feat(ImageCPRMapper): add ImageCPRMapper in WebGPU

Author: daker

Sources/Rendering/WebGPU/Helpers/ImageSampling.js

@@ -0,0 +1,75 @@
+import { TextureChannelMode } from 'vtk.js/Sources/Rendering/WebGPU/ImageMapper/Constants';
+
+function textureSamplerMatches(textureView, options) {
+  const sampler = textureView?.getSampler?.();
+  if (!sampler) {
+    return false;
+  }
+  const current = sampler.getOptions();
+  return (
+    current.minFilter === options.minFilter &&
+    current.magFilter === options.magFilter &&
+    current.addressModeU === (options.addressModeU ?? 'clamp-to-edge') &&
+    current.addressModeV === (options.addressModeV ?? 'clamp-to-edge') &&
+    current.addressModeW === (options.addressModeW ?? 'clamp-to-edge')
+  );
+}
+
+function getTextureChannelMode(independentComponents, numberOfComponents) {
+  if (independentComponents) {
+    switch (numberOfComponents) {
+      case 1:
+        return TextureChannelMode.INDEPENDENT_1;
+      case 2:
+        return TextureChannelMode.INDEPENDENT_2;
+      case 3:
+        return TextureChannelMode.INDEPENDENT_3;
+      default:
+        return TextureChannelMode.INDEPENDENT_4;
+    }
+  }
+
+  switch (numberOfComponents) {
+    case 1:
+      return TextureChannelMode.SINGLE;
+    case 2:
+      return TextureChannelMode.DEPENDENT_LA;
+    case 3:
+      return TextureChannelMode.DEPENDENT_RGB;
+    default:
+      return TextureChannelMode.DEPENDENT_RGBA;
+  }
+}
+
+function getLUTRowCenterExpression(componentIndex, rowsVar = 'tfunRows') {
+  return `${2 * componentIndex + 0.5} / ${rowsVar}`;
+}
+
+function getUseLabelOutline(
+  property,
+  independentComponents,
+  numberOfComponents
+) {
+  return (
+    property.getUseLabelOutline() &&
+    !independentComponents &&
+    numberOfComponents === 1
+  );
+}
+
+function computeFnToString(property, fn, numberOfComponents) {
+  const pwfun = fn.apply(property);
+  if (pwfun) {
+    const iComps = property.getIndependentComponents();
+    return `${property.getMTime()}-${iComps}-${numberOfComponents}`;
+  }
+  return '0';
+}
+
+export {
+  computeFnToString,
+  getLUTRowCenterExpression,
+  getTextureChannelMode,
+  getUseLabelOutline,
+  textureSamplerMatches,
+};