Refine group mixing and visualization

blade-helpers/src/hud.rs

@@ -22,7 +22,7 @@ impl ExposeHud for blade_render::RayConfig {
             egui::widgets::Slider::new(&mut self.spatial_tap_history, 0..=50)
                 .text("Spatial tap history"),
         );
-        ui.checkbox(&mut self.spatial_jitter, "Spatial jittering");
+        ui.add(egui::widgets::Slider::new(&mut self.group_mixer, 1..=10).text("Group mixer"));
         ui.add(
             egui::widgets::Slider::new(&mut self.spatial_min_distance, 1..=10)
                 .text("Spatial minimum distance (px)"),

blade-render/Cargo.toml

@@ -39,7 +39,6 @@ glam = { workspace = true }
 log = { workspace = true }
 mikktspace = { package = "bevy_mikktspace", version = "0.12", optional = true }
 mint = { workspace = true }
-nanorand = { workspace = true, features = ["wyrand"] }
 profiling = { workspace = true }
 slab = { workspace = true, optional = true }
 strum = { workspace = true }

blade-render/code/color.inc.wgsl

@@ -0,0 +1,19 @@
+fn hsv_to_rgb(h: f32, s: f32, v: f32) -> vec3<f32> {
+    let c = v * s;
+    let x = c * (1.0 - abs((h / 60.0) % 2.0 - 1.0));
+    var q = vec3<f32>(v - c);
+    if (h < 60.0) {
+        q.r += c; q.g += x;
+    } else if (h < 120.0) {
+        q.g += c; q.r += x;
+    } else if (h < 180.0) {
+        q.g += c; q.b += x;
+    } else if (h < 240.0) {
+        q.b += c; q.g += x;
+    } else if (h < 300.0) {
+        q.b += c; q.r += x;
+    } else {
+        q.r += c; q.b += x;
+    }
+    return q;
+}

blade-render/code/ray-trace.wgsl

@@ -1,3 +1,4 @@
+#include "color.inc.wgsl"
 #include "quaternion.inc.wgsl"
 #include "random.inc.wgsl"
 #include "env-importance.inc.wgsl"
@@ -26,6 +27,7 @@ const DECOUPLED_SHADING: bool = false;
 //TODO: crashes on AMD 6850U if `GROUP_SIZE_TOTAL` > 32
 const GROUP_SIZE: vec2<u32> = vec2<u32>(8, 4);
 const GROUP_SIZE_TOTAL: u32 = GROUP_SIZE.x * GROUP_SIZE.y;
+const GROUP_VISUALIZE: bool = false;
 
 struct MainParams {
     frame_index: u32,
@@ -38,7 +40,6 @@ struct MainParams {
     spatial_min_distance: i32,
     t_start: f32,
     use_motion_vectors: u32,
-    grid_offset: vec2<u32>,
     grid_scale: vec2<u32>,
 }
 
@@ -231,7 +232,6 @@ fn thread_index_to_coord(thread_index: u32, group_id: vec3<u32>) -> vec2<i32> {
     let cluster_offset = group_id.xy - cluster_id * parameters.grid_scale;
     let local_id = vec2<u32>(thread_index % GROUP_SIZE.x, thread_index / GROUP_SIZE.x);
     let global_id = (cluster_id * GROUP_SIZE + local_id) * parameters.grid_scale + cluster_offset;
-    //TODO: also use the offset
     return vec2<i32>(global_id);
 }
 
@@ -557,6 +557,14 @@ fn main(
     if (any(vec2<u32>(pixel_coord) >= camera.target_size)) {
         return;
     }
+    if (GROUP_VISUALIZE)
+    {
+        var rng = random_init(group_id.y * 1000u + group_id.x, 0u);
+        let h = random_gen(&rng) * 360.0;
+        let color = hsv_to_rgb(h, 0.5, 1.0);
+        textureStore(out_diffuse, pixel_coord, vec4<f32>(color, 1.0));
+        return;
+    }
 
     let global_index = u32(pixel_coord.y) * camera.target_size.x + u32(pixel_coord.x);
     var rng = random_init(global_index, parameters.frame_index);

blade-render/src/render/mod.rs

@@ -11,7 +11,6 @@ pub use env_map::EnvironmentMap;
 use std::{collections::HashMap, mem, num::NonZeroU32, path::Path, ptr};
 
 const MAX_RESOURCES: u32 = 1000;
-const GRID_SCALES: u32 = 4;
 const RADIANCE_FORMAT: blade_graphics::TextureFormat = blade_graphics::TextureFormat::Rgba16Float;
 
 fn mat4_transform(t: &blade_graphics::Transform) -> glam::Mat4 {
@@ -96,9 +95,9 @@ pub struct RayConfig {
     pub spatial_tap_history: u32,
     /// Minimal distance to a spatially reused pixel (in the current frame).
     pub spatial_min_distance: u32,
-    /// Enable jittering of the compute grid, to allow spatial samples to mix
+    /// Scale and mix the groups into clusters, to allow spatial samples to mix
     /// outside of the original workgroup pixel bounds.
-    pub spatial_jitter: bool,
+    pub group_mixer: u32,
     pub t_start: f32,
 }
 
@@ -300,20 +299,6 @@ struct Blur {
     atrous_pipeline: blade_graphics::ComputePipeline,
 }
 
-#[derive(Clone, Copy)]
-struct GridMapping {
-    offset: mint::Vector2<u32>,
-    scale: mint::Vector2<u32>,
-}
-impl Default for GridMapping {
-    fn default() -> Self {
-        Self {
-            offset: [0; 2].into(),
-            scale: [1; 2].into(),
-        }
-    }
-}
-
 /// Blade Renderer is a comprehensive rendering solution for
 /// end user applications.
 ///
@@ -341,7 +326,6 @@ pub struct Renderer {
     textures: blade_graphics::TextureArray<MAX_RESOURCES>,
     samplers: Samplers,
     reservoir_size: u32,
-    grid_mapping: GridMapping,
     debug: DebugRender,
     surface_size: blade_graphics::Extent,
     surface_info: blade_graphics::SurfaceInfo,
@@ -351,7 +335,6 @@ pub struct Renderer {
     // This way we can embed user info into the allocator.
     texture_resource_lookup:
         HashMap<blade_graphics::ResourceIndex, blade_asset::Handle<crate::Texture>>,
-    random: nanorand::WyRand,
 }
 
 #[repr(C)]
@@ -387,7 +370,6 @@ struct MainParams {
     spatial_min_distance: u32,
     t_start: f32,
     use_motion_vectors: u32,
-    grid_offset: [u32; 2],
     grid_scale: [u32; 2],
 }
 
@@ -743,14 +725,12 @@ impl Renderer {
             textures: blade_graphics::TextureArray::new(),
             samplers,
             reservoir_size: sp.reservoir_size,
-            grid_mapping: GridMapping::default(),
             debug,
             surface_size: config.surface_size,
             surface_info: config.surface_info,
             frame_index: 0,
             frame_scene_built: 0,
             texture_resource_lookup: HashMap::default(),
-            random: nanorand::WyRand::new(),
         }
     }
 
@@ -1128,21 +1108,6 @@ impl Renderer {
         }
         self.targets.camera_params[self.frame_index % 2] = self.make_camera_params(camera);
         self.post_proc_input_index = self.frame_index % 2;
-
-        self.grid_mapping = {
-            let wg_size = self.main_pipeline.get_workgroup_size();
-            let random = nanorand::Rng::generate::<u64>(&mut self.random);
-            let r_offset = random as u32;
-            let r_scale = (random >> 32) as u32;
-            GridMapping {
-                offset: [r_offset % wg_size[0], (r_offset / wg_size[0]) % wg_size[1]].into(),
-                scale: [
-                    1 << (r_scale % GRID_SCALES),
-                    1 << ((r_scale / GRID_SCALES) % GRID_SCALES),
-                ]
-                .into(),
-            }
-        };
     }
 
     /// Ray trace the scene.
@@ -1186,11 +1151,12 @@ impl Renderer {
         }
 
         if let mut pass = command_encoder.compute() {
-            let grid_mapping = if ray_config.spatial_jitter {
-                self.grid_mapping
-            } else {
-                GridMapping::default()
+            let grid_scale = {
+                let limit = ray_config.group_mixer;
+                let r = self.frame_index as u32;
+                [r % limit + 1, (r / limit) % limit + 1]
             };
+
             let groups = self.main_pipeline.get_dispatch_for(self.surface_size);
             let mut pc = pass.with(&self.main_pipeline);
             pc.bind(
@@ -1211,8 +1177,7 @@ impl Renderer {
                         spatial_min_distance: ray_config.spatial_min_distance,
                         t_start: ray_config.t_start,
                         use_motion_vectors: (self.frame_scene_built == self.frame_index) as u32,
-                        grid_offset: grid_mapping.offset.into(),
-                        grid_scale: grid_mapping.scale.into(),
+                        grid_scale,
                     },
                     acc_struct: self.acceleration_structure,
                     prev_acc_struct: if self.frame_scene_built < self.frame_index

examples/scene/main.rs

@@ -265,7 +265,7 @@ impl Example {
                 spatial_taps: 1,
                 spatial_tap_history: 5,
                 spatial_min_distance: 4,
-                spatial_jitter: true,
+                group_mixer: 10,
                 t_start: 0.1,
             },
             denoiser_enabled: true,

src/lib.rs

@@ -490,7 +490,7 @@ impl Engine {
                 spatial_taps: 1,
                 spatial_tap_history: 5,
                 spatial_min_distance: 4,
-                spatial_jitter: true,
+                group_mixer: 10,
                 t_start: 0.01,
             },
             denoiser_enabled: true,