Gl.TexImage2D (gb.opengl)

Static Sub TexImage2D ( Image As Image [ , Level As Integer, Border As Integer ] )

Specify a two-dimensional texture image.

Parameters

target: Specifies the target texture. Must be Gl.TEXTURE_2D, Gl.PROXY_TEXTURE_2D, Gl.TEXTURE_1D_ARRAY, Gl.PROXY_TEXTURE_1D_ARRAY, Gl.TEXTURE_RECTANGLE, Gl.PROXY_TEXTURE_RECTANGLE, Gl.TEXTURE_CUBE_MAP_POSITIVE_X, Gl.TEXTURE_CUBE_MAP_NEGATIVE_X, Gl.TEXTURE_CUBE_MAP_POSITIVE_Y, Gl.TEXTURE_CUBE_MAP_NEGATIVE_Y, Gl.TEXTURE_CUBE_MAP_POSITIVE_Z, Gl.TEXTURE_CUBE_MAP_NEGATIVE_Z, or Gl.PROXY_TEXTURE_CUBE_MAP.
level: Specifies the level-of-detail number. Level 0 is the base image level. Level n is the nth mipmap reduction image. If target is Gl.TEXTURE_RECTANGLE or Gl.PROXY_TEXTURE_RECTANGLE, level must be 0.
internalFormat: Specifies the number of color components in the texture. Must be one of the following symbolic constants: Gl.COMPRESSED_RED, Gl.COMPRESSED_RG, Gl.COMPRESSED_RGB, Gl.COMPRESSED_RGBA, Gl.COMPRESSED_SRGB, Gl.COMPRESSED_SRGB_ALPHA, Gl.DEPTH_COMPONENT, Gl.DEPTH_COMPONENT16, Gl.DEPTH_COMPONENT24, Gl.DEPTH_COMPONENT32, Gl.R3_G3_B2, Gl.RED, Gl.RG, Gl.RGB, Gl.RGB4, Gl.RGB5, Gl.RGB8, Gl.RGB10, Gl.RGB12, Gl.RGB16, Gl.RGBA, Gl.RGBA2, Gl.RGBA4, Gl.RGB5_A1, Gl.RGBA8, Gl.RGB10_A2, Gl.RGBA12, Gl.RGBA16, Gl.SRGB, Gl.SRGB8, Gl.SRGB_ALPHA, or Gl.SRGB8_ALPHA8.
width: Specifies the width of the texture image. All implementations support texture images that are at least 1024 texels wide.
height: Specifies the height of the texture image, or the number of layers in a texture array, in the case of the Gl.TEXTURE_1D_ARRAY and Gl.PROXY_TEXTURE_1D_ARRAY targets. All implementations support 2D texture images that are at least 1024 texels high, and texture arrays that are at least 256 layers deep.
border: This value must be 0.
format: Specifies the format of the pixel data. The following symbolic values are accepted: Gl.RED, Gl.RG, Gl.RGB, Gl.BGR, Gl.RGBA, and Gl.BGRA.
type: Specifies the data type of the pixel data. The following symbolic values are accepted: Gl.UNSIGNED_BYTE, Gl.BYTE, Gl.UNSIGNED_SHORT, Gl.SHORT, Gl.UNSIGNED_INT, Gl.INT, Gl.FLOAT, Gl.UNSIGNED_BYTE_3_3_2, Gl.UNSIGNED_BYTE_2_3_3_REV, Gl.UNSIGNED_SHORT_5_6_5, Gl.UNSIGNED_SHORT_5_6_5_REV, Gl.UNSIGNED_SHORT_4_4_4_4, Gl.UNSIGNED_SHORT_4_4_4_4_REV, Gl.UNSIGNED_SHORT_5_5_5_1, Gl.UNSIGNED_SHORT_1_5_5_5_REV, Gl.UNSIGNED_INT_8_8_8_8, Gl.UNSIGNED_INT_8_8_8_8_REV, Gl.UNSIGNED_INT_10_10_10_2, and Gl.UNSIGNED_INT_2_10_10_10_REV.
data: Specifies a pointer to the image data in memory.

Description

Texturing allows elements of an image array to be read by shaders.

To define texture images, call Gl.TexImage2D. The arguments describe the parameters of the texture image, such as height, width, width of the border, level-of-detail number (see Gl.TexParameter), and number of color components provided. The last three arguments describe how the image is represented in memory.

If target is Gl.PROXY_TEXTURE_2D, Gl.PROXY_TEXTURE_1D_ARRAY, Gl.PROXY_TEXTURE_CUBE_MAP, or Gl.PROXY_TEXTURE_RECTANGLE, no data is read from data, but all of the texture image state is recalculated, checked for consistency, and checked against the implementation's capabilities. If the implementation cannot handle a texture of the requested texture size, it sets all of the image state to 0, but does not generate an error (see Gl.GetError). To query for an entire mipmap array, use an image array level greater than or equal to 1.

If target is Gl.TEXTURE_2D, Gl.TEXTURE_RECTANGLE or one of the Gl.TEXTURE_CUBE_MAP targets, data is read from data as a sequence of signed or unsigned bytes, shorts, or longs, or single-precision floating-point values, depending on type. These values are grouped into sets of one, two, three, or four values, depending on format, to form elements. Each data byte is treated as eight 1-bit elements, with bit ordering determined by Gl.UNPACK_LSB_FIRST (see Gl.PixelStore).

If target is Gl.TEXTURE_1D_ARRAY, data is interpreted as an array of one-dimensional images.

If a non-zero named buffer object is bound to the Gl.PIXEL_UNPACK_BUFFER target (see Gl.BindBuffer) while a texture image is specified, data is treated as a byte offset into the buffer object's data store.

The first element corresponds to the lower left corner of the texture image. Subsequent elements progress left-to-right through the remaining texels in the lowest row of the texture image, and then in successively higher rows of the texture image. The final element corresponds to the upper right corner of the texture image.

format determines the composition of each element in data. It can assume one of these symbolic values:

Gl.RED: Each element is a single red component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for green and blue, and 1 for alpha. Each component is then multiplied by the signed scale factor Gl.c_SCALE, added to the signed bias Gl.c_BIAS, and clamped to the range /wiki/0,1.
Gl.RG: Each element is a red/green double. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for blue, and 1 for alpha. Each component is then multiplied by the signed scale factor Gl.c_SCALE, added to the signed bias Gl.c_BIAS, and clamped to the range /wiki/0,1.
Gl.RGB
Gl.BGR: Each element is an RGB triple. The GL converts it to floating point and assembles it into an RGBA element by attaching 1 for alpha. Each component is then multiplied by the signed scale factor Gl.c_SCALE, added to the signed bias Gl.c_BIAS, and clamped to the range /wiki/0,1.
Gl.RGBA
Gl.BGRA: Each element contains all four components. Each component is multiplied by the signed scale factor Gl.c_SCALE, added to the signed bias Gl.c_BIAS, and clamped to the range /wiki/0,1.
Gl.DEPTH_COMPONENT: Each element is a single depth value. The GL converts it to floating point, multiplies by the signed scale factor Gl.DEPTH_SCALE, adds the signed bias Gl.DEPTH_BIAS, and clamps to the range /wiki/0,1.
Gl.DEPTH_STENCIL: Each element is a pair of depth and stencil values. The depth component of the pair is interpreted as in Gl.DEPTH_COMPONENT. The stencil component is interpreted based on specified the depth + stencil internal format.

If an application wants to store the texture at a certain resolution or in a certain format, it can request the resolution and format with internalFormat. The GL will choose an internal representation that closely approximates that requested by internalFormat, but it may not match exactly. (The representations specified by Gl.RED, Gl.RG, Gl.RGB, and Gl.RGBA must match exactly.)

If the internalFormat parameter is one of the generic compressed formats, Gl.COMPRESSED_RED, Gl.COMPRESSED_RG, Gl.COMPRESSED_RGB, or Gl.COMPRESSED_RGBA, the GL will replace the internal format with the symbolic constant for a specific internal format and compress the texture before storage. If no corresponding internal format is available, or the GL can not compress that image for any reason, the internal format is instead replaced with a corresponding base internal format.

If the internalFormat parameter is Gl.SRGB, Gl.SRGB8, Gl.SRGB_ALPHA, or Gl.SRGB8_ALPHA8, the texture is treated as if the red, green, or blue components are encoded in the sRGB color space. Any alpha component is left unchanged. The conversion from the sRGB encoded component

c_{s}

to a linear component

c_{l}

is:

c_{l} {\begin{cases} \frac{c_{s}}{12.92} & if c_{s} \leq 0.04045 \\ {(\frac{c_{s} + 0.055}{1.055})}^{2.4} & if c_{s} > 0.04045 \end{cases}

Assume

c_{s}

is the sRGB component in the range /wiki/0,1.

Use the Gl.PROXY_TEXTURE_2D, Gl.PROXY_TEXTURE_1D_ARRAY, Gl.PROXY_TEXTURE_RECTANGLE, or Gl.PROXY_TEXTURE_CUBE_MAP target to try out a resolution and format. The implementation will update and recompute its best match for the requested storage resolution and format. To then query this state, call Gl.GetTexLevelParameter. If the texture cannot be accommodated, texture state is set to 0.

A one-component texture image uses only the red component of the RGBA color extracted from data. A two-component image uses the R and G values. A three-component image uses the R, G, and B values. A four-component image uses all of the RGBA components.

Image-based shadowing can be enabled by comparing texture r coordinates to depth texture values to generate a boolean result. See Gl.TexParameter for details on texture comparison.

Notes

The Gl.PixelStore mode affects texture images.

data may be a null pointer. In this case, texture memory is allocated to accommodate a texture of width width and height height. You can then download subtextures to initialize this texture memory. The image is undefined if the user tries to apply an uninitialized portion of the texture image to a primitive.

Gl.TexImage2D specifies the two-dimensional texture for the current texture unit, specified with Gl.ActiveTexture.

Errors

Gl.INVALID_ENUM is generated if target is not Gl.TEXTURE_2D, Gl.TEXTURE_1D_ARRAY, Gl.TEXTURE_RECTANGLE, Gl.PROXY_TEXTURE_2D, Gl.PROXY_TEXTURE_1D_ARRAY, Gl.PROXY_TEXTURE_RECTANGLE, Gl.PROXY_TEXTURE_CUBE_MAP, Gl.TEXTURE_CUBE_MAP_POSITIVE_X, Gl.TEXTURE_CUBE_MAP_NEGATIVE_X, Gl.TEXTURE_CUBE_MAP_POSITIVE_Y, Gl.TEXTURE_CUBE_MAP_NEGATIVE_Y, Gl.TEXTURE_CUBE_MAP_POSITIVE_Z, or Gl.TEXTURE_CUBE_MAP_NEGATIVE_Z.

Gl.INVALID_ENUM is generated if target is one of the six cube map 2D image targets and the width and height parameters are not equal.

Gl.INVALID_ENUM is generated if type is not a type constant.

Gl.INVALID_VALUE is generated if width is less than 0 or greater than Gl.MAX_TEXTURE_SIZE.

Gl.INVALID_VALUE is generated if target is not Gl.TEXTURE_1D_ARRAY or Gl.PROXY_TEXTURE_1D_ARRAY and height is less than 0 or greater than Gl.MAX_TEXTURE_SIZE.

Gl.INVALID_VALUE is generated if target is Gl.TEXTURE_1D_ARRAY or Gl.PROXY_TEXTURE_1D_ARRAY and height is less than 0 or greater than Gl.MAX_ARRAY_TEXTURE_LAYERS.

Gl.INVALID_VALUE is generated if level is less than 0.

Gl.INVALID_VALUE may be generated if level is greater than

\log_{2} (\max)

, where max is the returned value of Gl.MAX_TEXTURE_SIZE.

Gl.INVALID_VALUE is generated if internalFormat is not one of the accepted resolution and format symbolic constants.

Gl.INVALID_VALUE is generated if width or height is less than 0 or greater than Gl.MAX_TEXTURE_SIZE.

Gl.INVALID_VALUE is generated if non-power-of-two textures are not supported and the width or height cannot be represented as

2^{k} + 2 (border)

for some integer value of k.

Gl.INVALID_VALUE is generated if border is not 0.

Gl.INVALID_OPERATION is generated if type is one of Gl.UNSIGNED_BYTE_3_3_2, Gl.UNSIGNED_BYTE_2_3_3_REV, Gl.UNSIGNED_SHORT_5_6_5, Gl.UNSIGNED_SHORT_5_6_5_REV, or Gl.UNSIGNED_INT_10F_11F_11F_REV, and format is not Gl.RGB.

Gl.INVALID_OPERATION is generated if type is one of Gl.UNSIGNED_SHORT_4_4_4_4, Gl.UNSIGNED_SHORT_4_4_4_4_REV, Gl.UNSIGNED_SHORT_5_5_5_1, Gl.UNSIGNED_SHORT_1_5_5_5_REV, Gl.UNSIGNED_INT_8_8_8_8, Gl.UNSIGNED_INT_8_8_8_8_REV, Gl.UNSIGNED_INT_10_10_10_2, Gl.UNSIGNED_INT_2_10_10_10_REV, or Gl.UNSIGNED_INT_5_9_9_9_REV, and format is neither Gl.RGBA nor Gl.BGRA.

Gl.INVALID_OPERATION is generated if target is not Gl.TEXTURE_2D, Gl.PROXY_TEXTURE_2D, Gl.TEXTURE_RECTANGLE, or Gl.PROXY_TEXTURE_RECTANGLE, and internalFormat is Gl.DEPTH_COMPONENT, Gl.DEPTH_COMPONENT16, Gl.DEPTH_COMPONENT24, or Gl.DEPTH_COMPONENT32F.

Gl.INVALID_OPERATION is generated if format is Gl.DEPTH_COMPONENT and internalFormat is not Gl.DEPTH_COMPONENT, Gl.DEPTH_COMPONENT16, Gl.DEPTH_COMPONENT24, or Gl.DEPTH_COMPONENT32F.

Gl.INVALID_OPERATION is generated if internalFormat is Gl.DEPTH_COMPONENT, Gl.DEPTH_COMPONENT16, Gl.DEPTH_COMPONENT24, or Gl.DEPTH_COMPONENT32F, and format is not Gl.DEPTH_COMPONENT.

Gl.INVALID_OPERATION is generated if a non-zero buffer object name is bound to the Gl.PIXEL_UNPACK_BUFFER target and the buffer object's data store is currently mapped.

Gl.INVALID_OPERATION is generated if a non-zero buffer object name is bound to the Gl.PIXEL_UNPACK_BUFFER target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size.

Gl.INVALID_OPERATION is generated if a non-zero buffer object name is bound to the Gl.PIXEL_UNPACK_BUFFER target and data is not evenly divisible into the number of bytes needed to store in memory a datum indicated by type.

Gl.INVALID_VALUE is generated if target is Gl.TEXTURE_RECTANGLE or Gl.PROXY_TEXTURE_RECTANGLE and level is not 0.

Associated Gets

Gl.GetTexImage

Gl.Get with argument Gl.PIXEL_UNPACK_BUFFER_BINDING