glCopyTexImage2D
[New
- Windows 95, OEM Service Release 2]
The glCopyTexImage2D
function copies pixels from the frame buffer into a two-dimensional texture
image.
void glCopyTexImage2D(
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GLenum target, |
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GLint level, |
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GLenum internalFormat, |
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GLint x, |
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GLint y, |
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GLsizei width, |
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GLsizei height, |
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GLint border |
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); |
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Parameters
target
The target to
which the image data will be changed. Must have the value GL_TEXTURE_2D.
level
The
level-of-detail number. Level 0 is the base image. Level n is the nth
mipmap reduction image.
internalFormat
The
internal format and resolution of the texture data. The values 1, 2, 3, and 4
are not accepted for internalFormat. The parameter can assume one of the
following symbolic values:
|
Constant |
Base
Format |
R Bits |
G Bits |
B Bits |
A Bits |
L Bits |
I Bits |
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ALPHA |
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ALPHA4 |
ALPHA |
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4 |
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ALPHA8 |
ALPHA |
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8 |
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ALPHA12 |
ALPHA |
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12 |
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ALPHA16 |
ALPHA |
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16 |
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LUMINANCE |
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LUMINANCE4 |
LUMINANCE |
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4 |
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LUMINANCE8 |
LUMINANCE |
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8 |
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LUMINANCE12 |
LUMINANCE |
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12 |
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LUMINANCE16 |
LUMINANCE |
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16 |
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LUMINANCE_ALPHA |
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LUMINANCE4_ALPHA4 |
LUMINANCE_ALPHA |
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4 |
4 |
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LUMINANCE6_ALPHA2 |
LUMINANCE_ALPHA |
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2 |
6 |
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LUMINANCE8_ALPHA8 |
LUMINANCE_ALPHA |
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8 |
8 |
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LUMINANCE12_ALPHA4 |
LUMINANCE_ALPHA |
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4 |
12 |
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LUMINANCE12_ALPHA12 |
LUMINANCE_ALPHA |
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12 |
12 |
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LUMINANCE16_ALPHA16 |
LUMINANCE_ALPHA |
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16 |
16 |
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INTENSITY |
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INTENSITY4 |
INTENSITY |
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4 |
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INTENSITY8 |
INTENSITY |
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8 |
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INTENSITY12 |
INTENSITY |
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12 |
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INTENSITY16 |
INTENSITY |
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16 |
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GL_RGB |
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GL_R3_G3_B2 |
GL_RGB |
3 |
3 |
2 |
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GL_RGB4 |
GL_RGB |
4 |
4 |
4 |
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GL_RGB5 |
GL_RGB |
5 |
5 |
5 |
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GL_RGB8 |
GL_RGB |
8 |
8 |
8 |
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GL_RGB10 |
GL_RGB |
10 |
10 |
10 |
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GL_RGB12 |
GL_RGB |
12 |
12 |
12 |
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GL_RGB16 |
GL_RGB |
16 |
16 |
16 |
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GL_RGBA |
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GL_RGBA2 |
GL_RGBA |
2 |
2 |
2 |
2 |
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GL_RGBA4 |
GL_RGBA |
4 |
4 |
4 |
4 |
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GL_RGB5_A1 |
GL_RGBA |
5 |
5 |
5 |
1 |
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GL_RGBA8 |
GL_RGBA |
8 |
8 |
8 |
8 |
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GL_RGB10_A2 |
GL_RGBA |
10 |
10 |
10 |
2 |
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GL_RGBA12 |
GL_RGBA |
12 |
12 |
12 |
12 |
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GL_RGBA16 |
GL_RGBA |
16 |
16 |
16 |
16 |
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x, y
The window
coordinates of the lower-left corner of the rectangular region of pixels to be
copied.
width
The width of
the texture image. Must be 2^n + 2 * border for some integer n.
height
The height of
the texture image. Must be 2^n + 2 * border for some integer n.
border
The width of
the border. Must be either zero or 1.
Remarks
The glCopyTexImage2D
function defines a two-dimensional texture image using pixels from the current
frame buffer, rather than from main memory as is the case for glTexImage2D.
Using the
mipmap level specified with level, texture arrays are defined as a
rectangle of pixels with the lower-left corner located at the coordinates x
and y, width equal to width + (2 * border), and a height
equal to height + (2 * border). The internal format of the
texture array is specified with the internalFormat parameter.
The glCopyTexImage2D
function processes the pixels in a row in the same way as glCopyPixels except that before the
final conversion of the pixels, all pixel component values are clamped to the
range [0, 1] and converted to the texture s internal format for storage in the
texture array. Pixel ordering is determined with lower x and y
coordinates corresponding to lower s and t texture coordinates.
If any of the pixels within a specified row of the current frame buffer are
outside the window associated with the current rendering context, then their
values are undefined.
You cannot
include calls to glCopyTexImage2D in display lists.
Note The glCopyTexImage2D
function is only available in OpenGL version 1.1 or later.
Texturing has
no effect in color-index mode. The glPixelStore and glPixelTransfer functions affect texture
images in exactly the way they affect glDrawPixels.
The following
function retrieves information related to glCopyTexImage2D:
glIsEnabled with argument GL_TEXTURE_2D
Error Codes
The following
are the error codes generated and their conditions.
|
Error
Code |
Condition |
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GL_INVALID_ENUM
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target was not an accepted value. |
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GL_INVALID_VALUE
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level was less than zero or greater than log sub 2(max),
where max is the returned value of GL_MAX_TEXTURE_SIZE. |
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GL_INVALID_VALUE |
border was not zero or 1. |
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GL_INVALID_VALUE |
width was less than zero, greater than 2 +
GL_MAX_TEXTURE_SIZE; or width cannot be represented as 2^n + 2
* border for some integer n. |
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GL_INVALID_OPERATION
|
glCopyTexImage2D was called between a call to glBegin and the
corresponding call to glEnd. |
See Also