在此页

• 句法
• 用法注意事项
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

WebGLRenderingContext.isContextLost() 方法返回 布尔 indicating whether or not the WebGL context has been lost and must be re-established before rendering can resume.

句法

let isLost = gl.isContextLost();
					

返回值

A 布尔 which is true if the context is lost, or false 若不。

用法注意事项

There are several reasons why a WebGL context may be lost, making it necessary to re-establish the context before resuming rendering. Examples include:

• Two or more pages are using the GPU, but together place too high a demand on the GPU, so the browser tells the two contexts that they've lost the connection, then selects one of the two to restore access for.
• The user's computer has multiple graphics processors (such as a laptop with both mobile and desktop class GPUs, the former used primarily when on battery power), and the user or system decides to switch GPUs. In this case, all contexts are lost, then restored after switching GPUs.
• Another page running in the user's browser performs an operation using the GPU that takes too long, causing hte browser to decide to reset the GPU in order to break the stall. This would cause every WebGL context to be lost throughout the entire browser.
• The user updates their graphics driver on an operating system that allows graphics drivers to be updated without restarting the system.

范例

For example, when checking for program linking success, you could also check if the context is not lost:

gl.linkProgram(program);
if (!gl.getProgramParameter(program, gl.LINK_STATUS) && !gl.isContextLost()) {
  var info = gl.getProgramInfoLog(program);
  console.log('Error linking program:\n' + info);
}
					

规范

规范	状态	注释
WebGL 1.0 The definition of 'WebGLRenderingContext.isContextLost' in that specification.	推荐	初始定义。

浏览器兼容性

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
isContextLost	Chrome 9	Edge 12	Firefox 4	IE 11	Opera 12	Safari 5.1	WebView Android Yes	Chrome Android 25	Firefox Android Yes	Opera Android 12	Safari iOS 8	Samsung Internet Android 1.5

图例

完整支持

完整支持

另请参阅

• WebGLContextEvent signals changes in the context state.
• Handling lost context in WebGL : Khronos WebGL wiki

元数据

• 最后修改： Dec 13, 2019

相关话题

1. WebGL API
2. WebGLRenderingContext
3. 特性

   1. canvas
   2. drawingBufferHeight
   3. drawingBufferWidth
4. 方法

   1. activeTexture()
   2. attachShader()
   3. bindAttribLocation()
   4. bindBuffer()
   5. bindFramebuffer()
   6. bindRenderbuffer()
   7. bindTexture()
   8. blendColor()
   9. blendEquation()
   10. blendEquationSeparate()
   11. blendFunc()
   12. blendFuncSeparate()
   13. bufferData()
   14. bufferSubData()
   15. checkFramebufferStatus()
   16. clear()
   17. clearColor()
   18. clearDepth()
   19. clearStencil()
   20. colorMask()
   21. commit()
   22. compileShader()
   23. compressedTexImage[23]D()
   24. compressedTexSubImage2D()
   25. copyTexImage2D()
   26. copyTexSubImage2D()
   27. createBuffer()
   28. createFramebuffer()
   29. createProgram()
   30. createRenderbuffer()
   31. createShader()
   32. createTexture()
   33. cullFace()
   34. deleteBuffer()
   35. deleteFramebuffer()
   36. deleteProgram()
   37. deleteRenderbuffer()
   38. deleteShader()
   39. deleteTexture()
   40. depthFunc()
   41. depthMask()
   42. depthRange()
   43. detachShader()
   44. disable()
   45. disableVertexAttribArray()
   46. drawArrays()
   47. drawElements()
   48. enable()
   49. enableVertexAttribArray()
   50. finish()
   51. flush()
   52. framebufferRenderbuffer()
   53. framebufferTexture2D()
   54. frontFace()
   55. generateMipmap()
   56. getActiveAttrib()
   57. getActiveUniform()
   58. getAttachedShaders()
   59. getAttribLocation()
   60. getBufferParameter()
   61. getContextAttributes()
   62. getError()
   63. getExtension()
   64. getFramebufferAttachmentParameter()
   65. getParameter()
   66. getProgramInfoLog()
   67. getProgramParameter()
   68. getRenderbufferParameter()
   69. getShaderInfoLog()
   70. getShaderParameter()
   71. getShaderPrecisionFormat()
   72. getShaderSource()
   73. getSupportedExtensions()
   74. getTexParameter()
   75. getUniform()
   76. getUniformLocation()
   77. getVertexAttrib()
   78. getVertexAttribOffset()
   79. hint()
   80. isBuffer()
   81. isContextLost()
   82. isEnabled()
   83. isFramebuffer()
   84. isProgram()
   85. isRenderbuffer()
   86. isShader()
   87. isTexture()
   88. lineWidth()
   89. linkProgram()
   90. pixelStorei()
   91. polygonOffset()
   92. readPixels()
   93. renderbufferStorage()
   94. sampleCoverage()
   95. scissor()
   96. shaderSource()
   97. stencilFunc()
   98. stencilFuncSeparate()
   99. stencilMask()
   100. stencilMaskSeparate()
   101. stencilOp()
   102. stencilOpSeparate()
   103. texImage2D()
   104. texParameter[fi]()
   105. texSubImage2D()
   106. uniform[1234][fi][v]()
   107. uniformMatrix[234]fv()
   108. useProgram()
   109. validateProgram()
   110. vertexAttrib[1234]f[v]()
   111. vertexAttribPointer()
   112. viewport()
5. WebGL 相关页面

   1. ANGLE_instanced_arrays
   2. EXT_blend_minmax
   3. EXT_color_buffer_half_float
   4. EXT_disjoint_timer_query
   5. EXT_frag_depth
   6. EXT_sRGB
   7. EXT_shader_texture_lod
   8. EXT_texture_filter_anisotropic
   9. OES_element_index_uint
   10. OES_standard_derivatives
   11. OES_texture_float
   12. OES_texture_float_linear
   13. OES_texture_half_float
   14. OES_texture_half_float_linear
   15. OES_vertex_array_object
   16. WEBGL_color_buffer_float
   17. WEBGL_compressed_texture_atc
   18. WEBGL_compressed_texture_etc1
   19. WEBGL_compressed_texture_pvrtc
   20. WEBGL_compressed_texture_s3tc
   21. WEBGL_compressed_texture_s3tc_srgb
   22. WEBGL_debug_renderer_info
   23. WEBGL_debug_shaders
   24. WEBGL_depth_texture
   25. WEBGL_draw_buffers
   26. WEBGL_lose_context
   27. WebGL2RenderingContext
   28. WebGLActiveInfo
   29. WebGLBuffer
   30. WebGLContextEvent
   31. WebGLFramebuffer
   32. WebGLObject
   33. WebGLProgram
   34. WebGLQuery
   35. WebGLRenderbuffer
   36. WebGLSampler
   37. WebGLShader
   38. WebGLShaderPrecisionFormat
   39. WebGLSync
   40. WebGLTexture
   41. WebGLTransformFeedback
   42. WebGLUniformLocation
   43. WebGLVertexArrayObject