Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 | 35x 35x 35x 35x 35x 107x 359x 107x 107x 872x 17343x 17343x 17343x 17343x 107x 30x 106x 30x 30x 30x 106x 106x 32x 31x 31x 31x 31x 31x 558x 558x 65x 107x 107x 107x 31x 31x 30x 30x 31x 1x 30x 30x 30x 30x 540x 30x 106x 106x 106x 30x 32x 18x 18x 18x 18x 18x 56x 56x 1x 55x 37x 17x 17x 17x 17x 35x 35x 134x 2344x 598x 17x 35x 35x 35x 35x 35x 1x 1x 2x 4x 4x 1x 17x 19x 19x 3x 16x 16x 16x 2x 2x 4x 1x 2x 2x 1x 1x 1x 1x 1x 1x 1x 2x 18x 18x 18x 18x 106x 870x 17339x 17339x 17339x 17339x 32x 77x 32x 32x 32x 32x 32x 32x 32x 109x 6x 6x 6x 109x 2x 107x 107x 107x 107x 107x 30x 30x 30x 30x 30x 30x 30x 30x 30x 30x 30x | /**
* Atlas Sprite Sheet Generator for Cyberia Online.
* Consolidates all object layer frames (8 directions, multiple modes) into a single PNG atlas.
* @module src/api/atlas-sprite-sheet/atlas-sprite-sheet.generator.js
* @namespace CyberiaAtlasSpriteSheetGenerator
*/
import { Jimp, rgbaToInt } from 'jimp';
import sharp from 'sharp';
import { loggerFactory } from '../../server/ops/logger.js';
import { hexToRgba } from '../../client/components/objectlayer-studio/RenderSource.js';
import {
OBJECT_LAYER_DIRECTION_CODES,
getKeyframeDirectionsByCode,
} from '../../client/components/objectlayer-studio/ObjectLayerProtocol.js';
const logger = loggerFactory(import.meta);
/** Direction code of the frame an item is previewed by: down idle. */
export const IDLE_PREVIEW_DIRECTION_CODE = '08';
/**
* Pixels per cell of the upscaled derived render, when no factor is given.
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
export const DEFAULT_ATLAS_UPSCALE_FACTOR = 20;
/**
* Pixels per cell of the primary render: the one `data.render.cid` addresses and the client
* runtime downloads. One pixel per cell, so it carries every cell and nothing more.
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
export const PRIMARY_CELL_PIXEL_DIM = 1;
/**
* Longer side, in pixels, of the idle preview every client shows as an item's picture.
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
export const IDLE_PREVIEW_SIZE = 300;
/**
* @typedef {Object} AtlasFrame
* @property {number} x - X position in atlas
* @property {number} y - Y position in atlas
* @property {number} width - Frame width
* @property {number} height - Frame height
* @property {number} frameIndex - Frame index in animation
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
/**
* Atlas Sprite Sheet Generator Engine
* @class
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
export class AtlasSpriteSheetGenerator {
/**
* The image of one frame of a render source, each cell `cellPixelDim` pixels wide.
* @static
* @param {Object} source - Render source.
* @param {Uint8Array} pixels - The frame's palette indexes.
* @param {number} cellPixelDim - Pixel dimension per cell
* @returns {Jimp} The generated image
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
static frameImage(source, pixels, cellPixelDim = 1) {
Iif (!source.width || !source.height) throw new Error('Invalid frame dimensions');
const colors = source.palette.map((hex) => rgbaToInt(...hexToRgba(hex)));
const image = new Jimp({ width: cellPixelDim * source.width, height: cellPixelDim * source.height, color: 0 });
for (let y = 0; y < source.height; y++)
for (let x = 0; x < source.width; x++) {
const color = colors[pixels[y * source.width + x]];
for (let dy = 0; dy < cellPixelDim; dy++)
for (let dx = 0; dx < cellPixelDim; dx++)
image.setPixelColor(color, x * cellPixelDim + dx, y * cellPixelDim + dy);
}
return image;
}
/**
* Calculates optimal atlas dimensions based on frame count and size
* @static
* @param {Array} frameImages - Array of frame image objects
* @returns {number} Recommended atlas dimension (power of 2)
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
static calculateOptimalDimension(frameImages) {
Iif (
!frameImages?.length ||
frameImages.some(
({ width, height }) => !Number.isInteger(width) || !Number.isInteger(height) || width <= 0 || height <= 0,
)
) {
throw new Error('Invalid frame dimensions');
}
const cols = Math.ceil(Math.sqrt(frameImages.length));
const rows = Math.ceil(frameImages.length / cols);
return AtlasSpriteSheetGenerator.nextPowerOf2(
Math.max(
cols * Math.max(...frameImages.map((frame) => frame.width)),
rows * Math.max(...frameImages.map((frame) => frame.height)),
),
);
}
/**
* Consolidates all frames of a render source into one atlas sprite sheet.
*
* One packing produces the primary render at {@link PRIMARY_CELL_PIXEL_DIM} pixels per cell,
* and `metadata`, which describes it. `upscaleFactor` is recorded for the upscaled render
* {@link AtlasSpriteSheetGenerator.upscaledFromRender} derives from it.
*
* @static
* @param {Object} objectLayerRenderFrames - The render source
* @param {string} itemKey - The item label the render is generated for
* @param {number} [upscaleFactor=DEFAULT_ATLAS_UPSCALE_FACTOR] - Pixels per cell of the upscaled render
* @param {number} [maxAtlasDim=null] - Maximum atlas dimension (auto-calculated if null)
* @returns {Promise<{primary: Buffer, metadata: Object}>}
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
static async generateAtlas(
objectLayerRenderFrames,
itemKey,
upscaleFactor = DEFAULT_ATLAS_UPSCALE_FACTOR,
maxAtlasDim = null,
) {
if (!Number.isInteger(upscaleFactor) || upscaleFactor < 1) throw new Error('Invalid pixel scale');
const { frames } = objectLayerRenderFrames;
const frameDuration = Number(objectLayerRenderFrames.frameDurationMs);
// Direction order for consistent packing
const directionOrder = [
'down_idle',
'up_idle',
'left_idle',
'right_idle',
'down_left_idle',
'down_right_idle',
'up_left_idle',
'up_right_idle',
'down_walking',
'up_walking',
'left_walking',
'right_walking',
'down_left_walking',
'down_right_walking',
'up_left_walking',
'up_right_walking',
'default_idle',
'none_idle',
];
// The packing works on the primary render; the upscaled render reuses its layout.
const frameImages = [];
for (const direction of directionOrder) {
const directionFrames = frames[direction];
if (!directionFrames || directionFrames.length === 0) continue;
for (let frameIndex = 0; frameIndex < directionFrames.length; frameIndex++) {
try {
const frameImage = AtlasSpriteSheetGenerator.frameImage(
objectLayerRenderFrames,
directionFrames[frameIndex],
PRIMARY_CELL_PIXEL_DIM,
);
frameImages.push({
image: frameImage,
direction,
frameIndex,
width: frameImage.bitmap.width,
height: frameImage.bitmap.height,
});
} catch (error) {
logger.warn(`Failed to generate frame for ${itemKey} ${direction}[${frameIndex}]:`, error.message);
}
}
}
Iif (frameImages.length === 0) {
throw new Error(`No valid frames found for item: ${itemKey}`);
}
// Auto-calculate optimal dimension if not specified
if (maxAtlasDim === null || maxAtlasDim === undefined) {
maxAtlasDim = AtlasSpriteSheetGenerator.calculateOptimalDimension(frameImages);
logger.info(
`Auto-calculated optimal atlas dimension: ${maxAtlasDim}x${maxAtlasDim} for ${frameImages.length} frames`,
);
}
if (!Number.isInteger(maxAtlasDim) || maxAtlasDim <= 0 || maxAtlasDim > 4096) {
throw new Error('Atlas dimension must be between 1 and 4096');
}
// Simple grid packing algorithm
const { packedFrames, atlasWidth, atlasHeight } = AtlasSpriteSheetGenerator.packFramesGrid(
frameImages,
maxAtlasDim,
);
logger.info(`Packing ${packedFrames.length} frames into ${atlasWidth}x${atlasHeight} atlas`);
// Validate dimensions before creating Jimp image
Iif (isNaN(atlasWidth) || isNaN(atlasHeight) || atlasWidth <= 0 || atlasHeight <= 0) {
throw new Error(
`Invalid atlas dimensions: ${atlasWidth}x${atlasHeight} (maxAtlasDim: ${maxAtlasDim}, frameCount: ${frameImages.length})`,
);
}
const primaryImage = new Jimp({ width: atlasWidth, height: atlasHeight, color: 0x00000000 });
// Every direction, empty ones included: the layout pinned is the layout stored, byte for byte.
const frameMetadata = Object.fromEntries(directionOrder.map((direction) => [direction, []]));
for (const packedFrame of packedFrames) {
const { image, x, y, direction, frameIndex } = packedFrame;
AtlasSpriteSheetGenerator.blitFrame(primaryImage, image, x, y);
frameMetadata[direction][frameIndex] = {
x,
y,
width: image.bitmap.width,
height: image.bitmap.height,
frameIndex,
};
}
const metadata = {
itemKey,
atlasWidth,
atlasHeight,
cellPixelDim: PRIMARY_CELL_PIXEL_DIM,
upscaleFactor,
frame_duration: Number.isFinite(frameDuration) ? frameDuration : 100,
frames: frameMetadata,
};
return { primary: await primaryImage.getBuffer('image/png'), metadata };
}
/**
* The frame an item is previewed by: the first frame of the first down-idle keyframe the
* atlas carries, or the first frame of any direction when it has none.
*
* @static
* @param {Object} metadata - Atlas metadata as {@link generateAtlas} returns it.
* @returns {{x:number,y:number,width:number,height:number}|null} Frame box, in cells.
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
static idlePreviewFrame(metadata) {
const frames = metadata?.frames ?? {};
const preferred = getKeyframeDirectionsByCode(IDLE_PREVIEW_DIRECTION_CODE);
for (const direction of [...preferred, ...Object.keys(frames)]) {
const frame = frames[direction]?.[0];
Eif (frame) return frame;
}
return null;
}
/**
* Pixels per cell of a render, read from its width: every render is the cell grid `metadata`
* describes at some whole density, so the bytes say which one they are.
* @static
* @param {number} renderWidth - Render width in pixels.
* @param {Object} metadata - Atlas metadata.
* @returns {number}
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
static pixelsPerCell(renderWidth, metadata) {
const density = renderWidth / Number(metadata.atlasWidth);
if (!Number.isInteger(density) || density < 1)
throw new Error(`A ${renderWidth}px render is no whole multiple of ${metadata.atlasWidth} cells`);
return density;
}
/**
* Pixels per cell of the upscaled representation of a layout.
* @static
* @param {Object} metadata - Atlas metadata.
* @returns {number}
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
static upscaledPixelsPerCell(metadata) {
return Number(metadata.upscaleFactor) || Number(metadata.cellPixelDim) || PRIMARY_CELL_PIXEL_DIM;
}
/**
* Repeats every pixel of a raw RGBA image into a `factor`-square block. A block copy, never a
* resize: a resize premultiplies alpha and rounds, and a derived render must hold the exact
* colours of the one it comes from.
* @static
* @param {{data: Buffer, width: number, height: number}} image - Raw RGBA pixels.
* @param {number} factor - Whole scale factor.
* @returns {{data: Buffer, width: number, height: number}}
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
static repeatPixels({ data, width, height }, factor) {
Iif (factor === 1) return { data, width, height };
const outWidth = width * factor;
const out = Buffer.alloc(outWidth * height * factor * 4);
for (let y = 0; y < height; y++) {
const row = Buffer.alloc(outWidth * 4);
for (let x = 0; x < width; x++) {
const from = (y * width + x) * 4;
for (let dx = 0; dx < factor; dx++) data.copy(row, (x * factor + dx) * 4, from, from + 4);
}
for (let dy = 0; dy < factor; dy++) row.copy(out, (y * factor + dy) * outWidth * 4);
}
return { data: out, width: outWidth, height: height * factor };
}
/**
* One box of a render at one pixel per cell: the first pixel of every cell block, so a render at
* any whole density gives the same cells.
* @static
* @param {Buffer} render - PNG bytes of a render of the layout.
* @param {Object} metadata - Atlas metadata.
* @param {{x:number,y:number,width:number,height:number}} box - Frame box, in cells.
* @returns {Promise<{data: Buffer, width: number, height: number}>} Raw RGBA pixels.
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
static async cellBox(render, metadata, box) {
const image = sharp(render).ensureAlpha();
const { width } = await image.metadata();
const density = AtlasSpriteSheetGenerator.pixelsPerCell(width, metadata);
const { data } = await image
.extract({
left: box.x * density,
top: box.y * density,
width: box.width * density,
height: box.height * density,
})
.raw()
.toBuffer({ resolveWithObject: true });
if (density === 1) return { data, width: box.width, height: box.height };
const cells = Buffer.alloc(box.width * box.height * 4);
for (let y = 0; y < box.height; y++)
for (let x = 0; x < box.width; x++) {
const from = (y * density * box.width * density + x * density) * 4;
data.copy(cells, (y * box.width + x) * 4, from, from + 4);
}
return { data: cells, width: box.width, height: box.height };
}
/**
* One box of a render, at the upscaled density of its layout.
* @static
* @param {Buffer} render - PNG bytes of a render of the layout.
* @param {Object} metadata - Atlas metadata.
* @param {{x:number,y:number,width:number,height:number}} box - Frame box, in cells.
* @returns {Promise<{data: Buffer, width: number, height: number}>} Raw RGBA pixels.
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
static async upscaledBox(render, metadata, box) {
return AtlasSpriteSheetGenerator.repeatPixels(
await AtlasSpriteSheetGenerator.cellBox(render, metadata, box),
AtlasSpriteSheetGenerator.upscaledPixelsPerCell(metadata),
);
}
/**
* The upscaled render derived from a render of a layout: the same cell grid at
* `metadata.upscaleFactor` pixels per cell, every colour kept exactly.
* @static
* @param {Buffer} render - PNG bytes of a render of the layout.
* @param {Object} metadata - Atlas metadata.
* @returns {Promise<Buffer|null>} PNG bytes, or null when it would repeat the render it comes from.
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
static async upscaledFromRender(render, metadata) {
const { width } = await sharp(render).metadata();
if (
AtlasSpriteSheetGenerator.pixelsPerCell(width, metadata) ===
AtlasSpriteSheetGenerator.upscaledPixelsPerCell(metadata)
)
return null;
const whole = { x: 0, y: 0, width: Number(metadata.atlasWidth), height: Number(metadata.atlasHeight) };
const { data, width: outWidth, height } = await AtlasSpriteSheetGenerator.upscaledBox(render, metadata, whole);
return await sharp(data, { raw: { width: outWidth, height, channels: 4 } })
.png()
.toBuffer();
}
/**
* The frames an atlas holds for one direction code: those of the first keyframe of the code
* that has any.
* @static
* @param {Object} metadata - Atlas metadata.
* @param {string} directionCode - Direction folder code, e.g. `08`.
* @returns {Array<{x:number,y:number,width:number,height:number}>} Frame boxes, in cells.
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
static directionFrames(metadata, directionCode) {
const frames = metadata?.frames ?? {};
for (const keyframe of getKeyframeDirectionsByCode(directionCode))
if (frames[keyframe]?.length) return frames[keyframe];
return [];
}
/**
* Frame count of every direction code an atlas describes.
* @static
* @param {Object} metadata - Atlas metadata.
* @returns {Object<string, number>} Direction code → frames.
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
static frameCounts(metadata) {
return Object.fromEntries(
OBJECT_LAYER_DIRECTION_CODES.map((code) => [
code,
AtlasSpriteSheetGenerator.directionFrames(metadata, code).length,
]),
);
}
/**
* Animated WebP of one direction of a render, at the upscaled density of its layout. Frames of
* one direction may differ in size, so each is scaled to the largest, nearest-neighbour.
* @static
* @param {Buffer} render - PNG bytes of a render of the layout.
* @param {Object} metadata - Atlas metadata.
* @param {string} directionCode - Direction folder code.
* @param {number} frameDuration - Milliseconds per frame.
* @returns {Promise<Buffer|null>} WebP bytes, or null when the direction has no frame.
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
static async animationFromRender(render, metadata, directionCode, frameDuration) {
const boxes = AtlasSpriteSheetGenerator.directionFrames(metadata, directionCode);
if (!boxes.length) return null;
const scale = AtlasSpriteSheetGenerator.upscaledPixelsPerCell(metadata);
const width = Math.max(...boxes.map((box) => box.width)) * scale;
const height = Math.max(...boxes.map((box) => box.height)) * scale;
const frames = await Promise.all(
boxes.map(async (box) => {
const frame = await AtlasSpriteSheetGenerator.upscaledBox(render, metadata, box);
return await sharp(frame.data, { raw: { width: frame.width, height: frame.height, channels: 4 } })
.resize(width, height, { kernel: 'nearest', fit: 'fill' })
.png()
.toBuffer();
}),
);
// One frame is a still; animation takes two or more.
const image = frames.length === 1 ? sharp(frames[0]) : sharp(frames, { join: { animated: true } });
return await image.webp({ loop: 0, delay: frames.map(() => frameDuration), lossless: true }).toBuffer();
}
/**
* The idle preview of a render: its preview frame scaled nearest-neighbour until its longer side
* is {@link IDLE_PREVIEW_SIZE}, with no margin.
* @static
* @param {Buffer} render - PNG bytes of a render of the layout.
* @param {Object} metadata - Atlas metadata as {@link generateAtlas} returns it.
* @returns {Promise<Buffer|null>} PNG bytes of the idle preview, or null when the render has no frame.
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
static async idlePreviewFromRender(render, metadata) {
const frame = AtlasSpriteSheetGenerator.idlePreviewFrame(metadata);
Iif (!frame) return null;
const cells = await AtlasSpriteSheetGenerator.cellBox(render, metadata, frame);
return await sharp(cells.data, { raw: { width: cells.width, height: cells.height, channels: 4 } })
.resize(IDLE_PREVIEW_SIZE, IDLE_PREVIEW_SIZE, { kernel: 'nearest', fit: 'inside' })
.png()
.toBuffer();
}
/**
* Copies a frame image onto an atlas canvas at the given origin.
* @static
* @param {Jimp} atlasImage - Destination atlas canvas.
* @param {Jimp} frameImage - Source frame image.
* @param {number} originX - Destination X origin.
* @param {number} originY - Destination Y origin.
* @returns {void}
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
static blitFrame(atlasImage, frameImage, originX, originY) {
for (let srcY = 0; srcY < frameImage.bitmap.height; srcY++) {
for (let srcX = 0; srcX < frameImage.bitmap.width; srcX++) {
const destX = originX + srcX;
const destY = originY + srcY;
Iif (destX >= atlasImage.bitmap.width || destY >= atlasImage.bitmap.height) continue;
atlasImage.setPixelColor(frameImage.getPixelColor(srcX, srcY), destX, destY);
}
}
}
/**
* Simple grid-based frame packing algorithm
* @static
* @param {Array} frameImages - Array of frame image objects
* @param {number} maxDim - Maximum atlas dimension
* @returns {{packedFrames: Array, atlasWidth: number, atlasHeight: number}}
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
static packFramesGrid(frameImages, maxDim) {
Iif (frameImages.length === 0) {
throw new Error('No frames to pack');
}
// Sort frames by height (tallest first) for better packing
const sortedFrames = [...frameImages].sort((a, b) => b.height - a.height || b.width - a.width);
const packedFrames = [];
let currentX = 0;
let currentY = 0;
let rowHeight = 0;
let maxWidth = 0;
let totalHeight = 0;
for (const frame of sortedFrames) {
// Check if frame fits in current row
if (currentX + frame.width > maxDim) {
// Move to next row
currentX = 0;
currentY += rowHeight;
rowHeight = 0;
}
if (frame.width > maxDim || currentY + frame.height > maxDim) {
throw new Error(`Frames exceed atlas dimension ${maxDim}`);
}
packedFrames.push({
...frame,
x: currentX,
y: currentY,
});
currentX += frame.width;
rowHeight = Math.max(rowHeight, frame.height);
maxWidth = Math.max(maxWidth, currentX);
totalHeight = Math.max(totalHeight, currentY + frame.height);
}
const atlasWidth = maxWidth;
const atlasHeight = totalHeight;
return {
packedFrames,
atlasWidth,
atlasHeight,
};
}
/**
* Returns the next power of 2 greater than or equal to n
* @static
* @param {number} n - Input number
* @returns {number} Next power of 2
* @memberof CyberiaAtlasSpriteSheetGenerator
*/
static nextPowerOf2(n) {
Iif (n <= 0) return 1;
n--;
n |= n >> 1;
n |= n >> 2;
n |= n >> 4;
n |= n >> 8;
n |= n >> 16;
return n + 1;
}
}
|