glCopyTexImage2D

The glCopyTexImage2D function copies pixels from the frame buffer into a two-dimensional texture image.

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

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
ALPHA — — — — — — —
ALPHA4 ALPHA — — — 4 — —
ALPHA8 ALPHA — — — 8 — —
ALPHA12 ALPHA — — — 12 — —
ALPHA16 ALPHA — — — 16 — —
LUMINANCE — — — — — — —
LUMINANCE4 LUMINANCE — — — — 4 —
LUMINANCE8 LUMINANCE — — — — 8 —
LUMINANCE12 LUMINANCE — — — — 12 —
LUMINANCE16 LUMINANCE — — — — 16 —
LUMINANCE_ALPHA — — — — — — —
LUMINANCE4_ALPHA4 LUMINANCE_ALPHA — — — 4 4 —
LUMINANCE6_ALPHA2 LUMINANCE_ALPHA — — — 2 6 —
LUMINANCE8_ALPHA8 LUMINANCE_ALPHA — — — 8 8 —
LUMINANCE12_ALPHA4 LUMINANCE_ALPHA — — — 4 12 —
LUMINANCE12_ALPHA12 LUMINANCE_ALPHA — — — 12 12 —
LUMINANCE16_ALPHA16 LUMINANCE_ALPHA — — — 16 16 —
INTENSITY — — — — — — —
INTENSITY4 INTENSITY — — — — — 4
INTENSITY8 INTENSITY — — — — — 8
INTENSITY12 INTENSITY — — — — — 12
INTENSITY16 INTENSITY — — — — — 16
GL_RGB — — — — — — —
GL_R3_G3_B2 GL_RGB 3 3 2 — — —
GL_RGB4 GL_RGB 4 4 4 — — —
GL_RGB5 GL_RGB 5 5 5 — — —
GL_RGB8 GL_RGB 8 8 8 — — —
GL_RGB10 GL_RGB 10 10 10 — — —
GL_RGB12 GL_RGB 12 12 12 — — —
GL_RGB16 GL_RGB 16 16 16 — — —
GL_RGBA — — — — — — —
GL_RGBA2 GL_RGBA 2 2 2 2 — —
GL_RGBA4 GL_RGBA 4 4 4 4 — —
GL_RGB5_A1 GL_RGBA 5 5 5 1 — —
GL_RGBA8 GL_RGBA 8 8 8 8 — —
GL_RGB10_A2 GL_RGBA 10 10 10 2 — —
GL_RGBA12 GL_RGBA 12 12 12 12 — —
GL_RGBA16 GL_RGBA 16 16 16 16 — —

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
GL_INVALID_ENUM target was not an accepted value.
GL_INVALID_VALUE level was less than zero or greater than log sub 2(max), where max is the returned value of GL_MAX_TEXTURE_SIZE.
GL_INVALID_VALUE border was not zero or 1.
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.
GL_INVALID_OPERATION glCopyTexImage2D was called between a call to glBegin and the corresponding call to glEnd.

See Also

glBegin, glCopyTexImage1D, glDrawPixels, glEnd, glFog, glPixelStore, glPixelTransfer, glTexEnv, glTexGen, glTexImage1D, glTexImage2D, glTexParameter