glTexImage1D

Name

glTexImage1D — specify a one-dimensional texture image

C Specification

void glTexImage1D (GLenum        target,
                   GLint         level,
                   GLint         internalFormat,
                   GLsizei       width,
                   GLint         border,
                   GLenum        format,
                   GLenum        type,
                   const GLvoid *data);

Parameters

target: Specifies the target texture. Must be GL_TEXTURE_1D or GL_PROXY_TEXTURE_1D.
level: Specifies 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_COMPRESSED_ALPHA, GL_COMPRESSED_LUMINANCE, GL_COMPRESSED_LUMINANCE_ALPHA, GL_COMPRESSED_INTENSITY, GL_COMPRESSED_RGB, GL_COMPRESSED_RGBA, GL_DEPTH_COMPONENT, GL_DEPTH_COMPONENT16, GL_DEPTH_COMPONENT24, GL_DEPTH_COMPONENT32, 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_R3_G3_B2, 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_SLUMINANCE, GL_SLUMINANCE8, GL_SLUMINANCE_ALPHA, GL_SLUMINANCE8_ALPHA8, GL_SRGB, GL_SRGB8, GL_SRGB_ALPHA, or GL_SRGB8_ALPHA8.
width: Specifies the width of the texture image including the border if any. If the GL version does not support non-power-of-two sizes, this value must be 2ⁿ+2×border for some integer n. All implementations support texture images that are at least 64i texels wide. The height of the 1D texture image is 1.
border: Specifies the width of the border. Must be either 0 or 1.
format: Specifies the format of the pixel data. The following symbolic values are accepted: GL_COLOR_INDEX, GL_RED, GL_GREEN, GL_BLUE, GL_ALPHA, GL_RGB, GL_BGR, GL_RGBA, GL_BGRA, GL_LUMINANCE, and GL_LUMINANCE_ALPHA.
type: Specifies 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, 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 maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable and disable one-dimensional texturing, call 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 the internal resolution and format used to store the image. The last three arguments describe how the image is represented in memory; they are identical to the pixel formats used for glDrawPixels.

If target is GL_PROXY_TEXTURE_1D, 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 glGetError). To query for an entire mipmap array, use an image array level greater than or equal to 1.

If target is GL_TEXTURE_1D, 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. 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).

If a non-zero named buffer object is bound to the GL_PIXEL_UNPACK_BUFFER target (see glBindBuffer) 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 left end of the texture array. Subsequent elements progress left-to-right through the remaining texels in the texture array. The final element corresponds to the right end of the texture array.

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

GL_COLOR_INDEX: Each element is a single value, a color index. The GL converts it to fixed point (with an unspecified number of zero 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. 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 [0,1] (see glPixelTransfer).
GL_GREEN: Each element is a single green component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for red 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 [0,1] (see glPixelTransfer).
GL_BLUE: Each element is a single blue component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for red and green, 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 [0,1] (see glPixelTransfer).
GL_ALPHA: Each element is a single alpha component. The GL converts it to floating point and assembles it into an RGBA element by attaching 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_INTENSITY: Each element is a single intensity value. The GL converts it to floating point, then assembles it into an RGBA element by replicating the intensity value three times for red, green, blue, and 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_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 [0,1] (see glPixelTransfer).
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 [0,1] (see glPixelTransfer).
GL_LUMINANCE: Each element is a single luminance value. The GL converts it to floating point, then assembles it into an RGBA element by replicating the luminance value three times for red, green, and blue and 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 [0,1] (see glPixelTransfer).
GL_LUMINANCE_ALPHA: Each element is a luminance/alpha pair. The GL converts it to floating point, then assembles it 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).
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 [0,1] (see glPixelTransfer).

Refer to the glDrawPixels reference page for a description of the acceptable values for the type parameter.

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_LUMINANCE, GL_LUMINANCE_ALPHA, GL_RGB, and GL_RGBA must match exactly. The numeric values 1, 2, 3, and 4 may also be used to specify the above representations.)

If the internalFormat parameter is one of the generic compressed formats, GL_COMPRESSED_ALPHA, GL_COMPRESSED_INTENSITY, GL_COMPRESSED_LUMINANCE, GL_COMPRESSED_LUMINANCE_ALPHA, 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, GL_SRGB8_ALPHA8, GL_SLUMINANCE, GL_SLUMINANCE8, GL_SLUMINANCE_ALPHA, or GL_SLUMINANCE8_ALPHA8, the texture is treated as if the red, green, blue, or luminance 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:

Assume c_s is the sRGB component in the range [0,1].

Use the GL_PROXY_TEXTURE_1D 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 glGetTexLevelParameter. 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 from data. 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.

Depth textures can be treated as LUMINANCE, INTENSITY or ALPHA textures during texture filtering and application. Image-based shadowing can be enabled by comparing texture r coordinates to depth texture values to generate a boolean result. See glTexParameter for details on texture comparison.

Notes

Texturing has no effect in color index mode.

If the ARB_imaging extension is supported, RGBA elements may also be processed by the imaging pipeline. The following stages may be applied to an RGBA color before color component clamping to the range [0,1]:

1. Color component replacement by the color table specified for

GL_COLOR_TABLE, if enabled. See glColorTable.

2. One-dimensional convolution filtering, if enabled. See

glConvolutionFilter1D.

If a convolution filter changes the width of the texture (by processing with a GL_CONVOLUTION_BORDER_MODE of GL_REDUCE, for example), the width must 2ⁿ+2×border, for some integer n, after filtering.

3. RGBA components may be multiplied by GL_POST_CONVOLUTION_c_SCALE,

and added to GL_POST_CONVOLUTION_c_BIAS, if enabled. See glPixelTransfer.

4. Color component replacement by the color table specified for

GL_POST_CONVOLUTION_COLOR_TABLE, if enabled. See glColorTable.

5. Transformation by the color matrix.

See glMatrixMode.

6. RGBA components may be multiplied by GL_POST_COLOR_MATRIX_c_SCALE,

and added to GL_POST_COLOR_MATRIX_c_BIAS, if enabled. See glPixelTransfer.

7. Color component replacement by the color table specified for

GL_POST_COLOR_MATRIX_COLOR_TABLE, if enabled. See glColorTable.

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

GL_PROXY_TEXTURE_1D may be used only if the GL version is 1.1 or greater.

Internal formats other than 1, 2, 3, or 4 may be used only if the GL version is 1.1 or greater.

In GL version 1.1 or greater, data may be a null pointer. In this case texture memory is allocated to accommodate a texture of width width. You can then download subtextures to initialize the texture memory. The image is undefined if the program tries to apply an uninitialized portion of the texture image to a primitive.

Formats GL_BGR, and GL_BGRA and types 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 are available only if the GL version is 1.2 or greater.

When the ARB_multitexture extension is supported, or the GL version is 1.3 or greater, glTexImage1D specifies the one-dimensional texture for the current texture unit, specified with glActiveTexture.

GL_DEPTH_COMPONENT, GL_DEPTH_COMPONENT16, GL_DEPTH_COMPONENT24, and GL_DEPTH_COMPONENT32 are available only if the GL version is 1.4 or greater.

Non-power-of-two textures are supported if the GL version is 2.0 or greater, or if the implementation exports the GL_ARB_texture_non_power_of_two extension.

The GL_SRGB, GL_SRGB8, GL_SRGB_ALPHA, GL_SRGB8_ALPHA8, GL_SLUMINANCE, GL_SLUMINANCE8, GL_SLUMINANCE_ALPHA, and GL_SLUMINANCE8_ALPHA8 internal formats are only available if the GL version is 2.1 or greater.

Errors

GL_INVALID_ENUM is generated if target is not GL_TEXTURE_1D or GL_PROXY_TEXTURE_1D.

GL_INVALID_ENUM is generated if format is not an accepted format constant. Format constants other than GL_STENCIL_INDEX are accepted.

GL_INVALID_ENUM is generated if type is not a type constant.

GL_INVALID_ENUM is generated if type is GL_BITMAP and format is not GL_COLOR_INDEX.

GL_INVALID_VALUE is generated if level is less than 0.

GL_INVALID_VALUE may be generated if level is greater than log₂(max), where max is the returned value of GL_MAX_TEXTURE_SIZE.

GL_INVALID_VALUE is generated if internalFormat is not 1, 2, 3, 4, or one of the accepted resolution and format symbolic constants.

GL_INVALID_VALUE is generated if width is less than 0 or greater than 2 + GL_MAX_TEXTURE_SIZE.

GL_INVALID_VALUE is generated if non-power-of-two textures are not supported and the width cannot be represented as 2ⁿ+2×border for some integer value of n.

GL_INVALID_VALUE is generated if border is not 0 or 1.

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, or GL_UNSIGNED_SHORT_5_6_5_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, or GL_UNSIGNED_INT_2_10_10_10_REV and format is neither GL_RGBA nor GL_BGRA.

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_COMPONENT32.

GL_INVALID_OPERATION is generated if internalFormat is GL_DEPTH_COMPONENT, GL_DEPTH_COMPONENT16, GL_DEPTH_COMPONENT24, or GL_DEPTH_COMPONENT32, 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_OPERATION is generated if glTexImage1D is executed between the execution of glBegin and the corresponding execution of glEnd.

Associated Gets

glGetTexImage

glIsEnabled with argument GL_TEXTURE_1D

glGet with argument GL_PIXEL_UNPACK_BUFFER_BINDING