render: create a depth map for the directional light

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

@@ -22,8 +22,8 @@ pub use tint::*;
 mod fxaa;
 pub use fxaa::*;
 
-/* mod shadow_maps;
+mod shadows;
-pub use shadow_maps::*; */
+pub use shadows::*;
 
 mod mesh_prepare;
 pub use mesh_prepare::*;

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

@@ -0,0 +1,312 @@
+use std::{mem, num::NonZeroU64, rc::Rc, sync::Arc};
+
+use lyra_ecs::{query::Entities, AtomicRef, Entity, ResourceData};
+use lyra_game_derive::RenderGraphLabel;
+use lyra_math::{Transform, OPENGL_TO_WGPU_MATRIX};
+use rustc_hash::FxHashMap;
+use tracing::{debug, warn};
+use wgpu::util::DeviceExt;
+
+use crate::render::{
+    graph::{Node, NodeDesc, NodeType},
+    light::directional::DirectionalLight,
+    resource::{FragmentState, PipelineDescriptor, RenderPipeline, RenderPipelineDescriptor, Shader, VertexState},
+    transform_buffer_storage::TransformBuffers,
+    vertex::Vertex,
+};
+
+use super::{MeshBufferStorage, RenderAssets, RenderMeshes};
+
+const SHADOW_SIZE: glam::UVec2 = glam::UVec2::new(1024, 1024);
+
+#[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,
+}
+
+pub struct ShadowMapsPass {
+    bgl: Arc<wgpu::BindGroupLayout>,
+    /// depth maps for a light owned by an entity.
+    depth_maps: FxHashMap<Entity, LightDepthMap>,
+
+    // TODO: find a better way to extract these resources from the main world to be used in the
+    // render stage.
+    transform_buffers: Option<ResourceData>,
+    render_meshes: Option<ResourceData>,
+    mesh_buffers: Option<ResourceData>,
+    pipeline: Option<RenderPipeline>,
+}
+
+impl ShadowMapsPass {
+    pub fn new(device: &wgpu::Device) -> Self {
+        let bgl = Arc::new(device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
+            label: Some("shadows_bgl"),
+            entries: &[wgpu::BindGroupLayoutEntry {
+                binding: 0,
+                visibility: wgpu::ShaderStages::VERTEX,
+                ty: wgpu::BindingType::Buffer {
+                    ty: wgpu::BufferBindingType::Uniform,
+                    has_dynamic_offset: false,
+                    min_binding_size: Some(
+                        NonZeroU64::new(mem::size_of::<glam::Mat4>() as _).unwrap(),
+                    ),
+                },
+                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"),
+            size: wgpu::Extent3d {
+                width: SHADOW_SIZE.x,
+                height: SHADOW_SIZE.y,
+                depth_or_array_layers: 1,
+            },
+            mip_level_count: 1,
+            sample_count: 1,
+            dimension: wgpu::TextureDimension::D2,
+            format: wgpu::TextureFormat::Depth32Float,
+            usage: wgpu::TextureUsages::RENDER_ATTACHMENT | wgpu::TextureUsages::TEXTURE_BINDING,
+            view_formats: &[],
+        });
+
+        let view = tex.create_view(&wgpu::TextureViewDescriptor {
+            label: Some("shadows_map_view"),
+            ..Default::default()
+        });
+
+        let sampler = device.create_sampler(&wgpu::SamplerDescriptor {
+            label: Some("sampler_light_depth_map"),
+            address_mode_u: wgpu::AddressMode::ClampToEdge,
+            address_mode_v: wgpu::AddressMode::ClampToEdge,
+            address_mode_w: wgpu::AddressMode::ClampToEdge,
+            mag_filter: wgpu::FilterMode::Linear,
+            min_filter: wgpu::FilterMode::Linear,
+            mipmap_filter: wgpu::FilterMode::Linear,
+            border_color: Some(wgpu::SamplerBorderColor::OpaqueWhite),
+            ..Default::default()
+        });
+
+        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 light_proj = OPENGL_TO_WGPU_MATRIX * (ortho_proj * look_view);
+
+        let light_projection_buffer =
+            device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
+                label: Some("shadows_light_view_mat_buffer"),
+                usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
+                contents: bytemuck::bytes_of(&light_proj),
+            });
+
+        let bg = device.create_bind_group(&wgpu::BindGroupDescriptor {
+            label: Some("shadows_bind_group"),
+            layout: &self.bgl,
+            entries: &[wgpu::BindGroupEntry {
+                binding: 0,
+                resource: wgpu::BindingResource::Buffer(wgpu::BufferBinding {
+                    buffer: &light_projection_buffer,
+                    offset: 0,
+                    size: None,
+                }),
+            }],
+        });
+
+        self.depth_maps.insert(
+            entity,
+            LightDepthMap {
+                light_projection_buffer,
+                texture: tex,
+                view,
+                sampler,
+                bindgroup: bg,
+            },
+        );
+    }
+
+    fn transform_buffers(&self) -> AtomicRef<TransformBuffers> {
+        self.transform_buffers.as_ref().unwrap().get()
+    }
+
+    fn render_meshes(&self) -> AtomicRef<RenderMeshes> {
+        self.render_meshes.as_ref().unwrap().get()
+    }
+
+    fn mesh_buffers(&self) -> AtomicRef<RenderAssets<MeshBufferStorage>> {
+        self.mesh_buffers.as_ref().unwrap().get()
+    }
+}
+
+impl Node for ShadowMapsPass {
+    fn desc(
+        &mut self,
+        graph: &mut crate::render::graph::RenderGraph,
+    ) -> crate::render::graph::NodeDesc {
+        NodeDesc::new(NodeType::Render, None, vec![])
+    }
+
+    fn prepare(
+        &mut self,
+        graph: &mut crate::render::graph::RenderGraph,
+        world: &mut lyra_ecs::World,
+        context: &mut crate::render::graph::RenderGraphContext,
+    ) {
+        self.render_meshes = world.try_get_resource_data::<RenderMeshes>();
+        self.transform_buffers = world.try_get_resource_data::<TransformBuffers>();
+        self.mesh_buffers = world.try_get_resource_data::<RenderAssets<MeshBufferStorage>>();
+
+        for (entity, pos, light) in world.view_iter::<(Entities, &Transform, &DirectionalLight)>() {
+            if !self.depth_maps.contains_key(&entity) {
+                self.create_depth_map(graph.device(), entity, *pos);
+                debug!("Created depth map for {:?} light entity", entity);
+            }
+        }
+
+        if self.pipeline.is_none() {
+            let shader = Rc::new(Shader {
+                label: Some("shader_shadows".into()),
+                source: include_str!("../../shaders/shadows.wgsl").to_string(),
+            });
+
+            let bgl = self.bgl.clone();
+            let transforms = self.transform_buffers().bindgroup_layout.clone();
+
+            self.pipeline = Some(RenderPipeline::create(
+                &graph.device,
+                &RenderPipelineDescriptor {
+                    label: Some("pipeline_shadows".into()),
+                    layouts: vec![
+                        bgl,
+                        transforms,
+                    ],
+                    push_constant_ranges: vec![],
+                    vertex: VertexState {
+                        module: shader.clone(),
+                        entry_point: "vs_main".into(),
+                        buffers: vec![Vertex::position_desc().into()],
+                    },
+                    fragment: None, /* Some(FragmentState {
+                                        module: shader,
+                                        entry_point: "fs_main".into(),
+                                        targets: vec![],
+                                    }), */
+                    depth_stencil: Some(wgpu::DepthStencilState {
+                        format: wgpu::TextureFormat::Depth32Float,
+                        depth_write_enabled: true,
+                        depth_compare: wgpu::CompareFunction::Less,
+                        stencil: wgpu::StencilState::default(),
+                        bias: wgpu::DepthBiasState::default(),
+                    }),
+                    primitive: wgpu::PrimitiveState::default(),
+                    multisample: wgpu::MultisampleState::default(),
+                    multiview: None,
+                }
+            ));
+            /*  */
+        }
+    }
+
+    fn execute(
+        &mut self,
+        graph: &mut crate::render::graph::RenderGraph,
+        desc: &crate::render::graph::NodeDesc,
+        context: &mut crate::render::graph::RenderGraphContext,
+    ) {
+        let encoder = context.encoder.as_mut().unwrap();
+        let pipeline = self.pipeline.as_ref().unwrap();
+
+        let render_meshes = self.render_meshes();
+        let mesh_buffers = self.mesh_buffers();
+        let transforms = self.transform_buffers();
+
+        debug_assert_eq!(
+            self.depth_maps.len(),
+            1,
+            "shadows map pass only supports 1 light"
+        );
+        let (_, dir_depth_map) = self
+            .depth_maps
+            .iter()
+            .next()
+            .expect("missing directional light in scene");
+
+        {
+            let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
+                label: Some("pass_shadow_map"),
+                color_attachments: &[],
+                depth_stencil_attachment: Some(wgpu::RenderPassDepthStencilAttachment {
+                    view: &dir_depth_map.view,
+                    depth_ops: Some(wgpu::Operations {
+                        load: wgpu::LoadOp::Clear(1.0),
+                        store: true,
+                    }),
+                    stencil_ops: None,
+                }),
+            });
+            pass.set_pipeline(&pipeline);
+
+            for job in render_meshes.iter() {
+                // get the mesh (containing vertices) and the buffers from storage
+                let buffers = mesh_buffers.get(&job.mesh_uuid);
+                if buffers.is_none() {
+                    warn!("Skipping job since its mesh is missing {:?}", job.mesh_uuid);
+                    continue;
+                }
+                let buffers = buffers.unwrap();
+
+                pass.set_bind_group(0, &dir_depth_map.bindgroup, &[]);
+
+                // Get the bindgroup for job's transform and bind to it using an offset.
+                let bindgroup = transforms.bind_group(job.transform_id);
+                let offset = transforms.buffer_offset(job.transform_id);
+                pass.set_bind_group(1, bindgroup, &[offset]);
+
+                // if this mesh uses indices, use them to draw the mesh
+                if let Some((idx_type, indices)) = buffers.buffer_indices.as_ref() {
+                    let indices_len = indices.count() as u32;
+
+                    pass.set_vertex_buffer(
+                        buffers.buffer_vertex.slot(),
+                        buffers.buffer_vertex.buffer().slice(..),
+                    );
+                    pass.set_index_buffer(indices.buffer().slice(..), *idx_type);
+                    pass.draw_indexed(0..indices_len, 0, 0..1);
+                } else {
+                    let vertex_count = buffers.buffer_vertex.count();
+
+                    pass.set_vertex_buffer(
+                        buffers.buffer_vertex.slot(),
+                        buffers.buffer_vertex.buffer().slice(..),
+                    );
+                    pass.draw(0..vertex_count as u32, 0..1);
+                }
+            }
+        }
+    }
+}

lyra-game/src/render/renderer.rs

@@ -9,7 +9,7 @@ use lyra_game_derive::RenderGraphLabel;
 use tracing::{debug, instrument, warn};
 use winit::window::Window;
 
-use crate::render::graph::{BasePass, BasePassLabel, BasePassSlots, FxaaPass, FxaaPassLabel, LightBasePass, LightBasePassLabel, LightCullComputePass, LightCullComputePassLabel, MeshPass, MeshPrepNode, MeshPrepNodeLabel, MeshesPassLabel, PresentPass, PresentPassLabel, RenderGraphLabelValue, RenderTarget, SubGraphNode, ViewTarget};
+use crate::render::graph::{BasePass, BasePassLabel, BasePassSlots, FxaaPass, FxaaPassLabel, LightBasePass, LightBasePassLabel, LightCullComputePass, LightCullComputePassLabel, MeshPass, MeshPrepNode, MeshPrepNodeLabel, MeshesPassLabel, PresentPass, PresentPassLabel, RenderGraphLabelValue, RenderTarget, ShadowMapsPass, ShadowMapsPassLabel, SubGraphNode, ViewTarget};
 
 use super::graph::RenderGraph;
 use super::{resource::RenderPipeline, render_job::RenderJob};
@@ -152,8 +152,14 @@ impl BasicRenderer {
             forward_plus_graph.add_node(MeshPrepNodeLabel, mesh_prep);
             forward_plus_graph.add_node(MeshesPassLabel, MeshPass::new(material_bgl));
 
+            forward_plus_graph.add_node(ShadowMapsPassLabel, ShadowMapsPass::new(&device));
+
             forward_plus_graph.add_edge(LightBasePassLabel, LightCullComputePassLabel);
             forward_plus_graph.add_edge(MeshPrepNodeLabel, MeshesPassLabel);
+
+            // run ShadowMapsPass after MeshPrep and before MeshesPass
+            forward_plus_graph.add_edge(MeshPrepNodeLabel, ShadowMapsPassLabel);
+            forward_plus_graph.add_edge(ShadowMapsPassLabel, MeshesPassLabel);
             
             main_graph.add_sub_graph(TestSubGraphLabel, forward_plus_graph);
             main_graph.add_node(TestSubGraphLabel, SubGraphNode::new(TestSubGraphLabel, 

lyra-game/src/render/shaders/shadows.wgsl

@@ -0,0 +1,23 @@
+struct TransformData {
+    transform: mat4x4<f32>,
+    normal_matrix: mat4x4<f32>,
+}
+
+@group(0) @binding(0)
+var<uniform> u_light_space_matrix: mat4x4<f32>;
+
+@group(1) @binding(0)
+var<uniform> u_model_transform_data: TransformData;
+
+struct VertexOutput {
+    @builtin(position)
+    clip_position: vec4<f32>,
+}
+
+@vertex
+fn vs_main(
+    @location(0) position: vec3<f32>
+) -> VertexOutput {
+    let pos = u_light_space_matrix * u_model_transform_data.transform * vec4<f32>(position, 1.0);
+    return VertexOutput(pos);
+}

lyra-game/src/render/vertex.rs

@@ -15,6 +15,23 @@ impl Vertex {
             position, tex_coords, normals
         }
     }
+
+    /// Returns a [`wgpu::VertexBufferLayout`] with only the position as a vertex attribute.
+    /// 
+    /// The stride is still `std::mem::size_of::<Vertex>()`, but only position is included.
+    pub fn position_desc<'a>() -> wgpu::VertexBufferLayout<'a> {
+        wgpu::VertexBufferLayout {
+            array_stride: std::mem::size_of::<Vertex>() as wgpu::BufferAddress,
+            step_mode: wgpu::VertexStepMode::Vertex,
+            attributes: &[
+                wgpu::VertexAttribute {
+                    offset: 0,
+                    shader_location: 0,
+                    format: wgpu::VertexFormat::Float32x3, // Vec3
+                },
+            ]
+        }
+    }
 }
 
 impl DescVertexBufferLayout for Vertex {