glTexImage2D(3G)
glTexImage2D - specify a two-dimensional texture image
As shipped in IRIX 6.5.19. Last changed in IRIX 6.5.15.
NAME glTexImage2D - specify a two-dimensional texture image C SPECIFICATION void glTexImage2D( GLenum target, GLint level, GLint internalformat, GLsizei width, GLsizei height, GLint border, GLenum format, GLenum type, const GLvoid *pixels ) PARAMETERS target Specifies the target texture. Must be GL_TEXTURE_2D or GL_PROXY_TEXTURE_2D. 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_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_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 n 2 + 2(border) for some integer n. All implementations support texture images that are at least 64 texels wide. height Specifies the height of the texture image. Must be m 2 + I(border) for some integer m, where I is 2 when GL_INTERLACE_SGIX is disabled, and 1 otherwise. All implementations support texture images that are at least 64 texels high. 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_ABGR_EXT, 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. 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. To enable and disable two- dimensional texturing, call glEnable and glDisable with argument GL_TEXTURE_2D. To define texture images, call 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 number of color components provided. 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_2D, 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 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_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. 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. format determines the composition of each element in pixels. It can assume one of eleven 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_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 GL_ABGR_EXT 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). 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.) Use the GL_PROXY_TEXTURE_2D 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 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 internalformat 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. Normally glTexImage2D is synchronous: OpenGL executes a glTexImage2D command in the order it is issued in the OpenGL command stream. Calling glEnable with parameter GL_ASYNC_TEX_IMAGE_SGIX causes subsequent glTexImage2D commands to be asynchronous as defined by the SGIX_async extension. An asynchronous glTexImage2D command samples the OpenGL state vector at the point in the OpenGL command stream where the command is issued, but the results of the command (e.g. availability of texels for use in rasterization) do not happen until some unspecified time in the future. In particular, the order of the asynchronous command relative to other OpenGL commands issued later in the command stream is undefined. An implementation may choose to execute asynchronous commands in parallel with the normal command stream or at some convenient time in the future. Calling glDisable with parameter GL_ASYNC_TEX_IMAGE_SGIX restores the default synchronous behavior for subsequent glTexImage2D commands. It does not affect any pending asynchronous glTexImage commands, or wait for their completion. When an asynchronous glTexImage2D command is issued, it is associated with the current value of GL_ASYNC_MARKER_SGIX as defined by the SGIX_async extension. A program can determine if an asynchronous glTexImage2D command has completed by using the glFinishAsyncSGIX or glPollAsyncSGIX commands. There is a maximum number of asynchronous glTexImage commands that can be outstanding at any one time, defined by the implementation. This value can be queried with glGetIntegerv with argument GL_MAX_ASYNC_TEX_IMAGE_SGIX. NOTES Texturing has no effect in color index mode. If the GL_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. Two-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 n example), the width must 2 +2(height), for some integer n, and height m must be 2 +(border), for some integer m, 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 and GL_DEPTH_COMPONENT cannot be used. glPixelStore and glPixelTransfer modes affect texture images in exactly the way they affect glDrawPixels. GL_ABGR_EXT is part of the EXT_abgr extension, not part of the core GL command set. If GL_EXT_abgr is included in the string returned by glGetString, when called with argument GL_EXTENSIONS, extension EXT_abgr is supported by the GL. glTexImage2D and GL_PROXY_TEXTURE_2D are available 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, 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. 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. ERRORS GL_INVALID_ENUM is generated if target is not GL_TEXTURE_2D or GL_PROXY_TEXTURE_2D. GL_INVALID_ENUM is generated if format is not an accepted format constant. Format constants other than GL_STENCIL_INDEX and GL_DEPTH_COMPONENT 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 log max, where 2 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 or height is less than 0 or greater than 2 + GL_MAX_TEXTURE_SIZE, if width cannot be represented as k 2 + 2(border) for some integer value of k, or if height cannot be k represented as 2 + I(border) for some integer value of k, 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_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 not GL_RGBA, GL_BGRA or GL_ABGR_EXT. GL_INVALID_OPERATION is generated when the SGIX_subsample extension is supported, and the pixel storage mode GL_UNPACK_SUBSAMPLE_RATE_SGIX is not GL_PIXEL_SUBSAMPLE_4444_SGIX, and width is not a multiple of 2, or format is not a 3 or 4 component format, or type is a packed pixels type. GL_INVALID_OPERATION is generated if GL_ASYNC_TEX_IMAGE_SGIX is enabled and the number of asynchronous glTexImage commands that have been issued but not queried (using glFinishAsyncSGIX or glPollAsyncSGIX) exceeds GL_MAX_ASYNC_TEX_IMAGE_SGIX. ASSOCIATED GETS glGetTexImage glIsEnabled with argument GL_TEXTURE_2D MACHINE DEPENDENCIES The SGIX_async and SGIX_async_pixel extensions are implemented only on Octane2 VPro systems. 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, on Octane2 VPro systems, and on O2 systems. The EXT_packed_pixels extension is not supported on RealityEngine, RealityEngine2, and VTX systems. The SGIX_subsample and SGIX_resample extensions are supported only on Octane2 VPro systems. Applying the GL_PIXEL_SUBSAMPLE_2424_SGIX subsample rate is accelerated for direct immmediate mode transfers when the format is GL_RGB or GL_RGBA, and the type is GL_UNSIGNED_BYTE or GL_UNSIGNED_SHORT. 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, High Impact and Maximum Impact systems, and Octane2 VPro systems, texture objects (see glBindTextureEXT) are significantly faster than display- listed textures, and therefore are recommended for managing texture memory. SEE ALSO glColorTable, glConvolutionFilter2D, glCopyPixels, glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage1D, glCopyTexSubImage2D, glCopyTexSubImage3D, glDrawPixels, glMatrixMode, glPixelStore, glPixelTransfer, glSeparableFilter2D, glTexEnv, glTexGen, glTexImage1D, glTexImage3D, glTexSubImage1D, glTexSubImage2D, glTexSubImage3D, glTexParameter, glAsyncMarkerSGIX, glDeleteAsyncMarkersSGIX, glFinishAsyncSGIX, glGenAsyncMarkersSGIX, glIsAsyncMarkerSGIX, glPollAsyncSGIX