Advance M8-M11 parity workflows

web/protocol/nanovdb-render-golden.ts

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+import type { ErrorCode } from "./error";
+
+export const NANOVDB_RENDER_GOLDEN_SCHEMA_VERSION = 1 as const;
+export const NANOVDB_GOLDEN_MISMATCH_CODE = "NANOVDB_GOLDEN_MISMATCH" as const satisfies ErrorCode;
+
+export interface NanoVDBRenderGoldenThresholdsIR {
+  maxChannelError: number;
+  meanAbsoluteError: number;
+  rmsError: number;
+  alphaCoverageDeltaRatio: number;
+}
+
+export interface NanoVDBRenderGoldenComparisonIR {
+  schemaVersion: typeof NANOVDB_RENDER_GOLDEN_SCHEMA_VERSION;
+  status: "READY" | "BLOCKED";
+  pixelCount: number;
+  comparedChannels: number;
+  maxChannelError: number;
+  meanAbsoluteError: number;
+  rmsError: number;
+  referenceAlphaPixels: number;
+  actualAlphaPixels: number;
+  alphaCoverageDeltaRatio: number;
+  thresholds: NanoVDBRenderGoldenThresholdsIR;
+  errorCode: typeof NANOVDB_GOLDEN_MISMATCH_CODE | null;
+}
+
+function validateThresholds(value: NanoVDBRenderGoldenThresholdsIR): NanoVDBRenderGoldenThresholdsIR {
+  if (
+    !Number.isInteger(value.maxChannelError) || value.maxChannelError < 0 || value.maxChannelError > 255 ||
+    !Number.isFinite(value.meanAbsoluteError) || value.meanAbsoluteError < 0 || value.meanAbsoluteError > 255 ||
+    !Number.isFinite(value.rmsError) || value.rmsError < 0 || value.rmsError > 255 ||
+    !Number.isFinite(value.alphaCoverageDeltaRatio) || value.alphaCoverageDeltaRatio < 0 || value.alphaCoverageDeltaRatio > 1
+  ) {
+    throw new Error("NANOVDB_INVALID_ARGUMENT: render golden thresholds are invalid");
+  }
+  return { ...value };
+}
+
+export function compareNanoVDBRenderGolden(
+  reference: Uint8Array,
+  actual: Uint8Array,
+  thresholdsValue: NanoVDBRenderGoldenThresholdsIR,
+): NanoVDBRenderGoldenComparisonIR {
+  if (
+    !(reference instanceof Uint8Array) || !(actual instanceof Uint8Array) ||
+    reference.byteLength === 0 || reference.byteLength !== actual.byteLength ||
+    reference.byteLength % 4 !== 0
+  ) {
+    throw new Error("NANOVDB_INVALID_ARGUMENT: render golden images must be equal non-empty RGBA8 buffers");
+  }
+  const thresholds = validateThresholds(thresholdsValue);
+  let maximum = 0;
+  let absoluteTotal = 0;
+  let squaredTotal = 0;
+  let referenceAlphaPixels = 0;
+  let actualAlphaPixels = 0;
+  for (let index = 0; index < reference.byteLength; index++) {
+    const difference = Math.abs(reference[index] - actual[index]);
+    maximum = Math.max(maximum, difference);
+    absoluteTotal += difference;
+    squaredTotal += difference * difference;
+    if ((index & 3) === 3) {
+      if (reference[index] > 0) referenceAlphaPixels++;
+      if (actual[index] > 0) actualAlphaPixels++;
+    }
+  }
+  const pixelCount = reference.byteLength / 4;
+  const meanAbsoluteError = absoluteTotal / reference.byteLength;
+  const rmsError = Math.sqrt(squaredTotal / reference.byteLength);
+  const alphaCoverageDeltaRatio = Math.abs(referenceAlphaPixels - actualAlphaPixels) / pixelCount;
+  const matches = maximum <= thresholds.maxChannelError &&
+    meanAbsoluteError <= thresholds.meanAbsoluteError &&
+    rmsError <= thresholds.rmsError &&
+    alphaCoverageDeltaRatio <= thresholds.alphaCoverageDeltaRatio;
+  return {
+    schemaVersion: NANOVDB_RENDER_GOLDEN_SCHEMA_VERSION,
+    status: matches ? "READY" : "BLOCKED",
+    pixelCount,
+    comparedChannels: reference.byteLength,
+    maxChannelError: maximum,
+    meanAbsoluteError,
+    rmsError,
+    referenceAlphaPixels,
+    actualAlphaPixels,
+    alphaCoverageDeltaRatio,
+    thresholds,
+    errorCode: matches ? null : NANOVDB_GOLDEN_MISMATCH_CODE,
+  };
+}