refactor: split effects and masks into dedicated rust crates, introduce MediaTime and FrameRate

7 files changed, 749 insertions, 0 deletions

diff --git a/rust/crates/masks/Cargo.toml b/rust/crates/masks/Cargo.toml
new file mode 100644
index 00000000..58e10712
--- /dev/null
+++ b/rust/crates/masks/Cargo.toml
@@ -0,0 +1,13 @@
+[package]
+name = "masks"
+version = "0.1.0"
+edition = "2024"
+
+[lib]
+path = "src/masks.rs"
+crate-type = ["rlib"]
+
+[dependencies]
+bytemuck = { version = "1.25.0", features = ["derive"] }
+gpu = { version = "0.1.0", path = "../gpu" }
+wgpu = "29.0.1"
diff --git a/rust/crates/masks/src/feather.rs b/rust/crates/masks/src/feather.rs
new file mode 100644
index 00000000..e58572f4
--- /dev/null
+++ b/rust/crates/masks/src/feather.rs
@@ -0,0 +1,263 @@
+use bytemuck::{Pod, Zeroable};
+use gpu::{FULLSCREEN_SHADER_SOURCE, GPU_TEXTURE_FORMAT, GpuContext};
+use wgpu::util::DeviceExt;
+
+use crate::SdfPipeline;
+
+const JFA_DISTANCE_SHADER_SOURCE: &str = include_str!("shaders/jfa_distance.wgsl");
+
+pub struct ApplyMaskFeatherOptions<'a> {
+    pub mask: &'a wgpu::Texture,
+    pub width: u32,
+    pub height: u32,
+    pub feather: f32,
+}
+
+pub struct MaskFeatherPipeline {
+    sdf_pipeline: SdfPipeline,
+    inside_texture_bind_group_layout: wgpu::BindGroupLayout,
+    outside_texture_bind_group_layout: wgpu::BindGroupLayout,
+    uniform_bind_group_layout: wgpu::BindGroupLayout,
+    distance_pipeline: wgpu::RenderPipeline,
+}
+
+#[repr(C)]
+#[derive(Clone, Copy, Pod, Zeroable)]
+struct DistanceUniformBuffer {
+    resolution: [f32; 2],
+    feather_half: f32,
+    _padding: f32,
+}
+
+impl MaskFeatherPipeline {
+    pub fn new(context: &GpuContext) -> Self {
+        let device = context.device();
+        let inside_texture_bind_group_layout =
+            device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
+                label: Some("gpu-mask-distance-inside-layout"),
+                entries: &[
+                    wgpu::BindGroupLayoutEntry {
+                        binding: 0,
+                        visibility: wgpu::ShaderStages::FRAGMENT,
+                        ty: wgpu::BindingType::Texture {
+                            multisampled: false,
+                            view_dimension: wgpu::TextureViewDimension::D2,
+                            sample_type: wgpu::TextureSampleType::Float { filterable: true },
+                        },
+                        count: None,
+                    },
+                    wgpu::BindGroupLayoutEntry {
+                        binding: 1,
+                        visibility: wgpu::ShaderStages::FRAGMENT,
+                        ty: wgpu::BindingType::Sampler(wgpu::SamplerBindingType::Filtering),
+                        count: None,
+                    },
+                ],
+            });
+        let outside_texture_bind_group_layout =
+            device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
+                label: Some("gpu-mask-distance-outside-layout"),
+                entries: &[
+                    wgpu::BindGroupLayoutEntry {
+                        binding: 0,
+                        visibility: wgpu::ShaderStages::FRAGMENT,
+                        ty: wgpu::BindingType::Texture {
+                            multisampled: false,
+                            view_dimension: wgpu::TextureViewDimension::D2,
+                            sample_type: wgpu::TextureSampleType::Float { filterable: true },
+                        },
+                        count: None,
+                    },
+                    wgpu::BindGroupLayoutEntry {
+                        binding: 1,
+                        visibility: wgpu::ShaderStages::FRAGMENT,
+                        ty: wgpu::BindingType::Sampler(wgpu::SamplerBindingType::Filtering),
+                        count: None,
+                    },
+                ],
+            });
+        let uniform_bind_group_layout =
+            device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
+                label: Some("gpu-mask-distance-uniform-layout"),
+                entries: &[wgpu::BindGroupLayoutEntry {
+                    binding: 0,
+                    visibility: wgpu::ShaderStages::FRAGMENT,
+                    ty: wgpu::BindingType::Buffer {
+                        ty: wgpu::BufferBindingType::Uniform,
+                        has_dynamic_offset: false,
+                        min_binding_size: None,
+                    },
+                    count: None,
+                }],
+            });
+        let pipeline_layout = device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
+            label: Some("gpu-mask-distance-pipeline-layout"),
+            bind_group_layouts: &[
+                Some(&inside_texture_bind_group_layout),
+                Some(&outside_texture_bind_group_layout),
+                Some(&uniform_bind_group_layout),
+            ],
+            immediate_size: 0,
+        });
+        let vertex_shader_module = device.create_shader_module(wgpu::ShaderModuleDescriptor {
+            label: Some("gpu-mask-distance-fullscreen-shader"),
+            source: wgpu::ShaderSource::Wgsl(FULLSCREEN_SHADER_SOURCE.into()),
+        });
+        let fragment_shader_module = device.create_shader_module(wgpu::ShaderModuleDescriptor {
+            label: Some("gpu-mask-distance-fragment-shader"),
+            source: wgpu::ShaderSource::Wgsl(JFA_DISTANCE_SHADER_SOURCE.into()),
+        });
+        let distance_pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
+            label: Some("gpu-mask-distance-pipeline"),
+            layout: Some(&pipeline_layout),
+            vertex: wgpu::VertexState {
+                module: &vertex_shader_module,
+                entry_point: Some("vertex_main"),
+                buffers: &[wgpu::VertexBufferLayout {
+                    array_stride: std::mem::size_of::<[f32; 2]>() as u64,
+                    step_mode: wgpu::VertexStepMode::Vertex,
+                    attributes: &[wgpu::VertexAttribute {
+                        format: wgpu::VertexFormat::Float32x2,
+                        offset: 0,
+                        shader_location: 0,
+                    }],
+                }],
+                compilation_options: wgpu::PipelineCompilationOptions::default(),
+            },
+            fragment: Some(wgpu::FragmentState {
+                module: &fragment_shader_module,
+                entry_point: Some("fragment_main"),
+                targets: &[Some(wgpu::ColorTargetState {
+                    format: GPU_TEXTURE_FORMAT,
+                    blend: None,
+                    write_mask: wgpu::ColorWrites::ALL,
+                })],
+                compilation_options: wgpu::PipelineCompilationOptions::default(),
+            }),
+            primitive: wgpu::PrimitiveState::default(),
+            depth_stencil: None,
+            multisample: wgpu::MultisampleState::default(),
+            multiview_mask: None,
+            cache: None,
+        });
+
+        Self {
+            sdf_pipeline: SdfPipeline::new(context),
+            inside_texture_bind_group_layout,
+            outside_texture_bind_group_layout,
+            uniform_bind_group_layout,
+            distance_pipeline,
+        }
+    }
+
+    pub fn apply_mask_feather(
+        &self,
+        context: &GpuContext,
+        ApplyMaskFeatherOptions {
+            mask,
+            width,
+            height,
+            feather,
+        }: ApplyMaskFeatherOptions<'_>,
+    ) -> wgpu::Texture {
+        let sdf = self
+            .sdf_pipeline
+            .compute_signed_distance_field(context, mask, width, height);
+        let output_texture = context.create_render_texture(width, height, "masks-feather-output");
+        let inside_view = sdf
+            .inside_texture
+            .create_view(&wgpu::TextureViewDescriptor::default());
+        let outside_view = sdf
+            .outside_texture
+            .create_view(&wgpu::TextureViewDescriptor::default());
+        let output_view = output_texture.create_view(&wgpu::TextureViewDescriptor::default());
+        let inside_bind_group = context
+            .device()
+            .create_bind_group(&wgpu::BindGroupDescriptor {
+                label: Some("gpu-mask-distance-inside-bind-group"),
+                layout: &self.inside_texture_bind_group_layout,
+                entries: &[
+                    wgpu::BindGroupEntry {
+                        binding: 0,
+                        resource: wgpu::BindingResource::TextureView(&inside_view),
+                    },
+                    wgpu::BindGroupEntry {
+                        binding: 1,
+                        resource: wgpu::BindingResource::Sampler(context.nearest_sampler()),
+                    },
+                ],
+            });
+        let outside_bind_group = context
+            .device()
+            .create_bind_group(&wgpu::BindGroupDescriptor {
+                label: Some("gpu-mask-distance-outside-bind-group"),
+                layout: &self.outside_texture_bind_group_layout,
+                entries: &[
+                    wgpu::BindGroupEntry {
+                        binding: 0,
+                        resource: wgpu::BindingResource::TextureView(&outside_view),
+                    },
+                    wgpu::BindGroupEntry {
+                        binding: 1,
+                        resource: wgpu::BindingResource::Sampler(context.nearest_sampler()),
+                    },
+                ],
+            });
+        let uniform_buffer =
+            context
+                .device()
+                .create_buffer_init(&wgpu::util::BufferInitDescriptor {
+                    label: Some("gpu-mask-distance-uniform-buffer"),
+                    contents: bytemuck::bytes_of(&DistanceUniformBuffer {
+                        resolution: [width as f32, height as f32],
+                        feather_half: feather / 2.0,
+                        _padding: 0.0,
+                    }),
+                    usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
+                });
+        let uniform_bind_group = context
+            .device()
+            .create_bind_group(&wgpu::BindGroupDescriptor {
+                label: Some("gpu-mask-distance-uniform-bind-group"),
+                layout: &self.uniform_bind_group_layout,
+                entries: &[wgpu::BindGroupEntry {
+                    binding: 0,
+                    resource: uniform_buffer.as_entire_binding(),
+                }],
+            });
+        let mut encoder =
+            context
+                .device()
+                .create_command_encoder(&wgpu::CommandEncoderDescriptor {
+                    label: Some("gpu-mask-distance-command-encoder"),
+                });
+
+        {
+            let mut render_pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
+                label: Some("gpu-mask-distance-render-pass"),
+                color_attachments: &[Some(wgpu::RenderPassColorAttachment {
+                    view: &output_view,
+                    resolve_target: None,
+                    depth_slice: None,
+                    ops: wgpu::Operations {
+                        load: wgpu::LoadOp::Clear(wgpu::Color::TRANSPARENT),
+                        store: wgpu::StoreOp::Store,
+                    },
+                })],
+                depth_stencil_attachment: None,
+                occlusion_query_set: None,
+                timestamp_writes: None,
+                multiview_mask: None,
+            });
+            render_pass.set_pipeline(&self.distance_pipeline);
+            render_pass.set_vertex_buffer(0, context.fullscreen_quad().slice(..));
+            render_pass.set_bind_group(0, &inside_bind_group, &[]);
+            render_pass.set_bind_group(1, &outside_bind_group, &[]);
+            render_pass.set_bind_group(2, &uniform_bind_group, &[]);
+            render_pass.draw(0..6, 0..1);
+        }
+
+        context.queue().submit([encoder.finish()]);
+        output_texture
+    }
+}
diff --git a/rust/crates/masks/src/masks.rs b/rust/crates/masks/src/masks.rs
new file mode 100644
index 00000000..2bf33342
--- /dev/null
+++ b/rust/crates/masks/src/masks.rs
@@ -0,0 +1,5 @@
+mod feather;
+mod sdf;
+
+pub use feather::{ApplyMaskFeatherOptions, MaskFeatherPipeline};
+pub use sdf::{SdfPipeline, SignedDistanceFieldTextures};
diff --git a/rust/crates/masks/src/sdf.rs b/rust/crates/masks/src/sdf.rs
new file mode 100644
index 00000000..0e7ec01a
--- /dev/null
+++ b/rust/crates/masks/src/sdf.rs
@@ -0,0 +1,308 @@
+use bytemuck::{Pod, Zeroable};
+use gpu::{FULLSCREEN_SHADER_SOURCE, GPU_TEXTURE_FORMAT, GpuContext};
+use wgpu::util::DeviceExt;
+
+const JFA_INIT_SHADER_SOURCE: &str = include_str!("shaders/jfa_init.wgsl");
+const JFA_STEP_SHADER_SOURCE: &str = include_str!("shaders/jfa_step.wgsl");
+
+pub struct SignedDistanceFieldTextures {
+    pub inside_texture: wgpu::Texture,
+    pub outside_texture: wgpu::Texture,
+}
+
+pub struct SdfPipeline {
+    texture_bind_group_layout: wgpu::BindGroupLayout,
+    uniform_bind_group_layout: wgpu::BindGroupLayout,
+    init_pipeline: wgpu::RenderPipeline,
+    step_pipeline: wgpu::RenderPipeline,
+}
+
+#[repr(C)]
+#[derive(Clone, Copy, Pod, Zeroable)]
+struct JfaInitUniformBuffer {
+    resolution: [f32; 2],
+    invert: f32,
+    _padding: f32,
+}
+
+#[repr(C)]
+#[derive(Clone, Copy, Pod, Zeroable)]
+struct JfaStepUniformBuffer {
+    resolution: [f32; 2],
+    step_size: f32,
+    _padding: f32,
+}
+
+impl SdfPipeline {
+    pub fn new(context: &GpuContext) -> Self {
+        let device = context.device();
+        let texture_bind_group_layout =
+            device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
+                label: Some("gpu-sdf-texture-bind-group-layout"),
+                entries: &[
+                    wgpu::BindGroupLayoutEntry {
+                        binding: 0,
+                        visibility: wgpu::ShaderStages::FRAGMENT,
+                        ty: wgpu::BindingType::Texture {
+                            multisampled: false,
+                            view_dimension: wgpu::TextureViewDimension::D2,
+                            sample_type: wgpu::TextureSampleType::Float { filterable: true },
+                        },
+                        count: None,
+                    },
+                    wgpu::BindGroupLayoutEntry {
+                        binding: 1,
+                        visibility: wgpu::ShaderStages::FRAGMENT,
+                        ty: wgpu::BindingType::Sampler(wgpu::SamplerBindingType::Filtering),
+                        count: None,
+                    },
+                ],
+            });
+        let uniform_bind_group_layout =
+            device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
+                label: Some("gpu-sdf-uniform-bind-group-layout"),
+                entries: &[wgpu::BindGroupLayoutEntry {
+                    binding: 0,
+                    visibility: wgpu::ShaderStages::FRAGMENT,
+                    ty: wgpu::BindingType::Buffer {
+                        ty: wgpu::BufferBindingType::Uniform,
+                        has_dynamic_offset: false,
+                        min_binding_size: None,
+                    },
+                    count: None,
+                }],
+            });
+        let pipeline_layout = device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
+            label: Some("gpu-sdf-pipeline-layout"),
+            bind_group_layouts: &[
+                Some(&texture_bind_group_layout),
+                Some(&uniform_bind_group_layout),
+            ],
+            immediate_size: 0,
+        });
+        let vertex_shader_module = device.create_shader_module(wgpu::ShaderModuleDescriptor {
+            label: Some("gpu-sdf-fullscreen-shader"),
+            source: wgpu::ShaderSource::Wgsl(FULLSCREEN_SHADER_SOURCE.into()),
+        });
+        let init_shader_module = device.create_shader_module(wgpu::ShaderModuleDescriptor {
+            label: Some("gpu-jfa-init-shader"),
+            source: wgpu::ShaderSource::Wgsl(JFA_INIT_SHADER_SOURCE.into()),
+        });
+        let step_shader_module = device.create_shader_module(wgpu::ShaderModuleDescriptor {
+            label: Some("gpu-jfa-step-shader"),
+            source: wgpu::ShaderSource::Wgsl(JFA_STEP_SHADER_SOURCE.into()),
+        });
+        let init_pipeline = create_pipeline(
+            device,
+            "gpu-jfa-init-pipeline",
+            &pipeline_layout,
+            &vertex_shader_module,
+            &init_shader_module,
+        );
+        let step_pipeline = create_pipeline(
+            device,
+            "gpu-jfa-step-pipeline",
+            &pipeline_layout,
+            &vertex_shader_module,
+            &step_shader_module,
+        );
+
+        Self {
+            texture_bind_group_layout,
+            uniform_bind_group_layout,
+            init_pipeline,
+            step_pipeline,
+        }
+    }
+
+    pub fn compute_signed_distance_field(
+        &self,
+        context: &GpuContext,
+        source_texture: &wgpu::Texture,
+        width: u32,
+        height: u32,
+    ) -> SignedDistanceFieldTextures {
+        SignedDistanceFieldTextures {
+            inside_texture: self.run_jfa(context, source_texture, width, height, false),
+            outside_texture: self.run_jfa(context, source_texture, width, height, true),
+        }
+    }
+
+    fn run_jfa(
+        &self,
+        context: &GpuContext,
+        source_texture: &wgpu::Texture,
+        width: u32,
+        height: u32,
+        is_inverted: bool,
+    ) -> wgpu::Texture {
+        let ping_texture = context.create_render_texture(width, height, "gpu-jfa-ping-texture");
+        let pong_texture = context.create_render_texture(width, height, "gpu-jfa-pong-texture");
+
+        self.run_pass(
+            context,
+            source_texture,
+            &ping_texture,
+            &self.init_pipeline,
+            bytemuck::bytes_of(&JfaInitUniformBuffer {
+                resolution: [width as f32, height as f32],
+                invert: if is_inverted { 1.0 } else { 0.0 },
+                _padding: 0.0,
+            }),
+        );
+
+        let mut source_is_ping = true;
+        let steps = (width.max(height) as f32).log2().ceil() as u32;
+        for step_index in (0..steps).rev() {
+            let step_size = 2u32.pow(step_index).max(1);
+            let input_texture = if source_is_ping {
+                &ping_texture
+            } else {
+                &pong_texture
+            };
+            let output_texture = if source_is_ping {
+                &pong_texture
+            } else {
+                &ping_texture
+            };
+            self.run_pass(
+                context,
+                input_texture,
+                output_texture,
+                &self.step_pipeline,
+                bytemuck::bytes_of(&JfaStepUniformBuffer {
+                    resolution: [width as f32, height as f32],
+                    step_size: step_size as f32,
+                    _padding: 0.0,
+                }),
+            );
+            source_is_ping = !source_is_ping;
+        }
+
+        if source_is_ping {
+            ping_texture
+        } else {
+            pong_texture
+        }
+    }
+
+    fn run_pass(
+        &self,
+        context: &GpuContext,
+        input_texture: &wgpu::Texture,
+        output_texture: &wgpu::Texture,
+        pipeline: &wgpu::RenderPipeline,
+        uniform_buffer_bytes: &[u8],
+    ) {
+        let input_view = input_texture.create_view(&wgpu::TextureViewDescriptor::default());
+        let output_view = output_texture.create_view(&wgpu::TextureViewDescriptor::default());
+        let texture_bind_group = context
+            .device()
+            .create_bind_group(&wgpu::BindGroupDescriptor {
+                label: Some("gpu-sdf-texture-bind-group"),
+                layout: &self.texture_bind_group_layout,
+                entries: &[
+                    wgpu::BindGroupEntry {
+                        binding: 0,
+                        resource: wgpu::BindingResource::TextureView(&input_view),
+                    },
+                    wgpu::BindGroupEntry {
+                        binding: 1,
+                        resource: wgpu::BindingResource::Sampler(context.nearest_sampler()),
+                    },
+                ],
+            });
+        let uniform_buffer =
+            context
+                .device()
+                .create_buffer_init(&wgpu::util::BufferInitDescriptor {
+                    label: Some("gpu-sdf-uniform-buffer"),
+                    contents: uniform_buffer_bytes,
+                    usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
+                });
+        let uniform_bind_group = context
+            .device()
+            .create_bind_group(&wgpu::BindGroupDescriptor {
+                label: Some("gpu-sdf-uniform-bind-group"),
+                layout: &self.uniform_bind_group_layout,
+                entries: &[wgpu::BindGroupEntry {
+                    binding: 0,
+                    resource: uniform_buffer.as_entire_binding(),
+                }],
+            });
+        let mut encoder =
+            context
+                .device()
+                .create_command_encoder(&wgpu::CommandEncoderDescriptor {
+                    label: Some("gpu-sdf-command-encoder"),
+                });
+
+        {
+            let mut render_pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
+                label: Some("gpu-sdf-render-pass"),
+                color_attachments: &[Some(wgpu::RenderPassColorAttachment {
+                    view: &output_view,
+                    resolve_target: None,
+                    depth_slice: None,
+                    ops: wgpu::Operations {
+                        load: wgpu::LoadOp::Clear(wgpu::Color::WHITE),
+                        store: wgpu::StoreOp::Store,
+                    },
+                })],
+                depth_stencil_attachment: None,
+                occlusion_query_set: None,
+                timestamp_writes: None,
+                multiview_mask: None,
+            });
+            render_pass.set_pipeline(pipeline);
+            render_pass.set_vertex_buffer(0, context.fullscreen_quad().slice(..));
+            render_pass.set_bind_group(0, &texture_bind_group, &[]);
+            render_pass.set_bind_group(1, &uniform_bind_group, &[]);
+            render_pass.draw(0..6, 0..1);
+        }
+
+        context.queue().submit([encoder.finish()]);
+    }
+}
+
+fn create_pipeline(
+    device: &wgpu::Device,
+    label: &'static str,
+    layout: &wgpu::PipelineLayout,
+    vertex_shader_module: &wgpu::ShaderModule,
+    fragment_shader_module: &wgpu::ShaderModule,
+) -> wgpu::RenderPipeline {
+    device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
+        label: Some(label),
+        layout: Some(layout),
+        vertex: wgpu::VertexState {
+            module: vertex_shader_module,
+            entry_point: Some("vertex_main"),
+            buffers: &[wgpu::VertexBufferLayout {
+                array_stride: std::mem::size_of::<[f32; 2]>() as u64,
+                step_mode: wgpu::VertexStepMode::Vertex,
+                attributes: &[wgpu::VertexAttribute {
+                    format: wgpu::VertexFormat::Float32x2,
+                    offset: 0,
+                    shader_location: 0,
+                }],
+            }],
+            compilation_options: wgpu::PipelineCompilationOptions::default(),
+        },
+        fragment: Some(wgpu::FragmentState {
+            module: fragment_shader_module,
+            entry_point: Some("fragment_main"),
+            targets: &[Some(wgpu::ColorTargetState {
+                format: GPU_TEXTURE_FORMAT,
+                blend: None,
+                write_mask: wgpu::ColorWrites::ALL,
+            })],
+            compilation_options: wgpu::PipelineCompilationOptions::default(),
+        }),
+        primitive: wgpu::PrimitiveState::default(),
+        depth_stencil: None,
+        multisample: wgpu::MultisampleState::default(),
+        multiview_mask: None,
+        cache: None,
+    })
+}
diff --git a/rust/crates/masks/src/shaders/jfa_distance.wgsl b/rust/crates/masks/src/shaders/jfa_distance.wgsl
new file mode 100644
index 00000000..e65a7023
--- /dev/null
+++ b/rust/crates/masks/src/shaders/jfa_distance.wgsl
@@ -0,0 +1,50 @@
+struct VertexOutput {
+    @builtin(position) position: vec4f,
+    @location(0) tex_coord: vec2f,
+}
+
+struct DistanceUniforms {
+    resolution: vec2f,
+    feather_half: f32,
+    _padding: f32,
+}
+
+@group(0) @binding(0) var inside_texture: texture_2d<f32>;
+@group(0) @binding(1) var inside_sampler: sampler;
+@group(1) @binding(0) var outside_texture: texture_2d<f32>;
+@group(1) @binding(1) var outside_sampler: sampler;
+@group(2) @binding(0) var<uniform> uniforms: DistanceUniforms;
+
+fn decode_seed(encoded: vec4f) -> vec2f {
+    let x = floor(encoded.r * 255.0 + 0.5) * 256.0 + floor(encoded.g * 255.0 + 0.5);
+    let y = floor(encoded.b * 255.0 + 0.5) * 256.0 + floor(encoded.a * 255.0 + 0.5);
+    return vec2f(x, y);
+}
+
+fn is_no_seed(encoded: vec4f) -> bool {
+    return encoded.r > 0.99 && encoded.g > 0.99 && encoded.b > 0.99 && encoded.a > 0.99;
+}
+
+@fragment
+fn fragment_main(input: VertexOutput) -> @location(0) vec4f {
+    let pixel_coord = floor(input.tex_coord * uniforms.resolution);
+    let inside_encoded = textureSample(inside_texture, inside_sampler, input.tex_coord);
+    let outside_encoded = textureSample(outside_texture, outside_sampler, input.tex_coord);
+
+    let has_inside = !is_no_seed(inside_encoded);
+    let has_outside = !is_no_seed(outside_encoded);
+    let distance_to_inside = select(
+        100000.0,
+        distance(pixel_coord, decode_seed(inside_encoded)),
+        has_inside,
+    );
+    let distance_to_outside = select(
+        100000.0,
+        distance(pixel_coord, decode_seed(outside_encoded)),
+        has_outside,
+    );
+    let signed_distance = distance_to_outside - distance_to_inside;
+    let alpha = smoothstep(-uniforms.feather_half, uniforms.feather_half, signed_distance);
+
+    return vec4f(alpha, alpha, alpha, alpha);
+}
diff --git a/rust/crates/masks/src/shaders/jfa_init.wgsl b/rust/crates/masks/src/shaders/jfa_init.wgsl
new file mode 100644
index 00000000..29aa38c7
--- /dev/null
+++ b/rust/crates/masks/src/shaders/jfa_init.wgsl
@@ -0,0 +1,35 @@
+struct VertexOutput {
+    @builtin(position) position: vec4f,
+    @location(0) tex_coord: vec2f,
+}
+
+struct JfaInitUniforms {
+    resolution: vec2f,
+    invert: f32,
+    _padding: f32,
+}
+
+@group(0) @binding(0) var input_texture: texture_2d<f32>;
+@group(0) @binding(1) var input_sampler: sampler;
+@group(1) @binding(0) var<uniform> uniforms: JfaInitUniforms;
+
+fn encode_seed(seed: vec2f) -> vec4f {
+    let x_hi = floor(seed.x / 256.0);
+    let x_lo = seed.x - (x_hi * 256.0);
+    let y_hi = floor(seed.y / 256.0);
+    let y_lo = seed.y - (y_hi * 256.0);
+    return vec4f(x_hi / 255.0, x_lo / 255.0, y_hi / 255.0, y_lo / 255.0);
+}
+
+@fragment
+fn fragment_main(input: VertexOutput) -> @location(0) vec4f {
+    let mask = textureSample(input_texture, input_sampler, input.tex_coord).r;
+    let is_seed = select(mask > 0.5, mask < 0.5, uniforms.invert > 0.5);
+
+    if (is_seed) {
+        let pixel_coord = floor(input.tex_coord * uniforms.resolution);
+        return encode_seed(pixel_coord);
+    }
+
+    return vec4f(1.0, 1.0, 1.0, 1.0);
+}
diff --git a/rust/crates/masks/src/shaders/jfa_step.wgsl b/rust/crates/masks/src/shaders/jfa_step.wgsl
new file mode 100644
index 00000000..e20d7fb0
--- /dev/null
+++ b/rust/crates/masks/src/shaders/jfa_step.wgsl
@@ -0,0 +1,75 @@
+struct VertexOutput {
+    @builtin(position) position: vec4f,
+    @location(0) tex_coord: vec2f,
+}
+
+struct JfaStepUniforms {
+    resolution: vec2f,
+    step_size: f32,
+    _padding: f32,
+}
+
+@group(0) @binding(0) var input_texture: texture_2d<f32>;
+@group(0) @binding(1) var input_sampler: sampler;
+@group(1) @binding(0) var<uniform> uniforms: JfaStepUniforms;
+
+fn decode_seed(encoded: vec4f) -> vec2f {
+    let x = floor(encoded.r * 255.0 + 0.5) * 256.0 + floor(encoded.g * 255.0 + 0.5);
+    let y = floor(encoded.b * 255.0 + 0.5) * 256.0 + floor(encoded.a * 255.0 + 0.5);
+    return vec2f(x, y);
+}
+
+fn encode_seed(seed: vec2f) -> vec4f {
+    let x_hi = floor(seed.x / 256.0);
+    let x_lo = seed.x - (x_hi * 256.0);
+    let y_hi = floor(seed.y / 256.0);
+    let y_lo = seed.y - (y_hi * 256.0);
+    return vec4f(x_hi / 255.0, x_lo / 255.0, y_hi / 255.0, y_lo / 255.0);
+}
+
+fn is_no_seed(encoded: vec4f) -> bool {
+    return encoded.r > 0.99 && encoded.g > 0.99 && encoded.b > 0.99 && encoded.a > 0.99;
+}
+
+@fragment
+fn fragment_main(input: VertexOutput) -> @location(0) vec4f {
+    let pixel_coord = floor(input.tex_coord * uniforms.resolution);
+    let texel_size = vec2f(1.0, 1.0) / uniforms.resolution;
+
+    var best_distance = 10000000000.0;
+    var best_seed = vec2f(65535.0, 65535.0);
+
+    for (var y = -1; y <= 1; y = y + 1) {
+        for (var x = -1; x <= 1; x = x + 1) {
+            let offset = vec2f(f32(x), f32(y)) * uniforms.step_size;
+            let sample_uv = input.tex_coord + (offset * texel_size);
+
+            if (
+                sample_uv.x < 0.0 ||
+                sample_uv.x > 1.0 ||
+                sample_uv.y < 0.0 ||
+                sample_uv.y > 1.0
+            ) {
+                continue;
+            }
+
+            let encoded = textureSample(input_texture, input_sampler, sample_uv);
+            if (is_no_seed(encoded)) {
+                continue;
+            }
+
+            let seed = decode_seed(encoded);
+            let distance_to_seed = distance(pixel_coord, seed);
+            if (distance_to_seed < best_distance) {
+                best_distance = distance_to_seed;
+                best_seed = seed;
+            }
+        }
+    }
+
+    if (best_distance < 1000000000.0) {
+        return encode_seed(best_seed);
+    }
+
+    return vec4f(1.0, 1.0, 1.0, 1.0);
+}