/**
 * @license
 * Copyright 2018 Google LLC. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * =============================================================================
 */
import { env } from '@tensorflow/tfjs-core';
const contexts = {};
const WEBGL_ATTRIBUTES = {
    alpha: false,
    antialias: false,
    premultipliedAlpha: false,
    preserveDrawingBuffer: false,
    depth: false,
    stencil: false,
    failIfMajorPerformanceCaveat: true
};
export function clearWebGLContext(webGLVersion) {
    delete contexts[webGLVersion];
}
export function setWebGLContext(webGLVersion, gl) {
    contexts[webGLVersion] = gl;
}
export function getWebGLContext(webGLVersion, customCanvas) {
    if (!(webGLVersion in contexts) || customCanvas != null) {
        const newCtx = getWebGLRenderingContext(webGLVersion, customCanvas);
        if (newCtx !== null) {
            contexts[webGLVersion] = newCtx;
        }
        else {
            console.log('Could not get context for WebGL version', webGLVersion);
            return null;
        }
    }
    const gl = contexts[webGLVersion];
    if (gl == null || gl.isContextLost()) {
        delete contexts[webGLVersion];
        return getWebGLContext(webGLVersion);
    }
    gl.disable(gl.DEPTH_TEST);
    gl.disable(gl.STENCIL_TEST);
    gl.disable(gl.BLEND);
    gl.disable(gl.DITHER);
    gl.disable(gl.POLYGON_OFFSET_FILL);
    gl.disable(gl.SAMPLE_COVERAGE);
    gl.enable(gl.SCISSOR_TEST);
    gl.enable(gl.CULL_FACE);
    gl.cullFace(gl.BACK);
    return contexts[webGLVersion];
}
function createCanvas(webGLVersion) {
    // Use canvas element for Safari, since its offscreen canvas does not support
    // fencing.
    if (!env().getBool('IS_SAFARI') && typeof OffscreenCanvas !== 'undefined' &&
        webGLVersion === 2) {
        return new OffscreenCanvas(300, 150);
    }
    else if (typeof document !== 'undefined') {
        return document.createElement('canvas');
    }
    else {
        throw new Error('Cannot create a canvas in this context');
    }
}
function getWebGLRenderingContext(webGLVersion, customCanvas) {
    if (webGLVersion !== 1 && webGLVersion !== 2) {
        throw new Error('Cannot get WebGL rendering context, WebGL is disabled.');
    }
    const canvas = customCanvas == null ? createCanvas(webGLVersion) : customCanvas;
    canvas.addEventListener('webglcontextlost', (ev) => {
        ev.preventDefault();
        delete contexts[webGLVersion];
    }, false);
    if (env().getBool('SOFTWARE_WEBGL_ENABLED')) {
        WEBGL_ATTRIBUTES.failIfMajorPerformanceCaveat = false;
    }
    if (webGLVersion === 1) {
        return (
        // tslint:disable-next-line
        canvas.getContext('webgl', WEBGL_ATTRIBUTES) ||
            canvas
                .getContext('experimental-webgl', WEBGL_ATTRIBUTES));
    }
    return canvas.getContext('webgl2', WEBGL_ATTRIBUTES);
}
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All Rights Reserved.\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n * =============================================================================\n */\n\nimport {env} from '@tensorflow/tfjs-core';\n\nconst contexts: {[key: string]: WebGLRenderingContext} = {};\n\nconst WEBGL_ATTRIBUTES: WebGLContextAttributes = {\n  alpha: false,\n  antialias: false,\n  premultipliedAlpha: false,\n  preserveDrawingBuffer: false,\n  depth: false,\n  stencil: false,\n  failIfMajorPerformanceCaveat: true\n};\n\nexport function clearWebGLContext(webGLVersion: number) {\n  delete contexts[webGLVersion];\n}\n\nexport function setWebGLContext(\n    webGLVersion: number, gl: WebGLRenderingContext) {\n  contexts[webGLVersion] = gl;\n}\n\nexport function getWebGLContext(\n    webGLVersion: number,\n    customCanvas?: HTMLCanvasElement|OffscreenCanvas): WebGLRenderingContext {\n  if (!(webGLVersion in contexts) || customCanvas != null) {\n    const newCtx = getWebGLRenderingContext(webGLVersion, customCanvas);\n    if (newCtx !== null) {\n      contexts[webGLVersion] = newCtx;\n    } else {\n      console.log('Could not get context for WebGL version', webGLVersion);\n      return null;\n    }\n  }\n  const gl = contexts[webGLVersion];\n  if (gl == null || gl.isContextLost()) {\n    delete contexts[webGLVersion];\n    return getWebGLContext(webGLVersion);\n  }\n\n  gl.disable(gl.DEPTH_TEST);\n  gl.disable(gl.STENCIL_TEST);\n  gl.disable(gl.BLEND);\n  gl.disable(gl.DITHER);\n  gl.disable(gl.POLYGON_OFFSET_FILL);\n  gl.disable(gl.SAMPLE_COVERAGE);\n  gl.enable(gl.SCISSOR_TEST);\n  gl.enable(gl.CULL_FACE);\n  gl.cullFace(gl.BACK);\n\n  return contexts[webGLVersion];\n}\n\nfunction createCanvas(webGLVersion: number) {\n  // Use canvas element for Safari, since its offscreen canvas does not support\n  // fencing.\n  if (!env().getBool('IS_SAFARI') && typeof OffscreenCanvas !== 'undefined' &&\n      webGLVersion === 2) {\n    return new OffscreenCanvas(300, 150);\n  } else if (typeof document !== 'undefined') {\n    return document.createElement('canvas');\n  } else {\n    throw new Error('Cannot create a canvas in this context');\n  }\n}\n\nfunction getWebGLRenderingContext(\n    webGLVersion: number,\n    customCanvas?: HTMLCanvasElement|OffscreenCanvas): WebGLRenderingContext {\n  if (webGLVersion !== 1 && webGLVersion !== 2) {\n    throw new Error('Cannot get WebGL rendering context, WebGL is disabled.');\n  }\n  const canvas =\n      customCanvas == null ? createCanvas(webGLVersion) : customCanvas;\n\n  canvas.addEventListener('webglcontextlost', (ev: Event) => {\n    ev.preventDefault();\n    delete contexts[webGLVersion];\n  }, false);\n\n  if (env().getBool('SOFTWARE_WEBGL_ENABLED')) {\n    WEBGL_ATTRIBUTES.failIfMajorPerformanceCaveat = false;\n  }\n\n  if (webGLVersion === 1) {\n    return (\n        // tslint:disable-next-line\n        canvas.getContext('webgl', WEBGL_ATTRIBUTES) as WebGLRenderingContext ||\n        (canvas as HTMLCanvasElement)\n            .getContext('experimental-webgl',\n                        WEBGL_ATTRIBUTES) as WebGLRenderingContext);\n  }\n  return canvas.getContext('webgl2', WEBGL_ATTRIBUTES) as WebGLRenderingContext;\n}\n"]}