GlCopyTexImage2D: Difference between revisions

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(Created page with "'''_glCopyTexImage2D:''' copy pixels into a 2D texture image {{PageSyntax}} : SUB _glCopyTexImage2D (BYVAL target AS _UNSIGNED LONG, BYVAL level AS LONG, BYVAL internalFormat AS _UNSIGNED LONG, BYVAL x AS LONG, BYVAL y AS LONG, BYVAL width AS LONG, BYVAL height AS LONG, BYVAL border AS LONG) : void '''_glCopyTexImage2D'''(GLenum {{Parameter|target}}, GLint {{Parameter|level}}, GLenum {{Parameter|internalformat}}, GLint {{Parameter|x}}, GLint {{Parameter|y}}, GLsizei...")
 
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'''_glCopyTexImage2D:''' copy pixels into a 2D texture image
{{DISPLAYTITLE:_glCopyTexImage2D}}
The '''_glCopyTexImage2D''' statement copies pixels from the framebuffer into a two-dimensional texture image.




{{PageSyntax}}
{{PageSyntax}}
: [[_glCopyTexImage2D]] GLenum {{Parameter|target}}, GLint {{Parameter|level}}, GLenum {{Parameter|internalFormat}}, GLint {{Parameter|x}}, GLint {{Parameter|y}}, GLsizei {{Parameter|width}}, GLsizei {{Parameter|height}}, GLint {{Parameter|border}}


:  SUB _glCopyTexImage2D (BYVAL target AS _UNSIGNED LONG, BYVAL level AS LONG, BYVAL internalFormat AS _UNSIGNED LONG, BYVAL x AS LONG, BYVAL y AS LONG, BYVAL width AS LONG, BYVAL height AS LONG, BYVAL border AS LONG)
:  void '''_glCopyTexImage2D'''(GLenum {{Parameter|target}}, GLint {{Parameter|level}}, GLenum {{Parameter|internalformat}}, GLint {{Parameter|x}}, GLint {{Parameter|y}}, GLsizei {{Parameter|width}}, GLsizei {{Parameter|height}}, GLint {{Parameter|border}});


 
{{PageParameters}}
; target
* OpenGL is using its own set of variable types to describe its command parameters.
: Specifies the target texture. Must be {{KW|_GL_TEXTURE_2D}}, {{KW|_GL_TEXTURE_CUBE_MAP_POSITIVE_X}}, {{KW|_GL_TEXTURE_CUBE_MAP_NEGATIVE_X}}, {{KW|_GL_TEXTURE_CUBE_MAP_POSITIVE_Y}}, {{KW|_GL_TEXTURE_CUBE_MAP_NEGATIVE_Y}}, {{KW|_GL_TEXTURE_CUBE_MAP_POSITIVE_Z}}, or {{KW|_GL_TEXTURE_CUBE_MAP_NEGATIVE_Z}}.
* Use the following table to find the respective QB64 [[Variable Types]].
; level
{{OpenGLTypesPlugin}}
: 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: {{KW|_GL_COMPRESSED_RED}}, {{KW|_GL_COMPRESSED_RG}}, {{KW|_GL_COMPRESSED_RGB}}, {{KW|_GL_COMPRESSED_RGBA}}. {{KW|_GL_COMPRESSED_SRGB}}, {{KW|_GL_COMPRESSED_SRGB_ALPHA}}. {{KW|_GL_DEPTH_COMPONENT}}, {{KW|_GL_DEPTH_COMPONENT16}}, {{KW|_GL_DEPTH_COMPONENT24}}, {{KW|_GL_DEPTH_COMPONENT32}}, {{KW|_GL_RED}}, {{KW|_GL_RG}}, {{KW|_GL_RGB}}, {{KW|_GL_R3_G3_B2}}, {{KW|_GL_RGB4}}, {{KW|_GL_RGB5}}, {{KW|_GL_RGB8}}, {{KW|_GL_RGB10}}, {{KW|_GL_RGB12}}, {{KW|_GL_RGB16}}, {{KW|_GL_RGBA}}, {{KW|_GL_RGBA2}}, {{KW|_GL_RGBA4}}, {{KW|_GL_RGB5_A1}}, {{KW|_GL_RGBA8}}, {{KW|_GL_RGB10_A2}}, {{KW|_GL_RGBA12}}, {{KW|_GL_RGBA16}}, {{KW|_GL_SRGB}}, {{KW|_GL_SRGB8}}, {{KW|_GL_SRGB_ALPHA}}, or {{KW|_GL_SRGB8_ALPHA8}}.
; 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.
; height
: Specifies the height of the texture image.
; border
: This value must be 0.




{{PageDescription}}
{{PageDescription}}
 
* OpenGL's documentation is available in several places, so we won't reproduce it here for another time.
'''_glCopyTexImage2D''' defines a two-dimensional texture image, or cube-map texture image with pixels from the current {{KW|_GL_READ_BUFFER}}.
* The full description for this command can be found at [https://learn.microsoft.com/en-us/windows/win32/opengl/glcopyteximage2d Microsoft Docs] and is also valid for QB64 usage.
 
The screen-aligned pixel rectangle with lower left corner at ({{Parameter|x}}, {{Parameter|y}}) and with a width of {{Parameter|width}} and a height of {{Parameter|height}} defines the texture array at the mipmap level specified by {{Parameter|level}}. {{Parameter|internalformat}} specifies the internal format of the texture array.
 
The pixels in the rectangle 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.
 
Pixel ordering is such that lower x and y screen coordinates correspond to lower s and t texture coordinates.
 
If any of the pixels within the specified rectangle of the current {{KW|_GL_READ_BUFFER}} are outside the window associated with the current rendering context, then the values obtained for those pixels are undefined.
 
When {{Parameter|internalformat}} is one of the sRGB types, the GL does not automatically convert the source pixels to the sRGB color space. In this case, the '''_glPixelMap''' function can be used to accomplish the conversion.
 
 
{{PageNotes}}
 
1, 2, 3, and 4 are not accepted values for {{Parameter|internalformat}}.
 
An image with height or width of 0 indicates a NULL texture.
 
 
{{PageErrors}}
 
{{KW|_GL_INVALID_ENUM}} is generated if {{Parameter|target}} is not {{KW|_GL_TEXTURE_2D}}, {{KW|_GL_TEXTURE_CUBE_MAP_POSITIVE_X}}, {{KW|_GL_TEXTURE_CUBE_MAP_NEGATIVE_X}}, {{KW|_GL_TEXTURE_CUBE_MAP_POSITIVE_Y}}, {{KW|_GL_TEXTURE_CUBE_MAP_NEGATIVE_Y}}, {{KW|_GL_TEXTURE_CUBE_MAP_POSITIVE_Z}}, or {{KW|_GL_TEXTURE_CUBE_MAP_NEGATIVE_Z}}.
 
{{KW|_GL_INVALID_VALUE}} is generated if {{Parameter|level}} is less than 0.
 
{{KW|_GL_INVALID_VALUE}} may be generated if {{Parameter|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 {{Parameter|width}} is less than 0 or greater than {{KW|_GL_MAX_TEXTURE_SIZE}}.
 
{{KW|_GL_INVALID_VALUE}} is generated if {{Parameter|border}} is not 0.
 
{{KW|_GL_INVALID_VALUE}} is generated if {{Parameter|internalformat}} is not an accepted format.
 
{{KW|_GL_INVALID_OPERATION}} is generated if {{Parameter|internalformat}} is {{KW|_GL_DEPTH_COMPONENT}}, {{KW|_GL_DEPTH_COMPONENT16}}, {{KW|_GL_DEPTH_COMPONENT24}}, or {{KW|_GL_DEPTH_COMPONENT32}} and there is no depth buffer.
 
 
{{PageUseWith}}
 
{{KW|_glGetTexImage}}




{{PageSeeAlso}}
{{PageSeeAlso}}
 
* [[_GL|SUB _GL]]
[[_GL|SUB _GL]]
* [[_glBegin]], [[_glCopyTexImage1D]], [[_glDrawPixels]], [[_glEnd]]
{{KW|_glActiveTexture}}, {{KW|_glBindTexture}}, {{KW|_glBindFramebuffer}}, {{KW|_glCopyTexImage1D}}, {{KW|_glCopyImageSubData}}, {{KW|_glCopyTexSubImage1D}}, {{KW|_glCopyTexSubImage2D}}, {{KW|_glReadBuffer}}
* [https://learn.microsoft.com/en-us/windows/win32/opengl/glfog _glFog], [https://learn.microsoft.com/en-us/windows/win32/opengl/glpixelstore-functions _glPixelStore], [https://learn.microsoft.com/en-us/windows/win32/opengl/glpixeltransfer _glPixelTransfer], [https://learn.microsoft.com/en-us/windows/win32/opengl/gltexenv-functions _glTexEnv]
* [https://learn.microsoft.com/en-us/windows/win32/opengl/gltexgen-functions _glTexGen], [[_glTexImage1D]], [[_glTexImage2D]], [https://learn.microsoft.com/en-us/windows/win32/opengl/gltexparameter-functions _glTexParameter]




{{PageCopyright}}
{{PageNavigation}}

Latest revision as of 00:47, 28 January 2023

The _glCopyTexImage2D statement copies pixels from the framebuffer into a two-dimensional texture image.


Syntax

_glCopyTexImage2D GLenum target, GLint level, GLenum internalFormat, GLint x, GLint y, GLsizei width, GLsizei height, GLint border


Parameters

  • OpenGL is using its own set of variable types to describe its command parameters.
  • Use the following table to find the respective QB64 Variable Types.
   Table 2: Relations between the OpenGL variable types vs. C/C++ and QB64.
 ┌──────────────┬────────────────┬──────────────────────────────────────────┐
 │    OpenGL    │     C/C++      │     QB64                                 │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLenum       │ unsigned int   │ _UNSIGNED LONG                           │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLboolean    │ unsigned char  │ _UNSIGNED _BYTE                          │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLbitfield   │ unsigned int   │ _UNSIGNED LONG                           │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLbyte       │ signed char    │ _BYTE                                    │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLshort      │ short          │ INTEGER                                  │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLint        │ int            │ LONG                                     │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLsizei      │ int            │ LONG                                     │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLubyte      │ unsigned char  │ _UNSIGNED _BYTE                          │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLushort     │ unsigned short │ _UNSIGNED INTEGER                        │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLuint       │ unsigned int   │ _UNSIGNED LONG                           │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLfloat      │ float          │ SINGLE                                   │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLclampf     │ float          │ SINGLE                                   │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLdouble     │ double         │ DOUBLE                                   │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLclampd     │ double         │ DOUBLE                                   │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLvoid   (1) │ void           │ _OFFSET(any fixed lenght string or _BYTE │
 │              │                │         array element)                   │
 └──────────────┴────────────────┴──────────────────────────────────────────┘
 Note: If a parameter has an asterisk (*) in front, then it's a pointer to
       the designated OpenGL variable type, rather than a value of that type.
       Those must be passed using the _OFFSET(...) notation.

 E.g.  GLuint *anyParam is actually the offset of a _UNSIGNED LONG (~&)
       variable or array, which must be passed as _OFFSET(anyVar~&) or
       _OFFSET(anyArr~&()) respectively.

  (1)  This type is regularly only used for pointers (with asterisk (*)) to
       any byte sized memory data, hence _BYTE or fixed length strings.


Description

  • OpenGL's documentation is available in several places, so we won't reproduce it here for another time.
  • The full description for this command can be found at Microsoft Docs and is also valid for QB64 usage.


See also


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