218 lines
6.1 KiB
Plaintext
218 lines
6.1 KiB
Plaintext
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Syntax Rules for OpenGL Extensions
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----------------------------------
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This is a preliminary document. No ARB vote has been taken!
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Required abbreviations
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----------------------
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Accum Accumulation Buffer
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Attrib Attribute
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Aux Auxiliary
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CCW Counter Clockwise
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Clip Clipping
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CMYK Cyan Magenta Yellow Black
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Coeff Coefficient
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Coord Coordinate
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CW Clockwise
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Decr Decrement
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Dim Dimension
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Dst Destination
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Env Environment
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Eval Evaluate
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Exp Exponential
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Func Function
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Gequal Greater than or equal to
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Gen Generate
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Incr Increment
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Index Color Index
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Lequal Less than or equal to
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Light Model Lighting Model
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List Display List
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LSB Least significant bit
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Mag Magnify
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Max Maximum
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Min Minify
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Mult Multiply
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Op Operation
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Ortho Orthographic
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Pname ParameterName
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Pos Position (function names only)
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Quad Quadrilateral
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Rect Rectangle
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Ref Reference
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RGB Red Green Blue
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RGBA Red Green Blue Alpha
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Shade Model Shading Model
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Src Source
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Tex Texture (function names only)
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Abbreviations specifically not allowed
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--------------------------------------
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Bgn Begin
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C Color
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Pnt Point
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Cpack Color Pack
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N Normal
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Poly Polygon Poly means multiple
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T Texture Coordinate
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Tri Triangle
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V Vertex
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Compound words
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--------------
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Antialias
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Bitmap
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Cutoff
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Doublebuffer
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Feedback
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Framebuffer
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Modelview
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Noop
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Notequal
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Subpixel
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Viewport
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Writemask
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Name rules (for all names)
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--------------------------
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Always use the specified abbreviations. Never abbreviate terms
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that are already in the OpenGL API and are not abbreviated. If you
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add terms to your extensions, abbreviate consistently, maintaining
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a local versions of extensions to the list of abbreviations.
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Use Depth, never Z.
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Procedure name rules
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--------------------
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Limit procedure names to 2 words, 3 for procedures that return state.
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(This is really a recommendation, not a rule.)
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Never use set, as in SetFeedbackBuffer.
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Begin each word with a capital letter, except the second word of
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compound words.
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Use Verb-noun (DeleteList) and adjective-noun (EdgeFlag) formats.
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Append a corporate-specific suffix to all procedures. For example:
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glNewCommandSGI. All upper case is preferred for this suffix, but
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is not required. The suffix is always last, following OpenGL type
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and count suffixes. (e.g. glNewVertex3iSGI, not glNewVertexSGI3i.)
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Definition name rules
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---------------------
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Use all capital letters.
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Separate words with underbars, except words within compound words.
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Append simple numeric suffixes directly to the end of definition
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tokens (LIGHT0). Begin these sequences with 0.
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Use an underbar to separate complex suffixes from the token body
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(MAP_3V).
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Append a corporate-specific suffix to the token, after any other
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suffixes. For example: GL_NEW_TOKEN0_SGI. All upper case is
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required.
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Parameter name rules
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--------------------
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<target> is reserved for the notion of "which is affected", and for
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the corresponding "which is returned" get commands.
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<params> is reserved for an array of parameters whose contents are
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defined by a second enumerated argument, called <pname>.
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Begin number sequences with 1, not 0. (e.g. u1,u2, not u0,u1)
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Parameter order
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---------------
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<X> precedes <Y> precedes <Z> precedes <W>.
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<R> precedes <G> precedes <B> precedes <A>.
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The array being passed is always the last argument.
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If a passed array has a type, the type specification argument immediately
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precedes the array.
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<pname> always precedes <params>.
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<x> and <y> precede <width> and <height>
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<format> precedes <type>
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<target> is first
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<face> is first
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Parameter types
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---------------
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All integer quantity parameters (widths, heights, array lengths, etc.)
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should be typed GLsizei, not GLint or GLuint. Note that GLsizei
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generates an error only for negative values, so all integer quantity
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parameters should accept the value zero.
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Names (of display lists, textures, etc.) should be typed GLuint.
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Generic masks that do not have explicitly defined bit values (e.g.
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color index write masks and stencil write masks) should be typed
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GLuint. GLuint is also used for unsigned integer components, such as
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color components and depth components.
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Masks that do have explicitly defined bit values (e.g. attribute mask,
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clear mask) should be typed GLbitfield, not GLuint.
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All floating point parameters that are clamped to the range [0,1] when
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received should be typed GLclampf or GLclampd, not GLfloat or GLdouble.
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Extension name rules
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--------------------
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An extension name is prefixed with the same string that suffixes its
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procedures and definitions. The prefix and the individual words are
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separated with underbars, the prefix is all upper case, and the other
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text is all lower case. For example, extension SGI_cool_feature, which
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specifies glCoolProcedureSGI() and defines GL_COOL_DEFINITION_SGI.
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Suffix codes
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------------
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i signed 32-bit integer
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ui unsigned 32-bit integer
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s signed 16-bit integer
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us unsigned 16-bit integer
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b signed 8-bit integer
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ub unsigned 8-bit integer
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l signed 64-bit integer
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ul unsigned 64-bit integer
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f 32-bit float
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d 64-bit float
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v vector format
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Shared extensions
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-----------------
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An OpenGL extension may be deemed a shared extension if either:
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1. Two or more OpenGL licensees agree in good faith to implement
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and ship the extension, or
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2. The OpenGL ARB determines that it is in the best interest of
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the licensees that the extension be shared.
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The procedures and definitions that are defined by a shared extension
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are suffixed with EXT, rather than by a company-specific suffix.
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Likewise, the extension name is prefixed by EXT. To avoid name
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conflicts Silicon Graphics will maintain a registry of EXT extensions,
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including all their procedures and definitions, in a location that is
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accessible to all licensees.
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