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