glCopyTexSubImage1D function

Artikkel
12/11/2020

The glCopyTexSubImage1D function copies a sub-image of a one-dimensional texture image from the framebuffer.

Syntax

void WINAPI glCopyTexSubImage1D(
   GLenum  target,
   GLint   level,
   GLint   xoffset,
   GLint   x,
   GLint   y,
   GLsizei width
);

Parameters

target: The target to which the image data will be changed. Must have the value GL_TEXTURE_1D.
level: The level-of-detail number. Level 0 is the base image. Level n is the nth mipmap reduction image.
xoffset: The texel offset within the texture array.
x: The window x-plane coordinate of the lower-left corner of the row of pixels to be copied.
y: The window y-plane coordinate of the lower-left corner of the row of pixels to be copied.
width: The width of the sub-image of the texture image. Specifying a texture sub-image with zero width has no effect.

Return value

This function does not return a value.

Error codes

The following error codes can be retrieved by the glGetError function.

Name	Meaning
GL_INVALID_ENUM	target was not an accepted value.
GL_INVALID_VALUE	level was less than zero or level is greater than log2(max), where max is the returned value of GL_MAX_TEXTURE_SIZE.
GL_INVALID_VALUE	xoffset was less than border or (xoffset + width)was greater than (w + border), where w is GL_TEXTURE_WIDTH and border is GL_TEXTURE_BORDER. Note that w includes twice the border width.
GL_INVALID_VALUE	width was less than border or y was less than border, where border is the border width of the texture array.
GL_INVALID_OPERATION	The texture array was not defined by a previous glTexImage1D operation.
GL_INVALID_OPERATION	The function was called between a call to glBegin and the corresponding call to glEnd.

Remarks

The glCopyTexSubImage1D function replaces a portion of a one-dimensional texture image using pixels from the current framebuffer, rather than from main memory as is the case for glTexSubImage1D.

A row of pixels beginning with the window coordinates specified by x and y and with the length width replaces the portion of the texture array with the indexes xoffset through xoffset + (width - 1). The destination in the texture array cannot include any texels outside the originally specified texture array.

The glCopyTexSubImage1D 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 coordinates corresponding to lower texture coordinates. If any of the pixels within a specified row of the current framebuffer are outside the window associated with the current rendering context, then their values are undefined.

No change is made to the internalFormat, width, or border parameter of the specified texture array or to texel values outside the specified texture sub-image.

You cannot include calls to glCopyTexSubImage1D in display lists.

Note

The glCopyTexSubImage1D 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 the way pixels are drawn using glDrawPixels.

The following functions retrieve information related to glCopyTexSubImage1D:

glGetTexImage

glIsEnabled with argument GL_TEXTURE_1D

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Header	Gl.h
Library	Opengl32.lib
DLL	Opengl32.dll

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