glTexImage1D  2.LHZRQ

[New - Windows 95, OEM Service Release 2]

The glTexImage1D function specifies a one-dimensional texture image.

void glTexImage1D(

    GLenum target,

 

    GLint level,

 

    GLint components,

 

    GLsizei width,

 

    GLint border,

 

    GLenum 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.

components

The number of color components in the texture. Must be 1, 2, 3, or 4.

width

The width of the texture image. Must be 2^n + 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:

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 glPixelTransfer6MW9.AX). 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 glPixelTransfer6MW9.AX).

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 glPixelTransfer6MW9.AX).

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 Win32 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 Win32 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 glPixelTransfer6MW9.AX).

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.

 

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 glEnable194O61P 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 glTexParameter51MLQ7N), 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 glDrawPixelsHZW_GG.

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 glPixelStoreNHM7UO).

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 glDrawPixelsHZW_GG command, except that GL_STENCIL_INDEX and GL_DEPTH_COMPONENT cannot be used. The glPixelStoreNHM7UO and glPixelTransfer6MW9.AX 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:

glGetTexImageGJ_6Y8

glIsEnabled1MZ_ZK. with argument GL_TEXTURE_1D

 

Error Codes

The following are the error codes generated and their conditions.

Error Code

Condition

GL_INVALID_ENUM

target was not GL_TEXTURE_1D.

GL_INVALID_ENUM

format was not an accepted format constant. Format constants other than GL_STENCIL_INDEX and GL_DEPTH_COMPONENT were accepted.

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 log (2) max, where max was the returned value of GL_MAX_TEXTURE_SIZE.

GL_INVALID_VALUE

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

GL_INVALID_VALUE

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

GL_INVALID_VALUE

border was not 0 or 1.

GL_INVALID_OPERATION

glTexImage1D was called between a call to glBegin and the corresponding call to glEnd.

 

See Also

glBegin, glDrawPixels, glEnd, glFog, glGetTexImage, glIsEnabled, glPixelStore, glPixelTransfer, glTexEnv, glTexGen, glTexImage2D, glTexParameter