GPU accelerated maskeditor rendering (#6767)

## GPU accelerated brush engine for the mask editor

- Full GPU acceleration using TypeGPU and type-safe shaders
- Catmull-Rom Spline Smoothing
- arc-length equidistant resampling
- much improved performance, even for huge images
- photoshop like opacity clamping for brush strokes
- much improved soft brushes
- fallback to CPU fully implemented, much improved CPU rendering
features as well

### Tested Browsers
- Chrome (fully supported)
- Safari 26 (fully supported, prev versions CPU fallback)
- Firefox (CPU fallback, flags needed for full support)



https://github.com/user-attachments/assets/b7b5cb8a-2290-4a95-ae7d-180e11fccdb0



https://github.com/user-attachments/assets/4297aaa5-f249-499a-9b74-869677f1c73b



https://github.com/user-attachments/assets/602b4783-3e2b-489e-bcb9-70534bcaac5e

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6767-GPU-accelerated-maskeditor-rendering-2b16d73d3650818cb294e1fca03f6169)
by [Unito](https://www.unito.io)

Author: trsommer

package.json

@@ -75,6 +75,7 @@
     "@vitest/coverage-v8": "catalog:",
     "@vitest/ui": "catalog:",
     "@vue/test-utils": "catalog:",
+    "@webgpu/types": "catalog:",
     "cross-env": "catalog:",
     "eslint": "catalog:",
     "eslint-config-prettier": "catalog:",
@@ -112,6 +113,7 @@
     "typescript": "catalog:",
     "typescript-eslint": "catalog:",
     "unplugin-icons": "catalog:",
+    "unplugin-typegpu": "catalog:",
     "unplugin-vue-components": "catalog:",
     "uuid": "^11.1.0",
     "vite": "catalog:",
@@ -176,6 +178,7 @@
     "semver": "^7.7.2",
     "three": "^0.170.0",
     "tiptap-markdown": "^0.8.10",
+    "typegpu": "catalog:",
     "vue": "catalog:",
     "vue-i18n": "catalog:",
     "vue-router": "catalog:",

pnpm-lock.yaml

@@ -43,6 +43,7 @@ catalog:
   '@vue/test-utils': ^2.4.6
   '@vueuse/core': ^11.0.0
   '@vueuse/integrations': ^13.9.0
+  '@webgpu/types': ^0.1.66
   algoliasearch: ^5.21.0
   axios: ^1.8.2
   cross-env: ^10.1.0
@@ -83,9 +84,11 @@ catalog:
   tailwindcss-primeui: ^0.6.1
   tsx: ^4.15.6
   tw-animate-css: ^1.3.8
+  typegpu: ^0.8.2
   typescript: ^5.9.2
   typescript-eslint: ^8.44.0
   unplugin-icons: ^0.22.0
+  unplugin-typegpu: 0.8.0
   unplugin-vue-components: ^0.28.0
   vite: ^5.4.19
   vite-plugin-dts: ^4.5.4

pnpm-workspace.yaml

@@ -26,6 +26,10 @@
 <script setup lang="ts">
 import { computed } from 'vue'
 
+import {
+  getEffectiveBrushSize,
+  getEffectiveHardness
+} from '@/composables/maskeditor/brushUtils'
 import { BrushShape } from '@/extensions/core/maskeditor/types'
 import { useMaskEditorStore } from '@/stores/maskEditorStore'
 
@@ -36,11 +40,14 @@ const { containerRef } = defineProps<{
 const store = useMaskEditorStore()
 
 const brushOpacity = computed(() => {
-  return store.brushVisible ? '1' : '0'
+  return store.brushVisible ? 1 : 0
 })
 
 const brushRadius = computed(() => {
-  return store.brushSettings.size * store.zoomRatio
+  const size = store.brushSettings.size
+  const hardness = store.brushSettings.hardness
+  const effectiveSize = getEffectiveBrushSize(size, hardness)
+  return effectiveSize * store.zoomRatio
 })
 
 const brushSize = computed(() => {
@@ -78,19 +85,26 @@ const gradientVisible = computed(() => {
 })
 
 const gradientBackground = computed(() => {
+  const size = store.brushSettings.size
   const hardness = store.brushSettings.hardness
+  const effectiveSize = getEffectiveBrushSize(size, hardness)
+  const effectiveHardness = getEffectiveHardness(size, hardness, effectiveSize)
 
-  if (hardness === 1) {
+  if (effectiveHardness === 1) {
     return 'rgba(255, 0, 0, 0.5)'
   }
 
-  const midStop = hardness * 100
+  const midStop = effectiveHardness * 100
   const outerStop = 100
+  // Add an intermediate stop to approximate the squared falloff
+  // At 50% of the fade region, squared falloff is 0.25 (relative to max)
+  const fadeMidStop = midStop + (outerStop - midStop) * 0.5
 
   return `radial-gradient(
     circle,
     rgba(255, 0, 0, 0.5) 0%,
-    rgba(255, 0, 0, 0.25) ${midStop}%,
+    rgba(255, 0, 0, 0.5) ${midStop}%,
+    rgba(255, 0, 0, 0.125) ${fadeMidStop}%,
     rgba(255, 0, 0, 0) ${outerStop}%
   )`
 })

src/components/maskeditor/BrushCursor.vue

@@ -55,7 +55,7 @@
     <SliderControl
       :label="t('maskEditor.thickness')"
       :min="1"
-      :max="100"
+      :max="500"
       :step="1"
       :model-value="store.brushSettings.size"
       @update:model-value="onThicknessChange"
@@ -80,12 +80,12 @@
     />
 
     <SliderControl
-      :label="t('maskEditor.smoothingPrecision')"
+      label="Stepsize"
       :min="1"
       :max="100"
       :step="1"
-      :model-value="store.brushSettings.smoothingPrecision"
-      @update:model-value="onSmoothingPrecisionChange"
+      :model-value="store.brushSettings.stepSize"
+      @update:model-value="onStepSizeChange"
     />
   </div>
 </template>
@@ -119,8 +119,8 @@ const onHardnessChange = (value: number) => {
   store.setBrushHardness(value)
 }
 
-const onSmoothingPrecisionChange = (value: number) => {
-  store.setBrushSmoothingPrecision(value)
+const onStepSizeChange = (value: number) => {
+  store.setBrushStepSize(value)
 }
 
 const resetToDefault = () => {