView,
+    ShadowAtlasSampler,
+}
+
 #[derive(Debug, Clone, Hash, PartialEq, RenderGraphLabel)]
 pub struct ShadowMapsPassLabel;
 
 struct LightDepthMap {
     light_projection_buffer: wgpu::Buffer,
-    texture: wgpu::Texture,
-    view: wgpu::TextureView,
-    sampler: wgpu::Sampler,
     bindgroup: wgpu::BindGroup,
 }
 
@@ -41,12 +48,20 @@ pub struct ShadowMapsPass {
     render_meshes: Option<ResourceData>,
     mesh_buffers: Option<ResourceData>,
     pipeline: Option<RenderPipeline>,
+
+    /// The depth map atlas texture
+    atlas_texture: Rc<wgpu::Texture>,
+    /// The depth map atlas texture view
+    atlas_view: Arc<wgpu::TextureView>,
+    /// The depth map atlas sampler
+    atlas_sampler: Rc<wgpu::Sampler>,
 }
 
 impl ShadowMapsPass {
     pub fn new(device: &wgpu::Device) -> Self {
-        let bgl = Arc::new(device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
-            label: Some("shadows_bgl"),
+        let bgl = Arc::new(
+            device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
+                label: Some("bgl_shadows_light_projection"),
                 entries: &[wgpu::BindGroupLayoutEntry {
                     binding: 0,
                     visibility: wgpu::ShaderStages::VERTEX,
@@ -59,21 +74,11 @@ impl ShadowMapsPass {
                     },
                     count: None,
                 }],
-        }));
+            }),
+        );
 
-        Self {
-            bgl,
-            depth_maps: Default::default(),
-            transform_buffers: None,
-            render_meshes: None,
-            mesh_buffers: None,
-            pipeline: None,
-        }
-    }
-
-    fn create_depth_map(&mut self, device: &wgpu::Device, entity: Entity, light_pos: Transform) {
         let tex = device.create_texture(&wgpu::TextureDescriptor {
-            label: Some("texture_shadow_map_directional_light"),
+            label: Some("texture_shadow_map_atlas"),
             size: wgpu::Extent3d {
                 width: SHADOW_SIZE.x,
                 height: SHADOW_SIZE.y,
@@ -93,7 +98,7 @@ impl ShadowMapsPass {
         });
 
         let sampler = device.create_sampler(&wgpu::SamplerDescriptor {
-            label: Some("sampler_light_depth_map"),
+            label: Some("sampler_shadow_map_atlas"),
             address_mode_u: wgpu::AddressMode::ClampToEdge,
             address_mode_v: wgpu::AddressMode::ClampToEdge,
             address_mode_w: wgpu::AddressMode::ClampToEdge,
@@ -104,17 +109,29 @@ impl ShadowMapsPass {
             ..Default::default()
         });
 
+        Self {
+            bgl,
+            depth_maps: Default::default(),
+            transform_buffers: None,
+            render_meshes: None,
+            mesh_buffers: None,
+            pipeline: None,
+
+            atlas_sampler: Rc::new(sampler),
+            atlas_texture: Rc::new(tex),
+            atlas_view: Arc::new(view),
+        }
+    }
+
+    fn create_depth_map(&mut self, device: &wgpu::Device, entity: Entity, light_pos: Transform) {
         const NEAR_PLANE: f32 = 0.1;
         const FAR_PLANE: f32 = 80.0;
 
         let ortho_proj =
             glam::Mat4::orthographic_rh_gl(-20.0, 20.0, -20.0, 20.0, NEAR_PLANE, FAR_PLANE);
 
-        let look_view = glam::Mat4::look_to_rh(
-            light_pos.translation,
-            light_pos.forward(),
-            light_pos.up()
-        );
+        let look_view =
+            glam::Mat4::look_to_rh(light_pos.translation, light_pos.forward(), light_pos.up());
 
         let light_proj = OPENGL_TO_WGPU_MATRIX * (ortho_proj * look_view);
 
@@ -142,9 +159,6 @@ impl ShadowMapsPass {
             entity,
             LightDepthMap {
                 light_projection_buffer,
-                texture: tex,
-                view,
-                sampler,
                 bindgroup: bg,
             },
         );
@@ -168,7 +182,27 @@ impl Node for ShadowMapsPass {
         &mut self,
         graph: &mut crate::render::graph::RenderGraph,
     ) -> crate::render::graph::NodeDesc {
-        NodeDesc::new(NodeType::Render, None, vec![])
+        let mut node = NodeDesc::new(NodeType::Render, None, vec![]);
+
+        node.add_texture_slot(
+            ShadowMapsPassSlots::ShadowAtlasTexture,
+            SlotAttribute::Output,
+            Some(SlotValue::Texture(self.atlas_texture.clone())),
+        );
+
+        node.add_texture_view_slot(
+            ShadowMapsPassSlots::ShadowAtlasTextureView,
+            SlotAttribute::Output,
+            Some(SlotValue::TextureView(self.atlas_view.clone())),
+        );
+
+        node.add_sampler_slot(
+            ShadowMapsPassSlots::ShadowAtlasSampler,
+            SlotAttribute::Output,
+            Some(SlotValue::Sampler(self.atlas_sampler.clone())),
+        );
+
+        node
     }
 
     fn prepare(
@@ -201,10 +235,7 @@ impl Node for ShadowMapsPass {
                 &graph.device,
                 &RenderPipelineDescriptor {
                     label: Some("pipeline_shadows".into()),
-                    layouts: vec![
-                        bgl,
-                        transforms,
-                    ],
+                    layouts: vec![bgl, transforms],
                     push_constant_ranges: vec![],
                     vertex: VertexState {
                         module: shader.clone(),
@@ -226,7 +257,7 @@ impl Node for ShadowMapsPass {
                     primitive: wgpu::PrimitiveState::default(),
                     multisample: wgpu::MultisampleState::default(),
                     multiview: None,
-                }
+                },
             ));
             /*  */
         }
@@ -261,7 +292,7 @@ impl Node for ShadowMapsPass {
                 label: Some("pass_shadow_map"),
                 color_attachments: &[],
                 depth_stencil_attachment: Some(wgpu::RenderPassDepthStencilAttachment {
-                    view: &dir_depth_map.view,
+                    view: &self.atlas_view,
                     depth_ops: Some(wgpu::Operations {
                         load: wgpu::LoadOp::Clear(1.0),
                         store: true,