QB64-PE/internal/help/_glCopyTexSubImage1D.txt

'''_glCopyTexSubImage1D:''' copy a one-dimensional texture subimage


{{PageSyntax}}

:  SUB _glCopyTexSubImage1D (BYVAL target AS _UNSIGNED LONG, BYVAL level AS LONG, BYVAL xoffset AS LONG, BYVAL x AS LONG, BYVAL y AS LONG, BYVAL width AS LONG)

:  void '''_glCopyTexSubImage1D'''(GLenum {{Parameter|target}}, GLint {{Parameter|level}}, GLint {{Parameter|xoffset}}, GLint {{Parameter|x}}, GLint {{Parameter|y}}, GLsizei {{Parameter|width}});


; target
: Specifies the target texture. Must be {{KW|_GL_TEXTURE_1D}}.
; level
: Specifies the level-of-detail number. Level 0 is the base image level. Level ''n'' is the ''n''th mipmap reduction image.
; xoffset
: Specifies the texel offset within the texture array.
; x, y
: Specify the window coordinates of the left corner of the row of pixels to be copied.
; width
: Specifies the width of the texture subimage.


{{PageDescription}}

'''_glCopyTexSubImage1D''' replaces a portion of a one-dimensional texture image with pixels from the current {{KW|_GL_READ_BUFFER}} (rather than from main memory, as is the case for {{KW|_glTexSubImage1D}}).

The screen-aligned pixel row with left corner at ({{Parameter|x}},\ {{Parameter|y}}), and with length {{Parameter|width}} replaces the portion of the texture array with x indices {{Parameter|xoffset}} through ''xoffset + width - 1'', inclusive. The destination in the texture array may not include any texels outside the texture array as it was originally specified.

The pixels in the row are processed exactly as if {{KW|_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.

It is not an error to specify a subtexture with zero width, but such a specification has no effect. If any of the pixels within the specified row of the current {{KW|_GL_READ_BUFFER}} are outside the read window associated with the current rendering context, then the values obtained for those pixels are undefined.

No change is made to the ''internalformat'', ''width'', or ''border'' parameters of the specified texture array or to texel values outside the specified subregion.


{{PageNotes}}

The {{KW|_glPixelStore}} mode affects texture images.


{{PageErrors}}

{{KW|_GL_INVALID_ENUM}} is generated if /{{Parameter|target}} is not {{KW|_GL_TEXTURE_1D}}.

{{KW|_GL_INVALID_OPERATION}} is generated if the texture array has not been defined by a previous {{KW|_glTexImage1D}} or {{KW|_glCopyTexImage1D}} operation.

{{KW|_GL_INVALID_VALUE}} is generated if {{Parameter|level}} is less than 0.

{{KW|_GL_INVALID_VALUE}} may be generated if ''level'' is greater than log<sub>2</sub>(max), where ''max'' is the returned value of {{KW|_GL_MAX_TEXTURE_SIZE}}.

{{KW|_GL_INVALID_VALUE}} is generated if xoffset < 0 or xoffset + width > w, where w is the {{KW|_GL_TEXTURE_WIDTH}}.


{{PageUseWith}}

{{KW|_glGetTexImage}}


{{PageSeeAlso}}

{{KW|_GL}}
{{KW|_glActiveTexture}}, {{KW|_glBindTexture}}, {{KW|_glBindFramebuffer}}, {{KW|_glCopyImageSubData}}, {{KW|_glCopyTexSubImage2D}}, {{KW|_glCopyTexSubImage3D}}, {{KW|_glCopyTexImage1D}}, {{KW|_glReadBuffer}}


{{PageCopyright}}