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https://github.com/QB64-Phoenix-Edition/QB64pe.git
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6e01fc8dce
Added new _STRCMP and _STRICMP commands for quick string comparisons. Cleaned up QB64 to finish removing the QUI (quick user insert) code and folders. Altered UCASE and LCASE routines to be faster in some situations for us.
47 lines
2.8 KiB
Plaintext
47 lines
2.8 KiB
Plaintext
'''_glReadBuffer:''' select a color buffer source for pixel read operations from the current read framebuffer.
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{{PageSyntax}}
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SUB _glReadBuffer (BYVAL mode AS _UNSIGNED LONG)
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void '''_glReadBuffer'''(GLenum {{Parameter|mode}});
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; mode
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: Specifies a color buffer. Accepted values are {{KW|_GL_FRONT_LEFT}}, {{KW|_GL_FRONT_RIGHT}}, {{KW|_GL_BACK_LEFT}}, {{KW|_GL_BACK_RIGHT}}, {{KW|_GL_FRONT}}, {{KW|_GL_BACK}}, {{KW|_GL_LEFT}}, {{KW|_GL_RIGHT}}, and the constants {{KW|_GL_COLOR_ATTACHMENT''i''}}.
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{{PageDescription}}
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'''_glReadBuffer''' specifies which color buffer within the current bound {{KW|_GL_READ_FRAMEBUFFER}} will be used as the source for pixel reading commands. These commands include: {{KW|_glBlitFramebuffer}}, {{KW|_glReadPixels}}, {{KW|_glCopyTexImage1D}}, {{KW|_glCopyTexImage2D}}, {{KW|_glCopyTexSubImage1D}}, {{KW|_glCopyTexSubImage2D}}, and {{KW|_glCopyTexSubImage3D}}.
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{{Parameter|mode}} accepts one of twelve or more predefined values. If the [[default framebuffer]] (the zero [[framebuffer object]])is bound to {{KW|_GL_READ_FRAMEBUFFER}}, then the following enumerators can be used: {{KW|_GL_FRONT}}, {{KW|_GL_LEFT}}, and {{KW|_GL_FRONT_LEFT}} all name the front left buffer, {{KW|_GL_FRONT_RIGHT}} and {{KW|_GL_RIGHT}} name the front right buffer, and {{KW|_GL_BACK_LEFT}} and {{KW|_GL_BACK}} name the back left buffer. Nonstereo double-buffered configurations have only a front left and a back left buffer. Single-buffered configurations have a front left and a front right buffer if stereo, and only a front left buffer if nonstereo.
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If a non-zero framebuffer object is bound, then the constants {{KW|_GL_COLOR_ATTACHMENT''i''}} may be used to indicate the ''i''<sup>th</sup> color attachment, where ''i'' ranges from zero to the value of {{KW|_GL_MAX_COLOR_ATTACHMENTS}} minus one.
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It is an error to specify a nonexistent buffer to '''_glReadBuffer'''.
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For the default framebuffer, {{Parameter|mode}} is initially {{KW|_GL_FRONT}} in single-buffered configurations and {{KW|_GL_BACK}} in double-buffered configurations. For framebuffer objects, the default read buffer is {{KW|_GL_COLOR_ATTACHMENT0}}.
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{{PageErrors}}
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{{KW|_GL_INVALID_ENUM}} is generated if {{Parameter|mode}} is not one of the twelve (or more) accepted values.
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{{KW|_GL_INVALID_OPERATION}} is generated if {{Parameter|mode}} specifies a buffer that does not exist.
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{{PageUseWith}}
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{{KW|_glGet}} with argument {{KW|_GL_READ_BUFFER}}
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{{PageSeeAlso}}
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{{KW|_GL}}
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{{KW|_glBindFramebuffer}}, {{KW|_glDrawBuffer}}, {{KW|_glDrawBuffers}}, {{KW|_glReadPixels}}
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{{PageCopyright}}
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Copyright 1991-2006 Silicon Graphics, Inc. Copyright 2011 Khronos Group. This document is licensed under the SGI Free Software B License. For details, see [http://oss.sgi.com/projects/FreeB/ http://oss.sgi.com/projects/FreeB/]. |