glCopyTexSubImage2D(3gl)

1GLCOPYTEXSUBIMAGE2D(3G)                                GLCOPYTEXSUBIMAGE2D(3G)
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NAME

6       glCopyTexSubImage2D - copy a two-dimensional texture subimage
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C SPECIFICATION

10       void glCopyTexSubImage2D( GLenum target,
11                                 GLint level,
12                                 GLint xoffset,
13                                 GLint yoffset,
14                                 GLint x,
15                                 GLint y,
16                                 GLsizei width,
17                                 GLsizei height )
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PARAMETERS

21       target   Specifies the target texture.  Must be GL_TEXTURE_2D.
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23       level    Specifies  the  level-of-detail  number.   Level 0 is the base
24                image level.  Level n is the nth mipmap reduction image.
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26       xoffset  Specifies a texel offset in the x direction within the texture
27                array.
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29       yoffset  Specifies a texel offset in the y direction within the texture
30                array.
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32       x, y     Specify the window coordinates of the lower left corner of the
33                rectangular region of pixels to be copied.
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35       width    Specifies the width of the texture subimage.
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37       height   Specifies the height of the texture subimage.
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DESCRIPTION

40       glCopyTexSubImage2D replaces a rectangular portion of a two-dimensional
41       texture image with pixels from the current GL_READ_BUFFER (rather  than
42       from main memory, as is the case for glTexSubImage2D).
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44       The screen-aligned pixel rectangle with lower left corner at (x, y) and
45       with width width and height height replaces the portion of the  texture
46       array  with x indices xoffset through xoffset+width−1, inclusive, and y
47       indices yoffset through  yoffset+height−1,  inclusive,  at  the  mipmap
48       level specified by level.
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50       The  pixels  in  the rectangle are processed exactly as if glCopyPixels
51       had been called, but the process stops just  before  final  conversion.
52       At  this  point,  all  pixel  component values are clamped to the range
53       [0, 1] and then converted to the texture's internal  for storage in the
54       texel array.
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56       The destination rectangle in the texture array may not include any tex‐
57       els outside the texture array as it was originally  specified.   It  is
58       not  an  error  to  specify a subtexture with zero width or height, but
59       such a specification has no effect.
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61       If any of the pixels within the  specified  rectangle  of  the  current
62       GL_READ_BUFFER  are outside the read window associated with the current
63       rendering context, then the values obtained for those pixels are  unde‐
64       fined.
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66       No  change  is  made  to  the  internalformat, width, height, or border
67       parameters of the specified texture array or to  texel  values  outside
68       the specified subregion.
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NOTES

71       glCopyTexSubImage2D  is  available  only  if  the  GL version is 1.1 or
72       greater.
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74       Texturing has no effect in color index mode.
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76       glPixelStore and glPixelTransfer modes affect texture images in exactly
77       the way they affect glDrawPixels.
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79       When  the  GL_ARB_imaging  extension  is supported, the RGBA components
80       read from the framebuffer may be processed  by  the  imaging  pipeline.
81       See glTexImage1D for specific details.
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ERRORS

84       GL_INVALID_ENUM is generated if target is not GL_TEXTURE_2D.
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86       GL_INVALID_OPERATION  is  generated  if  the texture array has not been
87       defined by a previous glTexImage2D or glCopyTexImage2D operation.
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89       GL_INVALID_VALUE is generated if level is less than 0.
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91       GL_INVALID_VALUE may be generated if level  is  greater  than  log2max,
92       where max is the returned value of GL_MAX_TEXTURE_SIZE.
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94       GL_INVALID_VALUE is generated if x<−b or if y<−b, where b is the border
95       width of the texture array.
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97       GL_INVALID_VALUE is  generated  if  xoffset<−b,  (xoffset+width)>(w−b),
98       yoffset<−b, or (yoffset+height)>(h−b), where w is the GL_TEXTURE_WIDTH,
99       h is the  GL_TEXTURE_HEIGHT, and b is the GL_TEXTURE_BORDER of the tex‐
100       ture  image being modified.  Note that w and h include twice the border
101       width.
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103       GL_INVALID_OPERATION is generated if  glCopyTexSubImage2D  is  executed
104       between  the  execution  of  glBegin and the corresponding execution of
105       glEnd.
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ASSOCIATED GETS

108       glGetTexImage
109       glIsEnabled with argument GL_TEXTURE_2D
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