WebGLRenderingContext.getParameter()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

WebGL API 的 WebGLRenderingContext.getParameter() 方法为传入的参数名称返回一个值。

语法

getParameter(pname)

参数

pname: 一个指定要返回哪个参数值的 GLenum。请参阅下文的可能值。

返回值

取决于参数。

参数名称

WebGL 1

使用 WebGLRenderingContext 时，你可以查询以下 pname 参数。

常量	返回类型	描述
`gl.ACTIVE_TEXTURE`	`GLenum`
`gl.ALIASED_LINE_WIDTH_RANGE`	`Float32Array` (with 2 elements)
`gl.ALIASED_POINT_SIZE_RANGE`	`Float32Array` (with 2 elements)
`gl.ALPHA_BITS`	`GLint`
`gl.ARRAY_BUFFER_BINDING`	`WebGLBuffer`
`gl.BLEND`	`GLboolean`
`gl.BLEND_COLOR`	`Float32Array` (with 4 values)
`gl.BLEND_DST_ALPHA`	`GLenum`
`gl.BLEND_DST_RGB`	`GLenum`
`gl.BLEND_EQUATION`	`GLenum`
`gl.BLEND_EQUATION_ALPHA`	`GLenum`
`gl.BLEND_EQUATION_RGB`	`GLenum`
`gl.BLEND_SRC_ALPHA`	`GLenum`
`gl.BLEND_SRC_RGB`	`GLenum`
`gl.BLUE_BITS`	`GLint`
`gl.COLOR_CLEAR_VALUE`	`Float32Array` (with 4 values)
`gl.COLOR_WRITEMASK`	sequence<`GLboolean`> (with 4 values)
`gl.COMPRESSED_TEXTURE_FORMATS`	`Uint32Array`	返回压缩的纹理格式。当使用 `WEBGL_compressed_texture_s3tc` 扩展时： `ext.COMPRESSED_RGB_S3TC_DXT1_EXT` `ext.COMPRESSED_RGBA_S3TC_DXT1_EXT` `ext.COMPRESSED_RGBA_S3TC_DXT3_EXT` `ext.COMPRESSED_RGBA_S3TC_DXT5_EXT` 当使用 `WEBGL_compressed_texture_s3tc_srgb` 扩展时： `ext.COMPRESSED_SRGB_S3TC_DXT1_EXT` `ext.COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT` `ext.COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT` `ext.COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT` 当使用 `WEBGL_compressed_texture_es3` 扩展时： `ext.COMPRESSED_R11_EAC` `ext.COMPRESSED_SIGNED_R11_EAC` `ext.COMPRESSED_RG11_EAC` `ext.COMPRESSED_SIGNED_RG11_EAC` `ext.COMPRESSED_RGB8_ETC2` `ext.COMPRESSED_RGBA8_ETC2_EAC` `ext.COMPRESSED_SRGB8_ETC2` `ext.COMPRESSED_SRGB8_ALPHA8_ETC2_EAC` `ext.COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2` `ext.COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2` 当使用 `WEBGL_compressed_texture_pvrtc` 扩展时： `ext.COMPRESSED_RGB_PVRTC_4BPPV1_IMG` `ext.COMPRESSED_RGBA_PVRTC_4BPPV1_IMG` `ext.COMPRESSED_RGB_PVRTC_2BPPV1_IMG` `ext.COMPRESSED_RGBA_PVRTC_2BPPV1_IMG` 当使用 `WEBGL_compressed_texture_etc1` 扩展时： `ext.COMPRESSED_RGB_ETC1_WEBGL` 当使用 `WEBGL_compressed_texture_atc` 扩展时： `ext.COMPRESSED_RGB_ATC_WEBGL` `ext.COMPRESSED_RGBA_ATC_EXPLICIT_ALPHA_WEBGL` `ext.COMPRESSED_RGBA_ATC_INTERPOLATED_ALPHA_WEBGL` 当使用 `WEBGL_compressed_texture_astc` 扩展时： `ext.COMPRESSED_RGBA_ASTC_4x4_KHR ext.COMPRESSED_SRGB8_ALPHA8_ASTC_4x4_KHR` `ext.COMPRESSED_RGBA_ASTC_5x4_KHR ext.COMPRESSED_SRGB8_ALPHA8_ASTC_5x4_KHR` `ext.COMPRESSED_RGBA_ASTC_5x5_KHR ext.COMPRESSED_SRGB8_ALPHA8_ASTC_5x5_KHR` `ext.COMPRESSED_RGBA_ASTC_6x5_KHR ext.COMPRESSED_SRGB8_ALPHA8_ASTC_6x5_KHR` `ext.COMPRESSED_RGBA_ASTC_6x6_KHR ext.COMPRESSED_SRGB8_ALPHA8_ASTC_6x6_KHR` `ext.COMPRESSED_RGBA_ASTC_8x5_KHR ext.COMPRESSED_SRGB8_ALPHA8_ASTC_8x5_KHR` `ext.COMPRESSED_RGBA_ASTC_8x6_KHR ext.COMPRESSED_SRGB8_ALPHA8_ASTC_8x6_KHR` `ext.COMPRESSED_RGBA_ASTC_8x8_KHR ext.COMPRESSED_SRGB8_ALPHA8_ASTC_8x8_KHR` `ext.COMPRESSED_RGBA_ASTC_10x5_KHR ext.COMPRESSED_SRGB8_ALPHA8_ASTC_10x5_KHR` `ext.COMPRESSED_RGBA_ASTC_10x6_KHR ext.COMPRESSED_SRGB8_ALPHA8_ASTC_10x6_KHR` `ext.COMPRESSED_RGBA_ASTC_10x6_KHR ext.COMPRESSED_SRGB8_ALPHA8_ASTC_10x6_KHR` `ext.COMPRESSED_RGBA_ASTC_10x10_KHR ext.COMPRESSED_SRGB8_ALPHA8_ASTC_10x10_KHR` `ext.COMPRESSED_RGBA_ASTC_12x10_KHR ext.COMPRESSED_SRGB8_ALPHA8_ASTC_12x10_KHR` `ext.COMPRESSED_RGBA_ASTC_12x12_KHR ext.COMPRESSED_SRGB8_ALPHA8_ASTC_12x12_KHR`
`gl.CULL_FACE`	`GLboolean`
`gl.CULL_FACE_MODE`	`GLenum`
`gl.CURRENT_PROGRAM`	`WebGLProgram`
`gl.DEPTH_BITS`	`GLint`
`gl.DEPTH_CLEAR_VALUE`	`GLfloat`
`gl.DEPTH_FUNC`	`GLenum`
`gl.DEPTH_RANGE`	`Float32Array` (with 2 elements)
`gl.DEPTH_TEST`	`GLboolean`
`gl.DEPTH_WRITEMASK`	`GLboolean`
`gl.DITHER`	`GLboolean`
`gl.ELEMENT_ARRAY_BUFFER_BINDING`	`WebGLBuffer`
`gl.FRAMEBUFFER_BINDING`	`WebGLFramebuffer`
`gl.FRONT_FACE`	`GLenum`
`gl.GENERATE_MIPMAP_HINT`	`GLenum`
`gl.GREEN_BITS`	`GLint`
`gl.IMPLEMENTATION_COLOR_READ_FORMAT`	`GLenum`
`gl.IMPLEMENTATION_COLOR_READ_TYPE`	`GLenum`
`gl.LINE_WIDTH`	`GLfloat`
`gl.MAX_COMBINED_TEXTURE_IMAGE_UNITS`	`GLint`
`gl.MAX_CUBE_MAP_TEXTURE_SIZE`	`GLint`
`gl.MAX_FRAGMENT_UNIFORM_VECTORS`	`GLint`
`gl.MAX_RENDERBUFFER_SIZE`	`GLint`
`gl.MAX_TEXTURE_IMAGE_UNITS`	`GLint`
`gl.MAX_TEXTURE_SIZE`	`GLint`
`gl.MAX_VARYING_VECTORS`	`GLint`
`gl.MAX_VERTEX_ATTRIBS`	`GLint`
`gl.MAX_VERTEX_TEXTURE_IMAGE_UNITS`	`GLint`
`gl.MAX_VERTEX_UNIFORM_VECTORS`	`GLint`
`gl.MAX_VIEWPORT_DIMS`	`Int32Array` (with 2 elements)
`gl.PACK_ALIGNMENT`	`GLint`
`gl.POLYGON_OFFSET_FACTOR`	`GLfloat`
`gl.POLYGON_OFFSET_FILL`	`GLboolean`
`gl.POLYGON_OFFSET_UNITS`	`GLfloat`
`gl.RED_BITS`	`GLint`
`gl.RENDERBUFFER_BINDING`	`WebGLRenderbuffer`
`gl.RENDERER`	`DOMString`
`gl.SAMPLE_BUFFERS`	`GLint`
`gl.SAMPLE_COVERAGE_INVERT`	`GLboolean`
`gl.SAMPLE_COVERAGE_VALUE`	`GLfloat`
`gl.SAMPLES`	`GLint`
`gl.SCISSOR_BOX`	`Int32Array` (with 4 elements)
`gl.SCISSOR_TEST`	`GLboolean`
`gl.SHADING_LANGUAGE_VERSION`	`DOMString`
`gl.STENCIL_BACK_FAIL`	`GLenum`
`gl.STENCIL_BACK_FUNC`	`GLenum`
`gl.STENCIL_BACK_PASS_DEPTH_FAIL`	`GLenum`
`gl.STENCIL_BACK_PASS_DEPTH_PASS`	`GLenum`
`gl.STENCIL_BACK_REF`	`GLint`
`gl.STENCIL_BACK_VALUE_MASK`	`GLuint`
`gl.STENCIL_BACK_WRITEMASK`	`GLuint`
`gl.STENCIL_BITS`	`GLint`
`gl.STENCIL_CLEAR_VALUE`	`GLint`
`gl.STENCIL_FAIL`	`GLenum`
`gl.STENCIL_FUNC`	`GLenum`
`gl.STENCIL_PASS_DEPTH_FAIL`	`GLenum`
`gl.STENCIL_PASS_DEPTH_PASS`	`GLenum`
`gl.STENCIL_REF`	`GLint`
`gl.STENCIL_TEST`	`GLboolean`
`gl.STENCIL_VALUE_MASK`	`GLuint`
`gl.STENCIL_WRITEMASK`	`GLuint`
`gl.SUBPIXEL_BITS`	`GLint`
`gl.TEXTURE_BINDING_2D`	`WebGLTexture`
`gl.TEXTURE_BINDING_CUBE_MAP`	`WebGLTexture`
`gl.UNPACK_ALIGNMENT`	`GLint`
`gl.UNPACK_COLORSPACE_CONVERSION_WEBGL`	`GLenum`
`gl.UNPACK_FLIP_Y_WEBGL`	`GLboolean`
`gl.UNPACK_PREMULTIPLY_ALPHA_WEBGL`	`GLboolean`
`gl.VENDOR`	`DOMString`
`gl.VERSION`	`DOMString`
`gl.VIEWPORT`	`Int32Array` (with 4 elements)

WebGL 2

使用 WebGL2RenderingContext 时，你可以查询以下 pname 参数。

常量	返回类型	描述
`gl.COPY_READ_BUFFER_BINDING`	`WebGLBuffer`
`gl.COPY_WRITE_BUFFER_BINDING`	`WebGLBuffer`
`gl.DRAW_BUFFERi`	`GLenum`
`gl.DRAW_FRAMEBUFFER_BINDING`	`WebGLFramebuffer`
`gl.FRAGMENT_SHADER_DERIVATIVE_HINT`	`GLenum`
`gl.MAX_3D_TEXTURE_SIZE`	`GLint`
`gl.MAX_ARRAY_TEXTURE_LAYERS`	`GLint`
`gl.MAX_CLIENT_WAIT_TIMEOUT_WEBGL`	`GLint64`
`gl.MAX_COLOR_ATTACHMENTS`	`GLint`
`gl.MAX_COMBINED_FRAGMENT_UNIFORM_COMPONENTS`	`GLint64`
`gl.MAX_COMBINED_UNIFORM_BLOCKS`	`GLint`
`gl.MAX_COMBINED_VERTEX_UNIFORM_COMPONENTS`	`GLint64`
`gl.MAX_DRAW_BUFFERS`	`GLint`
`gl.MAX_ELEMENT_INDEX`	`GLint64`
`gl.MAX_ELEMENTS_INDICES`	`GLint`
`gl.MAX_ELEMENTS_VERTICES`	`GLint`
`gl.MAX_FRAGMENT_INPUT_COMPONENTS`	`GLint`
`gl.MAX_FRAGMENT_UNIFORM_BLOCKS`	`GLint`
`gl.MAX_FRAGMENT_UNIFORM_COMPONENTS`	`GLint`
`gl.MAX_PROGRAM_TEXEL_OFFSET`	`GLint`
`gl.MAX_SAMPLES`	`GLint`
`gl.MAX_SERVER_WAIT_TIMEOUT`	`GLint64`
`gl.MAX_TEXTURE_LOD_BIAS`	`GLfloat`
`gl.MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS`	`GLint`
`gl.MAX_TRANSFORM_FEEDBACK_SEPARATE_ATTRIBS`	`GLint`
`gl.MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS`	`GLint`
`gl.MAX_UNIFORM_BLOCK_SIZE`	`GLint64`
`gl.MAX_UNIFORM_BUFFER_BINDINGS`	`GLint`
`gl.MAX_VARYING_COMPONENTS`	`GLint`
`gl.MAX_VERTEX_OUTPUT_COMPONENTS`	`GLint`
`gl.MAX_VERTEX_UNIFORM_BLOCKS`	`GLint`
`gl.MAX_VERTEX_UNIFORM_COMPONENTS`	`GLint`
`gl.MIN_PROGRAM_TEXEL_OFFSET`	`GLint`
`gl.PACK_ROW_LENGTH`	`GLint`
`gl.PACK_SKIP_PIXELS`	`GLint`
`gl.PACK_SKIP_ROWS`	`GLint`
`gl.PIXEL_PACK_BUFFER_BINDING`	`WebGLBuffer`
`gl.PIXEL_UNPACK_BUFFER_BINDING`	`WebGLBuffer`
`gl.RASTERIZER_DISCARD`	`GLboolean`
`gl.READ_BUFFER`	`GLenum`
`gl.READ_FRAMEBUFFER_BINDING`	`WebGLFramebuffer`
`gl.SAMPLE_ALPHA_TO_COVERAGE`	`GLboolean`
`gl.SAMPLE_COVERAGE`	`GLboolean`
`gl.SAMPLER_BINDING`	`WebGLSampler`
`gl.TEXTURE_BINDING_2D_ARRAY`	`WebGLTexture`
`gl.TEXTURE_BINDING_3D`	`WebGLTexture`
`gl.TRANSFORM_FEEDBACK_ACTIVE`	`GLboolean`
`gl.TRANSFORM_FEEDBACK_BINDING`	`WebGLTransformFeedback`
`gl.TRANSFORM_FEEDBACK_BUFFER_BINDING`	`WebGLBuffer`
`gl.TRANSFORM_FEEDBACK_PAUSED`	`GLboolean`
`gl.UNIFORM_BUFFER_BINDING`	`WebGLBuffer`
`gl.UNIFORM_BUFFER_OFFSET_ALIGNMENT`	`GLint`
`gl.UNPACK_IMAGE_HEIGHT`	`GLint`
`gl.UNPACK_ROW_LENGTH`	`GLint`
`gl.UNPACK_SKIP_IMAGES`	`GLint`
`gl.UNPACK_SKIP_PIXELS`	`GLint`
`gl.UNPACK_SKIP_ROWS`	`GLint`
`gl.VERTEX_ARRAY_BINDING`	`WebGLVertexArrayObject`

WebGL 扩展

当使用 WebGL 扩展时，你可以查询以下 pname 参数：

常量	返回类型	扩展	描述
`ext.MAX_TEXTURE_MAX_ANISOTROPY_EXT`	`GLfloat`	`EXT_texture_filter_anisotropic`	最大可用各向异性。
`ext.FRAGMENT_SHADER_DERIVATIVE_HINT_OES`	`GLenum`	`OES_standard_derivatives`	GLSL 内置函数的导数计算精度：`dFdx`、 `dFdy` 和 `fwidth`。
`ext.MAX_COLOR_ATTACHMENTS_WEBGL`	`GLint`	`WEBGL_draw_buffers`	帧缓冲区颜色附着点的最大数量。
`ext.MAX_DRAW_BUFFERS_WEBGL`	`GLint`	`WEBGL_draw_buffers`	绘图缓冲区的最大数量。
`ext.DRAW_BUFFER0_WEBGL ext.DRAW_BUFFER1_WEBGL ext.DRAW_BUFFER2_WEBGL ext.DRAW_BUFFER3_WEBGL ext.DRAW_BUFFER4_WEBGL ext.DRAW_BUFFER5_WEBGL ext.DRAW_BUFFER6_WEBGL ext.DRAW_BUFFER7_WEBGL ext.DRAW_BUFFER8_WEBGL ext.DRAW_BUFFER9_WEBGL ext.DRAW_BUFFER10_WEBGL ext.DRAW_BUFFER11_WEBGL ext.DRAW_BUFFER12_WEBGL ext.DRAW_BUFFER13_WEBGL ext.DRAW_BUFFER14_WEBGL ext.DRAW_BUFFER15_WEBGL`	`GLenum`	`WEBGL_draw_buffers`	绘图缓冲区。
`ext.VERTEX_ARRAY_BINDING_OES`	`WebGLVertexArrayObjectOES`	`OES_vertex_array_object`	绑定的顶点数组对象（VAO）。
`ext.TIMESTAMP_EXT`	`GLuint64EXT`	`EXT_disjoint_timer_query`	当前时间。
`ext.GPU_DISJOINT_EXT`	`GLboolean`	`EXT_disjoint_timer_query`	返回 GPU 是否执行了任何不相交的操作。

示例

gl.getParameter(gl.DITHER);
gl.getParameter(gl.VERSION);
gl.getParameter(gl.VIEWPORT);

规范

Specification
WebGL Specification # 5.14.3
WebGL 2.0 Specification # 3.7.2

浏览器兼容性

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