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81 lines
5 KiB
Markdown
81 lines
5 KiB
Markdown
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**_glCopyTexSubImage2D:** copy a two-dimensional texture subimage
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## Syntax
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> SUB _glCopyTexSubImage2D (BYVAL target AS _UNSIGNED LONG, BYVAL level AS LONG, BYVAL xoffset AS LONG, BYVAL yoffset AS LONG, BYVAL x AS LONG, BYVAL y AS LONG, BYVAL width AS LONG, BYVAL height AS LONG)
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> void **_glCopyTexSubImage2D**(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLint x, GLint y, GLsizei width, GLsizei height);
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; target
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> Specifies the target texture. Must be [_GL_TEXTURE_2D](_GL_TEXTURE_2D), [_GL_TEXTURE_CUBE_MAP_POSITIVE_X](_GL_TEXTURE_CUBE_MAP_POSITIVE_X), [_GL_TEXTURE_CUBE_MAP_NEGATIVE_X](_GL_TEXTURE_CUBE_MAP_NEGATIVE_X), [_GL_TEXTURE_CUBE_MAP_POSITIVE_Y](_GL_TEXTURE_CUBE_MAP_POSITIVE_Y), [_GL_TEXTURE_CUBE_MAP_NEGATIVE_Y](_GL_TEXTURE_CUBE_MAP_NEGATIVE_Y), [_GL_TEXTURE_CUBE_MAP_POSITIVE_Z](_GL_TEXTURE_CUBE_MAP_POSITIVE_Z), [_GL_TEXTURE_CUBE_MAP_NEGATIVE_Z](_GL_TEXTURE_CUBE_MAP_NEGATIVE_Z), or [_GL_TEXTURE_1D_ARRAY](_GL_TEXTURE_1D_ARRAY).
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; level
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> Specifies the level-of-detail number. Level 0 is the base image level. Level *n* is the *n*th mipmap reduction image.
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; xoffset
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> Specifies a texel offset in the x direction within the texture array.
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; yoffset
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> Specifies a texel offset in the y direction within the texture array.
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; x, y
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> Specify the window coordinates of the lower left corner of the rectangular region of pixels to be copied.
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; width
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> Specifies the width of the texture subimage.
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; height
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> Specifies the height of the texture subimage.
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## Description
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**_glCopyTexSubImage2D** replaces a rectangular portion of a two-dimensional texture image, cube-map texture image or a linear portion of a number of slices of a one-dimensional array texture with pixels from the current [_GL_READ_BUFFER](_GL_READ_BUFFER) (rather than from main memory, as is the case for [_glTexSubImage2D](_glTexSubImage2D)).
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The screen-aligned pixel rectangle with lower left corner at (*x*, *y*) and with width width and height height replaces the portion of the texture array with x indices xoffset through *xoffset + width - 1*, inclusive, and y indices yoffset through *yoffset + height - 1*, inclusive, at the mipmap level specified by level.
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The pixels in the rectangle are processed exactly as if [_glReadPixels](_glReadPixels) 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.
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The destination rectangle in the texture array may not include any texels outside the texture array as it was originally specified. It is not an error to specify a subtexture with zero width or height, but such a specification has no effect.
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When target is [_GL_TEXTURE_1D_ARRAY](_GL_TEXTURE_1D_ARRAY) then the y coordinate and height are treated as the start slice and number of slices to modify.
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If any of the pixels within the specified rectangle of the current [_GL_READ_BUFFER](_GL_READ_BUFFER) are outside the read window associated with the current rendering context, then the values obtained for those pixels are undefined.
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No change is made to the *internalformat*, *width*, *height*, or *border* parameters of the specified texture array or to texel values outside the specified subregion.
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## Notes
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[_glPixelStore](_glPixelStore) modes affect texture images.
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## Error(s)
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[_GL_INVALID_ENUM](_GL_INVALID_ENUM) is generated if target is not [_GL_TEXTURE_2D](_GL_TEXTURE_2D), [_GL_TEXTURE_CUBE_MAP_POSITIVE_X](_GL_TEXTURE_CUBE_MAP_POSITIVE_X), [_GL_TEXTURE_CUBE_MAP_NEGATIVE_X](_GL_TEXTURE_CUBE_MAP_NEGATIVE_X), [_GL_TEXTURE_CUBE_MAP_POSITIVE_Y](_GL_TEXTURE_CUBE_MAP_POSITIVE_Y), [_GL_TEXTURE_CUBE_MAP_NEGATIVE_Y](_GL_TEXTURE_CUBE_MAP_NEGATIVE_Y), [_GL_TEXTURE_CUBE_MAP_POSITIVE_Z](_GL_TEXTURE_CUBE_MAP_POSITIVE_Z), [_GL_TEXTURE_CUBE_MAP_NEGATIVE_Z](_GL_TEXTURE_CUBE_MAP_NEGATIVE_Z), or [_GL_TEXTURE_1D_ARRAY](_GL_TEXTURE_1D_ARRAY).
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[_GL_INVALID_OPERATION](_GL_INVALID_OPERATION) is generated if the texture array has not been defined by a previous [_glTexImage2D](_glTexImage2D) or [_glCopyTexImage2D](_glCopyTexImage2D) operation.
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[_GL_INVALID_VALUE](_GL_INVALID_VALUE) is generated if level is less than 0.
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[_GL_INVALID_VALUE](_GL_INVALID_VALUE) may be generated if *level* is greater than log<sub>2</sub>(max), where *max* is the returned value of [_GL_MAX_TEXTURE_SIZE](_GL_MAX_TEXTURE_SIZE).
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[_GL_INVALID_VALUE](_GL_INVALID_VALUE) is generated if xoffset < 0, xoffset + width > w, yoffset < 0, or yoffset + height > h, where w is the [_GL_TEXTURE_WIDTH](_GL_TEXTURE_WIDTH) and h is the [_GL_TEXTURE_HEIGHT](_GL_TEXTURE_HEIGHT) of the texture image being modified.
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## Use With
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[_glGetTexImage](_glGetTexImage)
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## See Also
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[_GL](_GL)
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[_glActiveTexture](_glActiveTexture), [_glBindTexture](_glBindTexture), [_glBindFramebuffer](_glBindFramebuffer), [_glCopyImageSubData](_glCopyImageSubData), [_glCopyTexSubImage1D](_glCopyTexSubImage1D), [_glCopyTexSubImage3D](_glCopyTexSubImage3D), [_glCopyTexImage2D](_glCopyTexImage2D), [_glReadBuffer](_glReadBuffer)
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