fglTexSubImage2D(3G)
fglTexSubImage2D - specify a two-dimensional texture subimage
As shipped in IRIX 6.5.7. Unchanged since IRIX 6.5.
NAME fglTexSubImage2D - specify a two-dimensional texture subimage FORTRAN SPECIFICATION SUBROUTINE fglTexSubImage2D( INTEGER*4 target, INTEGER*4 level, INTEGER*4 xoffset, INTEGER*4 yoffset, INTEGER*4 width, INTEGER*4 height, INTEGER*4 format, INTEGER*4 type, CHARACTER*8 pixels ) PARAMETERS target Specifies the target texture. Must be GL_TEXTURE_2D. level Specifies the level-of-detail number. Level 0 is the base image level. Level n is the nth mipmap reduction image. xoffset Specifies a texel offset in the x direction within the texture array. yoffset Specifies a texel offset in the y direction within the texture array. width Specifies the width of the texture subimage. height Specifies the height of the texture subimage. 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_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, and GL_FLOAT. 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 fglEnable and fglDisable with argument GL_TEXTURE_2D. fglTexSubImage2D redefines a contiguous subregion of an existing two- dimensional texture image. The texels referenced by pixels replace the portion of the existing texture array with x indices xoffset and xoffset + width - 1, inclusive, and y indices yoffset and yoffset + height - 1, inclusive. This region may not include any texels outside the range of the texture array as it was originally specified. It is not an error to specify a subtexture with zero width or height, but such a specification has no effect. NOTES fglTexSubImage2D is available only if the GL version is 1.1 or greater. Texturing has no effect in color index mode. fglPixelStore and fglPixelTransfer modes affect texture images in exactly the way they affect fglDrawPixels. 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 InfiniteReality systems, there is a performance benefit when the width of the image to be transferred to texture memory is a multiple of 8. Texture borders are not supported on InfiniteReality systems. Applications should use borderless textures and GL_CLAMP_TO_EDGE_SGIS wrap mode. 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, fglTexSubImage2D and fglTexSubImage2DEXT are supported with the following restrictions: 1. Performance is significantly better if the texture subimage X offset, Y offset, width and height are multiples of 32. 2. fglTexSubImage2D and fglTexSubImage2DEXT may be used only with a texture that was created using fglTexImage2D with a NULL texture image. 3. fglTexSubImage2D and fglTexSubImage2DEXT may not be used with a mipmap texture. Only level 0 is supported. 4. Only the following texel format and type combinations are supported: GL_LUMINANCE and GL_UNSIGNED_BYTE, GL_LUMINANCE and GL_UNSIGNED_SHORT, GL_LUMINANCE_ALPHA and GL_UNSIGNED_BYTE, GL_LUMINANCE_ALPHA and GL_UNSIGNED_SHORT, GL_RGB and GL_UNSIGNED_BYTE and GL_RGBA and GL_UNSIGNED_BYTE. Any other combination of format and type will result in a GL_INVALID_ENUM error. 5. Using fglTexSubImage2D or fglTexSubImage2DEXT in conjunction with pixel mapping results in a GL_INVALID_OPERATION error (see fglPixelTransfer and fglPixelMap). 6. fglTexSubImage2D and fglTexSubImage2DEXT may not be used in display lists or when rendering remotely. 7. GL_INTERLACE_SGIX is not supported (see fglEnable). On High Impact and Maximum Impact systems, if the right side of the image to be transferred to texture memory is not the right side of the texture, then its index must be a multiple of 32, where index = xoffset+width. Otherwise it will generate a GL_INVALID_VALUE error. ERRORS GL_INVALID_ENUM is generated if target is not GL_TEXTURE_2D. GL_INVALID_OPERATION is generated if the texture array has not been defined by a previous fglTexImage2D operation. GL_INVALID_VALUE is generated if level is less than 0. P GL_INVALID_VALUE may be generated if level is greater than log max, 2 where max is the returned value of GL_MAX_TEXTURE_SIZE. GL_INVALID_VALUE is generated if xoffset < -b, (xoffset + width) > (w - b), yoffset < -b, or (yoffset + height) > (h - b). Where w is the GL_TEXTURE_WIDTH, h is the GL_TEXTURE_HEIGHT, and b is the border width of the texture image being modified. Note that w and h include twice the border width. GL_INVALID_VALUE is generated if width or height is less than 0. GL_INVALID_ENUM is generated if format is not an accepted format constant. 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_OPERATION is generated if fglTexSubImage2D is executed between the execution of fglBegin and the corresponding execution of fglEnd. ASSOCIATED GETS fglGetTexImage fglIsEnabled with argument GL_TEXTURE_2D SEE ALSO fglCopyTexImage1D, fglCopyTexImage2D, fglCopyTexSubImage1D, fglCopyTexSubImage2D, fglDrawPixels, fglPixelStore, fglPixelTransfer, fglTexEnv, fglTexGen, fglTexImage1D, fglTexImage2D, fglTexSubImage1D, fglTexParameter