DataUtils: Add toRGB9E5() and fromRGB9E5(). (#887)

types/three/src/extras/DataUtils.d.ts

@@ -13,3 +13,26 @@ export function toHalfFloat(val: number): number;
  * @see {@link https://github.com/mrdoob/three.js/blob/master/src/extras/DataUtils.js | Source}
  */
 export function fromHalfFloat(val: number): number;
+
+/**
+ * This method packs three floats into a single Uint32 value which is required for the `RGB9E5` texture format.
+ * @param r A float representing the R channel.
+ * @param g A float representing the G channel.
+ * @param b A float representing the B channel.
+ * @param target An instance of `Uint32Array` with length `1`.
+ */
+export function toRGB9E5(r: number, g: number, b: number, target: Uint32Array): Uint32Array;
+
+/**
+ * This method unpacks three floats from a single Uint32 value holding a `RGB9E5` texel.
+ * @param val An instance of `Uint32Array` with length `1`.
+ * @param target An array holding the three unpacked floats.
+ */
+export function fromRGB9E5(val: Uint32Array, target: number[]): number[];
+
+export const DataUtils: {
+    toHalfFloat: typeof toHalfFloat;
+    fromHalfFloat: typeof fromHalfFloat;
+    toRGB9E5: typeof toRGB9E5;
+    fromRGB9E5: typeof fromRGB9E5;
+};