import { ExtensionType } from '../../../../extensions/Extensions';
import { BufferUsage } from '../../shared/buffer/const';
import { BUFFER_TYPE } from './const';
import { GlBuffer } from './GlBuffer';
import type { Buffer } from '../../shared/buffer/Buffer';
import type { System } from '../../shared/system/System';
import type { GlRenderingContext } from '../context/GlRenderingContext';
import type { WebGLRenderer } from '../WebGLRenderer';
/**
* System plugin to the renderer to manage buffers.
*
* WebGL uses Buffers as a way to store objects to the GPU.
* This system makes working with them a lot easier.
*
* Buffers are used in three main places in WebGL
* - geometry information
* - Uniform information (via uniform buffer objects - a WebGL 2 only feature)
* - Transform feedback information. (WebGL 2 only feature)
*
* This system will handle the binding of buffers to the GPU as well as uploading
* them. With this system, you never need to work directly with GPU buffers, but instead work with
* the Buffer class.
* @class
* @memberof rendering
*/
export class GlBufferSystem implements System
{
/** @ignore */
public static extension = {
type: [
ExtensionType.WebGLSystem,
],
name: 'buffer',
} as const;
private _gl: GlRenderingContext;
private _gpuBuffers: {[key: number]: GlBuffer} = Object.create(null);
/** Cache keeping track of the base bound buffer bases */
private readonly _boundBufferBases: {[key: number]: GlBuffer} = Object.create(null);
private _renderer: WebGLRenderer;
private _minBaseLocation = 0;
private _maxBindings: number;
private _nextBindBaseIndex = this._minBaseLocation;
private _bindCallId = 0;
/**
* @param {Renderer} renderer - The renderer this System works for.
*/
constructor(renderer: WebGLRenderer)
{
this._renderer = renderer;
this._renderer.renderableGC.addManagedHash(this, '_gpuBuffers');
}
/**
* @ignore
*/
public destroy(): void
{
this._renderer = null;
this._gl = null;
this._gpuBuffers = null;
(this._boundBufferBases as null) = null;
}
/** Sets up the renderer context and necessary buffers. */
protected contextChange(): void
{
const gl = this._gl = this._renderer.gl;
this._gpuBuffers = Object.create(null);
this._maxBindings = gl.MAX_UNIFORM_BUFFER_BINDINGS ? gl.getParameter(gl.MAX_UNIFORM_BUFFER_BINDINGS) : 0;
}
public getGlBuffer(buffer: Buffer): GlBuffer
{
return this._gpuBuffers[buffer.uid] || this.createGLBuffer(buffer);
}
/**
* This binds specified buffer. On first run, it will create the webGL buffers for the context too
* @param buffer - the buffer to bind to the renderer
*/
public bind(buffer: Buffer): void
{
const { _gl: gl } = this;
const glBuffer = this.getGlBuffer(buffer);
gl.bindBuffer(glBuffer.type, glBuffer.buffer);
}
/**
* Binds an uniform buffer to at the given index.
*
* A cache is used so a buffer will not be bound again if already bound.
* @param glBuffer - the buffer to bind
* @param index - the base index to bind it to.
*/
public bindBufferBase(glBuffer: GlBuffer, index: number): void
{
const { _gl: gl } = this;
if (this._boundBufferBases[index] !== glBuffer)
{
this._boundBufferBases[index] = glBuffer;
glBuffer._lastBindBaseLocation = index;
gl.bindBufferBase(gl.UNIFORM_BUFFER, index, glBuffer.buffer);
}
}
public nextBindBase(hasTransformFeedback: boolean)
{
this._bindCallId++;
this._minBaseLocation = 0;
if (hasTransformFeedback)
{
this._boundBufferBases[0] = null;
this._minBaseLocation = 1;
if (this._nextBindBaseIndex < 1)
{
this._nextBindBaseIndex = 1;
}
}
}
public freeLocationForBufferBase(glBuffer: GlBuffer): number
{
let freeIndex = this.getLastBindBaseLocation(glBuffer);
// check if it is already bound..
if (freeIndex >= this._minBaseLocation)
{
glBuffer._lastBindCallId = this._bindCallId;
return freeIndex;
}
let loop = 0;
let nextIndex = this._nextBindBaseIndex;
while (loop < 2)
{
if (nextIndex >= this._maxBindings)
{
nextIndex = this._minBaseLocation;
loop++;
}
const curBuf = this._boundBufferBases[nextIndex];
if (curBuf && curBuf._lastBindCallId === this._bindCallId)
{
nextIndex++;
continue;
}
break;
}
freeIndex = nextIndex;
this._nextBindBaseIndex = nextIndex + 1;
if (loop >= 2)
{
// TODO: error
return -1;
}
glBuffer._lastBindCallId = this._bindCallId;
this._boundBufferBases[freeIndex] = null;
return freeIndex;
}
public getLastBindBaseLocation(glBuffer: GlBuffer): number
{
const index = glBuffer._lastBindBaseLocation;
if (this._boundBufferBases[index] === glBuffer)
{
return index;
}
return -1;
}
/**
* Binds a buffer whilst also binding its range.
* This will make the buffer start from the offset supplied rather than 0 when it is read.
* @param glBuffer - the buffer to bind
* @param index - the base index to bind at, defaults to 0
* @param offset - the offset to bind at (this is blocks of 256). 0 = 0, 1 = 256, 2 = 512 etc
* @param size - the size to bind at (this is blocks of 256).
*/
public bindBufferRange(glBuffer: GlBuffer, index?: number, offset?: number, size?: number): void
{
const { _gl: gl } = this;
offset ||= 0;
index ||= 0;
this._boundBufferBases[index] = null;
gl.bindBufferRange(gl.UNIFORM_BUFFER, index || 0, glBuffer.buffer, offset * 256, size || 256);
}
/**
* Will ensure the data in the buffer is uploaded to the GPU.
* @param {Buffer} buffer - the buffer to update
*/
public updateBuffer(buffer: Buffer): GlBuffer
{
const { _gl: gl } = this;
const glBuffer = this.getGlBuffer(buffer);
if (buffer._updateID === glBuffer.updateID)
{
return glBuffer;
}
glBuffer.updateID = buffer._updateID;
gl.bindBuffer(glBuffer.type, glBuffer.buffer);
const data = buffer.data;
const drawType = (buffer.descriptor.usage & BufferUsage.STATIC) ? gl.STATIC_DRAW : gl.DYNAMIC_DRAW;
if (data)
{
if (glBuffer.byteLength >= data.byteLength)
{
// assuming our buffers are aligned to 4 bits...
// offset is always zero for now!
gl.bufferSubData(glBuffer.type, 0, data, 0, buffer._updateSize / data.BYTES_PER_ELEMENT);
}
else
{
glBuffer.byteLength = data.byteLength;
// assuming our buffers are aligned to 4 bits...
gl.bufferData(glBuffer.type, data, drawType);
}
}
else
{
glBuffer.byteLength = buffer.descriptor.size;
gl.bufferData(glBuffer.type, glBuffer.byteLength, drawType);
}
return glBuffer;
}
/** dispose all WebGL resources of all managed buffers */
public destroyAll(): void
{
const gl = this._gl;
for (const id in this._gpuBuffers)
{
gl.deleteBuffer(this._gpuBuffers[id].buffer);
}
this._gpuBuffers = Object.create(null);
}
/**
* Disposes buffer
* @param {Buffer} buffer - buffer with data
* @param {boolean} [contextLost=false] - If context was lost, we suppress deleteVertexArray
*/
protected onBufferDestroy(buffer: Buffer, contextLost?: boolean): void
{
const glBuffer = this._gpuBuffers[buffer.uid];
const gl = this._gl;
if (!contextLost)
{
gl.deleteBuffer(glBuffer.buffer);
}
this._gpuBuffers[buffer.uid] = null;
}
/**
* creates and attaches a GLBuffer object tied to the current context.
* @param buffer
* @protected
*/
protected createGLBuffer(buffer: Buffer): GlBuffer
{
const { _gl: gl } = this;
let type = BUFFER_TYPE.ARRAY_BUFFER;
if ((buffer.descriptor.usage & BufferUsage.INDEX))
{
type = BUFFER_TYPE.ELEMENT_ARRAY_BUFFER;
}
else if ((buffer.descriptor.usage & BufferUsage.UNIFORM))
{
type = BUFFER_TYPE.UNIFORM_BUFFER;
}
const glBuffer = new GlBuffer(gl.createBuffer(), type);
this._gpuBuffers[buffer.uid] = glBuffer;
buffer.on('destroy', this.onBufferDestroy, this);
return glBuffer;
}
}