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glgetcompressedteximage(3g) [osx man page]

GLGETCOMPRESSEDTEXIM(3G)					    OpenGL 3.3						  GLGETCOMPRESSEDTEXIM(3G)

NAME
glGetCompressedTexImage - return a compressed texture image C SPECIFICATION
void glGetCompressedTexImage(GLenum target, GLint lod, GLvoid * img); PARAMETERS
target Specifies which texture is to be obtained. GL_TEXTURE_1D, GL_TEXTURE_2D, GL_TEXTURE_3D, GL_TEXTURE_CUBE_MAP_POSITIVE_X, GL_TEXTURE_CUBE_MAP_NEGATIVE_X, GL_TEXTURE_CUBE_MAP_POSITIVE_Y, GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, GL_TEXTURE_CUBE_MAP_POSITIVE_Z, and GL_TEXTURE_CUBE_MAP_NEGATIVE_Z are accepted. lod Specifies the level-of-detail number of the desired image. Level 0 is the base image level. Level n is the nth mipmap reduction image. img Returns the compressed texture image. DESCRIPTION
glGetCompressedTexImage returns the compressed texture image associated with target and lod into img. img should be an array of GL_TEXTURE_COMPRESSED_IMAGE_SIZE bytes. target specifies whether the desired texture image was one specified by glTexImage1D() (GL_TEXTURE_1D), glTexImage2D() (GL_TEXTURE_2D or any of GL_TEXTURE_CUBE_MAP_*), or glTexImage3D() (GL_TEXTURE_3D). lod specifies the level-of-detail number of the desired image. If a non-zero named buffer object is bound to the GL_PIXEL_PACK_BUFFER target (see glBindBuffer()) while a texture image is requested, img is treated as a byte offset into the buffer object's data store. To minimize errors, first verify that the texture is compressed by calling glGetTexLevelParameter() with argument GL_TEXTURE_COMPRESSED. If the texture is compressed, then determine the amount of memory required to store the compressed texture by calling glGetTexLevelParameter() with argument GL_TEXTURE_COMPRESSED_IMAGE_SIZE. Finally, retrieve the internal format of the texture by calling glGetTexLevelParameter() with argument GL_TEXTURE_INTERNAL_FORMAT. To store the texture for later use, associate the internal format and size with the retrieved texture image. These data can be used by the respective texture or subtexture loading routine used for loading target textures. ERRORS
GL_INVALID_VALUE is generated if lod is less than zero or greater than the maximum number of LODs permitted by the implementation. GL_INVALID_OPERATION is generated if glGetCompressedTexImage is used to retrieve a texture that is in an uncompressed internal format. GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to the GL_PIXEL_PACK_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_PACK_BUFFER target and the data would be packed to the buffer object such that the memory writes required would exceed the data store size. ASSOCIATED GETS
glGetTexLevelParameter() with argument GL_TEXTURE_COMPRESSED glGetTexLevelParameter() with argument GL_TEXTURE_COMPRESSED_IMAGE_SIZE glGetTexLevelParameter() with argument GL_TEXTURE_INTERNAL_FORMAT glGet() with argument GL_PIXEL_PACK_BUFFER_BINDING SEE ALSO
glActiveTexture(), glCompressedTexImage1D(), glCompressedTexImage2D(), glCompressedTexImage3D(), glCompressedTexSubImage1D(), glCompressedTexSubImage2D(), glCompressedTexSubImage3D(), glReadPixels(), glTexImage1D(), glTexImage2D(), glTexImage3D(), glTexParameter(), glTexSubImage1D(), glTexSubImage2D(), glTexSubImage3D() COPYRIGHT
Copyright (C) 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/. OpenGL 3.3 03/08/2011 GLGETCOMPRESSEDTEXIM(3G)

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GLCOMPRESSEDTEXSUBIM(3G)					    OpenGL 3.3						  GLCOMPRESSEDTEXSUBIM(3G)

NAME
glCompressedTexSubImage2D - specify a two-dimensional texture subimage in a compressed format C SPECIFICATION
void glCompressedTexSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, GLsizei imageSize, const GLvoid * data); PARAMETERS
target Specifies the target texture. Must be GL_TEXTURE_2D, GL_TEXTURE_CUBE_MAP_POSITIVE_X, GL_TEXTURE_CUBE_MAP_NEGATIVE_X, GL_TEXTURE_CUBE_MAP_POSITIVE_Y, GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, GL_TEXTURE_CUBE_MAP_POSITIVE_Z, or GL_TEXTURE_CUBE_MAP_NEGATIVE_Z. 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 compressed image data stored at address data. imageSize Specifies the number of unsigned bytes of image data starting at the address specified by data. data Specifies a pointer to the compressed image data in memory. DESCRIPTION
Texturing allows elements of an image array to be read by shaders. glCompressedTexSubImage2D redefines a contiguous subregion of an existing two-dimensional texture image. The texels referenced by data replace the portion of the existing texture array with x indices xoffset and xoffset + width - 1, and the 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 width of 0, but such a specification has no effect. internalformat must be a known compressed image format (such as GL_RGTC) or an extension-specified compressed-texture format. The format of the compressed texture image is selected by the GL implementation that compressed it (see glTexImage2D()) and should be queried at the time the texture was compressed with glGetTexLevelParameter(). 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. ERRORS
GL_INVALID_ENUM is generated if internalformat is of the generic compressed internal formats: GL_COMPRESSED_RED, GL_COMPRESSED_RG, GL_COMPRESSED_RGB, GL_COMPRESSED_RGBA. GL_COMPRESSED_SRGB, or GL_COMPRESSED_SRGB_ALPHA. GL_INVALID_VALUE is generated if imageSize is not consistent with the format, dimensions, and contents of the specified compressed image data. GL_INVALID_OPERATION is generated if parameter combinations are not supported by the specific compressed internal format as specified in the specific texture compression extension. 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. Undefined results, including abnormal program termination, are generated if data is not encoded in a manner consistent with the extension specification defining the internal compression format. ASSOCIATED GETS
glGetCompressedTexImage() glGet() with argument GL_TEXTURE_COMPRESSED glGet() with argument GL_PIXEL_UNPACK_BUFFER_BINDING glGetTexLevelParameter() with arguments GL_TEXTURE_INTERNAL_FORMAT and GL_TEXTURE_COMPRESSED_IMAGE_SIZE SEE ALSO
glActiveTexture(), glCompressedTexImage1D(), glCompressedTexImage2D(), glCompressedTexImage3D(), glCompressedTexSubImage1D(), glCompressedTexSubImage3D(), glCopyTexImage1D(), glCopyTexImage2D(), glCopyTexSubImage1D(), glCopyTexSubImage2D(), glCopyTexSubImage3D(), glPixelStore(), glTexImage2D(), glTexImage3D(), glTexSubImage1D(), glTexSubImage2D(), glTexSubImage3D(), glTexParameter() COPYRIGHT
Copyright (C) 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/. OpenGL 3.3 03/08/2011 GLCOMPRESSEDTEXSUBIM(3G)
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