three-stdlib/misc/WebGL.js

stand-alone library of threejs examples

let webGLAvailable, webGL2Available;
function isWebGLAvailable() {
  var _a;
  if (webGLAvailable !== void 0)
    return webGLAvailable;
  try {
    let gl;
    const canvas = document.createElement("canvas");
    webGLAvailable = !!(window.WebGLRenderingContext && (gl = canvas.getContext("webgl")));
    if (gl)
      (_a = gl.getExtension("WEBGL_lose_context")) == null ? void 0 : _a.loseContext();
    return webGLAvailable;
  } catch (e) {
    return webGLAvailable = false;
  }
}
function isWebGL2Available() {
  var _a;
  if (webGL2Available !== void 0)
    return webGL2Available;
  try {
    let gl;
    const canvas = document.createElement("canvas");
    webGL2Available = !!(window.WebGL2RenderingContext && (gl = canvas.getContext("webgl2")));
    if (gl)
      (_a = gl.getExtension("WEBGL_lose_context")) == null ? void 0 : _a.loseContext();
    return webGL2Available;
  } catch (e) {
    return webGL2Available = false;
  }
}
function getWebGLErrorMessage() {
  return getErrorMessage(1);
}
function getWebGL2ErrorMessage() {
  return getErrorMessage(2);
}
function getErrorMessage(version) {
  const names = {
    1: "WebGL",
    2: "WebGL 2"
  };
  const contexts = {
    1: window.WebGLRenderingContext,
    2: window.WebGL2RenderingContext
  };
  const element = document.createElement("div");
  element.id = "webglmessage";
  element.style.fontFamily = "monospace";
  element.style.fontSize = "13px";
  element.style.fontWeight = "normal";
  element.style.textAlign = "center";
  element.style.background = "#fff";
  element.style.color = "#000";
  element.style.padding = "1.5em";
  element.style.width = "400px";
  element.style.margin = "5em auto 0";
  let message = 'Your $0 does not seem to support <a href="http://khronos.org/webgl/wiki/Getting_a_WebGL_Implementation" style="color:#000">$1</a>';
  if (contexts[version]) {
    message = message.replace("$0", "graphics card");
  } else {
    message = message.replace("$0", "browser");
  }
  message = message.replace("$1", names[version]);
  element.innerHTML = message;
  return element;
}
export {
  getErrorMessage,
  getWebGL2ErrorMessage,
  getWebGLErrorMessage,
  isWebGL2Available,
  isWebGLAvailable
};
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