WebGL2RenderingContext

在本文章中

常量
状态信息
缓冲区
帧缓冲区
渲染缓冲区
纹理
程序和着色器
Uniforms 和 Attributes
绘图缓冲区
查询对象
采样对象
同步对象
变换反馈
Uniform 缓冲对象
顶点数组对象
规范
浏览器兼容性
另请参见

这是一个实验中的功能
此功能某些浏览器尚在开发中，请参考浏览器兼容性表格以得到在不同浏览器中适合使用的前缀。由于该功能对应的标准文档可能被重新修订，所以在未来版本的浏览器中该功能的语法和行为可能随之改变。

WebGL2RenderingContext 接口在底层使用了OpenGL ES 3.0 为 HTML 的 <canvas> 元素提供了绘图上下文。

要获取该接口的实例对象需要调用一个 <canvas> 标签对象的 getContext() 函数，并将 "webgl2" 作为参数传递：

var canvas = document.getElementById('myCanvas');
var gl = canvas.getContext('webgl2');

WebGL 2 是 WebGL 1 的扩展。 WebGL2RenderingContext 接口实现了 WebGLRenderingContext 接口的所有成员。有一些 WebGL 1 上下文中的方法在使用 WebGL 2 上下文的时候可以接受附加值。您可以通过 WebGL 1 的参考页了解这些信息。

这个 WebGL 教程中提供了关于如何开始使用 WebGL 的更多信息、示例以及资源。

常量

请看 WebGL 常量页面。

状态信息

WebGL2RenderingContext.getIndexedParameter(): 返回指定目标的索引值。

缓冲区

WebGL2RenderingContext.copyBufferSubData(): 将缓冲区的部分数据复制到另一个缓冲区。
WebGL2RenderingContext.getBufferSubData(): 从缓冲区中读取数据，然后将其写入到 ArrayBuffer 或 SharedArrayBuffer 中。

帧缓冲区

WebGL2RenderingContext.blitFramebuffer(): 将一个像素块从读取帧缓区冲传输到绘制帧缓冲区。
WebGL2RenderingContext.framebufferTextureLayer(): Attaches a single layer of a texture to a framebuffer.
WebGL2RenderingContext.invalidateFramebuffer(): Invalidates the contents of attachments in a framebuffer.
WebGL2RenderingContext.invalidateSubFramebuffer(): Invalidates portions of the contents of attachments in a framebuffer
WebGL2RenderingContext.readBuffer(): Selects a color buffer as the source for pixels.

渲染缓冲区

WebGL2RenderingContext.getInternalformatParameter(): Returns information about implementation-dependent support for internal formats.
WebGL2RenderingContext.renderbufferStorageMultisample(): Creates and initializes a renderbuffer object's data store and allows specifying the number of samples to be used.

纹理

WebGL2RenderingContext.texStorage2D(): Specifies all levels of two-dimensional texture storage.
WebGL2RenderingContext.texStorage3D(): Specifies all levels of a three-dimensional texture or two-dimensional array texture.
WebGL2RenderingContext.texImage3D(): Specifies a three-dimensional texture image.
WebGL2RenderingContext.texSubImage3D(): Specifies a sub-rectangle of the current 3D texture.
WebGL2RenderingContext.copyTexSubImage3D(): Copies pixels from the current WebGLFramebuffer into an existing 3D texture sub-image.
WebGL2RenderingContext.compressedTexImage3D(): Specifies a three-dimensional texture image in a compressed format.
WebGL2RenderingContext.compressedTexSubImage3D(): Specifies a three-dimensional sub-rectangle for a texture image in a compressed format.

程序和着色器

WebGL2RenderingContext.getFragDataLocation(): Returns the binding of color numbers to user-defined varying out variables.

Uniforms 和 Attributes

WebGL2RenderingContext.uniform[1234][fiu][v](): Methods specifying values of uniform variables.
WebGL2RenderingContext.uniformMatrix[1234][fv](): Methods specifying matrix values for uniform variables.
WebGL2RenderingContext.vertexAttribI[iuv](): Methods specifying integer values for generic vertex attributes.
WebGL2RenderingContext.vertexAttribIPointer(): Specifies integer data formats and locations of vertex attributes in a vertex attributes array.

绘图缓冲区

WebGL2RenderingContext.vertexAttribDivisor(): Modifies the rate at which generic vertex attributes advance when rendering multiple instances of primitives with gl.drawArraysInstanced() and gl.drawElementsInstanced().
WebGL2RenderingContext.drawArraysInstanced(): Renders primitives from array data. In addition, it can execute multiple instances of the range of elements.
WebGL2RenderingContext.drawElementsInstanced(): Renders primitives from array data. In addition, it can execute multiple instances of a set of elements.
WebGL2RenderingContext.drawRangeElements(): Renders primitives from array data in a given range.
WebGL2RenderingContext.drawBuffers(): Specifies a list of color buffers to be drawn into.
WebGL2RenderingContext.clearBuffer[fiuv](): Clears buffers from the currently bound framebuffer.

查询对象

Methods for working with WebGLQuery objects.

WebGL2RenderingContext.createQuery(): Creates a new WebGLQuery object.
WebGL2RenderingContext.deleteQuery(): Deletes a given WebGLQuery object.
WebGL2RenderingContext.isQuery(): Returns true if a given object is a valid WebGLQuery object.
WebGL2RenderingContext.beginQuery(): Begins an asynchronous query.
WebGL2RenderingContext.endQuery(): Marks the end of an asynchronous query.
WebGL2RenderingContext.getQuery(): Returns a WebGLQuery object for a given target.
WebGL2RenderingContext.getQueryParameter(): Returns information about a query.

采样对象

WebGL2RenderingContext.createSampler(): Creates a new WebGLSampler object.
WebGL2RenderingContext.deleteSampler(): Deletes a given WebGLSampler object.
WebGL2RenderingContext.bindSampler(): Binds a given WebGLSampler to a texture unit.
WebGL2RenderingContext.isSampler(): Returns true if a given object is a valid WebGLSampler object.
WebGL2RenderingContext.samplerParameter[if](): Sets sampler parameters.
WebGL2RenderingContext.getSamplerParameter(): Returns sampler parameter information.

同步对象

WebGL2RenderingContext.fenceSync(): Creates a new WebGLSync object and inserts it into the GL command stream.
WebGL2RenderingContext.isSync(): Returns true if the passed object is a valid WebGLSync object.
WebGL2RenderingContext.deleteSync(): Deletes a given WebGLSync object.
WebGL2RenderingContext.clientWaitSync(): Blocks and waits for a WebGLSync object to become signaled or a given timeout to be passed.
WebGL2RenderingContext.waitSync(): Returns immediately, but waits on the GL server until the given WebGLSync object is signaled.
WebGL2RenderingContext.getSyncParameter(): Returns parameter information of a WebGLSync object.

变换反馈

WebGL2RenderingContext.createTransformFeedback(): Creates and initializes WebGLTransformFeedback objects.
WebGL2RenderingContext.deleteTransformFeedback(): Deletes a given WebGLTransformFeedback object.
WebGL2RenderingContext.isTransformFeedback(): Returns true if the passed object is a valid WebGLTransformFeedback object.
WebGL2RenderingContext.bindTransformFeedback(): Binds a passed WebGLTransformFeedback object to the current GL state.
WebGL2RenderingContext.beginTransformFeedback(): Starts a transform feedback operation.
WebGL2RenderingContext.endTransformFeedback(): Ends a transform feedback operation.
WebGL2RenderingContext.transformFeedbackVaryings(): Specifies values to record in WebGLTransformFeedback buffers.
WebGL2RenderingContext.getTransformFeedbackVarying(): Returns information about varying variables from WebGLTransformFeedback buffers.
WebGL2RenderingContext.pauseTransformFeedback(): Pauses a transform feedback operation.
WebGL2RenderingContext.resumeTransformFeedback(): Resumes a transform feedback operation.

Uniform 缓冲对象

WebGL2RenderingContext.bindBufferBase(): Binds a given WebGLBuffer to a given binding point (target) at a given index.
WebGL2RenderingContext.bindBufferRange(): Binds a range of a given WebGLBuffer to a given binding point (target) at a given index.
WebGL2RenderingContext.getUniformIndices(): Retrieves the indices of a number of uniforms within a WebGLProgram.
WebGL2RenderingContext.getActiveUniforms(): Retrieves information about active uniforms within a WebGLProgram.
WebGL2RenderingContext.getUniformBlockIndex(): Retrieves the index of a uniform block within a WebGLProgram.
WebGL2RenderingContext.getActiveUniformBlockParameter(): Retrieves information about an active uniform block within a WebGLProgram.
WebGL2RenderingContext.getActiveUniformBlockName(): Retrieves the name of the active uniform block at a given index within a WebGLProgram.
WebGL2RenderingContext.uniformBlockBinding(): Assigns binding points for active uniform blocks.

顶点数组对象

Methods for working with WebGLVertexArrayObject (VAO) objects.

WebGL2RenderingContext.createVertexArray(): Creates a new WebGLVertexArrayObject.
WebGL2RenderingContext.deleteVertexArray(): Deletes a given WebGLVertexArrayObject.
WebGL2RenderingContext.isVertexArray(): Returns true if a given object is a valid WebGLVertexArrayObject.
WebGL2RenderingContext.bindVertexArray(): Binds a given WebGLVertexArrayObject to the buffer.

规范

Specification	Status	Comment
WebGL 2.0 WebGL2RenderingContext	Editor's Draft	Initial definition.

Feature	Chrome	Firefox (Gecko)	Internet Explorer	Opera	Safari
Basic support	未实现 [2]	Nightly build [1]	未实现	未实现	未实现

Feature	Android	Chrome for Android	Firefox Mobile (Gecko)	IE Mobile	Opera Mobile	Safari Mobile
Basic support	未实现	未实现	未实现	未实现	未实现	未实现

[1] WebGL 2 is enabled by default in Firefox Nightly. To enable it in a release version of Firefox, set the preference webgl.enable-prototype-webgl2 to true in about:config.

[2] To use an experimental implementation of WebGL 2 in Chrome, you have to start Chrome with the runtime flag --enable-unsafe-es3-apis.

另请参见

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