import { ENV } from '@pixi/constants';
import { settings } from '../settings';
import type { ISystem } from '../system/ISystem';
import type { Renderer } from '../Renderer';
import type { WebGLExtensions } from './WebGLExtensions';
import type { IRenderingContext } from '../IRenderer';
import type { ExtensionMetadata } from '@pixi/extensions';
import { extensions, ExtensionType } from '@pixi/extensions';
let CONTEXT_UID_COUNTER = 0;
export interface ISupportDict
{
uint32Indices: boolean;
}
export interface ContextOptions
{
context?: IRenderingContext;
/**
* Use premultipliedAlpha instead
* @deprecated since 7.0.0
*/
useContextAlpha?: boolean | 'notMultiplied';
premultipliedAlpha?: boolean;
powerPreference?: WebGLPowerPreference;
preserveDrawingBuffer?: boolean;
antialias?: boolean;
}
/**
* System plugin to the renderer to manage the context.
* @memberof PIXI
*/
export class ContextSystem implements ISystem
{
/** @ignore */
static extension: ExtensionMetadata = {
type: ExtensionType.RendererSystem,
name: 'context',
};
/**
* Either 1 or 2 to reflect the WebGL version being used.
* @readonly
*/
public webGLVersion: number;
/**
* Features supported by current context.
* @type {object}
* @readonly
* @property {boolean} uint32Indices - Support for 32-bit indices buffer.
*/
readonly supports: ISupportDict;
preserveDrawingBuffer: boolean;
powerPreference: WebGLPowerPreference;
/**
* Pass-thru setting for the canvas' context `alpha` property. This is typically
* not something you need to fiddle with. If you want transparency, use `backgroundAlpha`.
* @member {boolean}
* @deprecated since 7.0.0
*/
useContextAlpha: boolean | 'notMultiplied';
protected CONTEXT_UID: number;
protected gl: IRenderingContext;
/**
* Extensions available.
* @type {object}
* @readonly
* @property {WEBGL_draw_buffers} drawBuffers - WebGL v1 extension
* @property {WEBGL_depth_texture} depthTexture - WebGL v1 extension
* @property {OES_texture_float} floatTexture - WebGL v1 extension
* @property {WEBGL_lose_context} loseContext - WebGL v1 extension
* @property {OES_vertex_array_object} vertexArrayObject - WebGL v1 extension
* @property {EXT_texture_filter_anisotropic} anisotropicFiltering - WebGL v1 and v2 extension
*/
public extensions: WebGLExtensions;
private renderer: Renderer;
/** @param renderer - The renderer this System works for. */
constructor(renderer: Renderer)
{
this.renderer = renderer;
this.webGLVersion = 1;
this.extensions = {};
this.supports = {
uint32Indices: false,
};
// Bind functions
this.handleContextLost = this.handleContextLost.bind(this);
this.handleContextRestored = this.handleContextRestored.bind(this);
}
/**
* `true` if the context is lost
* @readonly
*/
get isLost(): boolean
{
return (!this.gl || this.gl.isContextLost());
}
/**
* Handles the context change event.
* @param {WebGLRenderingContext} gl - New WebGL context.
*/
protected contextChange(gl: IRenderingContext): void
{
this.gl = gl;
this.renderer.gl = gl;
this.renderer.CONTEXT_UID = CONTEXT_UID_COUNTER++;
// restore a context if it was previously lost
if (gl.isContextLost() && gl.getExtension('WEBGL_lose_context'))
{
gl.getExtension('WEBGL_lose_context').restoreContext();
}
}
init(options: ContextOptions): void
{
/*
* The options passed in to create a new WebGL context.
*/
if (options.context)
{
this.initFromContext(options.context);
}
else
{
const alpha = this.renderer.background.alpha < 1;
const premultipliedAlpha = options.premultipliedAlpha ?? true;
this.preserveDrawingBuffer = options.preserveDrawingBuffer;
this.useContextAlpha = options.useContextAlpha;
this.powerPreference = options.powerPreference;
this.initFromOptions({
alpha,
premultipliedAlpha,
antialias: options.antialias,
stencil: true,
preserveDrawingBuffer: options.preserveDrawingBuffer,
powerPreference: options.powerPreference,
});
}
}
/**
* Initializes the context.
* @protected
* @param {WebGLRenderingContext} gl - WebGL context
*/
initFromContext(gl: IRenderingContext): void
{
this.gl = gl;
this.validateContext(gl);
this.renderer.gl = gl;
this.renderer.CONTEXT_UID = CONTEXT_UID_COUNTER++;
this.renderer.runners.contextChange.emit(gl);
(this.renderer.view as any).addEventListener('webglcontextlost', this.handleContextLost, false);
this.renderer.view.addEventListener('webglcontextrestored', this.handleContextRestored, false);
}
/**
* Initialize from context options
* @protected
* @see https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement/getContext
* @param {object} options - context attributes
*/
initFromOptions(options: WebGLContextAttributes): void
{
const gl = this.createContext(this.renderer.view, options);
this.initFromContext(gl);
}
/**
* Helper class to create a WebGL Context
* @param canvas - the canvas element that we will get the context from
* @param options - An options object that gets passed in to the canvas element containing the
* context attributes
* @see https://developer.mozilla.org/en/docs/Web/API/HTMLCanvasElement/getContext
* @returns {WebGLRenderingContext} the WebGL context
*/
createContext(canvas: HTMLCanvasElement, options: WebGLContextAttributes): IRenderingContext
{
let gl;
if (settings.PREFER_ENV >= ENV.WEBGL2)
{
gl = canvas.getContext('webgl2', options);
}
if (gl)
{
this.webGLVersion = 2;
}
else
{
this.webGLVersion = 1;
gl = canvas.getContext('webgl', options) || canvas.getContext('experimental-webgl', options);
if (!gl)
{
// fail, not able to get a context
throw new Error('This browser does not support WebGL. Try using the canvas renderer');
}
}
this.gl = gl as IRenderingContext;
this.getExtensions();
return this.gl;
}
/** Auto-populate the extensions. */
protected getExtensions(): void
{
// time to set up default extensions that Pixi uses.
const { gl } = this;
const common = {
anisotropicFiltering: gl.getExtension('EXT_texture_filter_anisotropic'),
floatTextureLinear: gl.getExtension('OES_texture_float_linear'),
s3tc: gl.getExtension('WEBGL_compressed_texture_s3tc'),
s3tc_sRGB: gl.getExtension('WEBGL_compressed_texture_s3tc_srgb'), // eslint-disable-line camelcase
etc: gl.getExtension('WEBGL_compressed_texture_etc'),
etc1: gl.getExtension('WEBGL_compressed_texture_etc1'),
pvrtc: gl.getExtension('WEBGL_compressed_texture_pvrtc')
|| gl.getExtension('WEBKIT_WEBGL_compressed_texture_pvrtc'),
atc: gl.getExtension('WEBGL_compressed_texture_atc'),
astc: gl.getExtension('WEBGL_compressed_texture_astc')
};
if (this.webGLVersion === 1)
{
Object.assign(this.extensions, common, {
drawBuffers: gl.getExtension('WEBGL_draw_buffers'),
depthTexture: gl.getExtension('WEBGL_depth_texture'),
loseContext: gl.getExtension('WEBGL_lose_context'),
vertexArrayObject: gl.getExtension('OES_vertex_array_object')
|| gl.getExtension('MOZ_OES_vertex_array_object')
|| gl.getExtension('WEBKIT_OES_vertex_array_object'),
uint32ElementIndex: gl.getExtension('OES_element_index_uint'),
// Floats and half-floats
floatTexture: gl.getExtension('OES_texture_float'),
floatTextureLinear: gl.getExtension('OES_texture_float_linear'),
textureHalfFloat: gl.getExtension('OES_texture_half_float'),
textureHalfFloatLinear: gl.getExtension('OES_texture_half_float_linear'),
});
}
else if (this.webGLVersion === 2)
{
Object.assign(this.extensions, common, {
// Floats and half-floats
colorBufferFloat: gl.getExtension('EXT_color_buffer_float')
});
}
}
/**
* Handles a lost webgl context
* @param {WebGLContextEvent} event - The context lost event.
*/
protected handleContextLost(event: WebGLContextEvent): void
{
event.preventDefault();
}
/** Handles a restored webgl context. */
protected handleContextRestored(): void
{
this.renderer.runners.contextChange.emit(this.gl);
}
destroy(): void
{
const view = this.renderer.view;
this.renderer = null;
// remove listeners
(view as any).removeEventListener('webglcontextlost', this.handleContextLost);
view.removeEventListener('webglcontextrestored', this.handleContextRestored);
this.gl.useProgram(null);
if (this.extensions.loseContext)
{
this.extensions.loseContext.loseContext();
}
}
/** Handle the post-render runner event. */
protected postrender(): void
{
if (this.renderer.objectRenderer.renderingToScreen)
{
this.gl.flush();
}
}
/**
* Validate context.
* @param {WebGLRenderingContext} gl - Render context.
*/
protected validateContext(gl: IRenderingContext): void
{
const attributes = gl.getContextAttributes();
const isWebGl2 = 'WebGL2RenderingContext' in globalThis && gl instanceof globalThis.WebGL2RenderingContext;
if (isWebGl2)
{
this.webGLVersion = 2;
}
// this is going to be fairly simple for now.. but at least we have room to grow!
if (attributes && !attributes.stencil)
{
/* eslint-disable max-len, no-console */
console.warn('Provided WebGL context does not have a stencil buffer, masks may not render correctly');
/* eslint-enable max-len, no-console */
}
const hasuint32 = isWebGl2 || !!(gl as WebGLRenderingContext).getExtension('OES_element_index_uint');
this.supports.uint32Indices = hasuint32;
if (!hasuint32)
{
/* eslint-disable max-len, no-console */
console.warn('Provided WebGL context does not support 32 index buffer, complex graphics may not render correctly');
/* eslint-enable max-len, no-console */
}
}
}
extensions.add(ContextSystem);