import { BaseTexture } from '@pixi/core';
import { BasePrepare } from '@pixi/prepare';
import type { AbstractRenderer } from '@pixi/core';
import type { CanvasRenderer } from '@pixi/canvas-renderer';
import type { IDisplayObjectExtended } from '@pixi/prepare';
const CANVAS_START_SIZE = 16;
/**
* Built-in hook to upload PIXI.Texture objects to the GPU.
*
* @private
* @param {*} prepare - Instance of CanvasPrepare
* @param {*} item - Item to check
* @return {boolean} If item was uploaded.
*/
function uploadBaseTextures(prepare: AbstractRenderer | BasePrepare, item: IDisplayObjectExtended): boolean
{
const tempPrepare = prepare as CanvasPrepare;
if (item instanceof BaseTexture)
{
const image = (item as any).source;
// Sometimes images (like atlas images) report a size of zero, causing errors on windows phone.
// So if the width or height is equal to zero then use the canvas size
// Otherwise use whatever is smaller, the image dimensions or the canvas dimensions.
const imageWidth = image.width === 0 ? tempPrepare.canvas.width : Math.min(tempPrepare.canvas.width, image.width);
const imageHeight = image.height === 0 ? tempPrepare.canvas.height
: Math.min(tempPrepare.canvas.height, image.height);
// Only a small subsections is required to be drawn to have the whole texture uploaded to the GPU
// A smaller draw can be faster.
tempPrepare.ctx.drawImage(
image, 0, 0, imageWidth, imageHeight, 0, 0,
tempPrepare.canvas.width, tempPrepare.canvas.height
);
return true;
}
return false;
}
/**
* The prepare manager provides functionality to upload content to the GPU.
*
* This cannot be done directly for Canvas like in WebGL, but the effect can be achieved by drawing
* textures to an offline canvas. This draw call will force the texture to be moved onto the GPU.
*
* An instance of this class is automatically created by default, and can be found at `renderer.plugins.prepare`
*
* @class
* @extends PIXI.BasePrepare
* @memberof PIXI
*/
export class CanvasPrepare extends BasePrepare
{
/** @internal */
canvas: HTMLCanvasElement;
/** @internal */
ctx: CanvasRenderingContext2D;
/**
* @param {PIXI.CanvasRenderer} renderer - A reference to the current renderer
*/
constructor(renderer: CanvasRenderer)
{
super(renderer);
this.uploadHookHelper = this;
/**
* An offline canvas to render textures to
* @type {HTMLCanvasElement}
* @private
*/
this.canvas = document.createElement('canvas');
this.canvas.width = CANVAS_START_SIZE;
this.canvas.height = CANVAS_START_SIZE;
/**
* The context to the canvas
* @type {CanvasRenderingContext2D}
* @private
*/
this.ctx = this.canvas.getContext('2d');
// Add textures to upload
this.registerUploadHook(uploadBaseTextures);
}
/**
* Destroys the plugin, don't use after this.
*
*/
public destroy(): void
{
super.destroy();
this.ctx = null;
this.canvas = null;
}
}