playcanvas
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Open-source WebGL/WebGPU 3D engine for the web
78 lines (75 loc) • 2.96 kB
JavaScript
import { BUFFERUSAGE_INDIRECT, BUFFERUSAGE_COPY_DST } from '../constants.js';
import { StorageBuffer } from '../storage-buffer.js';
/**
* @import { GraphicsDevice } from '../graphics-device.js'
*/ /**
* WebGPU implementation of DrawCommands.
*
* @ignore
*/ class WebgpuDrawCommands {
/**
* Allocate AoS buffer and backing storage buffer.
* @param {number} maxCount - Number of sub-draws.
*/ allocate(maxCount) {
// Skip reallocation if size matches exactly
if (this.gpuIndirect && this.gpuIndirect.length === 5 * maxCount) {
return;
}
this.storage?.destroy();
this.gpuIndirect = new Uint32Array(5 * maxCount);
this.gpuIndirectSigned = new Int32Array(this.gpuIndirect.buffer);
this.storage = new StorageBuffer(this.device, this.gpuIndirect.byteLength, BUFFERUSAGE_INDIRECT | BUFFERUSAGE_COPY_DST);
}
/**
* Write a single draw entry.
* @param {number} i - Draw index.
* @param {number} indexOrVertexCount - Count of indices/vertices.
* @param {number} instanceCount - Instance count.
* @param {number} firstIndexOrVertex - First index/vertex.
* @param {number} baseVertex - Base vertex (signed).
* @param {number} firstInstance - First instance.
*/ add(i, indexOrVertexCount, instanceCount, firstIndexOrVertex, baseVertex = 0, firstInstance = 0) {
const o = i * 5;
this.gpuIndirect[o + 0] = indexOrVertexCount;
this.gpuIndirect[o + 1] = instanceCount;
this.gpuIndirect[o + 2] = firstIndexOrVertex;
this.gpuIndirectSigned[o + 3] = baseVertex;
this.gpuIndirect[o + 4] = firstInstance;
}
/**
* Upload AoS data to storage buffer.
* @param {number} count - Number of active draws.
* @returns {number} Total primitive count.
*/ update(count) {
if (this.storage && count > 0) {
const used = count * 5; // 5 uints per draw
this.storage.write(0, this.gpuIndirect, 0, used);
}
// calculate total primitives for stats
let totalPrimitives = 0;
if (this.gpuIndirect && count > 0) {
for(let d = 0; d < count; d++){
const offset = d * 5;
const indexOrVertexCount = this.gpuIndirect[offset + 0];
const instanceCount = this.gpuIndirect[offset + 1];
totalPrimitives += indexOrVertexCount * instanceCount;
}
}
return totalPrimitives;
}
destroy() {
this.storage?.destroy();
this.storage = null;
}
/**
* @param {GraphicsDevice} device - Graphics device.
*/ constructor(device){
/** @type {Uint32Array|null} */ this.gpuIndirect = null;
/** @type {Int32Array|null} */ this.gpuIndirectSigned = null;
/**
* @type {StorageBuffer|null}
*/ this.storage = null;
this.device = device;
}
}
export { WebgpuDrawCommands };