fglCopyTexImage2DEXT(3G) OpenGL Reference fglCopyTexImage2DEXT(3G)NAME
fglCopyTexImage2DEXT - copy pixels into a 2D texture image
FORTRAN SPECIFICATION
SUBROUTINE fglCopyTexImage2DEXT( INTEGER*4 target,
INTEGER*4 level,
INTEGER*4 internalformat,
INTEGER*4 x,
INTEGER*4 y,
INTEGER*4 width,
INTEGER*4 height,
INTEGER*4 border )
PARAMETERS
target The target texture. Must be GL_TEXTURE_2D or
GL_DETAIL_TEXTURE_2D_SGIS.
level The level-of-detail number. Level 0 is the base image
level. Level n is the nth mipmap reduction image.
internalformat The internal storage format of the texture image. Must
be one of the following symbolic constants: GL_ALPHA,
GL_ALPHA4_EXT, GL_ALPHA8_EXT, GL_ALPHA12_EXT,
GL_ALPHA16_EXT, GL_LUMINANCE, GL_LUMINANCE4_EXT,
GL_LUMINANCE8_EXT, GL_LUMINANCE12_EXT,
GL_LUMINANCE16_EXT, GL_LUMINANCE_ALPHA,
GL_LUMINANCE4_ALPHA4_EXT, GL_LUMINANCE6_ALPHA2_EXT,
GL_LUMINANCE8_ALPHA8_EXT, GL_LUMINANCE12_ALPHA4_EXT,
GL_LUMINANCE12_ALPHA12_EXT, GL_LUMINANCE16_ALPHA16_EXT,
GL_INTENSITY_EXT, GL_INTENSITY4_EXT, GL_INTENSITY8_EXT,
GL_INTENSITY12_EXT, GL_INTENSITY16_EXT,
GL_DEPTH_COMPONENT, GL_DEPTH_COMPONENT16_SGIX,
GL_DEPTH_COMPONENT24_SGIX, GL_DEPTH_COMPONENT32_SGIX,
GL_RGB, GL_RGB2_EXT, GL_RGB4_EXT, GL_RGB5_EXT,
GL_RGB8_EXT, GL_RGB10_EXT, GL_RGB12_EXT, GL_RGB16_EXT,
GL_RGBA, GL_RGBA2_EXT, GL_RGBA4_EXT, GL_RGB5_A1_EXT,
GL_RGBA8_EXT, GL_RGB10_A2_EXT, GL_RGBA12_EXT,
GL_RGBA16_EXT. (Note that the values 1, 2, 3, and 4,
which are accepted by fglTexImage2D, are not accepted by
fglCopyTexImage2DEXT.)
x The x coordinate of the lower-left corner of the pixel
rectangle to be transferred to the texture array.
y The y coordinate of the lower-left corner of the pixel
rectangle to be transferred to the texture array.
width The width of the texture image.
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fglCopyTexImage2DEXT(3G) OpenGL Reference fglCopyTexImage2DEXT(3G)
height The height of the texture image.
border The border width of the texture. Must be 0 or 1.
DESCRIPTION
fglCopyTexImage2DEXT defines a two-dimensional texture image with pixels
from the current GL_READ_BUFFER (rather than from main memory, as is the
case for fglTexImage2D).
The screen-aligned pixel rectangle with lower-left corner at (x, y)
having width width+2*border and height height+2*border is used to define
the texture array at the mipmap level specified by level. (But see the
discussion of GL_INTERLACE_SGIX below.) The internal format of the
texture array is selected by internalformat.
The pixels in the rectangle are processed exactly as if fglCopyPixels had
been called, but the process stops just before final conversion. At this
point all pixel component values are clamped to the range [0, 1] and then
converted to the texture's internal format for storage in the texel
array.
Pixel ordering is such that lower x screen coordinates correspond to
lower i texture coordinates, and lower y screen coordinates correspond to
lower j texture coordinates.
If any of the pixels within the specified rectangle of the current
GL_READ_BUFFER are outside the window associated with the current
rendering context, then the values obtained for those pixels are
undefined.
When GL_INTERLACE_READ_INGR is enabled, every other row of the source
pixel rectangle is read. The height of the source pixel rectangle is
equivalent to 2xheight. Only rows (y+0,y+2,...) of the source rectangle
are used to define the rows of the texture image that are affected by the
copy.
When GL_INTERLACE_SGIX is enabled, source pixels define every other row
of the texture image, rather than successive rows of the texture image.
Rows (0,2,4,...) of the texture image are defined, while rows
(1,3,5,...) are left undefined. 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 2xheight.
If internalformat is one of GL_DEPTH_COMPONENT,
GL_DEPTH_COMPONENT16_SGIX, GL_DEPTH_COMPONENT24_SGIX, or
GL_DEPTH_COMPONENT32_SGIX, the pixel values will be read from the depth
buffer instead of the current GL_READ_BUFFER.
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fglCopyTexImage2DEXT(3G) OpenGL Reference fglCopyTexImage2DEXT(3G)NOTES
fglCopyTexImage2DEXT is part of the EXT_copy_texture extension. See
fglIntro for more information about using extensions.
ERRORS
GL_INVALID_ENUM is generated when target is not one of the allowable
values.
GL_INVALID_VALUE is generated if level is less than zero or greater than
log (max), where max is the returned value of GL_MAX_TEXTURE_SIZE.
2
GL_INVALID_VALUE is generated if the specified image is too large.
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
k
2 +2border for some integer k, or when height cannot be represented as
k
2 +Ixborder, 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_VALUE is generated if internalformat is not one of the
allowable values.
GL_INVALID_OPERATION is generated if fglCopyTexImage2DEXT is executed
between the execution of fglBegin and the corresponding execution of
fglEnd.
ASSOCIATED GETS
fglGetTexImage
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 support fglCopyTexImage2D
and fglCopyTexImage2DEXT with the following restrictions:
1. Only level 0 is supported; other levels result in a
GL_INVALID_VALUE error.
2. fglCopyTexImage2D and fglCopyTexImage2DEXT cannot be used if a
GLX video source is the current read drawable (see
fglXMakeCurrentReadSGI). Executing it will generate a
GL_INVALID_OPERATION error.
3. GL_INTERLACE_SGIX is not supported (see fglEnable).
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fglCopyTexImage2DEXT(3G) OpenGL Reference fglCopyTexImage2DEXT(3G)
4. Borders are not supported; hence the width of the border should
be 0.
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.
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 INGR_interlace_read extension is supported only on Octane2 VPro
systems, and on O2 systems.
SEE ALSO
fglTexImage2D, fglCopyTexSubImage2DEXT, fglCopyPixels.
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