GLCOPYTEXIMAGE2D() MachTen Programmer’s Manual GLCOPYTEXIMAGE2D()

NAME
glCopyTexImage2D - copy pixels into a 2D texture image

C SPECIFICATION
void glCopyTexImage2D( GLenum target,
GLint level,
GLenum internalFormat,
GLint x,
GLint y,
GLsizei width,
GLsizei height,
GLint border )

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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.

internalFormat Specifies the internal format of the tex-
ture. Must be one of the following sym-
bolic 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_RGB,
GL_R3_G3_B2, 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, or GL_RGBA16.

x, y Specify the window coordinates of the
lower left corner of the rectangular
region of pixels to be copied.

width Specifies the width of the texture image.
Must be 0 or $2**n ~+~ 2*$border for some
integer $n$.

height Specifies the height of the texture image.
Must be 0 or $2**m ~+~ 2*$border for some
integer $m$.

border Specifies the width of the border. Must
be either 0 or 1.

DESCRIPTION
glCopyTexImage2D defines a two-dimensional texture image
with pixels from the current GL_READ_BUFFER.

The screen-aligned pixel rectangle with lower left corner
at (x, y) and with a width of width$~+~2~*~$border and a
height of height$~+~2~*~$border defines the texture array
at the mipmap level specified by level. internalFormat
specifies the internal format of the texture array.

The pixels in the rectangle are processed exactly as if
glCopyPixels had been called, but the process stops just
before final conversion. At this point all pixel compo-
nent values are clamped to the range $[0,1]$ and then con-
verted to the texture’s internal format for storage in the
texel array.

Pixel ordering is such that lower $x$ and $y$ screen coor-
dinates correspond to lower $s$ and $t$ texture coordi-
nates.

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.

NOTES
glCopyTexImage2D is available only if the GL version is
1.1 or greater.

Texturing has no effect in color index mode.

1, 2, 3, and 4 are not accepted values for internalFormat.

An image with height or width of 0 indicates a NULL tex-
ture.

ERRORS
GL_INVALID_ENUM is generated if target is not
GL_TEXTURE_2D.

GL_INVALID_VALUE is generated if level is less than 0.

GL_INVALID_VALUE may be generated if level is greater than
$log sub 2 max$, where $max$ is the returned value of
GL_MAX_TEXTURE_SIZE.

GL_INVALID_VALUE is generated if width or height is less
than 0, greater than $2~+~$GL_MAX_TEXTURE_SIZE, or if
width or height cannot be represented as $2**k ~+~
2~*~$border for some integer $k$.

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 glCopyTexImage2D is
executed between the execution of glBegin and the corre-
sponding execution of glEnd.

ASSOCIATED GETS
glGetTexImage
glIsEnabled with argument GL_TEXTURE_2D

SEE ALSO
glCopyPixels, glCopyTexImage1D, glCopyTexSubImage1D,
glCopyTexSubImage2D, glPixelStore, glPixelTransfer, glTex-
Env, glTexGen, glTexImage1D, glTexImage2D, glTexSubIm-
age1D, glTexSubImage2D,
glTexParameter

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