Texture

A Texture is a WebGL object that contains one or more images that all have the same image format. Shaders can read from textures (through a sampler uniform) and they can be set up as render targets (by attaching them to a framebuffer).

Note: This section describes the Texture base class that implements functionality common to all four types of WebGL:

For more details see OpenGL Wiki.

Note that textures have a lot of optional capabilities made available by extensions, see the Limits section below.

Usage

Creating a texture

const texture = device.createTexture({sampler: {addressModeU: 'clamp-to-edge'});

Using Textures

const texture = device.createTexture, ...);

// For ease of use, the `Model` class can bind textures for a draw call
model.draw({
  uniforms({uMVMatrix: matrix, texture1: texture, texture2: texture})
});

// Alternatively, bind the textures using the `Texture` API directly
texture.bind(0);
texture.bind(1);
model.draw({
  uniforms({uMVMatrix: matrix})
});

• For additional usage examples, Texture inherits from Resource.

Types

BufferProps

Property	Type	Description
usage?	number	Bit mask of Usage flags
byteLength?	number	Length of buffer (cannot be changed after creation).
data?	ArrayBuffer | ArrayBufferView	Data to be copied into buffer. byteLength will be deduced if not supplied.
byteOffset?	number	Offset for data
indexType?	'uint16' | 'uint32'	If props.usage & Buffer.INDEX

Usage

Usage expresses two things: The type of texture and what operations can be performed on it.

Note that the allowed combinations are very limited, especially in WebGPU.

Usage Flag	Value	Description
Texture.COPY_SRC	0x01
Texture.COPY_DST	0x02
Texture.TEXTURE	0x04
Texture.STORAGE_BINDING	0x08
Texture.RENDER_ATTACHMENT	0x10

TextureDimension

| Dimension | WebGPU | WebGL2 | Description | | ------------ | ------ | ------ | | -------------------------------------------------------------------- | | 1d | ✅ | ❌ | Contains a one dimensional texture (typically used for compute ) | | 2d | ✅ | ✅ | Contains a "normal" image texture | | 2d-array | ✅ | ✅ | Holds an "array" of 2D textures. | | 3d | ✅ | ✅ | Holds a "stack" of textures which enables 3D interpolation. | | cube | ✅ | ✅ | Holds 6 textures representing sides of a cube. | | cube-array | ✅ | ❌ | Holds an array where every 6 textures represent the sides of a cube. |

TextureData

WebGL allows textures to be created from a number of different data sources.

Type	Description
null	A texture will be created with the appropriate format, size and width. Bytes will be "uninitialized".
typed array	Bytes will be interpreted according to format/type parameters and pixel store parameters.
Buffer	Bytes will be interpreted according to format/type parameters and pixel store parameters.
Image (HTMLImageElement)	image will be used to fill the texture. width and height will be deduced.
Video (HTMLVideoElement)	video will be used to continously update the texture. width and height will be deduced.
Canvas (HTMLCanvasElement)	canvas will be used to fill the texture. width and height will be deduced.
ImageData	canvas.getImageData() - Used to fill the texture. width and height will be deduced.

Members

A number of read only accessors are available:

• width - width of one face of the cube map

• height - height of one face of the cube map

• format - internal format of the face textures

• border - Always 0.

• type - type used to create face textures

• dataFormat - data format used to create face textures.

• offset - offset used to create face textures.

• handle - The underlying WebGL or WebGPU object.

• id - An identifying string that is intended to help debugging.

Sampler parameters can be accessed using Texture.getParameter, e.g:

texture.getParameter(GL.TEXTURE_MAG_FILTER);

Members

• device: Device - holds a reference to the Device that created this Texture.
• handle: unknown - holds the underlying WebGL or WebGPU shader object
• props: TextureProps - holds a copy of the TextureProps used to create this Texture.

Methods

constructor(props: TextureProps)

Texture is an abstract class and cannot be instantiated directly. Create with device.createTexture(...).

destroy(): void

Free up any GPU resources associated with this texture immediately (instead of waiting for garbage collection).

resize(options : Object) : Texture2D

Call to resize a texture. If size has changed, reinitializes texture with current format. Note: calling resize clears image and mipmaps.

• width (GLint) - width to resize to.
• height (GLint) - height to resize to.
• mipmaps (bool) - turn on/off mipmapping. default false.

generateMipmap() : Texture2D

Call to regenerate mipmaps after modifying texture(s)

WebGL References gl.generateMipmap

setImageData(options : Object) : Texture2D

Allocates storage and sets image data

  Texture.setImageData({
    target = this.target,
    pixels = null,
    data = null,
    width,
    height,
    level = 0,
    type,
    offset = 0,
    border = 0,
    compressed = false,
    parameters= {}
  });

• data (*) - Image data. Can be one of several data types see table below
• pixels (*) - alternative to data
• width (GLint) -
• height (GLint) -
• level (GLint) -
• format (GLenum) - format of image data.
• type (GLenum)

• format of array (autodetect from type) or
• (WEBGL2) format of buffer

• offset (Number) - (WEBGL2) offset from start of buffer
• border (GLint) - must be 0.
• compressed (Boolean) -
• parameters (Object) - GL parameters to be temporarily applied (most of the time, pixelStorage parameters) when updating the texture.

Valid image data types:

• null - create empty texture of specified format
• Typed array - initializes from image data in typed array according to format
• Buffer|WebGLBuffer - (WEBGL2) initialized from image data in WebGLBuffer accoeding to format.
• HTMLImageElement|Image - Initializes with content of image. Auto deduces texture width/height from image.
• HTMLCanvasElement - Inits with contents of canvas. Auto width/height.
• HTMLVideoElement - Creates video texture that continuously updates. Auto width/height.

setSubImageData(options : Object) : Texture2D

Redefines an area of an existing texture Note: does not allocate storage

  Texture.setSubImageData({
    target = this.target,
    pixels = null,
    data = null,
    x = 0,
    y = 0,
    width,
    height,
    level = 0,
    type,
    compressed = false,
    offset = 0,
    border = 0,
    parameters = {}
  });

• x (GLint) - xOffset from where texture to be updated
• y (GLint) - yOffset from where texture to be updated
• width (GLint) - width of the sub image to be updated
• height (GLint) - height of the sub image to be updated
• level (GLint) - mip level to be updated
• format (GLenum) - internal format of image data.
• typ (GLenum) - format of array (autodetect from type) or (WEBGL2) format of buffer or ArrayBufferView
• dataFormat (GLenum) - format of image data.
• offset (Number) - (WEBGL2) offset from start of buffer
• border (GLint) - must be 0.
• parameters - temporary settings to be applied, can be used to supply pixel store settings.

See also gl.compressedTexSubImage2D, gl.texSubImage2D, gl.bindTexture, gl.bindBuffer

update()

Update this texture if HTMLVideoElement is used as the data source. This method is automatically called before every draw call if this texture is bound to a uniform.

Remarks

• Textures can be supplied as uniforms to shaders that can sample them using texture coordinates and color pixels accordingly.
• Parameters that affect texture sampling can be set on textures or sampler objects.
• Textures can be created from a number of different sources, including typed arrays, HTML Images, HTML Canvases, HTML Videos and WebGLBuffers (WebGL 2).
• The WebGL Context has global "pixel store" parameters that control how pixel data is laid out, including Y direction, color space etc.
• Textures are read from supplied data and written to the specified format/type parameters and pixel store parameters.