playcanvas
Version:
PlayCanvas WebGL game engine
110 lines (107 loc) • 5.57 kB
JavaScript
import { Debug } from '../../core/debug.js';
import { TRACEID_VRAM_SB } from '../../core/constants.js';
import { BUFFERUSAGE_STORAGE } from './constants.js';
/**
* @import { GraphicsDevice } from './graphics-device.js'
*/ let id = 0;
/**
* A storage buffer represents a memory which both the CPU and the GPU can access. Typically it is
* used to provide data for compute shader, and to store the result of the computation.
* Note that this class is only supported on the WebGPU platform.
*
* @category Graphics
*/ class StorageBuffer {
/**
* Create a new StorageBuffer instance.
*
* @param {GraphicsDevice} graphicsDevice - The graphics device used to manage this storage buffer.
* @param {number} byteSize - The size of the storage buffer in bytes.
* @param {number} [bufferUsage] - The usage type of the storage buffer. Can be a combination
* of {@link BUFFERUSAGE_READ}, {@link BUFFERUSAGE_WRITE}, {@link BUFFERUSAGE_COPY_SRC} and
* {@link BUFFERUSAGE_COPY_DST} flags. This parameter can be omitted if no special usage is
* required.
* @param {boolean} [addStorageUsage] - If true, automatically adds BUFFERUSAGE_STORAGE flag.
* Set to false for staging buffers that use BUFFERUSAGE_WRITE. Defaults to true.
*/ constructor(graphicsDevice, byteSize, bufferUsage = 0, addStorageUsage = true){
this.id = id++;
this.device = graphicsDevice;
this.byteSize = byteSize;
this.bufferUsage = bufferUsage;
const usage = addStorageUsage ? BUFFERUSAGE_STORAGE | bufferUsage : bufferUsage;
this.impl = graphicsDevice.createBufferImpl(usage);
this.impl.allocate(graphicsDevice, byteSize);
this.device.buffers.push(this);
this.adjustVramSizeTracking(graphicsDevice._vram, this.byteSize);
}
/**
* Frees resources associated with this storage buffer.
*/ destroy() {
// stop tracking the buffer
const device = this.device;
const idx = device.buffers.indexOf(this);
if (idx !== -1) {
device.buffers.splice(idx, 1);
}
this.adjustVramSizeTracking(device._vram, -this.byteSize);
this.impl.destroy(device);
}
adjustVramSizeTracking(vram, size) {
Debug.trace(TRACEID_VRAM_SB, `${this.id} size: ${size} vram.sb: ${vram.sb} => ${vram.sb + size}`);
vram.sb += size;
}
/**
* Read the contents of a storage buffer.
*
* @param {number} [offset] - The byte offset of data to read. Defaults to 0.
* @param {number} [size] - The byte size of data to read. Defaults to the full size of the
* buffer minus the offset.
* @param {ArrayBufferView|null} [data] - Typed array to populate with the data read from the
* storage buffer. When typed array is supplied, enough space needs to be reserved, otherwise
* only partial data is copied. If not specified, the data is returned in an Uint8Array.
* Defaults to null.
* @param {boolean} [immediate] - If true, the read operation will be executed as soon as
* possible. This has a performance impact, so it should be used only when necessary. Defaults
* to false.
* @returns {Promise<ArrayBufferView>} A promise that resolves with the data read from the
* storage buffer.
* @ignore
*/ read(offset = 0, size = this.byteSize, data = null, immediate = false) {
return this.impl.read(this.device, offset, size, data, immediate);
}
/**
* Issues a write operation of the provided data into a storage buffer.
*
* @param {number} bufferOffset - The offset in bytes to start writing to the storage buffer.
* @param {ArrayBufferView} data - The data to write to the storage buffer.
* @param {number} dataOffset - Offset in data to begin writing from. Given in elements if data
* is a TypedArray and bytes otherwise.
* @param {number} size - Size of content to write from data to buffer. Given in elements if
* data is a TypedArray and bytes otherwise.
*/ write(bufferOffset = 0, data, dataOffset = 0, size) {
this.impl.write(this.device, bufferOffset, data, dataOffset, size);
}
/**
* Clear the content of a storage buffer to 0.
*
* @param {number} [offset] - The byte offset of data to clear. Defaults to 0.
* @param {number} [size] - The byte size of data to clear. Defaults to the full size of the
* buffer minus the offset.
*/ clear(offset = 0, size = this.byteSize) {
this.impl.clear(this.device, offset, size);
}
/**
* Copy data from another storage buffer into this storage buffer.
*
* @param {StorageBuffer} srcBuffer - The source storage buffer to copy from.
* @param {number} [srcOffset] - The byte offset in the source buffer. Defaults to 0.
* @param {number} [dstOffset] - The byte offset in this buffer. Defaults to 0.
* @param {number} [size] - The byte size of data to copy. Defaults to the full size of the
* source buffer minus the source offset.
*/ copy(srcBuffer, srcOffset = 0, dstOffset = 0, size = srcBuffer.byteSize - srcOffset) {
Debug.assert(srcOffset + size <= srcBuffer.byteSize, 'Source copy range exceeds buffer size');
Debug.assert(dstOffset + size <= this.byteSize, 'Destination copy range exceeds buffer size');
const commandEncoder = this.device.getCommandEncoder();
commandEncoder.copyBufferToBuffer(srcBuffer.impl.buffer, srcOffset, this.impl.buffer, dstOffset, size);
}
}
export { StorageBuffer };