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)

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 n^th mipmap reduction image.
internalformat	Specifies the internal format of the texture. Must be one of the following symbolic 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 2ⁿ + 2 * border for some integer n.
height	Specifies the height of the texture image. Must be 2^m + 2 * border for some integer m. If GL_INTERLACE_EXT is enabled, the height must be 2^m + border since the height will be doubled. All implementations support texture images that are at least 64 texels high.
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 component values are clamped to the range [0,1] and then converted to the texture's internal format for storage in the texel array.

The screen-aligned pixel rectangle with lower-left corner at (x,y), width width and height height is used to define the texture image. If GL_INTERLACE_READ_I3D is enabled, every other row is skipped such that the pixel rectangle with lower-left corner at (x,y), width width and height 2 * height - 1 is used to define the texture image. If any pixels within this region are outside the window that is associated with the GL context, the values obtained for those pixels are undefined.

Pixel ordering is such that lower x and y screen coordinates correspond to lower s and t texture coordinates.

When GL_INTERLACE_EXT is enabled, only rows (0,2,4,...) of the texture (where the border is considered part of the texture) are defined. Rows (1,3,5,...) are left undefined and can only be defined using glTexSubImage2D or glCopyTexSubImage2D.

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 texture.

EXTENSIONS

Some routines and constants for this function are part of an extension, not part of the core GL command set. The following extension names must be present in the string returned by glGetString when called with argument GL_EXTENSIONS to use these routines and constants.

EXT_interlace: GL_INTERLACE_EXT is part of the EXT_interlace extension.
EXT_interlace_read: GL_INTERLACE_READ_I3D is part of the EXT_interlace_read extension.

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 LOG₂(max), where max is the returned value of GL_MAX_TEXTURE_SIZE.

GL_INVALID_VALUE is generated if internalformat is not one of the allowable values.

GL_INVALID_VALUE is generated if width or height is less than 0 or greater than 2 + GL_MAX_TEXTURE_SIZE, or if width cannot be represented as 2^k + 2 * border for some integer value of k, or when height cannot be represented as 2^k + I * border, where I is 1 when GL_INTERLACE_EXT is enabled and 2 otherwise.

GL_INVALID_VALUE is generated if border is not 0 or 1.

GL_INVALID_OPERATION is generated if glCopyTexImage2D is executed between the execution of glBegin and the corresponding execution of glEnd.

ASSOCIATED GETS

glGetTexImage
glIsEnabled with argument GL_TEXTURE_2D