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WebGLRenderingContext.getParameter()

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The WebGLRenderingContext.getParameter() method of the WebGL API returns a value for the passed parameter name.

Syntax

any gl.getParameter(pname);

Parameters

pname: A GLenum specifying which parameter value to return. See below for possible values.

Return value

Depends on the parameter.

Parameter names

WebGL 1

You can query the following pname parameters when using a WebGLRenderingContext.

Constant	Returned type	Description
`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`	Returns the compressed texture formats. When using the `WEBGL_compressed_texture_s3tc` extension: `ext.COMPRESSED_RGB_S3TC_DXT1_EXT` `ext.COMPRESSED_RGBA_S3TC_DXT1_EXT` `ext.COMPRESSED_RGBA_S3TC_DXT3_EXT` `ext.COMPRESSED_RGBA_S3TC_DXT5_EXT` When using the `WEBGL_compressed_texture_es3` extension: `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` When using the `WEBGL_compressed_texture_pvrtc` extension: `ext.COMPRESSED_RGB_PVRTC_4BPPV1_IMG` `ext.COMPRESSED_RGBA_PVRTC_4BPPV1_IMG` `ext.COMPRESSED_RGB_PVRTC_2BPPV1_IMG` `ext.COMPRESSED_RGBA_PVRTC_2BPPV1_IMG` When using the `WEBGL_compressed_texture_etc1` extension: `ext.COMPRESSED_RGB_ETC1_WEBGL` When using the `WEBGL_compressed_texture_atc` extension: `ext.COMPRESSED_RGB_ATC_WEBGL` `ext.COMPRESSED_RGBA_ATC_EXPLICIT_ALPHA_WEBGL` `ext.COMPRESSED_RGBA_ATC_INTERPOLATED_ALPHA_WEBGL`
`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

You can query the following pname parameters when using a WebGL2RenderingContext.

Constant	Returned type	Description
`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 extensions

You can query the following pname parameters when using WebGL extensions:

Constant	Returned type	Extension	Description
`ext.MAX_TEXTURE_MAX_ANISOTROPY_EXT`	`GLfloat`	`EXT_texture_filter_anisotropic`	Maximum available anisotropy.
`ext.FRAGMENT_SHADER_DERIVATIVE_HINT_OES`	`GLenum`	`OES_standard_derivatives`	Accuracy of the derivative calculation for the GLSL built-in functions: `dFdx`, `dFdy`, and `fwidth`.
`ext.MAX_COLOR_ATTACHMENTS_WEBGL`	`GLint`	`WEBGL_draw_buffers`	The maximum number of framebuffer color attachment points.
`ext.MAX_DRAW_BUFFERS_WEBGL`	`GLint`	`WEBGL_draw_buffers`	The maximum number of draw buffers.
`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`	Drawing buffers.
`ext.VERTEX_ARRAY_BINDING_OES`	`WebGLVertexArrayObjectOES`	`OES_vertex_array_object`	Bound vertex array object (VAO).
`ext.TIMESTAMP_EXT`	`GLuint64EXT`	`EXT_disjoint_timer_query`	The current time.
`ext.GPU_DISJOINT_EXT`	`GLboolean`	`EXT_disjoint_timer_query`	Returns whether or not the GPU performed any disjoint operation.

Examples

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

Specifications

Specification	Status	Comment
WebGL 1.0 The definition of 'getParameter' in that specification.	Recommendation	Initial definition.
WebGL 2.0 The definition of 'getParameter' in that specification.	Editor's Draft	Adds additional parameter names.
OpenGL ES 2.0 The definition of 'glGet' in that specification.	Standard	Man page of the (similar) OpenGL API.

Feature	Chrome	Firefox (Gecko)	Internet Explorer	Opera	Safari
Basic support	9	4.0 (2.0)	11	12	5.1

Feature	Android	Chrome for Android	Firefox Mobile (Gecko)	IE Mobile	Opera Mobile	Safari Mobile
Basic support	?	25	(Yes)	?	12	8.1

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此页面的贡献者： fscholz

最后编辑者: fscholz, Apr 21, 2016, 3:42:18 AM

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