glTexImage2D(3G)
glTexImage2D - specify a two-dimensional texture image
As shipped in IRIX 6.5.5. Unchanged since IRIX 6.5.
NAME glTexImage2D - specify a two-dimensional texture image C SPECIFICATION void glTexImage2D( GLenum target, GLint level, GLint components, GLsizei width, GLsizei height, GLint border, GLenum format, GLenum type, const GLvoid *pixels ) PARAMETERS target Specifies the target texture. Must be GL_TEXTURE_2D, GL_PROXY_TEXTURE_2D, GL_PROXY_TEXTURE_2D_EXT, or GL_DETAIL_TEXTURE_2D_SGIS. level Specifies the level-of-detail number. Level 0 is the base image level. Level n is the nth mipmap reduction image. components is used to request the internal storage format of the texture image. It must be 1, 2, 3, or 4, or one of the following symbolic constants: GL_ALPHA, GL_ALPHA4, GL_ALPHA4_EXT, GL_ALPHA8, GL_ALPHA8_EXT, GL_ALPHA12, GL_ALPHA12_EXT, GL_ALPHA16, GL_ALPHA16_EXT, GL_LUMINANCE, GL_LUMINANCE4, GL_LUMINANCE4_EXT, GL_LUMINANCE8, GL_LUMINANCE8_EXT, GL_LUMINANCE12, GL_LUMINANCE12_EXT, GL_LUMINANCE16, GL_LUMINANCE16_EXT, GL_LUMINANCE_ALPHA, GL_LUMINANCE4_ALPHA4, GL_LUMINANCE4_ALPHA4_EXT, GL_LUMINANCE6_ALPHA2, GL_LUMINANCE6_ALPHA2_EXT, GL_LUMINANCE8_ALPHA8, GL_LUMINANCE8_ALPHA8_EXT, GL_LUMINANCE12_ALPHA4, GL_LUMINANCE12_ALPHA4_EXT, GL_LUMINANCE12_ALPHA12, GL_LUMINANCE12_ALPHA12_EXT, GL_LUMINANCE16_ALPHA16, GL_LUMINANCE16_ALPHA16_EXT, GL_INTENSITY, GL_INTENSITY_EXT, GL_INTENSITY4, GL_INTENSITY4_EXT, GL_INTENSITY8, GL_INTENSITY8_EXT, GL_INTENSITY12, GL_INTENSITY12_EXT, GL_INTENSITY16, GL_INTENSITY16_EXT, GL_RGB, GL_R3_G3_B2, GL_RGB2_EXT, GL_RGB4, GL_RGB4_EXT, GL_RGB5, GL_RGB5_EXT, GL_RGB8, GL_RGB8_EXT, GL_RGB10, GL_RGB10_EXT, GL_RGB12, GL_RGB12_EXT, GL_RGB16, GL_RGB16_EXT, GL_RGBA, GL_RGBA2, GL_RGBA2_EXT, GL_RGBA4, GL_RGBA4_EXT, GL_RGB5_A1, GL_RGB5_A1_EXT, GL_RGBA8, GL_RGB10_A2, GL_RGB10_A2_EXT, GL_RGBA12, GL_RGBA12_EXT, GL_RGBA16, GL_RGBA16_EXT, GL_DEPTH_COMPONENT, GL_DEPTH_COMPONENT16_SGIX, GL_DEPTH_COMPONENT24_SGIX, GL_DEPTH_COMPONENT32_SGIX, GL_DUAL_ALPHA4_SGIS, GL_DUAL_ALPHA8_SGIS, GL_DUAL_ALPHA12_SGIS, GL_DUAL_ALPHA16_SGIS, GL_DUAL_LUMINANCE4_SGIS, GL_DUAL_LUMINANCE8_SGIS, GL_DUAL_LUMINANCE12_SGIS, GL_DUAL_LUMINANCE16_SGIS, GL_DUAL_INTENSITY4_SGIS, GL_DUAL_INTENSITY8_SGIS, GL_DUAL_INTENSITY12_SGIS, GL_DUAL_INTENSITY16_SGIS, GL_DUAL_LUMINANCE_ALPHA4_SGIS, GL_DUAL_LUMINANCE_ALPHA8_SGIS, GL_QUAD_ALPHA4_SGIS, GL_QUAD_ALPHA8_SGIS, GL_QUAD_LUMINANCE4_SGIS, GL_QUAD_LUMINANCE8_SGIS, GL_QUAD_INTENSITY4_SGIS, or GL_QUAD_INTENSITY8_SGIS. width Specifies the width of the texture image. Must be 2**n+2*border for some integer n. height Specifies the height of the texture image. Must 2**m+I*border for some integer m, where I is 2 when GL_INTERLACE_SGIX is disabled, and 1 otherwise. 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_RGBA, GL_ABGR_EXT, GL_LUMINANCE, GL_LUMINANCE_ALPHA, and GL_DEPTH_COMPONENT. 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_EXT, GL_UNSIGNED_SHORT_4_4_4_4_EXT, GL_UNSIGNED_SHORT_5_5_5_1_EXT, GL_UNSIGNED_INT_8_8_8_8_EXT, and GL_UNSIGNED_INT_10_10_10_2_EXT. pixels 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. Two-dimensional texturing is enabled and disabled using glEnable and glDisable with argument GL_TEXTURE_2D. Texture images are defined with glTexImage2D. The arguments describe the parameters of the texture image, such as height, 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 the way the image is represented in memory, and they are identical to the pixel formats used for glDrawPixels. If target is GL_PROXY_TEXTURE_2D or GL_PROXY_TEXTURE_2D_EXT no data is read from pixels, 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 will set all of the texture image state to 0 (GL_TEXTURE_WIDTH, GL_TEXTURE_HEIGHT, GL_TEXTURE_BORDER, GL_TEXTURE_INTERNAL_FORMAT, GL_TEXTURE_COMPONENTS, GL_TEXTURE_RED_SIZE, GL_TEXTURE_RED_SIZE_EXT, GL_TEXTURE_GREEN_SIZE, GL_TEXTURE_GREEN_SIZE_EXT, GL_TEXTURE_BLUE_SIZE, GL_TEXTURE_BLUE_SIZE_EXT, GL_TEXTURE_ALPHA_SIZE, GL_TEXTURE_ALPHA_SIZE_EXT, GL_TEXTURE_LUMINANCE_SIZE, GL_TEXTURE_LUMINANCE_SIZE_EXT, GL_TEXTURE_INTENSITY_SIZE), and GL_TEXTURE_INTENSITY_SIZE_EXT), but no error will be generated. If target is GL_TEXTURE_2D or GL_DETAIL_TEXTURE_2D_SGIS, 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. (Note that if type is set to GL_UNSIGNED_BYTE_3_3_2_EXT, GL_UNSIGNED_SHORT_4_4_4_4_EXT, GL_UNSIGNED_SHORT_5_5_5_1_EXT, GL_UNSIGNED_INT_8_8_8_8_EXT, or GL_UNSIGNED_INT_10_10_10_2_EXT then it is a special case in which all the elements of each group are packed into a single unsigned byte, unsigned short, or unsigned int. This is described in glDrawPixels.) 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). 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. When GL_INTERLACE_SGIX is enabled, only rows (0,2,4,...) of the texture image (where the border is considered part of the texture image) are defined. Rows (1,3,5,...) are left undefined and can only be defined using glTexSubImage2D, glTexSubImage2DEXT, glCopyTexSubImage2D or glCopyTexSubImage2DEXT. Note, that when GL_INTERLACE_SGIX is enabled the total height (i.e., the height of interior texture image plus twice the border) of the defined texture is 2*height. Each element of pixels is converted to an RGBA element according to format, as detailed below. Except for GL_COLOR_INDEX, after the conversion to RGBA, 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], where c is RED, GREEN, BLUE, or ALPHA, respectively (see glPixelTransfer). According to format, the conversion to RGBA is as follows: GL_COLOR_INDEX Each element is a single value, a color index. It is converted 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. 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. 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. 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. GL_ALPHA Each element is a single alpha component. It is converted to floating point and assembled into an RGBA element by attaching 0.0 for red, green, and blue. GL_RGB Each element is an RGB triple: first red, then green, and then blue. It is converted to floating point and assembled into an RGBA element by attaching 1.0 for alpha. GL_RGBA, GL_ABGR_EXT Each element contains all four components; for GL_RGBA, the red component is first, followed by green, then blue, and then alpha; for GL_ABGR_EXT the order is alpha, blue, green, and then red. GL_LUMINANCE Each element is a single luminance value. It is converted to floating point, then assembled into an RGBA element by replicating the luminance value three times for red, green, and blue and attaching 1.0 for alpha. GL_LUMINANCE_ALPHA Each element is a luminance/alpha pair. It is converted to floating point, then assembled into an RGBA element by replicating the luminance value three times for red, green, and blue. Please refer to the glDrawPixels reference page for a description of the acceptable values for the type parameter. An application may desire that the texture be stored at a certain resolution, or that it be stored in a certain format. This resolution and format can be requested by components. The GL will choose an internal representation that closely approximates that requested by components, 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.) The GL_PROXY_TEXTURE_2D or GL_PROXY_TEXTURE_2D_EXT target can be used to try out a particular resolution and format. The implementation will compute its best match for the requested storage resolution and format. This state can then be queried using glGetTexLevelParameter. If the texture cannot be accomodated texture state will be set to 0. 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. The mapping of components from the canonical RGBA to the internal storage formats that begin with GL_DUAL_ and GL_QUAD_ needs to be clarified. There are three cases. The first case is for the GL_DUAL_ formats that are groups of GL_ALPHA, GL_LUMINANCE, and GL_INTENSITY. The R value goes to the first group while the A value goes to the second group. The second case is for the GL_DUAL_ formats that are groups of GL_LUMINANCE_ALPHA. The R and G values go to the first group while the B and A values go to the second group. The third case is for the GL_QUAD_ formats. The R value goes to the first group, the G value to the second group, the B value to the third group, and the A value to the fourth group. When components is set to GL_DEPTH_COMPONENT, GL_DEPTH_COMPONENT16_SGIX, GL_DEPTH_COMPONENT24_SGIX, or GL_DEPTH_COMPONENT32_SGIX, and format has the value GL_DEPTH_COMPONENT, glTexImage2D defines a depth texture that can be used for shadow mapping. See glIntro and glTexParameter for more information. NOTES Texturing has no effect in color index mode. glPixelStore and glPixelTransfer modes affect texture images in exactly the way they affect glDrawPixels. glTexImage2D and GL_PROXY_TEXTURE_2D are only available if the GL version is 1.1 or greater. Internal formats other than 1, 2, 3, or 4 may only be used if the GL version is 1.1 or greater. In GL version 1.1 or greater, pixels 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. abgr is supported only when the extensions string contains GL_EXT_abgr. If type is set to GL_UNSIGNED_BYTE_3_3_2_EXT, GL_UNSIGNED_SHORT_4_4_4_4_EXT, GL_UNSIGNED_SHORT_5_5_5_1_EXT, GL_UNSIGNED_INT_8_8_8_8_EXT, or GL_UNSIGNED_INT_10_10_10_2_EXT and the EXT_packed_pixels extension is not supported then a GL_INVALID_ENUM error is generated. See glIntro for more information on using extensions. ERRORS GL_INVALID_ENUM is generated when target is not one of the allowable values. GL_INVALID_ENUM is generated when format is not an accepted format. GL_INVALID_ENUM is generated when type is not an accepted type. 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 zero GL_INVALID_VALUE is generated if components is not 1, 2, 3, or 4 or one of the accepted symbolic constants. GL_INVALID_VALUE is generated if width or height is less than zero, greater than 2+GL_MAX_TEXTURE_SIZE, when width cannot be represented as 2**k+2*border for some integer k, or when height cannot be represented as 2**k+I*border, where I is 2 when GL_INTERLACE_SGIX is disabled and 1 otherwise. GL_INVALID_VALUE is generated if border is not 0 or 1. GL_INVALID_OPERATION is generated if glTexImage2D is executed between the execution of glBegin and the corresponding execution of glEnd. GL_INVALID_VALUE is generated if the implementation cannot accomodate a texture of the requested size. GL_INVALID_VALUE is generated if target is GL_DETAIL_TEXTURE_2D_SGIS and level is not zero. GL_INVALID_VALUE is generated if target is GL_DETAIL_TEXTURE_2D_SGIS and border is not zero. ASSOCIATED GETS glGetTexImage glIsEnabled with argument GL_TEXTURE_2D glGetTexLevelParameter with a first argument of GL_PROXY_TEXTURE_2D or GL_PROXY_TEXTURE_2D_EXT and a third argument of GL_TEXTURE_RED_SIZE, GL_TEXTURE_RED_SIZE_EXT, GL_TEXTURE_GREEN_SIZE, GL_TEXTURE_GREEN_SIZE_EXT, GL_TEXTURE_BLUE_SIZE, GL_TEXTURE_BLUE_SIZE_EXT, GL_TEXTURE_ALPHA_SIZE, GL_TEXTURE_ALPHA_SIZE_EXT, GL_TEXTURE_LUMINANCE_SIZE, GL_TEXTURE_LUMINANCE_SIZE_EXT, GL_TEXTURE_INTENSITY_SIZE, GL_TEXTURE_INTENSITY_SIZE_EXT, GL_TEXTURE_WIDTH, GL_TEXTURE_HEIGHT, GL_TEXTURE_BORDER, GL_TEXTURE_INTERNAL_FORMAT, or GL_TEXTURE_COMPONENTS. MACHINE DEPENDENCIES RealityEngine, RealityEngine2, and VTX systems do not support color matrix transformations on images as they are loaded to or read back from texture memory. RealityEngine, RealityEngine2, and VTX systems do not support convolving images as they are loaded into texture memory. On RealityEngine, RealityEngine2, and VTX systems the width and height of a detail texture must both be 256. On High Impact and Maximum Impact systems, detail texture size must be 128x128 or 256x256. Detail texturing acts as if the mipmap stack were extended by a number of levels equal to the absolute value of the GL_DETAIL_TEXTURE_LEVEL_SGIS parameter. The number of normal mipmap levels plus the number of detail levels must not exceed the maximum number of levels that can be supported on the hardware. For example, on InfiniteReality systems the maximum number of levels is 15. A detail texture at level -4 could be supported on a base texture of size 2K (that is, a base texture with 11 levels) but not on a base texture that is larger than 2K (one with 12 or more levels). Failure to observe this constraint causes detail textures to swim or jitter. RealityEngine, RealityEngine2, and VTX systems do not support histogram or minmax operations on images as they are being loaded into texture memory. The SGIX_interlace extension is supported only on InfiniteReality systems, on RealityEngine, RealityEngine2, and VTX systems, and on O2 systems. The EXT_packed_pixels extension is not supported on RealityEngine, RealityEngine2, and VTX systems. On RealityEngine, RealityEngine2, and VTX systems: 1. The texture environment must be defined and texturing must be enabled before loading a texture. 2. Texture formats composed only of alpha are not supported. 3. Borders are not supported; hence the border width must be 0. 4. Proxy textures are not supported. 5. glTexImage2D with a NULL texture image may not be used inside a display list. 6. GL_INTERLACE_SGIX is not supported (see glEnable). On High Impact and Maximum Impact systems the number of bits per component, represented internally, is the same for all components and will be 4, 8, or 12 bits per component. All specified internal formats will receive an equal or greater representation in this scheme, up to the 12-bit limit. High Impact and Maximum Impact on Indigo2 systems do not support texture internal formats of the type GL_INTENSITY or GL_ALPHA, although High Impact and Maximum Impact on Octane systems do support these types. High Impact and Maximum Impact on Indigo2 systems without the TRAM option card support 4 bits per component for GL_RGB and GL_RGBA, 4/8 bits per component for GL_LUMINANCE_ALPHA, and 4/8/12 bits per component for GL_LUMINANCE. Texture borders are not supported on InfiniteReality systems, so the border width should always be zero. Applications should use the texture wrap mode GL_CLAMP_TO_EDGE_SGIS to obtain behavior similar to that of borders. The SGIS_texture_select extension is supported only on InfiniteReality systems, High Impact and Maximum Impact on Octane systems, and High Impact and Maximum Impact on Indigo2 systems with the TRAM option card. On InfiniteReality, RealityEngine, RealityEngine2, and VTX systems, and High Impact and Maximum Impact systems, texture objects (see glBindTextureEXT) are significantly faster than display-listed textures, and therefore are recommended for managing texture memory. SEE ALSO glConvolutionFilter2DEXT, glDetailTexFuncSGIS, glDrawPixels, glFog, glEnable, glHistogramEXT, glMinmaxEXT, glPixelStore, glPixelTransfer, glSeparableFilter2DEXT, glTexEnv, glTexGen, glTexImage1D, glTexParameter.