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glTexImage1D function

Applies to: desktop apps only

The glTexImage1D function specifies a one-dimensional texture image.

Syntax

void WINAPI glTexImage1D(
  GLenum target,
  GLint level,
  GLint internalformat,
  GLsizei width,
  GLint border,
  GLint format,
  GLenum type,
  const GLvoid *pixels
);

Parameters

target

The target texture. Must be GL_TEXTURE_1D.

level

The level-of-detail number. Level 0 is the base image level. Level n is the nTh mipmap reduction image.

internalformat

Specifies the number of color components in the texture. Must be 1, 2, 3, or 4, or one of the following symbolic constants: GL_ALPHA, GL_ALPHA4, GL_ALPHA8, GL_ALPHA12, GL_ALPHA16, GL_LUMINANCE, GL_LUMINANCE4, GL_LUMINANCE8, GL_LUMINANCE12, GL_LUMINANCE16, GL_LUMINANCE_ALPHA, GL_LUMINANCE4_ALPHA4, GL_LUMINANCE6_ALPHA2, GL_LUMINANCE8_ALPHA8, GL_LUMINANCE12_ALPHA4, GL_LUMINANCE12_ALPHA12, GL_LUMINANCE16_ALPHA16, GL_INTENSITY, GL_INTENSITY4, GL_INTENSITY8, GL_INTENSITY12, GL_INTENSITY16, GL_RGB, GL_R3_G3_B2, 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, or GL_RGBA16.

width

The width of the texture image. Must be 2n + 2( border ) for some integer n. The height of the texture image is 1.

border

The width of the border. Must be either 0 or 1.

format

The format of the pixel data. It can assume one of nine symbolic values.

ValueMeaning
GL_COLOR_INDEX

Each element is a single value, a color index. It is converted to fixed point (with an unspecified number of 0 bits to the right of the binary point), shifted left or right, depending on the value and sign of GL_INDEX_SHIFT, and added to GL_INDEX_OFFSET (see glPixelTransfer). The resulting index is converted to a set of color components using the GL_PIXEL_MAP_I_TO_R, GL_PIXEL_MAP_I_TO_G, GL_PIXEL_MAP_I_TO_B, and GL_PIXEL_MAP_I_TO_A tables, and clamped to the range [0,1].

GL_RED

Each element is a single red component. It is converted to floating point and assembled into an RGBA element by attaching 0.0 for green and blue, and 1.0 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 [0,1] (see glPixelTransfer).

GL_GREEN

Each element is a single green component. It is converted to floating point and assembled into an RGBA element by attaching 0.0 for red and blue, and 1.0 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 [0,1] (see glPixelTransfer).

GL_BLUE

Each element is a single blue component. It is converted to floating point and assembled into an RGBA element by attaching 0.0 for red and green, and 1.0 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 [0,1] (see glPixelTransfer).

GL_ALPHA

Each element is a single red component. It is converted to floating point and assembled into an RGBA element by attaching 0.0 for red, green, and blue. 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 [0,1] (see glPixelTransfer).

GL_RGB

Each element is an RGB triple. It is converted to floating point and assembled into an RGBA element by attaching 1.0 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 [0,1] (see glPixelTransfer).

GL_RGBA

Each element is a complete RGBA element. It is converted to floating point. 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 [0,1] (see glPixelTransfer).

GL_BGR_EXT

Each pixel is a group of three components in this order: blue, green, red.

GL_BGR_EXT provides a format that matches the memory layout of Windows device-independent bitmaps (DIBs). Thus your applications can use the same data with Windows function calls and OpenGL pixel function calls.

GL_BGRA_EXT

Each pixel is a group of four components in this order: blue, green, red, alpha.

GL_BGRA_EXT provides a format that matches the memory layout of Windows device-independent bitmaps (DIBs). Thus your applications can use the same data with Windows function calls and OpenGL pixel function calls.

GL_LUMINANCE

Each element is a single luminance value. It is converted to floating point, and then assembled into an RGBA element by replicating the luminance value three times for red, green, and blue, and attaching 1.0 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 [0,1] (see glPixelTransfer).

GL_LUMINANCE_ALPHA

Each element is a luminance/alpha pair. It is converted to floating point, and then assembled into an RGBA element by replicating the luminance value three times for red, green, and blue. 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 [0,1] (see glPixelTransfer).

 

type

The data type of the pixel data. The following symbolic values are accepted: GL_UNSIGNED_BYTE, GL_BYTE, GL_BITMAP, GL_UNSIGNED_SHORT, GL_SHORT, GL_UNSIGNED_INT, GL_INT, and GL_FLOAT.

pixels

A pointer to the image data in memory.

Return value

This function does not return a value.

Error codes

The following error codes can be retrieved by the glGetError function.

NameMeaning
GL_INVALID_ENUM

target was not an GL_TEXTURE.

GL_INVALID_ENUM

format was not an accepted format constant. Only format constants other than GL_STENCIL_INDEX and GL_DEPTH_COMPONENT are accepted. See the parameter description of format for a list of possible values.

GL_INVALID_ENUM

type was not a type constant.

GL_INVALID_ENUM

type was GL_BITMAP and format was not GL_COLOR_INDEX.

GL_INVALID_VALUE

level was less than zero or greater than log2max, where max was the returned value of GL_MAX_TEXTURE_SIZE.

GL_INVALID_VALUE

internalformat was was not 1, 2, 3, or 4.

GL_INVALID_VALUE

width was less than zero or greater than 2 + GL_MAX_TEXTURE_SIZE, or it could not be represented as 2n + 2(border) for some integer value of n.

GL_INVALID_VALUE

border was not 0 or 1.

GL_INVALID_OPERATION

The function was called between a call to glBegin and the corresponding call to glEnd.

Remarks

The glTexImage1D function specifies a one-dimensional texture image. Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. One-dimensional texturing is enabled and disabled using glEnable and glDisable with argument GL_TEXTURE_1D.

Texture images are defined with glTexImage1D. The arguments describe the parameters of the texture image, such as width, width of the border, level-of-detail number (see glTexParameter), and number of color components provided. The last three arguments describe the way the image is represented in memory. These arguments are identical to the pixel formats used for glDrawPixels.

Data is read from pixels 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. If type is GL_BITMAP, the data is considered as a string of unsigned bytes (and format must be GL_COLOR_INDEX). Each data byte is treated as eight 1-bit elements, with bit ordering determined by GL_UNPACK_LSB_FIRST (see glPixelStore).

A texture image can have up to four components per texture element, depending on components. A one-component texture image uses only the red component of the RGBA color extracted from pixels. A two-component image uses the R and A values. A three-component image uses the R, G, and B values. A four-component image uses all of the RGBA components.

Texturing has no effect in color-index mode.

The texture image can be represented by the same data formats as the pixels in a glDrawPixels command, except that GL_STENCIL_INDEX and GL_DEPTH_COMPONENT cannot be used. The glPixelStore and glPixelTransfer modes affect texture images in exactly the way they affect glDrawPixels.

A texture image with zero width indicates the null texture. If the null texture is specified for level-of-detail 0, it is as if texturing were disabled.

The following functions retrieve information related to glTexImageID:

glGetTexImage

glIsEnabled with argument GL_TEXTURE_1D

Requirements

Minimum supported client

Windows 2000 Professional

Minimum supported server

Windows 2000 Server

Header

Gl.h

Library

Opengl32.lib

DLL

Opengl32.dll

See also

glBegin
glCopyPixels
glCopyTexImage1D
glCopyTexImage2D
glCopyTexSubImage1D
glCopyTexSubImage2D
glDrawPixels
glEnd
glFog
glGetTexImage
glIsEnabled
glPixelStore
glPixelTransfer
glTexEnv
glTexGen
glTexImage2D
glTexSubImage1D
glTexSubImage2D
glTexParameter

 

 

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Build date: 3/6/2012

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